From c33fa9f5609e918824446ef9a75319d4a802f1f4 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 17 Apr 2008 20:05:36 +0200 Subject: uaccess: add probe_kernel_write() add probe_kernel_read() and probe_kernel_write(). Uninlined and restricted to kernel range memory only, as suggested by Linus. Signed-off-by: Ingo Molnar Reviewed-by: Thomas Gleixner --- include/linux/uaccess.h | 22 ++++++++++++++++++++++ mm/Makefile | 2 +- mm/maccess.c | 49 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 72 insertions(+), 1 deletion(-) create mode 100644 mm/maccess.c diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 975c963e5789..fec6decfb983 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -84,4 +84,26 @@ static inline unsigned long __copy_from_user_nocache(void *to, ret; \ }) +/* + * probe_kernel_read(): safely attempt to read from a location + * @dst: pointer to the buffer that shall take the data + * @src: address to read from + * @size: size of the data chunk + * + * Safely read from address @src to the buffer at @dst. If a kernel fault + * happens, handle that and return -EFAULT. + */ +extern long probe_kernel_read(void *dst, void *src, size_t size); + +/* + * probe_kernel_write(): safely attempt to write to a location + * @dst: address to write to + * @src: pointer to the data that shall be written + * @size: size of the data chunk + * + * Safely write to address @dst from the buffer at @src. If a kernel fault + * happens, handle that and return -EFAULT. + */ +extern long probe_kernel_write(void *dst, void *src, size_t size); + #endif /* __LINUX_UACCESS_H__ */ diff --git a/mm/Makefile b/mm/Makefile index a5b0dd93427a..18c143b3c46c 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -8,7 +8,7 @@ mmu-$(CONFIG_MMU) := fremap.o highmem.o madvise.o memory.o mincore.o \ vmalloc.o obj-y := bootmem.o filemap.o mempool.o oom_kill.o fadvise.o \ - page_alloc.o page-writeback.o pdflush.o \ + maccess.o page_alloc.o page-writeback.o pdflush.o \ readahead.o swap.o truncate.o vmscan.o \ prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \ page_isolation.o $(mmu-y) diff --git a/mm/maccess.c b/mm/maccess.c new file mode 100644 index 000000000000..24f81b971403 --- /dev/null +++ b/mm/maccess.c @@ -0,0 +1,49 @@ +/* + * Access kernel memory without faulting. + */ +#include +#include +#include + +/** + * probe_kernel_read(): safely attempt to read from a location + * @dst: pointer to the buffer that shall take the data + * @src: address to read from + * @size: size of the data chunk + * + * Safely read from address @src to the buffer at @dst. If a kernel fault + * happens, handle that and return -EFAULT. + */ +long probe_kernel_read(void *dst, void *src, size_t size) +{ + long ret; + + pagefault_disable(); + ret = __copy_from_user_inatomic(dst, + (__force const void __user *)src, size); + pagefault_enable(); + + return ret ? -EFAULT : 0; +} +EXPORT_SYMBOL_GPL(probe_kernel_read); + +/** + * probe_kernel_write(): safely attempt to write to a location + * @dst: address to write to + * @src: pointer to the data that shall be written + * @size: size of the data chunk + * + * Safely write to address @dst from the buffer at @src. If a kernel fault + * happens, handle that and return -EFAULT. + */ +long probe_kernel_write(void *dst, void *src, size_t size) +{ + long ret; + + pagefault_disable(); + ret = __copy_to_user_inatomic((__force void __user *)dst, src, size); + pagefault_enable(); + + return ret ? -EFAULT : 0; +} +EXPORT_SYMBOL_GPL(probe_kernel_write); -- cgit v1.2.3 From dc7d552705215ac50a0617fcf51bb9c736255b8e Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 17 Apr 2008 20:05:37 +0200 Subject: kgdb: core kgdb core code. Handles the protocol and the arch details. [ mingo@elte.hu: heavily modified, simplified and cleaned up. ] [ xemul@openvz.org: use find_task_by_pid_ns ] Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar Signed-off-by: Jan Kiszka Reviewed-by: Thomas Gleixner --- include/linux/kgdb.h | 271 ++++++++ kernel/Makefile | 1 + kernel/kgdb.c | 1693 ++++++++++++++++++++++++++++++++++++++++++++++++++ lib/Kconfig.debug | 2 + lib/Kconfig.kgdb | 27 + 5 files changed, 1994 insertions(+) create mode 100644 include/linux/kgdb.h create mode 100644 kernel/kgdb.c create mode 100644 lib/Kconfig.kgdb diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h new file mode 100644 index 000000000000..b0985b79b638 --- /dev/null +++ b/include/linux/kgdb.h @@ -0,0 +1,271 @@ +/* + * This provides the callbacks and functions that KGDB needs to share between + * the core, I/O and arch-specific portions. + * + * Author: Amit Kale and + * Tom Rini + * + * 2001-2004 (c) Amit S. Kale and 2003-2005 (c) MontaVista Software, Inc. + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ +#ifndef _KGDB_H_ +#define _KGDB_H_ + +#include +#include +#include + +#include +#include + +struct pt_regs; + +/* + * kgdb_skipexception - Bail out of KGDB when we've been triggered. + * @exception: Exception vector number + * @regs: Current &struct pt_regs. + * + * On some architectures we need to skip a breakpoint exception when + * it occurs after a breakpoint has been removed. + */ +extern int kgdb_skipexception(int exception, struct pt_regs *regs); + +/* + * kgdb_post_primary_code - Save error vector/code numbers. + * @regs: Original pt_regs. + * @e_vector: Original error vector. + * @err_code: Original error code. + * + * This is needed on architectures which support SMP and KGDB. + * This function is called after all the secondary cpus have been put + * to a know spin state and the primary CPU has control over KGDB. + */ +extern void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, + int err_code); + +/* + * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. + * @regs: Current &struct pt_regs. + * + * This function will be called if the particular architecture must + * disable hardware debugging while it is processing gdb packets or + * handling exception. + */ +extern void kgdb_disable_hw_debug(struct pt_regs *regs); + +struct tasklet_struct; +struct task_struct; +struct uart_port; + +/* To enter the debugger explicitly. */ +void kgdb_breakpoint(void); + +extern int kgdb_connected; + +extern atomic_t kgdb_setting_breakpoint; +extern atomic_t kgdb_cpu_doing_single_step; + +extern struct task_struct *kgdb_usethread; +extern struct task_struct *kgdb_contthread; + +enum kgdb_bptype { + BP_BREAKPOINT = 0, + BP_HARDWARE_BREAKPOINT, + BP_WRITE_WATCHPOINT, + BP_READ_WATCHPOINT, + BP_ACCESS_WATCHPOINT +}; + +enum kgdb_bpstate { + BP_UNDEFINED = 0, + BP_REMOVED, + BP_SET, + BP_ACTIVE +}; + +struct kgdb_bkpt { + unsigned long bpt_addr; + unsigned char saved_instr[BREAK_INSTR_SIZE]; + enum kgdb_bptype type; + enum kgdb_bpstate state; +}; + +#ifndef KGDB_MAX_BREAKPOINTS +# define KGDB_MAX_BREAKPOINTS 1000 +#endif + +#define KGDB_HW_BREAKPOINT 1 + +/* + * Functions each KGDB-supporting architecture must provide: + */ + +/* + * kgdb_arch_init - Perform any architecture specific initalization. + * + * This function will handle the initalization of any architecture + * specific callbacks. + */ +extern int kgdb_arch_init(void); + +/* + * kgdb_arch_exit - Perform any architecture specific uninitalization. + * + * This function will handle the uninitalization of any architecture + * specific callbacks, for dynamic registration and unregistration. + */ +extern void kgdb_arch_exit(void); + +/* + * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @regs: The &struct pt_regs of the current process. + * + * Convert the pt_regs in @regs into the format for registers that + * GDB expects, stored in @gdb_regs. + */ +extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs); + +/* + * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @p: The &struct task_struct of the desired process. + * + * Convert the register values of the sleeping process in @p to + * the format that GDB expects. + * This function is called when kgdb does not have access to the + * &struct pt_regs and therefore it should fill the gdb registers + * @gdb_regs with what has been saved in &struct thread_struct + * thread field during switch_to. + */ +extern void +sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p); + +/* + * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. + * @gdb_regs: A pointer to hold the registers we've received from GDB. + * @regs: A pointer to a &struct pt_regs to hold these values in. + * + * Convert the GDB regs in @gdb_regs into the pt_regs, and store them + * in @regs. + */ +extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs); + +/* + * kgdb_arch_handle_exception - Handle architecture specific GDB packets. + * @vector: The error vector of the exception that happened. + * @signo: The signal number of the exception that happened. + * @err_code: The error code of the exception that happened. + * @remcom_in_buffer: The buffer of the packet we have read. + * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. + * @regs: The &struct pt_regs of the current process. + * + * This function MUST handle the 'c' and 's' command packets, + * as well packets to set / remove a hardware breakpoint, if used. + * If there are additional packets which the hardware needs to handle, + * they are handled here. The code should return -1 if it wants to + * process more packets, and a %0 or %1 if it wants to exit from the + * kgdb callback. + */ +extern int +kgdb_arch_handle_exception(int vector, int signo, int err_code, + char *remcom_in_buffer, + char *remcom_out_buffer, + struct pt_regs *regs); + +/* + * kgdb_roundup_cpus - Get other CPUs into a holding pattern + * @flags: Current IRQ state + * + * On SMP systems, we need to get the attention of the other CPUs + * and get them be in a known state. This should do what is needed + * to get the other CPUs to call kgdb_wait(). Note that on some arches, + * the NMI approach is not used for rounding up all the CPUs. For example, + * in case of MIPS, smp_call_function() is used to roundup CPUs. In + * this case, we have to make sure that interrupts are enabled before + * calling smp_call_function(). The argument to this function is + * the flags that will be used when restoring the interrupts. There is + * local_irq_save() call before kgdb_roundup_cpus(). + * + * On non-SMP systems, this is not called. + */ +extern void kgdb_roundup_cpus(unsigned long flags); + +/* Optional functions. */ +extern int kgdb_validate_break_address(unsigned long addr); +extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr); +extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle); + +/* + * struct kgdb_arch - Describe architecture specific values. + * @gdb_bpt_instr: The instruction to trigger a breakpoint. + * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT. + * @set_breakpoint: Allow an architecture to specify how to set a software + * breakpoint. + * @remove_breakpoint: Allow an architecture to specify how to remove a + * software breakpoint. + * @set_hw_breakpoint: Allow an architecture to specify how to set a hardware + * breakpoint. + * @remove_hw_breakpoint: Allow an architecture to specify how to remove a + * hardware breakpoint. + * @remove_all_hw_break: Allow an architecture to specify how to remove all + * hardware breakpoints. + * @correct_hw_break: Allow an architecture to specify how to correct the + * hardware debug registers. + */ +struct kgdb_arch { + unsigned char gdb_bpt_instr[BREAK_INSTR_SIZE]; + unsigned long flags; + + int (*set_breakpoint)(unsigned long, char *); + int (*remove_breakpoint)(unsigned long, char *); + int (*set_hw_breakpoint)(unsigned long, int, enum kgdb_bptype); + int (*remove_hw_breakpoint)(unsigned long, int, enum kgdb_bptype); + void (*remove_all_hw_break)(void); + void (*correct_hw_break)(void); +}; + +/* + * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB. + * @name: Name of the I/O driver. + * @read_char: Pointer to a function that will return one char. + * @write_char: Pointer to a function that will write one char. + * @flush: Pointer to a function that will flush any pending writes. + * @init: Pointer to a function that will initialize the device. + * @pre_exception: Pointer to a function that will do any prep work for + * the I/O driver. + * @post_exception: Pointer to a function that will do any cleanup work + * for the I/O driver. + */ +struct kgdb_io { + const char *name; + int (*read_char) (void); + void (*write_char) (u8); + void (*flush) (void); + int (*init) (void); + void (*pre_exception) (void); + void (*post_exception) (void); +}; + +extern struct kgdb_arch arch_kgdb_ops; + +extern int kgdb_register_io_module(struct kgdb_io *local_kgdb_io_ops); +extern void kgdb_unregister_io_module(struct kgdb_io *local_kgdb_io_ops); + +extern int kgdb_hex2long(char **ptr, long *long_val); +extern int kgdb_mem2hex(char *mem, char *buf, int count); +extern int kgdb_hex2mem(char *buf, char *mem, int count); + +extern int kgdb_isremovedbreak(unsigned long addr); + +extern int +kgdb_handle_exception(int ex_vector, int signo, int err_code, + struct pt_regs *regs); +extern int kgdb_nmicallback(int cpu, void *regs); + +extern int kgdb_single_step; +extern atomic_t kgdb_active; + +#endif /* _KGDB_H_ */ diff --git a/kernel/Makefile b/kernel/Makefile index 6c584c55a6e9..05c8003718ee 100644 --- a/kernel/Makefile +++ b/kernel/Makefile @@ -53,6 +53,7 @@ obj-$(CONFIG_AUDIT) += audit.o auditfilter.o obj-$(CONFIG_AUDITSYSCALL) += auditsc.o obj-$(CONFIG_AUDIT_TREE) += audit_tree.o obj-$(CONFIG_KPROBES) += kprobes.o +obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_DETECT_SOFTLOCKUP) += softlockup.o obj-$(CONFIG_GENERIC_HARDIRQS) += irq/ obj-$(CONFIG_SECCOMP) += seccomp.o diff --git a/kernel/kgdb.c b/kernel/kgdb.c new file mode 100644 index 000000000000..017ee782bc08 --- /dev/null +++ b/kernel/kgdb.c @@ -0,0 +1,1693 @@ +/* + * KGDB stub. + * + * Maintainer: Jason Wessel + * + * Copyright (C) 2000-2001 VERITAS Software Corporation. + * Copyright (C) 2002-2004 Timesys Corporation + * Copyright (C) 2003-2004 Amit S. Kale + * Copyright (C) 2004 Pavel Machek + * Copyright (C) 2004-2006 Tom Rini + * Copyright (C) 2004-2006 LinSysSoft Technologies Pvt. Ltd. + * Copyright (C) 2005-2008 Wind River Systems, Inc. + * Copyright (C) 2007 MontaVista Software, Inc. + * Copyright (C) 2008 Red Hat, Inc., Ingo Molnar + * + * Contributors at various stages not listed above: + * Jason Wessel ( jason.wessel@windriver.com ) + * George Anzinger + * Anurekh Saxena (anurekh.saxena@timesys.com) + * Lake Stevens Instrument Division (Glenn Engel) + * Jim Kingdon, Cygnus Support. + * + * Original KGDB stub: David Grothe , + * Tigran Aivazian + * + * This file is licensed under the terms of the GNU General Public License + * version 2. This program is licensed "as is" without any warranty of any + * kind, whether express or implied. + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include + +static int kgdb_break_asap; + +struct kgdb_state { + int ex_vector; + int signo; + int err_code; + int cpu; + int pass_exception; + long threadid; + long kgdb_usethreadid; + struct pt_regs *linux_regs; +}; + +static struct debuggerinfo_struct { + void *debuggerinfo; + struct task_struct *task; +} kgdb_info[NR_CPUS]; + +/** + * kgdb_connected - Is a host GDB connected to us? + */ +int kgdb_connected; +EXPORT_SYMBOL_GPL(kgdb_connected); + +/* All the KGDB handlers are installed */ +static int kgdb_io_module_registered; + +/* Guard for recursive entry */ +static int exception_level; + +static struct kgdb_io *kgdb_io_ops; +static DEFINE_SPINLOCK(kgdb_registration_lock); + +/* kgdb console driver is loaded */ +static int kgdb_con_registered; +/* determine if kgdb console output should be used */ +static int kgdb_use_con; + +static int __init opt_kgdb_con(char *str) +{ + kgdb_use_con = 1; + return 0; +} + +early_param("kgdbcon", opt_kgdb_con); + +module_param(kgdb_use_con, int, 0644); + +/* + * Holds information about breakpoints in a kernel. These breakpoints are + * added and removed by gdb. + */ +static struct kgdb_bkpt kgdb_break[KGDB_MAX_BREAKPOINTS] = { + [0 ... KGDB_MAX_BREAKPOINTS-1] = { .state = BP_UNDEFINED } +}; + +/* + * The CPU# of the active CPU, or -1 if none: + */ +atomic_t kgdb_active = ATOMIC_INIT(-1); + +/* + * We use NR_CPUs not PERCPU, in case kgdb is used to debug early + * bootup code (which might not have percpu set up yet): + */ +static atomic_t passive_cpu_wait[NR_CPUS]; +static atomic_t cpu_in_kgdb[NR_CPUS]; +atomic_t kgdb_setting_breakpoint; + +struct task_struct *kgdb_usethread; +struct task_struct *kgdb_contthread; + +int kgdb_single_step; + +/* Our I/O buffers. */ +static char remcom_in_buffer[BUFMAX]; +static char remcom_out_buffer[BUFMAX]; + +/* Storage for the registers, in GDB format. */ +static unsigned long gdb_regs[(NUMREGBYTES + + sizeof(unsigned long) - 1) / + sizeof(unsigned long)]; + +/* to keep track of the CPU which is doing the single stepping*/ +atomic_t kgdb_cpu_doing_single_step = ATOMIC_INIT(-1); + +/* + * If you are debugging a problem where roundup (the collection of + * all other CPUs) is a problem [this should be extremely rare], + * then use the nokgdbroundup option to avoid roundup. In that case + * the other CPUs might interfere with your debugging context, so + * use this with care: + */ +int kgdb_do_roundup = 1; + +static int __init opt_nokgdbroundup(char *str) +{ + kgdb_do_roundup = 0; + + return 0; +} + +early_param("nokgdbroundup", opt_nokgdbroundup); + +/* + * Finally, some KGDB code :-) + */ + +/* + * Weak aliases for breakpoint management, + * can be overriden by architectures when needed: + */ +int __weak kgdb_validate_break_address(unsigned long addr) +{ + char tmp_variable[BREAK_INSTR_SIZE]; + + return probe_kernel_read(tmp_variable, (char *)addr, BREAK_INSTR_SIZE); +} + +int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr) +{ + int err; + + err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE); + if (err) + return err; + + return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr, + BREAK_INSTR_SIZE); +} + +int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle) +{ + return probe_kernel_write((char *)addr, + (char *)bundle, BREAK_INSTR_SIZE); +} + +unsigned long __weak kgdb_arch_pc(int exception, struct pt_regs *regs) +{ + return instruction_pointer(regs); +} + +int __weak kgdb_arch_init(void) +{ + return 0; +} + +/** + * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. + * @regs: Current &struct pt_regs. + * + * This function will be called if the particular architecture must + * disable hardware debugging while it is processing gdb packets or + * handling exception. + */ +void __weak kgdb_disable_hw_debug(struct pt_regs *regs) +{ +} + +/* + * GDB remote protocol parser: + */ + +static const char hexchars[] = "0123456789abcdef"; + +static int hex(char ch) +{ + if ((ch >= 'a') && (ch <= 'f')) + return ch - 'a' + 10; + if ((ch >= '0') && (ch <= '9')) + return ch - '0'; + if ((ch >= 'A') && (ch <= 'F')) + return ch - 'A' + 10; + return -1; +} + +/* scan for the sequence $# */ +static void get_packet(char *buffer) +{ + unsigned char checksum; + unsigned char xmitcsum; + int count; + char ch; + + do { + /* + * Spin and wait around for the start character, ignore all + * other characters: + */ + while ((ch = (kgdb_io_ops->read_char())) != '$') + /* nothing */; + + kgdb_connected = 1; + checksum = 0; + xmitcsum = -1; + + count = 0; + + /* + * now, read until a # or end of buffer is found: + */ + while (count < (BUFMAX - 1)) { + ch = kgdb_io_ops->read_char(); + if (ch == '#') + break; + checksum = checksum + ch; + buffer[count] = ch; + count = count + 1; + } + buffer[count] = 0; + + if (ch == '#') { + xmitcsum = hex(kgdb_io_ops->read_char()) << 4; + xmitcsum += hex(kgdb_io_ops->read_char()); + + if (checksum != xmitcsum) + /* failed checksum */ + kgdb_io_ops->write_char('-'); + else + /* successful transfer */ + kgdb_io_ops->write_char('+'); + if (kgdb_io_ops->flush) + kgdb_io_ops->flush(); + } + } while (checksum != xmitcsum); +} + +/* + * Send the packet in buffer. + * Check for gdb connection if asked for. + */ +static void put_packet(char *buffer) +{ + unsigned char checksum; + int count; + char ch; + + /* + * $#. + */ + while (1) { + kgdb_io_ops->write_char('$'); + checksum = 0; + count = 0; + + while ((ch = buffer[count])) { + kgdb_io_ops->write_char(ch); + checksum += ch; + count++; + } + + kgdb_io_ops->write_char('#'); + kgdb_io_ops->write_char(hexchars[checksum >> 4]); + kgdb_io_ops->write_char(hexchars[checksum & 0xf]); + if (kgdb_io_ops->flush) + kgdb_io_ops->flush(); + + /* Now see what we get in reply. */ + ch = kgdb_io_ops->read_char(); + + if (ch == 3) + ch = kgdb_io_ops->read_char(); + + /* If we get an ACK, we are done. */ + if (ch == '+') + return; + + /* + * If we get the start of another packet, this means + * that GDB is attempting to reconnect. We will NAK + * the packet being sent, and stop trying to send this + * packet. + */ + if (ch == '$') { + kgdb_io_ops->write_char('-'); + if (kgdb_io_ops->flush) + kgdb_io_ops->flush(); + return; + } + } +} + +static char *pack_hex_byte(char *pkt, u8 byte) +{ + *pkt++ = hexchars[byte >> 4]; + *pkt++ = hexchars[byte & 0xf]; + + return pkt; +} + +/* + * Convert the memory pointed to by mem into hex, placing result in buf. + * Return a pointer to the last char put in buf (null). May return an error. + */ +int kgdb_mem2hex(char *mem, char *buf, int count) +{ + char *tmp; + int err; + + /* + * We use the upper half of buf as an intermediate buffer for the + * raw memory copy. Hex conversion will work against this one. + */ + tmp = buf + count; + + err = probe_kernel_read(tmp, mem, count); + if (!err) { + while (count > 0) { + buf = pack_hex_byte(buf, *tmp); + tmp++; + count--; + } + + *buf = 0; + } + + return err; +} + +/* + * Copy the binary array pointed to by buf into mem. Fix $, #, and + * 0x7d escaped with 0x7d. Return a pointer to the character after + * the last byte written. + */ +static int kgdb_ebin2mem(char *buf, char *mem, int count) +{ + int err = 0; + char c; + + while (count-- > 0) { + c = *buf++; + if (c == 0x7d) + c = *buf++ ^ 0x20; + + err = probe_kernel_write(mem, &c, 1); + if (err) + break; + + mem++; + } + + return err; +} + +/* + * Convert the hex array pointed to by buf into binary to be placed in mem. + * Return a pointer to the character AFTER the last byte written. + * May return an error. + */ +int kgdb_hex2mem(char *buf, char *mem, int count) +{ + char *tmp_raw; + char *tmp_hex; + + /* + * We use the upper half of buf as an intermediate buffer for the + * raw memory that is converted from hex. + */ + tmp_raw = buf + count * 2; + + tmp_hex = tmp_raw - 1; + while (tmp_hex >= buf) { + tmp_raw--; + *tmp_raw = hex(*tmp_hex--); + *tmp_raw |= hex(*tmp_hex--) << 4; + } + + return probe_kernel_write(mem, tmp_raw, count); +} + +/* + * While we find nice hex chars, build a long_val. + * Return number of chars processed. + */ +int kgdb_hex2long(char **ptr, long *long_val) +{ + int hex_val; + int num = 0; + + *long_val = 0; + + while (**ptr) { + hex_val = hex(**ptr); + if (hex_val < 0) + break; + + *long_val = (*long_val << 4) | hex_val; + num++; + (*ptr)++; + } + + return num; +} + +/* Write memory due to an 'M' or 'X' packet. */ +static int write_mem_msg(int binary) +{ + char *ptr = &remcom_in_buffer[1]; + unsigned long addr; + unsigned long length; + int err; + + if (kgdb_hex2long(&ptr, &addr) > 0 && *(ptr++) == ',' && + kgdb_hex2long(&ptr, &length) > 0 && *(ptr++) == ':') { + if (binary) + err = kgdb_ebin2mem(ptr, (char *)addr, length); + else + err = kgdb_hex2mem(ptr, (char *)addr, length); + if (err) + return err; + if (CACHE_FLUSH_IS_SAFE) + flush_icache_range(addr, addr + length + 1); + return 0; + } + + return -EINVAL; +} + +static void error_packet(char *pkt, int error) +{ + error = -error; + pkt[0] = 'E'; + pkt[1] = hexchars[(error / 10)]; + pkt[2] = hexchars[(error % 10)]; + pkt[3] = '\0'; +} + +/* + * Thread ID accessors. We represent a flat TID space to GDB, where + * the per CPU idle threads (which under Linux all have PID 0) are + * remapped to negative TIDs. + */ + +#define BUF_THREAD_ID_SIZE 16 + +static char *pack_threadid(char *pkt, unsigned char *id) +{ + char *limit; + + limit = pkt + BUF_THREAD_ID_SIZE; + while (pkt < limit) + pkt = pack_hex_byte(pkt, *id++); + + return pkt; +} + +static void int_to_threadref(unsigned char *id, int value) +{ + unsigned char *scan; + int i = 4; + + scan = (unsigned char *)id; + while (i--) + *scan++ = 0; + *scan++ = (value >> 24) & 0xff; + *scan++ = (value >> 16) & 0xff; + *scan++ = (value >> 8) & 0xff; + *scan++ = (value & 0xff); +} + +static struct task_struct *getthread(struct pt_regs *regs, int tid) +{ + /* + * Non-positive TIDs are remapped idle tasks: + */ + if (tid <= 0) + return idle_task(-tid); + + /* + * find_task_by_pid_ns() does not take the tasklist lock anymore + * but is nicely RCU locked - hence is a pretty resilient + * thing to use: + */ + return find_task_by_pid_ns(tid, &init_pid_ns); +} + +/* + * CPU debug state control: + */ + +#ifdef CONFIG_SMP +static void kgdb_wait(struct pt_regs *regs) +{ + unsigned long flags; + int cpu; + + local_irq_save(flags); + cpu = raw_smp_processor_id(); + kgdb_info[cpu].debuggerinfo = regs; + kgdb_info[cpu].task = current; + /* + * Make sure the above info reaches the primary CPU before + * our cpu_in_kgdb[] flag setting does: + */ + smp_wmb(); + atomic_set(&cpu_in_kgdb[cpu], 1); + + /* + * The primary CPU must be active to enter here, but this is + * guard in case the primary CPU had not been selected if + * this was an entry via nmi. + */ + while (atomic_read(&kgdb_active) == -1) + cpu_relax(); + + /* Wait till primary CPU goes completely into the debugger. */ + while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) + cpu_relax(); + + /* Wait till primary CPU is done with debugging */ + while (atomic_read(&passive_cpu_wait[cpu])) + cpu_relax(); + + kgdb_info[cpu].debuggerinfo = NULL; + kgdb_info[cpu].task = NULL; + + /* fix up hardware debug registers on local cpu */ + if (arch_kgdb_ops.correct_hw_break) + arch_kgdb_ops.correct_hw_break(); + + /* Signal the primary CPU that we are done: */ + atomic_set(&cpu_in_kgdb[cpu], 0); + local_irq_restore(flags); +} +#endif + +/* + * Some architectures need cache flushes when we set/clear a + * breakpoint: + */ +static void kgdb_flush_swbreak_addr(unsigned long addr) +{ + if (!CACHE_FLUSH_IS_SAFE) + return; + + if (current->mm) { + flush_cache_range(current->mm->mmap_cache, + addr, addr + BREAK_INSTR_SIZE); + } else { + flush_icache_range(addr, addr + BREAK_INSTR_SIZE); + } +} + +/* + * SW breakpoint management: + */ +static int kgdb_activate_sw_breakpoints(void) +{ + unsigned long addr; + int error = 0; + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_SET) + continue; + + addr = kgdb_break[i].bpt_addr; + error = kgdb_arch_set_breakpoint(addr, + kgdb_break[i].saved_instr); + if (error) + return error; + + kgdb_flush_swbreak_addr(addr); + kgdb_break[i].state = BP_ACTIVE; + } + return 0; +} + +static int kgdb_set_sw_break(unsigned long addr) +{ + int err = kgdb_validate_break_address(addr); + int breakno = -1; + int i; + + if (err) + return err; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_SET) && + (kgdb_break[i].bpt_addr == addr)) + return -EEXIST; + } + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state == BP_REMOVED && + kgdb_break[i].bpt_addr == addr) { + breakno = i; + break; + } + } + + if (breakno == -1) { + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state == BP_UNDEFINED) { + breakno = i; + break; + } + } + } + + if (breakno == -1) + return -E2BIG; + + kgdb_break[breakno].state = BP_SET; + kgdb_break[breakno].type = BP_BREAKPOINT; + kgdb_break[breakno].bpt_addr = addr; + + return 0; +} + +static int kgdb_deactivate_sw_breakpoints(void) +{ + unsigned long addr; + int error = 0; + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_ACTIVE) + continue; + addr = kgdb_break[i].bpt_addr; + error = kgdb_arch_remove_breakpoint(addr, + kgdb_break[i].saved_instr); + if (error) + return error; + + kgdb_flush_swbreak_addr(addr); + kgdb_break[i].state = BP_SET; + } + return 0; +} + +static int kgdb_remove_sw_break(unsigned long addr) +{ + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_SET) && + (kgdb_break[i].bpt_addr == addr)) { + kgdb_break[i].state = BP_REMOVED; + return 0; + } + } + return -ENOENT; +} + +int kgdb_isremovedbreak(unsigned long addr) +{ + int i; + + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if ((kgdb_break[i].state == BP_REMOVED) && + (kgdb_break[i].bpt_addr == addr)) + return 1; + } + return 0; +} + +int remove_all_break(void) +{ + unsigned long addr; + int error; + int i; + + /* Clear memory breakpoints. */ + for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { + if (kgdb_break[i].state != BP_SET) + continue; + addr = kgdb_break[i].bpt_addr; + error = kgdb_arch_remove_breakpoint(addr, + kgdb_break[i].saved_instr); + if (error) + return error; + kgdb_break[i].state = BP_REMOVED; + } + + /* Clear hardware breakpoints. */ + if (arch_kgdb_ops.remove_all_hw_break) + arch_kgdb_ops.remove_all_hw_break(); + + return 0; +} + +/* + * Remap normal tasks to their real PID, idle tasks to -1 ... -NR_CPUs: + */ +static inline int shadow_pid(int realpid) +{ + if (realpid) + return realpid; + + return -1-raw_smp_processor_id(); +} + +static char gdbmsgbuf[BUFMAX + 1]; + +static void kgdb_msg_write(const char *s, int len) +{ + char *bufptr; + int wcount; + int i; + + /* 'O'utput */ + gdbmsgbuf[0] = 'O'; + + /* Fill and send buffers... */ + while (len > 0) { + bufptr = gdbmsgbuf + 1; + + /* Calculate how many this time */ + if ((len << 1) > (BUFMAX - 2)) + wcount = (BUFMAX - 2) >> 1; + else + wcount = len; + + /* Pack in hex chars */ + for (i = 0; i < wcount; i++) + bufptr = pack_hex_byte(bufptr, s[i]); + *bufptr = '\0'; + + /* Move up */ + s += wcount; + len -= wcount; + + /* Write packet */ + put_packet(gdbmsgbuf); + } +} + +/* + * Return true if there is a valid kgdb I/O module. Also if no + * debugger is attached a message can be printed to the console about + * waiting for the debugger to attach. + * + * The print_wait argument is only to be true when called from inside + * the core kgdb_handle_exception, because it will wait for the + * debugger to attach. + */ +static int kgdb_io_ready(int print_wait) +{ + if (!kgdb_io_ops) + return 0; + if (kgdb_connected) + return 1; + if (atomic_read(&kgdb_setting_breakpoint)) + return 1; + if (print_wait) + printk(KERN_CRIT "KGDB: Waiting for remote debugger\n"); + return 1; +} + +/* + * All the functions that start with gdb_cmd are the various + * operations to implement the handlers for the gdbserial protocol + * where KGDB is communicating with an external debugger + */ + +/* Handle the '?' status packets */ +static void gdb_cmd_status(struct kgdb_state *ks) +{ + /* + * We know that this packet is only sent + * during initial connect. So to be safe, + * we clear out our breakpoints now in case + * GDB is reconnecting. + */ + remove_all_break(); + + remcom_out_buffer[0] = 'S'; + pack_hex_byte(&remcom_out_buffer[1], ks->signo); +} + +/* Handle the 'g' get registers request */ +static void gdb_cmd_getregs(struct kgdb_state *ks) +{ + struct task_struct *thread; + void *local_debuggerinfo; + int i; + + thread = kgdb_usethread; + if (!thread) { + thread = kgdb_info[ks->cpu].task; + local_debuggerinfo = kgdb_info[ks->cpu].debuggerinfo; + } else { + local_debuggerinfo = NULL; + for (i = 0; i < NR_CPUS; i++) { + /* + * Try to find the task on some other + * or possibly this node if we do not + * find the matching task then we try + * to approximate the results. + */ + if (thread == kgdb_info[i].task) + local_debuggerinfo = kgdb_info[i].debuggerinfo; + } + } + + /* + * All threads that don't have debuggerinfo should be + * in __schedule() sleeping, since all other CPUs + * are in kgdb_wait, and thus have debuggerinfo. + */ + if (local_debuggerinfo) { + pt_regs_to_gdb_regs(gdb_regs, local_debuggerinfo); + } else { + /* + * Pull stuff saved during switch_to; nothing + * else is accessible (or even particularly + * relevant). + * + * This should be enough for a stack trace. + */ + sleeping_thread_to_gdb_regs(gdb_regs, thread); + } + kgdb_mem2hex((char *)gdb_regs, remcom_out_buffer, NUMREGBYTES); +} + +/* Handle the 'G' set registers request */ +static void gdb_cmd_setregs(struct kgdb_state *ks) +{ + kgdb_hex2mem(&remcom_in_buffer[1], (char *)gdb_regs, NUMREGBYTES); + + if (kgdb_usethread && kgdb_usethread != current) { + error_packet(remcom_out_buffer, -EINVAL); + } else { + gdb_regs_to_pt_regs(gdb_regs, ks->linux_regs); + strcpy(remcom_out_buffer, "OK"); + } +} + +/* Handle the 'm' memory read bytes */ +static void gdb_cmd_memread(struct kgdb_state *ks) +{ + char *ptr = &remcom_in_buffer[1]; + unsigned long length; + unsigned long addr; + int err; + + if (kgdb_hex2long(&ptr, &addr) > 0 && *ptr++ == ',' && + kgdb_hex2long(&ptr, &length) > 0) { + err = kgdb_mem2hex((char *)addr, remcom_out_buffer, length); + if (err) + error_packet(remcom_out_buffer, err); + } else { + error_packet(remcom_out_buffer, -EINVAL); + } +} + +/* Handle the 'M' memory write bytes */ +static void gdb_cmd_memwrite(struct kgdb_state *ks) +{ + int err = write_mem_msg(0); + + if (err) + error_packet(remcom_out_buffer, err); + else + strcpy(remcom_out_buffer, "OK"); +} + +/* Handle the 'X' memory binary write bytes */ +static void gdb_cmd_binwrite(struct kgdb_state *ks) +{ + int err = write_mem_msg(1); + + if (err) + error_packet(remcom_out_buffer, err); + else + strcpy(remcom_out_buffer, "OK"); +} + +/* Handle the 'D' or 'k', detach or kill packets */ +static void gdb_cmd_detachkill(struct kgdb_state *ks) +{ + int error; + + /* The detach case */ + if (remcom_in_buffer[0] == 'D') { + error = remove_all_break(); + if (error < 0) { + error_packet(remcom_out_buffer, error); + } else { + strcpy(remcom_out_buffer, "OK"); + kgdb_connected = 0; + } + put_packet(remcom_out_buffer); + } else { + /* + * Assume the kill case, with no exit code checking, + * trying to force detach the debugger: + */ + remove_all_break(); + kgdb_connected = 0; + } +} + +/* Handle the 'R' reboot packets */ +static int gdb_cmd_reboot(struct kgdb_state *ks) +{ + /* For now, only honor R0 */ + if (strcmp(remcom_in_buffer, "R0") == 0) { + printk(KERN_CRIT "Executing emergency reboot\n"); + strcpy(remcom_out_buffer, "OK"); + put_packet(remcom_out_buffer); + + /* + * Execution should not return from + * machine_emergency_restart() + */ + machine_emergency_restart(); + kgdb_connected = 0; + + return 1; + } + return 0; +} + +/* Handle the 'q' query packets */ +static void gdb_cmd_query(struct kgdb_state *ks) +{ + struct task_struct *thread; + unsigned char thref[8]; + char *ptr; + int i; + + switch (remcom_in_buffer[1]) { + case 's': + case 'f': + if (memcmp(remcom_in_buffer + 2, "ThreadInfo", 10)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + + if (remcom_in_buffer[1] == 'f') + ks->threadid = 1; + + remcom_out_buffer[0] = 'm'; + ptr = remcom_out_buffer + 1; + + for (i = 0; i < 17; ks->threadid++) { + thread = getthread(ks->linux_regs, ks->threadid); + if (thread) { + int_to_threadref(thref, ks->threadid); + pack_threadid(ptr, thref); + ptr += BUF_THREAD_ID_SIZE; + *(ptr++) = ','; + i++; + } + } + *(--ptr) = '\0'; + break; + + case 'C': + /* Current thread id */ + strcpy(remcom_out_buffer, "QC"); + ks->threadid = shadow_pid(current->pid); + int_to_threadref(thref, ks->threadid); + pack_threadid(remcom_out_buffer + 2, thref); + break; + case 'T': + if (memcmp(remcom_in_buffer + 1, "ThreadExtraInfo,", 16)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + ks->threadid = 0; + ptr = remcom_in_buffer + 17; + kgdb_hex2long(&ptr, &ks->threadid); + if (!getthread(ks->linux_regs, ks->threadid)) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + if (ks->threadid > 0) { + kgdb_mem2hex(getthread(ks->linux_regs, + ks->threadid)->comm, + remcom_out_buffer, 16); + } else { + static char tmpstr[23 + BUF_THREAD_ID_SIZE]; + + sprintf(tmpstr, "Shadow task %d for pid 0", + (int)(-ks->threadid-1)); + kgdb_mem2hex(tmpstr, remcom_out_buffer, strlen(tmpstr)); + } + break; + } +} + +/* Handle the 'H' task query packets */ +static void gdb_cmd_task(struct kgdb_state *ks) +{ + struct task_struct *thread; + char *ptr; + + switch (remcom_in_buffer[1]) { + case 'g': + ptr = &remcom_in_buffer[2]; + kgdb_hex2long(&ptr, &ks->threadid); + thread = getthread(ks->linux_regs, ks->threadid); + if (!thread && ks->threadid > 0) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_usethread = thread; + ks->kgdb_usethreadid = ks->threadid; + strcpy(remcom_out_buffer, "OK"); + break; + case 'c': + ptr = &remcom_in_buffer[2]; + kgdb_hex2long(&ptr, &ks->threadid); + if (!ks->threadid) { + kgdb_contthread = NULL; + } else { + thread = getthread(ks->linux_regs, ks->threadid); + if (!thread && ks->threadid > 0) { + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_contthread = thread; + } + strcpy(remcom_out_buffer, "OK"); + break; + } +} + +/* Handle the 'T' thread query packets */ +static void gdb_cmd_thread(struct kgdb_state *ks) +{ + char *ptr = &remcom_in_buffer[1]; + struct task_struct *thread; + + kgdb_hex2long(&ptr, &ks->threadid); + thread = getthread(ks->linux_regs, ks->threadid); + if (thread) + strcpy(remcom_out_buffer, "OK"); + else + error_packet(remcom_out_buffer, -EINVAL); +} + +/* Handle the 'z' or 'Z' breakpoint remove or set packets */ +static void gdb_cmd_break(struct kgdb_state *ks) +{ + /* + * Since GDB-5.3, it's been drafted that '0' is a software + * breakpoint, '1' is a hardware breakpoint, so let's do that. + */ + char *bpt_type = &remcom_in_buffer[1]; + char *ptr = &remcom_in_buffer[2]; + unsigned long addr; + unsigned long length; + int error = 0; + + if (arch_kgdb_ops.set_hw_breakpoint && *bpt_type >= '1') { + /* Unsupported */ + if (*bpt_type > '4') + return; + } else { + if (*bpt_type != '0' && *bpt_type != '1') + /* Unsupported. */ + return; + } + + /* + * Test if this is a hardware breakpoint, and + * if we support it: + */ + if (*bpt_type == '1' && !(arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT)) + /* Unsupported. */ + return; + + if (*(ptr++) != ',') { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + if (!kgdb_hex2long(&ptr, &addr)) { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + if (*(ptr++) != ',' || + !kgdb_hex2long(&ptr, &length)) { + error_packet(remcom_out_buffer, -EINVAL); + return; + } + + if (remcom_in_buffer[0] == 'Z' && *bpt_type == '0') + error = kgdb_set_sw_break(addr); + else if (remcom_in_buffer[0] == 'z' && *bpt_type == '0') + error = kgdb_remove_sw_break(addr); + else if (remcom_in_buffer[0] == 'Z') + error = arch_kgdb_ops.set_hw_breakpoint(addr, + (int)length, *bpt_type); + else if (remcom_in_buffer[0] == 'z') + error = arch_kgdb_ops.remove_hw_breakpoint(addr, + (int) length, *bpt_type); + + if (error == 0) + strcpy(remcom_out_buffer, "OK"); + else + error_packet(remcom_out_buffer, error); +} + +/* Handle the 'C' signal / exception passing packets */ +static int gdb_cmd_exception_pass(struct kgdb_state *ks) +{ + /* C09 == pass exception + * C15 == detach kgdb, pass exception + */ + if (remcom_in_buffer[1] == '0' && remcom_in_buffer[2] == '9') { + + ks->pass_exception = 1; + remcom_in_buffer[0] = 'c'; + + } else if (remcom_in_buffer[1] == '1' && remcom_in_buffer[2] == '5') { + + ks->pass_exception = 1; + remcom_in_buffer[0] = 'D'; + remove_all_break(); + kgdb_connected = 0; + return 1; + + } else { + error_packet(remcom_out_buffer, -EINVAL); + return 0; + } + + /* Indicate fall through */ + return -1; +} + +/* + * This function performs all gdbserial command procesing + */ +static int gdb_serial_stub(struct kgdb_state *ks) +{ + int error = 0; + int tmp; + + /* Clear the out buffer. */ + memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); + + if (kgdb_connected) { + unsigned char thref[8]; + char *ptr; + + /* Reply to host that an exception has occurred */ + ptr = remcom_out_buffer; + *ptr++ = 'T'; + ptr = pack_hex_byte(ptr, ks->signo); + ptr += strlen(strcpy(ptr, "thread:")); + int_to_threadref(thref, shadow_pid(current->pid)); + ptr = pack_threadid(ptr, thref); + *ptr++ = ';'; + put_packet(remcom_out_buffer); + } + + kgdb_usethread = kgdb_info[ks->cpu].task; + ks->kgdb_usethreadid = shadow_pid(kgdb_info[ks->cpu].task->pid); + ks->pass_exception = 0; + + while (1) { + error = 0; + + /* Clear the out buffer. */ + memset(remcom_out_buffer, 0, sizeof(remcom_out_buffer)); + + get_packet(remcom_in_buffer); + + switch (remcom_in_buffer[0]) { + case '?': /* gdbserial status */ + gdb_cmd_status(ks); + break; + case 'g': /* return the value of the CPU registers */ + gdb_cmd_getregs(ks); + break; + case 'G': /* set the value of the CPU registers - return OK */ + gdb_cmd_setregs(ks); + break; + case 'm': /* mAA..AA,LLLL Read LLLL bytes at address AA..AA */ + gdb_cmd_memread(ks); + break; + case 'M': /* MAA..AA,LLLL: Write LLLL bytes at address AA..AA */ + gdb_cmd_memwrite(ks); + break; + case 'X': /* XAA..AA,LLLL: Write LLLL bytes at address AA..AA */ + gdb_cmd_binwrite(ks); + break; + /* kill or detach. KGDB should treat this like a + * continue. + */ + case 'D': /* Debugger detach */ + case 'k': /* Debugger detach via kill */ + gdb_cmd_detachkill(ks); + goto default_handle; + case 'R': /* Reboot */ + if (gdb_cmd_reboot(ks)) + goto default_handle; + break; + case 'q': /* query command */ + gdb_cmd_query(ks); + break; + case 'H': /* task related */ + gdb_cmd_task(ks); + break; + case 'T': /* Query thread status */ + gdb_cmd_thread(ks); + break; + case 'z': /* Break point remove */ + case 'Z': /* Break point set */ + gdb_cmd_break(ks); + break; + case 'C': /* Exception passing */ + tmp = gdb_cmd_exception_pass(ks); + if (tmp > 0) + goto default_handle; + if (tmp == 0) + break; + /* Fall through on tmp < 0 */ + case 'c': /* Continue packet */ + case 's': /* Single step packet */ + if (kgdb_contthread && kgdb_contthread != current) { + /* Can't switch threads in kgdb */ + error_packet(remcom_out_buffer, -EINVAL); + break; + } + kgdb_activate_sw_breakpoints(); + /* Fall through to default processing */ + default: +default_handle: + error = kgdb_arch_handle_exception(ks->ex_vector, + ks->signo, + ks->err_code, + remcom_in_buffer, + remcom_out_buffer, + ks->linux_regs); + /* + * Leave cmd processing on error, detach, + * kill, continue, or single step. + */ + if (error >= 0 || remcom_in_buffer[0] == 'D' || + remcom_in_buffer[0] == 'k') { + error = 0; + goto kgdb_exit; + } + + } + + /* reply to the request */ + put_packet(remcom_out_buffer); + } + +kgdb_exit: + if (ks->pass_exception) + error = 1; + return error; +} + +static int kgdb_reenter_check(struct kgdb_state *ks) +{ + unsigned long addr; + + if (atomic_read(&kgdb_active) != raw_smp_processor_id()) + return 0; + + /* Panic on recursive debugger calls: */ + exception_level++; + addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs); + kgdb_deactivate_sw_breakpoints(); + + /* + * If the break point removed ok at the place exception + * occurred, try to recover and print a warning to the end + * user because the user planted a breakpoint in a place that + * KGDB needs in order to function. + */ + if (kgdb_remove_sw_break(addr) == 0) { + exception_level = 0; + kgdb_skipexception(ks->ex_vector, ks->linux_regs); + kgdb_activate_sw_breakpoints(); + printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n"); + WARN_ON_ONCE(1); + + return 1; + } + remove_all_break(); + kgdb_skipexception(ks->ex_vector, ks->linux_regs); + + if (exception_level > 1) { + dump_stack(); + panic("Recursive entry to debugger"); + } + + printk(KERN_CRIT "KGDB: re-enter exception: ALL breakpoints killed\n"); + dump_stack(); + panic("Recursive entry to debugger"); + + return 1; +} + +/* + * kgdb_handle_exception() - main entry point from a kernel exception + * + * Locking hierarchy: + * interface locks, if any (begin_session) + * kgdb lock (kgdb_active) + */ +int +kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) +{ + struct kgdb_state kgdb_var; + struct kgdb_state *ks = &kgdb_var; + unsigned long flags; + int error = 0; + int i, cpu; + + ks->cpu = raw_smp_processor_id(); + ks->ex_vector = evector; + ks->signo = signo; + ks->ex_vector = evector; + ks->err_code = ecode; + ks->kgdb_usethreadid = 0; + ks->linux_regs = regs; + + if (kgdb_reenter_check(ks)) + return 0; /* Ouch, double exception ! */ + +acquirelock: + /* + * Interrupts will be restored by the 'trap return' code, except when + * single stepping. + */ + local_irq_save(flags); + + cpu = raw_smp_processor_id(); + + /* + * Acquire the kgdb_active lock: + */ + while (atomic_cmpxchg(&kgdb_active, -1, cpu) != -1) + cpu_relax(); + + /* + * Do not start the debugger connection on this CPU if the last + * instance of the exception handler wanted to come into the + * debugger on a different CPU via a single step + */ + if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && + atomic_read(&kgdb_cpu_doing_single_step) != cpu) { + + atomic_set(&kgdb_active, -1); + local_irq_restore(flags); + + goto acquirelock; + } + + if (!kgdb_io_ready(1)) { + error = 1; + goto kgdb_restore; /* No I/O connection, so resume the system */ + } + + /* + * Don't enter if we have hit a removed breakpoint. + */ + if (kgdb_skipexception(ks->ex_vector, ks->linux_regs)) + goto kgdb_restore; + + /* Call the I/O driver's pre_exception routine */ + if (kgdb_io_ops->pre_exception) + kgdb_io_ops->pre_exception(); + + kgdb_info[ks->cpu].debuggerinfo = ks->linux_regs; + kgdb_info[ks->cpu].task = current; + + kgdb_disable_hw_debug(ks->linux_regs); + + /* + * Get the passive CPU lock which will hold all the non-primary + * CPU in a spin state while the debugger is active + */ + if (!kgdb_single_step || !kgdb_contthread) { + for (i = 0; i < NR_CPUS; i++) + atomic_set(&passive_cpu_wait[i], 1); + } + +#ifdef CONFIG_SMP + /* Signal the other CPUs to enter kgdb_wait() */ + if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup) + kgdb_roundup_cpus(flags); +#endif + + /* + * spin_lock code is good enough as a barrier so we don't + * need one here: + */ + atomic_set(&cpu_in_kgdb[ks->cpu], 1); + + /* + * Wait for the other CPUs to be notified and be waiting for us: + */ + for_each_online_cpu(i) { + while (!atomic_read(&cpu_in_kgdb[i])) + cpu_relax(); + } + + /* + * At this point the primary processor is completely + * in the debugger and all secondary CPUs are quiescent + */ + kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code); + kgdb_deactivate_sw_breakpoints(); + kgdb_single_step = 0; + kgdb_contthread = NULL; + exception_level = 0; + + /* Talk to debugger with gdbserial protocol */ + error = gdb_serial_stub(ks); + + /* Call the I/O driver's post_exception routine */ + if (kgdb_io_ops->post_exception) + kgdb_io_ops->post_exception(); + + kgdb_info[ks->cpu].debuggerinfo = NULL; + kgdb_info[ks->cpu].task = NULL; + atomic_set(&cpu_in_kgdb[ks->cpu], 0); + + if (!kgdb_single_step || !kgdb_contthread) { + for (i = NR_CPUS-1; i >= 0; i--) + atomic_set(&passive_cpu_wait[i], 0); + /* + * Wait till all the CPUs have quit + * from the debugger. + */ + for_each_online_cpu(i) { + while (atomic_read(&cpu_in_kgdb[i])) + cpu_relax(); + } + } + +kgdb_restore: + /* Free kgdb_active */ + atomic_set(&kgdb_active, -1); + local_irq_restore(flags); + + return error; +} + +int kgdb_nmicallback(int cpu, void *regs) +{ +#ifdef CONFIG_SMP + if (!atomic_read(&cpu_in_kgdb[cpu]) && + atomic_read(&kgdb_active) != cpu) { + kgdb_wait((struct pt_regs *)regs); + return 0; + } +#endif + return 1; +} + +void kgdb_console_write(struct console *co, const char *s, unsigned count) +{ + unsigned long flags; + + /* If we're debugging, or KGDB has not connected, don't try + * and print. */ + if (!kgdb_connected || atomic_read(&kgdb_active) != -1) + return; + + local_irq_save(flags); + kgdb_msg_write(s, count); + local_irq_restore(flags); +} + +static struct console kgdbcons = { + .name = "kgdb", + .write = kgdb_console_write, + .flags = CON_PRINTBUFFER | CON_ENABLED, + .index = -1, +}; + +#ifdef CONFIG_MAGIC_SYSRQ +static void sysrq_handle_gdb(int key, struct tty_struct *tty) +{ + if (!kgdb_io_ops) { + printk(KERN_CRIT "ERROR: No KGDB I/O module available\n"); + return; + } + if (!kgdb_connected) + printk(KERN_CRIT "Entering KGDB\n"); + + kgdb_breakpoint(); +} + +static struct sysrq_key_op sysrq_gdb_op = { + .handler = sysrq_handle_gdb, + .help_msg = "Gdb", + .action_msg = "GDB", +}; +#endif + +static void kgdb_register_callbacks(void) +{ + if (!kgdb_io_module_registered) { + kgdb_io_module_registered = 1; + kgdb_arch_init(); +#ifdef CONFIG_MAGIC_SYSRQ + register_sysrq_key('g', &sysrq_gdb_op); +#endif + if (kgdb_use_con && !kgdb_con_registered) { + register_console(&kgdbcons); + kgdb_con_registered = 1; + } + } +} + +static void kgdb_unregister_callbacks(void) +{ + /* + * When this routine is called KGDB should unregister from the + * panic handler and clean up, making sure it is not handling any + * break exceptions at the time. + */ + if (kgdb_io_module_registered) { + kgdb_io_module_registered = 0; + kgdb_arch_exit(); +#ifdef CONFIG_MAGIC_SYSRQ + unregister_sysrq_key('g', &sysrq_gdb_op); +#endif + if (kgdb_con_registered) { + unregister_console(&kgdbcons); + kgdb_con_registered = 0; + } + } +} + +static void kgdb_initial_breakpoint(void) +{ + kgdb_break_asap = 0; + + printk(KERN_CRIT "kgdb: Waiting for connection from remote gdb...\n"); + kgdb_breakpoint(); +} + +/** + * kkgdb_register_io_module - register KGDB IO module + * @new_kgdb_io_ops: the io ops vector + * + * Register it with the KGDB core. + */ +int kgdb_register_io_module(struct kgdb_io *new_kgdb_io_ops) +{ + int err; + + spin_lock(&kgdb_registration_lock); + + if (kgdb_io_ops) { + spin_unlock(&kgdb_registration_lock); + + printk(KERN_ERR "kgdb: Another I/O driver is already " + "registered with KGDB.\n"); + return -EBUSY; + } + + if (new_kgdb_io_ops->init) { + err = new_kgdb_io_ops->init(); + if (err) { + spin_unlock(&kgdb_registration_lock); + return err; + } + } + + kgdb_io_ops = new_kgdb_io_ops; + + spin_unlock(&kgdb_registration_lock); + + printk(KERN_INFO "kgdb: Registered I/O driver %s.\n", + new_kgdb_io_ops->name); + + /* Arm KGDB now. */ + kgdb_register_callbacks(); + + if (kgdb_break_asap) + kgdb_initial_breakpoint(); + + return 0; +} +EXPORT_SYMBOL_GPL(kgdb_register_io_module); + +/** + * kkgdb_unregister_io_module - unregister KGDB IO module + * @old_kgdb_io_ops: the io ops vector + * + * Unregister it with the KGDB core. + */ +void kgdb_unregister_io_module(struct kgdb_io *old_kgdb_io_ops) +{ + BUG_ON(kgdb_connected); + + /* + * KGDB is no longer able to communicate out, so + * unregister our callbacks and reset state. + */ + kgdb_unregister_callbacks(); + + spin_lock(&kgdb_registration_lock); + + WARN_ON_ONCE(kgdb_io_ops != old_kgdb_io_ops); + kgdb_io_ops = NULL; + + spin_unlock(&kgdb_registration_lock); + + printk(KERN_INFO + "kgdb: Unregistered I/O driver %s, debugger disabled.\n", + old_kgdb_io_ops->name); +} +EXPORT_SYMBOL_GPL(kgdb_unregister_io_module); + +/** + * kgdb_breakpoint - generate breakpoint exception + * + * This function will generate a breakpoint exception. It is used at the + * beginning of a program to sync up with a debugger and can be used + * otherwise as a quick means to stop program execution and "break" into + * the debugger. + */ +void kgdb_breakpoint(void) +{ + atomic_set(&kgdb_setting_breakpoint, 1); + wmb(); /* Sync point before breakpoint */ + arch_kgdb_breakpoint(); + wmb(); /* Sync point after breakpoint */ + atomic_set(&kgdb_setting_breakpoint, 0); +} +EXPORT_SYMBOL_GPL(kgdb_breakpoint); + +static int __init opt_kgdb_wait(char *str) +{ + kgdb_break_asap = 1; + + if (kgdb_io_module_registered) + kgdb_initial_breakpoint(); + + return 0; +} + +early_param("kgdbwait", opt_kgdb_wait); diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 0796c1a090c0..e601d0e7ac5d 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -622,3 +622,5 @@ config PROVIDE_OHCI1394_DMA_INIT See Documentation/debugging-via-ohci1394.txt for more information. source "samples/Kconfig" + +source "lib/Kconfig.kgdb" diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb new file mode 100644 index 000000000000..9631ba3baaf3 --- /dev/null +++ b/lib/Kconfig.kgdb @@ -0,0 +1,27 @@ + +menuconfig KGDB + bool "KGDB: kernel debugging with remote gdb" + select FRAME_POINTER + depends on HAVE_ARCH_KGDB + depends on DEBUG_KERNEL && EXPERIMENTAL + help + If you say Y here, it will be possible to remotely debug the + kernel using gdb. Documentation of kernel debugger is available + at http://kgdb.sourceforge.net as well as in DocBook form + in Documentation/DocBook/. If unsure, say N. + +config HAVE_ARCH_KGDB_SHADOW_INFO + bool + +config HAVE_ARCH_KGDB + bool + +config KGDB_SERIAL_CONSOLE + tristate "KGDB: use kgdb over the serial console" + depends on KGDB + select CONSOLE_POLL + select MAGIC_SYSRQ + default y + help + Share a serial console with kgdb. Sysrq-g must be used + to break in initially. -- cgit v1.2.3 From f2d937f3bf00665ccf048b3b6616ef95859b0945 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 17 Apr 2008 20:05:37 +0200 Subject: consoles: polling support, kgdboc polled console handling support, to access a console in an irq-less way while in debug or irq context. absolutely zero impact as long as CONFIG_CONSOLE_POLL is disabled. (which is the default) [ jan.kiszka@siemens.com: lots of cleanups ] [ mingo@elte.hu: redesign, splitups, cleanups. ] Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar Signed-off-by: Jan Kiszka Reviewed-by: Thomas Gleixner --- drivers/char/tty_io.c | 47 +++++++++++++ drivers/serial/8250.c | 58 +++++++++++++++ drivers/serial/Kconfig | 3 + drivers/serial/Makefile | 1 + drivers/serial/kgdboc.c | 163 +++++++++++++++++++++++++++++++++++++++++++ drivers/serial/serial_core.c | 72 ++++++++++++++++++- include/linux/serial_core.h | 4 ++ include/linux/tty_driver.h | 12 ++++ 8 files changed, 357 insertions(+), 3 deletions(-) create mode 100644 drivers/serial/kgdboc.c diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c index 613ec816ce60..4d3c7018f0c3 100644 --- a/drivers/char/tty_io.c +++ b/drivers/char/tty_io.c @@ -1155,6 +1155,48 @@ static struct tty_driver *get_tty_driver(dev_t device, int *index) return NULL; } +#ifdef CONFIG_CONSOLE_POLL + +/** + * tty_find_polling_driver - find device of a polled tty + * @name: name string to match + * @line: pointer to resulting tty line nr + * + * This routine returns a tty driver structure, given a name + * and the condition that the tty driver is capable of polled + * operation. + */ +struct tty_driver *tty_find_polling_driver(char *name, int *line) +{ + struct tty_driver *p, *res = NULL; + int tty_line = 0; + char *str; + + mutex_lock(&tty_mutex); + /* Search through the tty devices to look for a match */ + list_for_each_entry(p, &tty_drivers, tty_drivers) { + str = name + strlen(p->name); + tty_line = simple_strtoul(str, &str, 10); + if (*str == ',') + str++; + if (*str == '\0') + str = 0; + + if (tty_line >= 0 && tty_line <= p->num && p->poll_init && + !p->poll_init(p, tty_line, str)) { + + res = p; + *line = tty_line; + break; + } + } + mutex_unlock(&tty_mutex); + + return res; +} +EXPORT_SYMBOL_GPL(tty_find_polling_driver); +#endif + /** * tty_check_change - check for POSIX terminal changes * @tty: tty to check @@ -3850,6 +3892,11 @@ void tty_set_operations(struct tty_driver *driver, driver->write_proc = op->write_proc; driver->tiocmget = op->tiocmget; driver->tiocmset = op->tiocmset; +#ifdef CONFIG_CONSOLE_POLL + driver->poll_init = op->poll_init; + driver->poll_get_char = op->poll_get_char; + driver->poll_put_char = op->poll_put_char; +#endif } diff --git a/drivers/serial/8250.c b/drivers/serial/8250.c index 77f7a7f0646e..96a585e1cee8 100644 --- a/drivers/serial/8250.c +++ b/drivers/serial/8250.c @@ -1740,6 +1740,60 @@ static inline void wait_for_xmitr(struct uart_8250_port *up, int bits) } } +#ifdef CONFIG_CONSOLE_POLL +/* + * Console polling routines for writing and reading from the uart while + * in an interrupt or debug context. + */ + +static int serial8250_get_poll_char(struct uart_port *port) +{ + struct uart_8250_port *up = (struct uart_8250_port *)port; + unsigned char lsr = serial_inp(up, UART_LSR); + + while (!(lsr & UART_LSR_DR)) + lsr = serial_inp(up, UART_LSR); + + return serial_inp(up, UART_RX); +} + + +static void serial8250_put_poll_char(struct uart_port *port, + unsigned char c) +{ + unsigned int ier; + struct uart_8250_port *up = (struct uart_8250_port *)port; + + /* + * First save the IER then disable the interrupts + */ + ier = serial_in(up, UART_IER); + if (up->capabilities & UART_CAP_UUE) + serial_out(up, UART_IER, UART_IER_UUE); + else + serial_out(up, UART_IER, 0); + + wait_for_xmitr(up, BOTH_EMPTY); + /* + * Send the character out. + * If a LF, also do CR... + */ + serial_out(up, UART_TX, c); + if (c == 10) { + wait_for_xmitr(up, BOTH_EMPTY); + serial_out(up, UART_TX, 13); + } + + /* + * Finally, wait for transmitter to become empty + * and restore the IER + */ + wait_for_xmitr(up, BOTH_EMPTY); + serial_out(up, UART_IER, ier); +} + +#endif /* CONFIG_CONSOLE_POLL */ + static int serial8250_startup(struct uart_port *port) { struct uart_8250_port *up = (struct uart_8250_port *)port; @@ -2386,6 +2440,10 @@ static struct uart_ops serial8250_pops = { .request_port = serial8250_request_port, .config_port = serial8250_config_port, .verify_port = serial8250_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif }; static struct uart_8250_port serial8250_ports[UART_NR]; diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index cf627cd1b4c8..f7cd9504d811 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -961,6 +961,9 @@ config SERIAL_CORE config SERIAL_CORE_CONSOLE bool +config CONSOLE_POLL + bool + config SERIAL_68328 bool "68328 serial support" depends on M68328 || M68EZ328 || M68VZ328 diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile index 640cfe44a56d..3cbea5494724 100644 --- a/drivers/serial/Makefile +++ b/drivers/serial/Makefile @@ -66,4 +66,5 @@ obj-$(CONFIG_SERIAL_UARTLITE) += uartlite.o obj-$(CONFIG_SERIAL_NETX) += netx-serial.o obj-$(CONFIG_SERIAL_OF_PLATFORM) += of_serial.o obj-$(CONFIG_SERIAL_KS8695) += serial_ks8695.o +obj-$(CONFIG_KGDB_SERIAL_CONSOLE) += kgdboc.o obj-$(CONFIG_SERIAL_QE) += ucc_uart.o diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c new file mode 100644 index 000000000000..341830791608 --- /dev/null +++ b/drivers/serial/kgdboc.c @@ -0,0 +1,163 @@ +/* + * Based on the same principle as kgdboe using the NETPOLL api, this + * driver uses a console polling api to implement a gdb serial inteface + * which is multiplexed on a console port. + * + * Maintainer: Jason Wessel + * + * 2007-2008 (c) Jason Wessel - Wind River Systems, Inc. + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ +#include +#include +#include +#include + +#define MAX_CONFIG_LEN 40 + +static struct kgdb_io kgdboc_io_ops; + +/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */ +static int configured = -1; + +static char config[MAX_CONFIG_LEN]; +static struct kparam_string kps = { + .string = config, + .maxlen = MAX_CONFIG_LEN, +}; + +static struct tty_driver *kgdb_tty_driver; +static int kgdb_tty_line; + +static int kgdboc_option_setup(char *opt) +{ + if (strlen(opt) > MAX_CONFIG_LEN) { + printk(KERN_ERR "kgdboc: config string too long\n"); + return -ENOSPC; + } + strcpy(config, opt); + + return 0; +} + +__setup("kgdboc=", kgdboc_option_setup); + +static int configure_kgdboc(void) +{ + struct tty_driver *p; + int tty_line = 0; + int err; + + err = kgdboc_option_setup(config); + if (err || !strlen(config) || isspace(config[0])) + goto noconfig; + + err = -ENODEV; + + p = tty_find_polling_driver(config, &tty_line); + if (!p) + goto noconfig; + + kgdb_tty_driver = p; + kgdb_tty_line = tty_line; + + err = kgdb_register_io_module(&kgdboc_io_ops); + if (err) + goto noconfig; + + configured = 1; + + return 0; + +noconfig: + config[0] = 0; + configured = 0; + + return err; +} + +static int __init init_kgdboc(void) +{ + /* Already configured? */ + if (configured == 1) + return 0; + + return configure_kgdboc(); +} + +static void cleanup_kgdboc(void) +{ + if (configured == 1) + kgdb_unregister_io_module(&kgdboc_io_ops); +} + +static int kgdboc_get_char(void) +{ + return kgdb_tty_driver->poll_get_char(kgdb_tty_driver, kgdb_tty_line); +} + +static void kgdboc_put_char(u8 chr) +{ + kgdb_tty_driver->poll_put_char(kgdb_tty_driver, kgdb_tty_line, chr); +} + +static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp) +{ + if (strlen(kmessage) >= MAX_CONFIG_LEN) { + printk(KERN_ERR "kgdboc: config string too long\n"); + return -ENOSPC; + } + + /* Only copy in the string if the init function has not run yet */ + if (configured < 0) { + strcpy(config, kmessage); + return 0; + } + + if (kgdb_connected) { + printk(KERN_ERR + "kgdboc: Cannot reconfigure while KGDB is connected.\n"); + + return -EBUSY; + } + + strcpy(config, kmessage); + + if (configured == 1) + cleanup_kgdboc(); + + /* Go and configure with the new params. */ + return configure_kgdboc(); +} + +static void kgdboc_pre_exp_handler(void) +{ + /* Increment the module count when the debugger is active */ + if (!kgdb_connected) + try_module_get(THIS_MODULE); +} + +static void kgdboc_post_exp_handler(void) +{ + /* decrement the module count when the debugger detaches */ + if (!kgdb_connected) + module_put(THIS_MODULE); +} + +static struct kgdb_io kgdboc_io_ops = { + .name = "kgdboc", + .read_char = kgdboc_get_char, + .write_char = kgdboc_put_char, + .pre_exception = kgdboc_pre_exp_handler, + .post_exception = kgdboc_post_exp_handler, +}; + +module_init(init_kgdboc); +module_exit(cleanup_kgdboc); +module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644); +MODULE_PARM_DESC(kgdboc, "[,baud]"); +MODULE_DESCRIPTION("KGDB Console TTY Driver"); +MODULE_LICENSE("GPL"); diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 0f5a17987cca..4d7eecbead9b 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1827,7 +1827,7 @@ uart_get_console(struct uart_port *ports, int nr, struct console *co) * options. The format of the string is , * eg: 115200n8r */ -void __init +void uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow) { char *s = options; @@ -1842,6 +1842,7 @@ uart_parse_options(char *options, int *baud, int *parity, int *bits, int *flow) if (*s) *flow = *s; } +EXPORT_SYMBOL_GPL(uart_parse_options); struct baud_rates { unsigned int rate; @@ -1872,7 +1873,7 @@ static const struct baud_rates baud_rates[] = { * @bits: number of data bits * @flow: flow control character - 'r' (rts) */ -int __init +int uart_set_options(struct uart_port *port, struct console *co, int baud, int parity, int bits, int flow) { @@ -1924,10 +1925,16 @@ uart_set_options(struct uart_port *port, struct console *co, port->mctrl |= TIOCM_DTR; port->ops->set_termios(port, &termios, &dummy); - co->cflag = termios.c_cflag; + /* + * Allow the setting of the UART parameters with a NULL console + * too: + */ + if (co) + co->cflag = termios.c_cflag; return 0; } +EXPORT_SYMBOL_GPL(uart_set_options); #endif /* CONFIG_SERIAL_CORE_CONSOLE */ static void uart_change_pm(struct uart_state *state, int pm_state) @@ -2182,6 +2189,60 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, } } +#ifdef CONFIG_CONSOLE_POLL + +static int uart_poll_init(struct tty_driver *driver, int line, char *options) +{ + struct uart_driver *drv = driver->driver_state; + struct uart_state *state = drv->state + line; + struct uart_port *port; + int baud = 9600; + int bits = 8; + int parity = 'n'; + int flow = 'n'; + + if (!state || !state->port) + return -1; + + port = state->port; + if (!(port->ops->poll_get_char && port->ops->poll_put_char)) + return -1; + + if (options) { + uart_parse_options(options, &baud, &parity, &bits, &flow); + return uart_set_options(port, NULL, baud, parity, bits, flow); + } + + return 0; +} + +static int uart_poll_get_char(struct tty_driver *driver, int line) +{ + struct uart_driver *drv = driver->driver_state; + struct uart_state *state = drv->state + line; + struct uart_port *port; + + if (!state || !state->port) + return -1; + + port = state->port; + return port->ops->poll_get_char(port); +} + +static void uart_poll_put_char(struct tty_driver *driver, int line, char ch) +{ + struct uart_driver *drv = driver->driver_state; + struct uart_state *state = drv->state + line; + struct uart_port *port; + + if (!state || !state->port) + return; + + port = state->port; + port->ops->poll_put_char(port, ch); +} +#endif + static const struct tty_operations uart_ops = { .open = uart_open, .close = uart_close, @@ -2206,6 +2267,11 @@ static const struct tty_operations uart_ops = { #endif .tiocmget = uart_tiocmget, .tiocmset = uart_tiocmset, +#ifdef CONFIG_CONSOLE_POLL + .poll_init = uart_poll_init, + .poll_get_char = uart_poll_get_char, + .poll_put_char = uart_poll_put_char, +#endif }; /** diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index 289942fc6655..7cb094a82456 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -213,6 +213,10 @@ struct uart_ops { void (*config_port)(struct uart_port *, int); int (*verify_port)(struct uart_port *, struct serial_struct *); int (*ioctl)(struct uart_port *, unsigned int, unsigned long); +#ifdef CONFIG_CONSOLE_POLL + void (*poll_put_char)(struct uart_port *, unsigned char); + int (*poll_get_char)(struct uart_port *); +#endif }; #define UART_CONFIG_TYPE (1 << 0) diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h index 85c95cd39bc3..21f69aca4505 100644 --- a/include/linux/tty_driver.h +++ b/include/linux/tty_driver.h @@ -125,6 +125,7 @@ #include struct tty_struct; +struct tty_driver; struct tty_operations { int (*open)(struct tty_struct * tty, struct file * filp); @@ -157,6 +158,11 @@ struct tty_operations { int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); +#ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct tty_driver *driver, int line, char *options); + int (*poll_get_char)(struct tty_driver *driver, int line); + void (*poll_put_char)(struct tty_driver *driver, int line, char ch); +#endif }; struct tty_driver { @@ -220,6 +226,11 @@ struct tty_driver { int (*tiocmget)(struct tty_struct *tty, struct file *file); int (*tiocmset)(struct tty_struct *tty, struct file *file, unsigned int set, unsigned int clear); +#ifdef CONFIG_CONSOLE_POLL + int (*poll_init)(struct tty_driver *driver, int line, char *options); + int (*poll_get_char)(struct tty_driver *driver, int line); + void (*poll_put_char)(struct tty_driver *driver, int line, char ch); +#endif struct list_head tty_drivers; }; @@ -230,6 +241,7 @@ struct tty_driver *alloc_tty_driver(int lines); void put_tty_driver(struct tty_driver *driver); void tty_set_operations(struct tty_driver *driver, const struct tty_operations *op); +extern struct tty_driver *tty_find_polling_driver(char *name, int *line); /* tty driver magic number */ #define TTY_DRIVER_MAGIC 0x5402 -- cgit v1.2.3 From 82da3ff89dc2a1842cff9b0d4cbc345cb90b59e1 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Thu, 17 Apr 2008 20:05:37 +0200 Subject: x86: kgdb support simplified and streamlined kgdb support on x86, both 32-bit and 64-bit, based on patch from: Subject: kgdb: core-lite From: Jason Wessel [ and countless other authors - see the patch for details. ] Signed-off-by: Ingo Molnar Signed-off-by: Jason Wessel Signed-off-by: Jan Kiszka Reviewed-by: Thomas Gleixner --- arch/x86/Kconfig | 1 + arch/x86/kernel/Makefile | 1 + arch/x86/kernel/kgdb.c | 417 +++++++++++++++++++++++++++++++++++++++++++++++ include/asm-x86/kgdb.h | 81 +++++++++ 4 files changed, 500 insertions(+) create mode 100644 arch/x86/kernel/kgdb.c create mode 100644 include/asm-x86/kgdb.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6c70fed0f9a0..5c4c8d7a46cc 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -23,6 +23,7 @@ config X86 select HAVE_KPROBES select HAVE_KRETPROBES select HAVE_KVM if ((X86_32 && !X86_VOYAGER && !X86_VISWS && !X86_NUMAQ) || X86_64) + select HAVE_ARCH_KGDB config GENERIC_LOCKBREAK diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile index 4eb5ce841106..4a4260c7f672 100644 --- a/arch/x86/kernel/Makefile +++ b/arch/x86/kernel/Makefile @@ -66,6 +66,7 @@ obj-$(CONFIG_MODULES) += module_$(BITS).o obj-$(CONFIG_ACPI_SRAT) += srat_32.o obj-$(CONFIG_EFI) += efi.o efi_$(BITS).o efi_stub_$(BITS).o obj-$(CONFIG_DOUBLEFAULT) += doublefault_32.o +obj-$(CONFIG_KGDB) += kgdb.o obj-$(CONFIG_VM86) += vm86_32.o obj-$(CONFIG_EARLY_PRINTK) += early_printk.o diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c new file mode 100644 index 000000000000..37194d6374d8 --- /dev/null +++ b/arch/x86/kernel/kgdb.c @@ -0,0 +1,417 @@ +/* + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + */ + +/* + * Copyright (C) 2004 Amit S. Kale + * Copyright (C) 2000-2001 VERITAS Software Corporation. + * Copyright (C) 2002 Andi Kleen, SuSE Labs + * Copyright (C) 2004 LinSysSoft Technologies Pvt. Ltd. + * Copyright (C) 2007 MontaVista Software, Inc. + * Copyright (C) 2007-2008 Jason Wessel, Wind River Systems, Inc. + */ +/**************************************************************************** + * Contributor: Lake Stevens Instrument Division$ + * Written by: Glenn Engel $ + * Updated by: Amit Kale + * Updated by: Tom Rini + * Updated by: Jason Wessel + * Modified for 386 by Jim Kingdon, Cygnus Support. + * Origianl kgdb, compatibility with 2.1.xx kernel by + * David Grothe + * Integrated into 2.2.5 kernel by Tigran Aivazian + * X86_64 changes from Andi Kleen's patch merged by Jim Houston + */ +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include + +#ifdef CONFIG_X86_32 +# include +#else +# include +#endif + +/* + * Put the error code here just in case the user cares: + */ +static int gdb_x86errcode; + +/* + * Likewise, the vector number here (since GDB only gets the signal + * number through the usual means, and that's not very specific): + */ +static int gdb_x86vector = -1; + +/** + * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @regs: The &struct pt_regs of the current process. + * + * Convert the pt_regs in @regs into the format for registers that + * GDB expects, stored in @gdb_regs. + */ +void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs) +{ + gdb_regs[GDB_AX] = regs->ax; + gdb_regs[GDB_BX] = regs->bx; + gdb_regs[GDB_CX] = regs->cx; + gdb_regs[GDB_DX] = regs->dx; + gdb_regs[GDB_SI] = regs->si; + gdb_regs[GDB_DI] = regs->di; + gdb_regs[GDB_BP] = regs->bp; + gdb_regs[GDB_PS] = regs->flags; + gdb_regs[GDB_PC] = regs->ip; +#ifdef CONFIG_X86_32 + gdb_regs[GDB_DS] = regs->ds; + gdb_regs[GDB_ES] = regs->es; + gdb_regs[GDB_CS] = regs->cs; + gdb_regs[GDB_SS] = __KERNEL_DS; + gdb_regs[GDB_FS] = 0xFFFF; + gdb_regs[GDB_GS] = 0xFFFF; +#else + gdb_regs[GDB_R8] = regs->r8; + gdb_regs[GDB_R9] = regs->r9; + gdb_regs[GDB_R10] = regs->r10; + gdb_regs[GDB_R11] = regs->r11; + gdb_regs[GDB_R12] = regs->r12; + gdb_regs[GDB_R13] = regs->r13; + gdb_regs[GDB_R14] = regs->r14; + gdb_regs[GDB_R15] = regs->r15; +#endif + gdb_regs[GDB_SP] = regs->sp; +} + +/** + * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs + * @gdb_regs: A pointer to hold the registers in the order GDB wants. + * @p: The &struct task_struct of the desired process. + * + * Convert the register values of the sleeping process in @p to + * the format that GDB expects. + * This function is called when kgdb does not have access to the + * &struct pt_regs and therefore it should fill the gdb registers + * @gdb_regs with what has been saved in &struct thread_struct + * thread field during switch_to. + */ +void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p) +{ + gdb_regs[GDB_AX] = 0; + gdb_regs[GDB_BX] = 0; + gdb_regs[GDB_CX] = 0; + gdb_regs[GDB_DX] = 0; + gdb_regs[GDB_SI] = 0; + gdb_regs[GDB_DI] = 0; + gdb_regs[GDB_BP] = *(unsigned long *)p->thread.sp; +#ifdef CONFIG_X86_32 + gdb_regs[GDB_DS] = __KERNEL_DS; + gdb_regs[GDB_ES] = __KERNEL_DS; + gdb_regs[GDB_PS] = 0; + gdb_regs[GDB_CS] = __KERNEL_CS; + gdb_regs[GDB_PC] = p->thread.ip; + gdb_regs[GDB_SS] = __KERNEL_DS; + gdb_regs[GDB_FS] = 0xFFFF; + gdb_regs[GDB_GS] = 0xFFFF; +#else + gdb_regs[GDB_PS] = *(unsigned long *)(p->thread.sp + 8); + gdb_regs[GDB_PC] = 0; + gdb_regs[GDB_R8] = 0; + gdb_regs[GDB_R9] = 0; + gdb_regs[GDB_R10] = 0; + gdb_regs[GDB_R11] = 0; + gdb_regs[GDB_R12] = 0; + gdb_regs[GDB_R13] = 0; + gdb_regs[GDB_R14] = 0; + gdb_regs[GDB_R15] = 0; +#endif + gdb_regs[GDB_SP] = p->thread.sp; +} + +/** + * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. + * @gdb_regs: A pointer to hold the registers we've received from GDB. + * @regs: A pointer to a &struct pt_regs to hold these values in. + * + * Convert the GDB regs in @gdb_regs into the pt_regs, and store them + * in @regs. + */ +void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) +{ + regs->ax = gdb_regs[GDB_AX]; + regs->bx = gdb_regs[GDB_BX]; + regs->cx = gdb_regs[GDB_CX]; + regs->dx = gdb_regs[GDB_DX]; + regs->si = gdb_regs[GDB_SI]; + regs->di = gdb_regs[GDB_DI]; + regs->bp = gdb_regs[GDB_BP]; + regs->flags = gdb_regs[GDB_PS]; + regs->ip = gdb_regs[GDB_PC]; +#ifdef CONFIG_X86_32 + regs->ds = gdb_regs[GDB_DS]; + regs->es = gdb_regs[GDB_ES]; + regs->cs = gdb_regs[GDB_CS]; +#else + regs->r8 = gdb_regs[GDB_R8]; + regs->r9 = gdb_regs[GDB_R9]; + regs->r10 = gdb_regs[GDB_R10]; + regs->r11 = gdb_regs[GDB_R11]; + regs->r12 = gdb_regs[GDB_R12]; + regs->r13 = gdb_regs[GDB_R13]; + regs->r14 = gdb_regs[GDB_R14]; + regs->r15 = gdb_regs[GDB_R15]; +#endif +} + +/** + * kgdb_post_primary_code - Save error vector/code numbers. + * @regs: Original pt_regs. + * @e_vector: Original error vector. + * @err_code: Original error code. + * + * This is needed on architectures which support SMP and KGDB. + * This function is called after all the slave cpus have been put + * to a know spin state and the primary CPU has control over KGDB. + */ +void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) +{ + /* primary processor is completely in the debugger */ + gdb_x86vector = e_vector; + gdb_x86errcode = err_code; +} + +#ifdef CONFIG_SMP +/** + * kgdb_roundup_cpus - Get other CPUs into a holding pattern + * @flags: Current IRQ state + * + * On SMP systems, we need to get the attention of the other CPUs + * and get them be in a known state. This should do what is needed + * to get the other CPUs to call kgdb_wait(). Note that on some arches, + * the NMI approach is not used for rounding up all the CPUs. For example, + * in case of MIPS, smp_call_function() is used to roundup CPUs. In + * this case, we have to make sure that interrupts are enabled before + * calling smp_call_function(). The argument to this function is + * the flags that will be used when restoring the interrupts. There is + * local_irq_save() call before kgdb_roundup_cpus(). + * + * On non-SMP systems, this is not called. + */ +void kgdb_roundup_cpus(unsigned long flags) +{ + send_IPI_allbutself(APIC_DM_NMI); +} +#endif + +/** + * kgdb_arch_handle_exception - Handle architecture specific GDB packets. + * @vector: The error vector of the exception that happened. + * @signo: The signal number of the exception that happened. + * @err_code: The error code of the exception that happened. + * @remcom_in_buffer: The buffer of the packet we have read. + * @remcom_out_buffer: The buffer of %BUFMAX bytes to write a packet into. + * @regs: The &struct pt_regs of the current process. + * + * This function MUST handle the 'c' and 's' command packets, + * as well packets to set / remove a hardware breakpoint, if used. + * If there are additional packets which the hardware needs to handle, + * they are handled here. The code should return -1 if it wants to + * process more packets, and a %0 or %1 if it wants to exit from the + * kgdb callback. + */ +int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, + char *remcomInBuffer, char *remcomOutBuffer, + struct pt_regs *linux_regs) +{ + unsigned long addr; + char *ptr; + int newPC; + + switch (remcomInBuffer[0]) { + case 'c': + case 's': + /* try to read optional parameter, pc unchanged if no parm */ + ptr = &remcomInBuffer[1]; + if (kgdb_hex2long(&ptr, &addr)) + linux_regs->ip = addr; + newPC = linux_regs->ip; + + /* clear the trace bit */ + linux_regs->flags &= ~TF_MASK; + atomic_set(&kgdb_cpu_doing_single_step, -1); + + /* set the trace bit if we're stepping */ + if (remcomInBuffer[0] == 's') { + linux_regs->flags |= TF_MASK; + kgdb_single_step = 1; + if (kgdb_contthread) { + atomic_set(&kgdb_cpu_doing_single_step, + raw_smp_processor_id()); + } + } + + return 0; + } + + /* this means that we do not want to exit from the handler: */ + return -1; +} + +static inline int +single_step_cont(struct pt_regs *regs, struct die_args *args) +{ + /* + * Single step exception from kernel space to user space so + * eat the exception and continue the process: + */ + printk(KERN_ERR "KGDB: trap/step from kernel to user space, " + "resuming...\n"); + kgdb_arch_handle_exception(args->trapnr, args->signr, + args->err, "c", "", regs); + + return NOTIFY_STOP; +} + +static int __kgdb_notify(struct die_args *args, unsigned long cmd) +{ + struct pt_regs *regs = args->regs; + + switch (cmd) { + case DIE_NMI: + if (atomic_read(&kgdb_active) != -1) { + /* KGDB CPU roundup */ + kgdb_nmicallback(raw_smp_processor_id(), regs); + return NOTIFY_STOP; + } + return NOTIFY_DONE; + + case DIE_NMI_IPI: + if (atomic_read(&kgdb_active) != -1) { + /* KGDB CPU roundup: */ + if (kgdb_nmicallback(raw_smp_processor_id(), regs)) + return NOTIFY_DONE; + return NOTIFY_STOP; + } + return NOTIFY_DONE; + + case DIE_NMIWATCHDOG: + if (atomic_read(&kgdb_active) != -1) { + /* KGDB CPU roundup: */ + kgdb_nmicallback(raw_smp_processor_id(), regs); + return NOTIFY_STOP; + } + /* Enter debugger: */ + break; + + case DIE_DEBUG: + if (atomic_read(&kgdb_cpu_doing_single_step) == + raw_smp_processor_id() && + user_mode(regs)) + return single_step_cont(regs, args); + /* fall through */ + default: + if (user_mode(regs)) + return NOTIFY_DONE; + } + + if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs)) + return NOTIFY_DONE; + + return NOTIFY_STOP; +} + +static int +kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr) +{ + unsigned long flags; + int ret; + + local_irq_save(flags); + ret = __kgdb_notify(ptr, cmd); + local_irq_restore(flags); + + return ret; +} + +static struct notifier_block kgdb_notifier = { + .notifier_call = kgdb_notify, + + /* + * Lowest-prio notifier priority, we want to be notified last: + */ + .priority = -INT_MAX, +}; + +/** + * kgdb_arch_init - Perform any architecture specific initalization. + * + * This function will handle the initalization of any architecture + * specific callbacks. + */ +int kgdb_arch_init(void) +{ + return register_die_notifier(&kgdb_notifier); +} + +/** + * kgdb_arch_exit - Perform any architecture specific uninitalization. + * + * This function will handle the uninitalization of any architecture + * specific callbacks, for dynamic registration and unregistration. + */ +void kgdb_arch_exit(void) +{ + unregister_die_notifier(&kgdb_notifier); +} + +/** + * + * kgdb_skipexception - Bail out of KGDB when we've been triggered. + * @exception: Exception vector number + * @regs: Current &struct pt_regs. + * + * On some architectures we need to skip a breakpoint exception when + * it occurs after a breakpoint has been removed. + * + * Skip an int3 exception when it occurs after a breakpoint has been + * removed. Backtrack eip by 1 since the int3 would have caused it to + * increment by 1. + */ +int kgdb_skipexception(int exception, struct pt_regs *regs) +{ + if (exception == 3 && kgdb_isremovedbreak(regs->ip - 1)) { + regs->ip -= 1; + return 1; + } + return 0; +} + +unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) +{ + if (exception == 3) + return instruction_pointer(regs) - 1; + return instruction_pointer(regs); +} + +struct kgdb_arch arch_kgdb_ops = { + /* Breakpoint instruction: */ + .gdb_bpt_instr = { 0xcc }, +}; diff --git a/include/asm-x86/kgdb.h b/include/asm-x86/kgdb.h new file mode 100644 index 000000000000..484c47554f3b --- /dev/null +++ b/include/asm-x86/kgdb.h @@ -0,0 +1,81 @@ +#ifndef _ASM_KGDB_H_ +#define _ASM_KGDB_H_ + +/* + * Copyright (C) 2001-2004 Amit S. Kale + * Copyright (C) 2008 Wind River Systems, Inc. + */ + +/* + * BUFMAX defines the maximum number of characters in inbound/outbound + * buffers at least NUMREGBYTES*2 are needed for register packets + * Longer buffer is needed to list all threads + */ +#define BUFMAX 1024 + +/* + * Note that this register image is in a different order than + * the register image that Linux produces at interrupt time. + * + * Linux's register image is defined by struct pt_regs in ptrace.h. + * Just why GDB uses a different order is a historical mystery. + */ +#ifdef CONFIG_X86_32 +enum regnames { + GDB_AX, /* 0 */ + GDB_CX, /* 1 */ + GDB_DX, /* 2 */ + GDB_BX, /* 3 */ + GDB_SP, /* 4 */ + GDB_BP, /* 5 */ + GDB_SI, /* 6 */ + GDB_DI, /* 7 */ + GDB_PC, /* 8 also known as eip */ + GDB_PS, /* 9 also known as eflags */ + GDB_CS, /* 10 */ + GDB_SS, /* 11 */ + GDB_DS, /* 12 */ + GDB_ES, /* 13 */ + GDB_FS, /* 14 */ + GDB_GS, /* 15 */ +}; +#else /* ! CONFIG_X86_32 */ +enum regnames { + GDB_AX, /* 0 */ + GDB_DX, /* 1 */ + GDB_CX, /* 2 */ + GDB_BX, /* 3 */ + GDB_SI, /* 4 */ + GDB_DI, /* 5 */ + GDB_BP, /* 6 */ + GDB_SP, /* 7 */ + GDB_R8, /* 8 */ + GDB_R9, /* 9 */ + GDB_R10, /* 10 */ + GDB_R11, /* 11 */ + GDB_R12, /* 12 */ + GDB_R13, /* 13 */ + GDB_R14, /* 14 */ + GDB_R15, /* 15 */ + GDB_PC, /* 16 */ + GDB_PS, /* 17 */ +}; +#endif /* CONFIG_X86_32 */ + +/* + * Number of bytes of registers: + */ +#ifdef CONFIG_X86_32 +# define NUMREGBYTES 64 +#else +# define NUMREGBYTES ((GDB_PS+1)*8) +#endif + +static inline void arch_kgdb_breakpoint(void) +{ + asm(" int $3"); +} +#define BREAK_INSTR_SIZE 1 +#define CACHE_FLUSH_IS_SAFE 1 + +#endif /* _ASM_KGDB_H_ */ -- cgit v1.2.3 From 6cdf6e06d70dcf42314edb2c43b7c7ebc56e32e5 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 17 Apr 2008 20:05:38 +0200 Subject: kgdb: document parameters document the kgdboc module/boot parameter. Signed-off-by: Jason Wessel Signed-off-by: Jan Kiszka Signed-off-by: Ingo Molnar --- Documentation/kernel-parameters.txt | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index dafd001bf833..c3de1767edd4 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -928,6 +928,11 @@ and is between 256 and 4096 characters. It is defined in the file kstack=N [X86-32,X86-64] Print N words from the kernel stack in oops dumps. + kgdboc= [HW] kgdb over consoles. + Requires a tty driver that supports console polling. + (only serial suported for now) + Format: [,baud] + l2cr= [PPC] lapic [X86-32,APIC] Enable the local APIC even if BIOS -- cgit v1.2.3 From c191e5ad6b3fd8cc84b2b6d62c02fcd6837c8a8f Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 15 Feb 2008 14:55:52 -0600 Subject: kgdb: fix kgdboc dynamic module configuration Fix the run time configuration of kgdboc such that it does not default to 9600 baud if you use the "echo" command to configure the sysfs module paramater. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- drivers/serial/kgdboc.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/serial/kgdboc.c b/drivers/serial/kgdboc.c index 341830791608..9cf03327386a 100644 --- a/drivers/serial/kgdboc.c +++ b/drivers/serial/kgdboc.c @@ -106,7 +106,9 @@ static void kgdboc_put_char(u8 chr) static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp) { - if (strlen(kmessage) >= MAX_CONFIG_LEN) { + int len = strlen(kmessage); + + if (len >= MAX_CONFIG_LEN) { printk(KERN_ERR "kgdboc: config string too long\n"); return -ENOSPC; } @@ -125,6 +127,9 @@ static int param_set_kgdboc_var(const char *kmessage, struct kernel_param *kp) } strcpy(config, kmessage); + /* Chop out \n char as a result of echo */ + if (config[len - 1] == '\n') + config[len - 1] = '\0'; if (configured == 1) cleanup_kgdboc(); -- cgit v1.2.3 From d359752407f8916c29ad53a5c30ac73e338f2797 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 15 Feb 2008 14:55:53 -0600 Subject: kgdb: fix NMI hangs This patch fixes the hang regression with kgdb when the NMI interrupt comes in while the master core is returning from an exception. Adjust the NMI logic such that KGDB will not stop NMI exceptions from occurring by in general returning NOTIFY_DONE. It is not possible to distinguish the debug NMI sync vs the normal NMI apic interrupt so kgdb needs to catch the unknown NMI if it the debugger was previously active on one of the cpus. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- arch/x86/kernel/kgdb.c | 18 +++++++++++++++--- arch/x86/kernel/traps_32.c | 2 ++ arch/x86/kernel/traps_64.c | 2 ++ include/asm-x86/kdebug.h | 1 + 4 files changed, 20 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 37194d6374d8..5d7a21119bf8 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -41,6 +41,7 @@ #include #include #include +#include #include #include @@ -290,6 +291,8 @@ single_step_cont(struct pt_regs *regs, struct die_args *args) return NOTIFY_STOP; } +static int was_in_debug_nmi[NR_CPUS]; + static int __kgdb_notify(struct die_args *args, unsigned long cmd) { struct pt_regs *regs = args->regs; @@ -299,15 +302,24 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd) if (atomic_read(&kgdb_active) != -1) { /* KGDB CPU roundup */ kgdb_nmicallback(raw_smp_processor_id(), regs); + was_in_debug_nmi[raw_smp_processor_id()] = 1; + touch_nmi_watchdog(); return NOTIFY_STOP; } return NOTIFY_DONE; case DIE_NMI_IPI: if (atomic_read(&kgdb_active) != -1) { - /* KGDB CPU roundup: */ - if (kgdb_nmicallback(raw_smp_processor_id(), regs)) - return NOTIFY_DONE; + /* KGDB CPU roundup */ + kgdb_nmicallback(raw_smp_processor_id(), regs); + was_in_debug_nmi[raw_smp_processor_id()] = 1; + touch_nmi_watchdog(); + } + return NOTIFY_DONE; + + case DIE_NMIUNKNOWN: + if (was_in_debug_nmi[raw_smp_processor_id()]) { + was_in_debug_nmi[raw_smp_processor_id()] = 0; return NOTIFY_STOP; } return NOTIFY_DONE; diff --git a/arch/x86/kernel/traps_32.c b/arch/x86/kernel/traps_32.c index b22c01e05a18..c5421f30d678 100644 --- a/arch/x86/kernel/traps_32.c +++ b/arch/x86/kernel/traps_32.c @@ -708,6 +708,8 @@ io_check_error(unsigned char reason, struct pt_regs * regs) static __kprobes void unknown_nmi_error(unsigned char reason, struct pt_regs * regs) { + if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP) + return; #ifdef CONFIG_MCA /* Might actually be able to figure out what the guilty party * is. */ diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c index 045466681911..055b1650c69d 100644 --- a/arch/x86/kernel/traps_64.c +++ b/arch/x86/kernel/traps_64.c @@ -806,6 +806,8 @@ io_check_error(unsigned char reason, struct pt_regs * regs) static __kprobes void unknown_nmi_error(unsigned char reason, struct pt_regs * regs) { + if (notify_die(DIE_NMIUNKNOWN, "nmi", regs, reason, 2, SIGINT) == NOTIFY_STOP) + return; printk(KERN_EMERG "Uhhuh. NMI received for unknown reason %02x.\n", reason); printk(KERN_EMERG "Do you have a strange power saving mode enabled?\n"); diff --git a/include/asm-x86/kdebug.h b/include/asm-x86/kdebug.h index 99dcbafa1511..35231240ebdc 100644 --- a/include/asm-x86/kdebug.h +++ b/include/asm-x86/kdebug.h @@ -20,6 +20,7 @@ enum die_val { DIE_CALL, DIE_NMI_IPI, DIE_PAGE_FAULT, + DIE_NMIUNKNOWN, }; extern void printk_address(unsigned long address, int reliable); -- cgit v1.2.3 From 7c3078b637882303b1dcf6a16229d0e35f6b60a5 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 15 Feb 2008 14:55:54 -0600 Subject: kgdb: clocksource watchdog In order to not trip the clocksource watchdog, kgdb must touch the clocksource watchdog on the return to normal system run state. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- include/linux/clocksource.h | 1 + kernel/kgdb.c | 4 ++++ kernel/time/clocksource.c | 12 ++++++++++++ 3 files changed, 17 insertions(+) diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h index 85778a4b1209..35094479ca55 100644 --- a/include/linux/clocksource.h +++ b/include/linux/clocksource.h @@ -216,6 +216,7 @@ static inline void clocksource_calculate_interval(struct clocksource *c, /* used to install a new clocksource */ extern int clocksource_register(struct clocksource*); extern void clocksource_unregister(struct clocksource*); +extern void clocksource_touch_watchdog(void); extern struct clocksource* clocksource_get_next(void); extern void clocksource_change_rating(struct clocksource *cs, int rating); extern void clocksource_resume(void); diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 017ee782bc08..e3f603740425 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -28,6 +28,7 @@ * kind, whether express or implied. */ #include +#include #include #include #include @@ -574,6 +575,7 @@ static void kgdb_wait(struct pt_regs *regs) /* Signal the primary CPU that we are done: */ atomic_set(&cpu_in_kgdb[cpu], 0); + clocksource_touch_watchdog(); local_irq_restore(flags); } #endif @@ -1396,6 +1398,7 @@ acquirelock: atomic_read(&kgdb_cpu_doing_single_step) != cpu) { atomic_set(&kgdb_active, -1); + clocksource_touch_watchdog(); local_irq_restore(flags); goto acquirelock; @@ -1487,6 +1490,7 @@ acquirelock: kgdb_restore: /* Free kgdb_active */ atomic_set(&kgdb_active, -1); + clocksource_touch_watchdog(); local_irq_restore(flags); return error; diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c index 7f60097d443a..f61402b1f2d0 100644 --- a/kernel/time/clocksource.c +++ b/kernel/time/clocksource.c @@ -221,6 +221,18 @@ void clocksource_resume(void) spin_unlock_irqrestore(&clocksource_lock, flags); } +/** + * clocksource_touch_watchdog - Update watchdog + * + * Update the watchdog after exception contexts such as kgdb so as not + * to incorrectly trip the watchdog. + * + */ +void clocksource_touch_watchdog(void) +{ + clocksource_resume_watchdog(); +} + /** * clocksource_get_next - Returns the selected clocksource * -- cgit v1.2.3 From 67baf94cd260dc37504dbd15ba3faa2d8cf8a444 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 15 Feb 2008 14:55:55 -0600 Subject: kgdb: print breakpoint removed on exception If kgdb does remove a breakpoint that had a problem on the recursion check, it should also print the address of the breakpoint. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- kernel/kgdb.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/kernel/kgdb.c b/kernel/kgdb.c index e3f603740425..319c08c92ee2 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -1327,7 +1327,8 @@ static int kgdb_reenter_check(struct kgdb_state *ks) exception_level = 0; kgdb_skipexception(ks->ex_vector, ks->linux_regs); kgdb_activate_sw_breakpoints(); - printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed\n"); + printk(KERN_CRIT "KGDB: re-enter error: breakpoint removed %lx\n", + addr); WARN_ON_ONCE(1); return 1; -- cgit v1.2.3 From 64e9ee3095b61d0300ea548216a57d2536611309 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 15 Feb 2008 14:55:56 -0600 Subject: kgdb: add x86 HW breakpoints Add HW breakpoints into the arch specific portion of x86 kgdb. In the current x86 kernel.org kernels HW breakpoints are changed out in lazy fashion because there is no infrastructure around changing them when changing to a kernel task or entering the kernel mode via a system call. This lazy approach means that if a user process uses HW breakpoints the kgdb will loose out. This is an acceptable trade off because the developer debugging the kernel is assumed to know what is going on system wide and would be aware of this trade off. There is a minor bug fix to the kgdb core so as to correctly call the hw breakpoint functions with a valid value from the enum. There is also a minor change to the x86_64 startup code when using early HW breakpoints. When the debugger is connected, the cpu startup code must not zero out the HW breakpoint registers or you cannot hit the breakpoints you are interested in, in the first place. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- arch/x86/kernel/kgdb.c | 138 ++++++++++++++++++++++++++++++++++++++++++++++ arch/x86/kernel/setup64.c | 16 ++++++ kernel/kgdb.c | 4 +- 3 files changed, 156 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 5d7a21119bf8..7d651adcb222 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -182,6 +182,122 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs) #endif } +static struct hw_breakpoint { + unsigned enabled; + unsigned type; + unsigned len; + unsigned long addr; +} breakinfo[4]; + +static void kgdb_correct_hw_break(void) +{ + unsigned long dr7; + int correctit = 0; + int breakbit; + int breakno; + + get_debugreg(dr7, 7); + for (breakno = 0; breakno < 4; breakno++) { + breakbit = 2 << (breakno << 1); + if (!(dr7 & breakbit) && breakinfo[breakno].enabled) { + correctit = 1; + dr7 |= breakbit; + dr7 &= ~(0xf0000 << (breakno << 2)); + dr7 |= ((breakinfo[breakno].len << 2) | + breakinfo[breakno].type) << + ((breakno << 2) + 16); + if (breakno >= 0 && breakno <= 3) + set_debugreg(breakinfo[breakno].addr, breakno); + + } else { + if ((dr7 & breakbit) && !breakinfo[breakno].enabled) { + correctit = 1; + dr7 &= ~breakbit; + dr7 &= ~(0xf0000 << (breakno << 2)); + } + } + } + if (correctit) + set_debugreg(dr7, 7); +} + +static int +kgdb_remove_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) +{ + int i; + + for (i = 0; i < 4; i++) + if (breakinfo[i].addr == addr && breakinfo[i].enabled) + break; + if (i == 4) + return -1; + + breakinfo[i].enabled = 0; + + return 0; +} + +static void kgdb_remove_all_hw_break(void) +{ + int i; + + for (i = 0; i < 4; i++) + memset(&breakinfo[i], 0, sizeof(struct hw_breakpoint)); +} + +static int +kgdb_set_hw_break(unsigned long addr, int len, enum kgdb_bptype bptype) +{ + unsigned type; + int i; + + for (i = 0; i < 4; i++) + if (!breakinfo[i].enabled) + break; + if (i == 4) + return -1; + + switch (bptype) { + case BP_HARDWARE_BREAKPOINT: + type = 0; + len = 1; + break; + case BP_WRITE_WATCHPOINT: + type = 1; + break; + case BP_ACCESS_WATCHPOINT: + type = 3; + break; + default: + return -1; + } + + if (len == 1 || len == 2 || len == 4) + breakinfo[i].len = len - 1; + else + return -1; + + breakinfo[i].enabled = 1; + breakinfo[i].addr = addr; + breakinfo[i].type = type; + + return 0; +} + +/** + * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. + * @regs: Current &struct pt_regs. + * + * This function will be called if the particular architecture must + * disable hardware debugging while it is processing gdb packets or + * handling exception. + */ +void kgdb_disable_hw_debug(struct pt_regs *regs) +{ + /* Disable hardware debugging while we are in kgdb: */ + set_debugreg(0UL, 7); +} + /** * kgdb_post_primary_code - Save error vector/code numbers. * @regs: Original pt_regs. @@ -243,6 +359,7 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, struct pt_regs *linux_regs) { unsigned long addr; + unsigned long dr6; char *ptr; int newPC; @@ -269,6 +386,22 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, } } + get_debugreg(dr6, 6); + if (!(dr6 & 0x4000)) { + int breakno; + + for (breakno = 0; breakno < 4; breakno++) { + if (dr6 & (1 << breakno) && + breakinfo[breakno].type == 0) { + /* Set restore flag: */ + linux_regs->flags |= X86_EFLAGS_RF; + break; + } + } + } + set_debugreg(0UL, 6); + kgdb_correct_hw_break(); + return 0; } @@ -426,4 +559,9 @@ unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs) struct kgdb_arch arch_kgdb_ops = { /* Breakpoint instruction: */ .gdb_bpt_instr = { 0xcc }, + .flags = KGDB_HW_BREAKPOINT, + .set_hw_breakpoint = kgdb_set_hw_break, + .remove_hw_breakpoint = kgdb_remove_hw_break, + .remove_all_hw_break = kgdb_remove_all_hw_break, + .correct_hw_break = kgdb_correct_hw_break, }; diff --git a/arch/x86/kernel/setup64.c b/arch/x86/kernel/setup64.c index e24c45677094..143aa78c566b 100644 --- a/arch/x86/kernel/setup64.c +++ b/arch/x86/kernel/setup64.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include #include @@ -327,6 +328,17 @@ void __cpuinit cpu_init (void) load_TR_desc(); load_LDT(&init_mm.context); +#ifdef CONFIG_KGDB + /* + * If the kgdb is connected no debug regs should be altered. This + * is only applicable when KGDB and a KGDB I/O module are built + * into the kernel and you are using early debugging with + * kgdbwait. KGDB will control the kernel HW breakpoint registers. + */ + if (kgdb_connected && arch_kgdb_ops.correct_hw_break) + arch_kgdb_ops.correct_hw_break(); + else { +#endif /* * Clear all 6 debug registers: */ @@ -337,6 +349,10 @@ void __cpuinit cpu_init (void) set_debugreg(0UL, 3); set_debugreg(0UL, 6); set_debugreg(0UL, 7); +#ifdef CONFIG_KGDB + /* If the kgdb is connected no debug regs should be altered. */ + } +#endif fpu_init(); diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 319c08c92ee2..68aea78407e4 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -1139,10 +1139,10 @@ static void gdb_cmd_break(struct kgdb_state *ks) error = kgdb_remove_sw_break(addr); else if (remcom_in_buffer[0] == 'Z') error = arch_kgdb_ops.set_hw_breakpoint(addr, - (int)length, *bpt_type); + (int)length, *bpt_type - '0'); else if (remcom_in_buffer[0] == 'z') error = arch_kgdb_ops.remove_hw_breakpoint(addr, - (int) length, *bpt_type); + (int) length, *bpt_type - '0'); if (error == 0) strcpy(remcom_out_buffer, "OK"); -- cgit v1.2.3 From b4b8ac524d9b6ed7229017145afa1d7afbea4a48 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Wed, 20 Feb 2008 13:33:38 -0600 Subject: kgdb: fix optional arch functions and probe_kernel_* Fix two regressions dealing with the kgdb core. 1) kgdb_skipexception and kgdb_post_primary_code are optional functions that are only required on archs that need special exception fixups. 2) The kernel address space scope must be set on any probe_kernel_* function or archs such as ARCH=arm will not allow access to the kernel memory space. As an example, it is required to allow the full kernel address space is when you the kernel debugger to inspect a system call. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- kernel/kgdb.c | 11 +++++++++++ mm/maccess.c | 6 ++++++ 2 files changed, 17 insertions(+) diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 68aea78407e4..31425e0fbf20 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -200,6 +200,17 @@ int __weak kgdb_arch_init(void) return 0; } +int __weak kgdb_skipexception(int exception, struct pt_regs *regs) +{ + return 0; +} + +void __weak +kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code) +{ + return; +} + /** * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. * @regs: Current &struct pt_regs. diff --git a/mm/maccess.c b/mm/maccess.c index 24f81b971403..ac40796cfb15 100644 --- a/mm/maccess.c +++ b/mm/maccess.c @@ -17,11 +17,14 @@ long probe_kernel_read(void *dst, void *src, size_t size) { long ret; + mm_segment_t old_fs = get_fs(); + set_fs(KERNEL_DS); pagefault_disable(); ret = __copy_from_user_inatomic(dst, (__force const void __user *)src, size); pagefault_enable(); + set_fs(old_fs); return ret ? -EFAULT : 0; } @@ -39,10 +42,13 @@ EXPORT_SYMBOL_GPL(probe_kernel_read); long probe_kernel_write(void *dst, void *src, size_t size) { long ret; + mm_segment_t old_fs = get_fs(); + set_fs(KERNEL_DS); pagefault_disable(); ret = __copy_to_user_inatomic((__force void __user *)dst, src, size); pagefault_enable(); + set_fs(old_fs); return ret ? -EFAULT : 0; } -- cgit v1.2.3 From 84b5ae15216aa3ea0314f395536ef9829af21e14 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Wed, 20 Feb 2008 13:33:39 -0600 Subject: kgdb: kgdboc pl011 I/O module Implement the serial polling hooks for the pl011 uart for use with kgdboc. This patch was specifically tested on the ARM Versatile AB reference platform. [ mingo@elte.hu: minor cleanups. ] Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar Signed-off-by: Thomas Gleixner --- drivers/serial/amba-pl011.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/drivers/serial/amba-pl011.c b/drivers/serial/amba-pl011.c index 40604a092921..08adc1de4a79 100644 --- a/drivers/serial/amba-pl011.c +++ b/drivers/serial/amba-pl011.c @@ -314,6 +314,32 @@ static void pl011_break_ctl(struct uart_port *port, int break_state) spin_unlock_irqrestore(&uap->port.lock, flags); } +#ifdef CONFIG_CONSOLE_POLL +static int pl010_get_poll_char(struct uart_port *port) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + unsigned int status; + + do { + status = readw(uap->port.membase + UART01x_FR); + } while (status & UART01x_FR_RXFE); + + return readw(uap->port.membase + UART01x_DR); +} + +static void pl010_put_poll_char(struct uart_port *port, + unsigned char ch) +{ + struct uart_amba_port *uap = (struct uart_amba_port *)port; + + while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) + barrier(); + + writew(ch, uap->port.membase + UART01x_DR); +} + +#endif /* CONFIG_CONSOLE_POLL */ + static int pl011_startup(struct uart_port *port) { struct uart_amba_port *uap = (struct uart_amba_port *)port; @@ -572,6 +598,10 @@ static struct uart_ops amba_pl011_pops = { .request_port = pl010_request_port, .config_port = pl010_config_port, .verify_port = pl010_verify_port, +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = pl010_get_poll_char, + .poll_put_char = pl010_put_poll_char, +#endif }; static struct uart_amba_port *amba_ports[UART_NR]; -- cgit v1.2.3 From 737a460f21febe551ff1d2299b63bae9b154078f Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 7 Mar 2008 16:34:16 -0600 Subject: kgdb: fix several kgdb regressions kgdb core fixes: - Check to see that mm->mmap_cache is not null before calling flush_cache_range(), else on arch=ARM it will cause a fatal fault. - Breakpoints should only be restored if they are in the BP_ACTIVE state. - Fix a typo in comments to "kgdb_register_io_module" x86 kgdb fixes: - Fix the x86 arch handler such that on a kill or detach that the appropriate cleanup on the single stepping flags gets run. - Add in the DIE_NMIWATCHDOG call for x86_64 - Touch the nmi watchdog before returning the system to normal operation after performing any kind of kgdb operation, else the possibility exists to trigger the watchdog. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- arch/x86/kernel/kgdb.c | 4 ++++ arch/x86/kernel/traps_64.c | 7 ++++++- kernel/kgdb.c | 14 ++++++++------ 3 files changed, 18 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 7d651adcb222..8c7e555f6d39 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -370,6 +370,8 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code, ptr = &remcomInBuffer[1]; if (kgdb_hex2long(&ptr, &addr)) linux_regs->ip = addr; + case 'D': + case 'k': newPC = linux_regs->ip; /* clear the trace bit */ @@ -480,6 +482,8 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd) if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs)) return NOTIFY_DONE; + /* Must touch watchdog before return to normal operation */ + touch_nmi_watchdog(); return NOTIFY_STOP; } diff --git a/arch/x86/kernel/traps_64.c b/arch/x86/kernel/traps_64.c index 055b1650c69d..4e073320e70a 100644 --- a/arch/x86/kernel/traps_64.c +++ b/arch/x86/kernel/traps_64.c @@ -600,8 +600,13 @@ void die(const char * str, struct pt_regs * regs, long err) void __kprobes die_nmi(char *str, struct pt_regs *regs, int do_panic) { - unsigned long flags = oops_begin(); + unsigned long flags; + + if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == + NOTIFY_STOP) + return; + flags = oops_begin(); /* * We are in trouble anyway, lets at least try * to get a message out. diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 31425e0fbf20..85b7e5b934a7 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -600,7 +600,7 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) if (!CACHE_FLUSH_IS_SAFE) return; - if (current->mm) { + if (current->mm && current->mm->mmap_cache) { flush_cache_range(current->mm->mmap_cache, addr, addr + BREAK_INSTR_SIZE); } else { @@ -729,14 +729,16 @@ int remove_all_break(void) /* Clear memory breakpoints. */ for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { - if (kgdb_break[i].state != BP_SET) - continue; + if (kgdb_break[i].state != BP_ACTIVE) + goto setundefined; addr = kgdb_break[i].bpt_addr; error = kgdb_arch_remove_breakpoint(addr, kgdb_break[i].saved_instr); if (error) - return error; - kgdb_break[i].state = BP_REMOVED; + printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n", + addr); +setundefined: + kgdb_break[i].state = BP_UNDEFINED; } /* Clear hardware breakpoints. */ @@ -1605,7 +1607,7 @@ static void kgdb_initial_breakpoint(void) } /** - * kkgdb_register_io_module - register KGDB IO module + * kgdb_register_io_module - register KGDB IO module * @new_kgdb_io_ops: the io ops vector * * Register it with the KGDB core. -- cgit v1.2.3 From e8d31c204e36e019b9134f2a11926cac0fcf9b19 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Fri, 7 Mar 2008 16:34:17 -0600 Subject: kgdb: add kgdb internal test suite This patch adds regression tests for testing the kgdb core and arch specific implementation. The kgdb test suite is designed to be built into the kernel and not as a module because it uses a number of low level kernel and kgdb primitives which should not be exported externally. The kgdb test suite is designed as a KGDB I/O module which simulates the communications that a debugger would have with kgdb. The tests are broken up in to a line by line and referenced here as a "get" which is kgdb requesting input and "put" which is kgdb sending a response. The kgdb suite can be invoked from the kernel command line arguments system or executed dynamically at run time. The test suite uses the variable "kgdbts" to obtain the information about which tests to run and to configure the verbosity level. The following are the various characters you can use with the kgdbts= line: When using the "kgdbts=" you only choose one of the following core test types: A = Run all the core tests silently V1 = Run all the core tests with minimal output V2 = Run all the core tests in debug mode You can also specify optional tests: N## = Go to sleep with interrupts of for ## seconds to test the HW NMI watchdog F## = Break at do_fork for ## iterations S## = Break at sys_open for ## iterations NOTE: that the do_fork and sys_open tests are mutually exclusive. To invoke the kgdb test suite from boot you use a kernel start argument as follows: kgdbts=V1 kgdbwait Or if you wanted to perform the NMI test for 6 seconds and do_fork test for 100 forks, you could use: kgdbts=V1N6F100 kgdbwait The test suite can also be invoked at run time with: echo kgdbts=V1N6F100 > /sys/module/kgdbts/parameters/kgdbts Or as another example: echo kgdbts=V2 > /sys/module/kgdbts/parameters/kgdbts When developing a new kgdb arch specific implementation or using these tests for the purpose of regression testing, several invocations are required. 1) Boot with the test suite enabled by using the kernel arguments "kgdbts=V1F100 kgdbwait" ## If kgdb arch specific implementation has NMI use "kgdbts=V1N6F100 2) After the system boot run the basic test. echo kgdbts=V1 > /sys/module/kgdbts/parameters/kgdbts 3) Run the concurrency tests. It is best to use n+1 while loops where n is the number of cpus you have in your system. The example below uses only two loops. ## This tests break points on sys_open while [ 1 ] ; do find / > /dev/null 2>&1 ; done & while [ 1 ] ; do find / > /dev/null 2>&1 ; done & echo kgdbts=V1S10000 > /sys/module/kgdbts/parameters/kgdbts fg # and hit control-c fg # and hit control-c ## This tests break points on do_fork while [ 1 ] ; do date > /dev/null ; done & while [ 1 ] ; do date > /dev/null ; done & echo kgdbts=V1F1000 > /sys/module/kgdbts/parameters/kgdbts fg # and hit control-c Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- drivers/misc/Makefile | 1 + drivers/misc/kgdbts.c | 1083 +++++++++++++++++++++++++++++++++++++++++++++++++ lib/Kconfig.kgdb | 13 + 3 files changed, 1097 insertions(+) create mode 100644 drivers/misc/kgdbts.c diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index 3b12f5da8562..bbc69fdd1b9d 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -22,3 +22,4 @@ obj-$(CONFIG_FUJITSU_LAPTOP) += fujitsu-laptop.o obj-$(CONFIG_EEPROM_93CX6) += eeprom_93cx6.o obj-$(CONFIG_INTEL_MENLOW) += intel_menlow.o obj-$(CONFIG_ENCLOSURE_SERVICES) += enclosure.o +obj-$(CONFIG_KGDB_TESTS) += kgdbts.o diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c new file mode 100644 index 000000000000..cbc4822b5847 --- /dev/null +++ b/drivers/misc/kgdbts.c @@ -0,0 +1,1083 @@ +/* + * kgdbts is a test suite for kgdb for the sole purpose of validating + * that key pieces of the kgdb internals are working properly such as + * HW/SW breakpoints, single stepping, and NMI. + * + * Created by: Jason Wessel + * + * Copyright (c) 2008 Wind River Systems, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + * See the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ +/* Information about the kgdb test suite. + * ------------------------------------- + * + * The kgdb test suite is designed as a KGDB I/O module which + * simulates the communications that a debugger would have with kgdb. + * The tests are broken up in to a line by line and referenced here as + * a "get" which is kgdb requesting input and "put" which is kgdb + * sending a response. + * + * The kgdb suite can be invoked from the kernel command line + * arguments system or executed dynamically at run time. The test + * suite uses the variable "kgdbts" to obtain the information about + * which tests to run and to configure the verbosity level. The + * following are the various characters you can use with the kgdbts= + * line: + * + * When using the "kgdbts=" you only choose one of the following core + * test types: + * A = Run all the core tests silently + * V1 = Run all the core tests with minimal output + * V2 = Run all the core tests in debug mode + * + * You can also specify optional tests: + * N## = Go to sleep with interrupts of for ## seconds + * to test the HW NMI watchdog + * F## = Break at do_fork for ## iterations + * S## = Break at sys_open for ## iterations + * + * NOTE: that the do_fork and sys_open tests are mutually exclusive. + * + * To invoke the kgdb test suite from boot you use a kernel start + * argument as follows: + * kgdbts=V1 kgdbwait + * Or if you wanted to perform the NMI test for 6 seconds and do_fork + * test for 100 forks, you could use: + * kgdbts=V1N6F100 kgdbwait + * + * The test suite can also be invoked at run time with: + * echo kgdbts=V1N6F100 > /sys/module/kgdbts/parameters/kgdbts + * Or as another example: + * echo kgdbts=V2 > /sys/module/kgdbts/parameters/kgdbts + * + * When developing a new kgdb arch specific implementation or + * using these tests for the purpose of regression testing, + * several invocations are required. + * + * 1) Boot with the test suite enabled by using the kernel arguments + * "kgdbts=V1F100 kgdbwait" + * ## If kgdb arch specific implementation has NMI use + * "kgdbts=V1N6F100 + * + * 2) After the system boot run the basic test. + * echo kgdbts=V1 > /sys/module/kgdbts/parameters/kgdbts + * + * 3) Run the concurrency tests. It is best to use n+1 + * while loops where n is the number of cpus you have + * in your system. The example below uses only two + * loops. + * + * ## This tests break points on sys_open + * while [ 1 ] ; do find / > /dev/null 2>&1 ; done & + * while [ 1 ] ; do find / > /dev/null 2>&1 ; done & + * echo kgdbts=V1S10000 > /sys/module/kgdbts/parameters/kgdbts + * fg # and hit control-c + * fg # and hit control-c + * ## This tests break points on do_fork + * while [ 1 ] ; do date > /dev/null ; done & + * while [ 1 ] ; do date > /dev/null ; done & + * echo kgdbts=V1F1000 > /sys/module/kgdbts/parameters/kgdbts + * fg # and hit control-c + * + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#define v1printk(a...) do { \ + if (verbose) \ + printk(KERN_INFO a); \ + } while (0) +#define v2printk(a...) do { \ + if (verbose > 1) \ + printk(KERN_INFO a); \ + touch_nmi_watchdog(); \ + } while (0) +#define MAX_CONFIG_LEN 40 + +static const char hexchars[] = "0123456789abcdef"; +static struct kgdb_io kgdbts_io_ops; +static char get_buf[BUFMAX]; +static int get_buf_cnt; +static char put_buf[BUFMAX]; +static int put_buf_cnt; +static char scratch_buf[BUFMAX]; +static int verbose; +static int repeat_test; +static int test_complete; +static int send_ack; +static int final_ack; +static int hw_break_val; +static int hw_break_val2; +#if defined(CONFIG_ARM) || defined(CONFIG_MIPS) +static int arch_needs_sstep_emulation = 1; +#else +static int arch_needs_sstep_emulation; +#endif +static unsigned long sstep_addr; +static int sstep_state; + +/* Storage for the registers, in GDB format. */ +static unsigned long kgdbts_gdb_regs[(NUMREGBYTES + + sizeof(unsigned long) - 1) / + sizeof(unsigned long)]; +static struct pt_regs kgdbts_regs; + +/* -1 = init not run yet, 0 = unconfigured, 1 = configured. */ +static int configured = -1; + +static char config[MAX_CONFIG_LEN]; +static struct kparam_string kps = { + .string = config, + .maxlen = MAX_CONFIG_LEN, +}; + +static void fill_get_buf(char *buf); + +struct test_struct { + char *get; + char *put; + void (*get_handler)(char *); + int (*put_handler)(char *, char *); +}; + +struct test_state { + char *name; + struct test_struct *tst; + int idx; + int (*run_test) (int, int); + int (*validate_put) (char *); +}; + +static struct test_state ts; + +static int kgdbts_unreg_thread(void *ptr) +{ + /* Wait until the tests are complete and then ungresiter the I/O + * driver. + */ + while (!final_ack) + msleep_interruptible(1500); + + if (configured) + kgdb_unregister_io_module(&kgdbts_io_ops); + configured = 0; + + return 0; +} + +/* This is noinline such that it can be used for a single location to + * place a breakpoint + */ +static noinline void kgdbts_break_test(void) +{ + v2printk("kgdbts: breakpoint complete\n"); +} + +/* Lookup symbol info in the kernel */ +static unsigned long lookup_addr(char *arg) +{ + unsigned long addr = 0; + + if (!strcmp(arg, "kgdbts_break_test")) + addr = (unsigned long)kgdbts_break_test; + else if (!strcmp(arg, "sys_open")) + addr = (unsigned long)sys_open; + else if (!strcmp(arg, "do_fork")) + addr = (unsigned long)do_fork; + else if (!strcmp(arg, "hw_break_val")) + addr = (unsigned long)&hw_break_val; + return addr; +} + +static void break_helper(char *bp_type, char *arg, unsigned long vaddr) +{ + unsigned long addr; + + if (arg) + addr = lookup_addr(arg); + else + addr = vaddr; + + sprintf(scratch_buf, "%s,%lx,%i", bp_type, addr, + BREAK_INSTR_SIZE); + fill_get_buf(scratch_buf); +} + +static void sw_break(char *arg) +{ + break_helper("Z0", arg, 0); +} + +static void sw_rem_break(char *arg) +{ + break_helper("z0", arg, 0); +} + +static void hw_break(char *arg) +{ + break_helper("Z1", arg, 0); +} + +static void hw_rem_break(char *arg) +{ + break_helper("z1", arg, 0); +} + +static void hw_write_break(char *arg) +{ + break_helper("Z2", arg, 0); +} + +static void hw_rem_write_break(char *arg) +{ + break_helper("z2", arg, 0); +} + +static void hw_access_break(char *arg) +{ + break_helper("Z4", arg, 0); +} + +static void hw_rem_access_break(char *arg) +{ + break_helper("z4", arg, 0); +} + +static void hw_break_val_access(void) +{ + hw_break_val2 = hw_break_val; +} + +static void hw_break_val_write(void) +{ + hw_break_val++; +} + +static int check_and_rewind_pc(char *put_str, char *arg) +{ + unsigned long addr = lookup_addr(arg); + int offset = 0; + + kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs, + NUMREGBYTES); + gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs); + v2printk("Stopped at IP: %lx\n", instruction_pointer(&kgdbts_regs)); +#ifdef CONFIG_X86 + /* On x86 a breakpoint stop requires it to be decremented */ + if (addr + 1 == kgdbts_regs.ip) + offset = -1; +#endif + if (strcmp(arg, "silent") && + instruction_pointer(&kgdbts_regs) + offset != addr) { + printk(KERN_ERR "kgdbts: BP mismatch %lx expected %lx\n", + instruction_pointer(&kgdbts_regs) + offset, addr); + return 1; + } +#ifdef CONFIG_X86 + /* On x86 adjust the instruction pointer if needed */ + kgdbts_regs.ip += offset; +#endif + return 0; +} + +static int check_single_step(char *put_str, char *arg) +{ + unsigned long addr = lookup_addr(arg); + /* + * From an arch indepent point of view the instruction pointer + * should be on a different instruction + */ + kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs, + NUMREGBYTES); + gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs); + v2printk("Singlestep stopped at IP: %lx\n", + instruction_pointer(&kgdbts_regs)); + if (instruction_pointer(&kgdbts_regs) == addr) { + printk(KERN_ERR "kgdbts: SingleStep failed at %lx\n", + instruction_pointer(&kgdbts_regs)); + return 1; + } + + return 0; +} + +static void write_regs(char *arg) +{ + memset(scratch_buf, 0, sizeof(scratch_buf)); + scratch_buf[0] = 'G'; + pt_regs_to_gdb_regs(kgdbts_gdb_regs, &kgdbts_regs); + kgdb_mem2hex((char *)kgdbts_gdb_regs, &scratch_buf[1], NUMREGBYTES); + fill_get_buf(scratch_buf); +} + +static void skip_back_repeat_test(char *arg) +{ + int go_back = simple_strtol(arg, NULL, 10); + + repeat_test--; + if (repeat_test <= 0) + ts.idx++; + else + ts.idx -= go_back; + fill_get_buf(ts.tst[ts.idx].get); +} + +static int got_break(char *put_str, char *arg) +{ + test_complete = 1; + if (!strncmp(put_str+1, arg, 2)) { + if (!strncmp(arg, "T0", 2)) + test_complete = 2; + return 0; + } + return 1; +} + +static void emul_sstep_get(char *arg) +{ + if (!arch_needs_sstep_emulation) { + fill_get_buf(arg); + return; + } + switch (sstep_state) { + case 0: + v2printk("Emulate single step\n"); + /* Start by looking at the current PC */ + fill_get_buf("g"); + break; + case 1: + /* set breakpoint */ + break_helper("Z0", 0, sstep_addr); + break; + case 2: + /* Continue */ + fill_get_buf("c"); + break; + case 3: + /* Clear breakpoint */ + break_helper("z0", 0, sstep_addr); + break; + default: + printk(KERN_ERR "kgdbts: ERROR failed sstep get emulation\n"); + } + sstep_state++; +} + +static int emul_sstep_put(char *put_str, char *arg) +{ + if (!arch_needs_sstep_emulation) { + if (!strncmp(put_str+1, arg, 2)) + return 0; + return 1; + } + switch (sstep_state) { + case 1: + /* validate the "g" packet to get the IP */ + kgdb_hex2mem(&put_str[1], (char *)kgdbts_gdb_regs, + NUMREGBYTES); + gdb_regs_to_pt_regs(kgdbts_gdb_regs, &kgdbts_regs); + v2printk("Stopped at IP: %lx\n", + instruction_pointer(&kgdbts_regs)); + /* Want to stop at IP + break instruction size by default */ + sstep_addr = instruction_pointer(&kgdbts_regs) + + BREAK_INSTR_SIZE; + break; + case 2: + if (strncmp(put_str, "$OK", 3)) { + printk(KERN_ERR "kgdbts: failed sstep break set\n"); + return 1; + } + break; + case 3: + if (strncmp(put_str, "$T0", 3)) { + printk(KERN_ERR "kgdbts: failed continue sstep\n"); + return 1; + } + break; + case 4: + if (strncmp(put_str, "$OK", 3)) { + printk(KERN_ERR "kgdbts: failed sstep break unset\n"); + return 1; + } + /* Single step is complete so continue on! */ + sstep_state = 0; + return 0; + default: + printk(KERN_ERR "kgdbts: ERROR failed sstep put emulation\n"); + } + + /* Continue on the same test line until emulation is complete */ + ts.idx--; + return 0; +} + +static int final_ack_set(char *put_str, char *arg) +{ + if (strncmp(put_str+1, arg, 2)) + return 1; + final_ack = 1; + return 0; +} +/* + * Test to plant a breakpoint and detach, which should clear out the + * breakpoint and restore the original instruction. + */ +static struct test_struct plant_and_detach_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */ + { "D", "OK" }, /* Detach */ + { "", "" }, +}; + +/* + * Simple test to write in a software breakpoint, check for the + * correct stop location and detach. + */ +static struct test_struct sw_breakpoint_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */ + { "c", "T0*", }, /* Continue */ + { "g", "kgdbts_break_test", 0, check_and_rewind_pc }, + { "write", "OK", write_regs }, + { "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */ + { "D", "OK" }, /* Detach */ + { "D", "OK", 0, got_break }, /* If the test worked we made it here */ + { "", "" }, +}; + +/* + * Test a known bad memory read location to test the fault handler and + * read bytes 1-8 at the bad address + */ +static struct test_struct bad_read_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "m0,1", "E*" }, /* read 1 byte at address 1 */ + { "m0,2", "E*" }, /* read 1 byte at address 2 */ + { "m0,3", "E*" }, /* read 1 byte at address 3 */ + { "m0,4", "E*" }, /* read 1 byte at address 4 */ + { "m0,5", "E*" }, /* read 1 byte at address 5 */ + { "m0,6", "E*" }, /* read 1 byte at address 6 */ + { "m0,7", "E*" }, /* read 1 byte at address 7 */ + { "m0,8", "E*" }, /* read 1 byte at address 8 */ + { "D", "OK" }, /* Detach which removes all breakpoints and continues */ + { "", "" }, +}; + +/* + * Test for hitting a breakpoint, remove it, single step, plant it + * again and detach. + */ +static struct test_struct singlestep_break_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */ + { "c", "T0*", }, /* Continue */ + { "g", "kgdbts_break_test", 0, check_and_rewind_pc }, + { "write", "OK", write_regs }, /* Write registers */ + { "kgdbts_break_test", "OK", sw_rem_break }, /*remove breakpoint */ + { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ + { "g", "kgdbts_break_test", 0, check_single_step }, + { "kgdbts_break_test", "OK", sw_break, }, /* set sw breakpoint */ + { "c", "T0*", }, /* Continue */ + { "g", "kgdbts_break_test", 0, check_and_rewind_pc }, + { "write", "OK", write_regs }, /* Write registers */ + { "D", "OK" }, /* Remove all breakpoints and continues */ + { "", "" }, +}; + +/* + * Test for hitting a breakpoint at do_fork for what ever the number + * of iterations required by the variable repeat_test. + */ +static struct test_struct do_fork_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "do_fork", "OK", sw_break, }, /* set sw breakpoint */ + { "c", "T0*", }, /* Continue */ + { "g", "do_fork", 0, check_and_rewind_pc }, /* check location */ + { "write", "OK", write_regs }, /* Write registers */ + { "do_fork", "OK", sw_rem_break }, /*remove breakpoint */ + { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ + { "g", "do_fork", 0, check_single_step }, + { "do_fork", "OK", sw_break, }, /* set sw breakpoint */ + { "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */ + { "D", "OK", 0, final_ack_set }, /* detach and unregister I/O */ + { "", "" }, +}; + +/* Test for hitting a breakpoint at sys_open for what ever the number + * of iterations required by the variable repeat_test. + */ +static struct test_struct sys_open_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "sys_open", "OK", sw_break, }, /* set sw breakpoint */ + { "c", "T0*", }, /* Continue */ + { "g", "sys_open", 0, check_and_rewind_pc }, /* check location */ + { "write", "OK", write_regs }, /* Write registers */ + { "sys_open", "OK", sw_rem_break }, /*remove breakpoint */ + { "s", "T0*", emul_sstep_get, emul_sstep_put }, /* Single step */ + { "g", "sys_open", 0, check_single_step }, + { "sys_open", "OK", sw_break, }, /* set sw breakpoint */ + { "7", "T0*", skip_back_repeat_test }, /* Loop based on repeat_test */ + { "D", "OK", 0, final_ack_set }, /* detach and unregister I/O */ + { "", "" }, +}; + +/* + * Test for hitting a simple hw breakpoint + */ +static struct test_struct hw_breakpoint_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "kgdbts_break_test", "OK", hw_break, }, /* set hw breakpoint */ + { "c", "T0*", }, /* Continue */ + { "g", "kgdbts_break_test", 0, check_and_rewind_pc }, + { "write", "OK", write_regs }, + { "kgdbts_break_test", "OK", hw_rem_break }, /*remove breakpoint */ + { "D", "OK" }, /* Detach */ + { "D", "OK", 0, got_break }, /* If the test worked we made it here */ + { "", "" }, +}; + +/* + * Test for hitting a hw write breakpoint + */ +static struct test_struct hw_write_break_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "hw_break_val", "OK", hw_write_break, }, /* set hw breakpoint */ + { "c", "T0*", 0, got_break }, /* Continue */ + { "g", "silent", 0, check_and_rewind_pc }, + { "write", "OK", write_regs }, + { "hw_break_val", "OK", hw_rem_write_break }, /*remove breakpoint */ + { "D", "OK" }, /* Detach */ + { "D", "OK", 0, got_break }, /* If the test worked we made it here */ + { "", "" }, +}; + +/* + * Test for hitting a hw access breakpoint + */ +static struct test_struct hw_access_break_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "hw_break_val", "OK", hw_access_break, }, /* set hw breakpoint */ + { "c", "T0*", 0, got_break }, /* Continue */ + { "g", "silent", 0, check_and_rewind_pc }, + { "write", "OK", write_regs }, + { "hw_break_val", "OK", hw_rem_access_break }, /*remove breakpoint */ + { "D", "OK" }, /* Detach */ + { "D", "OK", 0, got_break }, /* If the test worked we made it here */ + { "", "" }, +}; + +/* + * Test for hitting a hw access breakpoint + */ +static struct test_struct nmi_sleep_test[] = { + { "?", "S0*" }, /* Clear break points */ + { "c", "T0*", 0, got_break }, /* Continue */ + { "D", "OK" }, /* Detach */ + { "D", "OK", 0, got_break }, /* If the test worked we made it here */ + { "", "" }, +}; + +static void fill_get_buf(char *buf) +{ + unsigned char checksum = 0; + int count = 0; + char ch; + + strcpy(get_buf, "$"); + strcat(get_buf, buf); + while ((ch = buf[count])) { + checksum += ch; + count++; + } + strcat(get_buf, "#"); + get_buf[count + 2] = hexchars[checksum >> 4]; + get_buf[count + 3] = hexchars[checksum & 0xf]; + get_buf[count + 4] = '\0'; + v2printk("get%i: %s\n", ts.idx, get_buf); +} + +static int validate_simple_test(char *put_str) +{ + char *chk_str; + + if (ts.tst[ts.idx].put_handler) + return ts.tst[ts.idx].put_handler(put_str, + ts.tst[ts.idx].put); + + chk_str = ts.tst[ts.idx].put; + if (*put_str == '$') + put_str++; + + while (*chk_str != '\0' && *put_str != '\0') { + /* If someone does a * to match the rest of the string, allow + * it, or stop if the recieved string is complete. + */ + if (*put_str == '#' || *chk_str == '*') + return 0; + if (*put_str != *chk_str) + return 1; + + chk_str++; + put_str++; + } + if (*chk_str == '\0' && (*put_str == '\0' || *put_str == '#')) + return 0; + + return 1; +} + +static int run_simple_test(int is_get_char, int chr) +{ + int ret = 0; + if (is_get_char) { + /* Send an ACK on the get if a prior put completed and set the + * send ack variable + */ + if (send_ack) { + send_ack = 0; + return '+'; + } + /* On the first get char, fill the transmit buffer and then + * take from the get_string. + */ + if (get_buf_cnt == 0) { + if (ts.tst[ts.idx].get_handler) + ts.tst[ts.idx].get_handler(ts.tst[ts.idx].get); + else + fill_get_buf(ts.tst[ts.idx].get); + } + + if (get_buf[get_buf_cnt] == '\0') { + printk(KERN_ERR + "kgdbts: ERROR GET: end of buffer on '%s' at %i\n", + ts.name, ts.idx); + get_buf_cnt = 0; + fill_get_buf("D"); + } + ret = get_buf[get_buf_cnt]; + get_buf_cnt++; + return ret; + } + + /* This callback is a put char which is when kgdb sends data to + * this I/O module. + */ + if (ts.tst[ts.idx].get[0] == '\0' && + ts.tst[ts.idx].put[0] == '\0') { + printk(KERN_ERR "kgdbts: ERROR: beyond end of test on" + " '%s' line %i\n", ts.name, ts.idx); + return 0; + } + + if (put_buf_cnt >= BUFMAX) { + printk(KERN_ERR "kgdbts: ERROR: put buffer overflow on" + " '%s' line %i\n", ts.name, ts.idx); + put_buf_cnt = 0; + return 0; + } + /* Ignore everything until the first valid packet start '$' */ + if (put_buf_cnt == 0 && chr != '$') + return 0; + + put_buf[put_buf_cnt] = chr; + put_buf_cnt++; + + /* End of packet == #XX so look for the '#' */ + if (put_buf_cnt > 3 && put_buf[put_buf_cnt - 3] == '#') { + put_buf[put_buf_cnt] = '\0'; + v2printk("put%i: %s\n", ts.idx, put_buf); + /* Trigger check here */ + if (ts.validate_put && ts.validate_put(put_buf)) { + printk(KERN_ERR "kgdbts: ERROR PUT: end of test " + "buffer on '%s' line %i expected %s got %s\n", + ts.name, ts.idx, ts.tst[ts.idx].put, put_buf); + } + ts.idx++; + put_buf_cnt = 0; + get_buf_cnt = 0; + send_ack = 1; + } + return 0; +} + +static void init_simple_test(void) +{ + memset(&ts, 0, sizeof(ts)); + ts.run_test = run_simple_test; + ts.validate_put = validate_simple_test; +} + +static void run_plant_and_detach_test(int is_early) +{ + char before[BREAK_INSTR_SIZE]; + char after[BREAK_INSTR_SIZE]; + + probe_kernel_read(before, (char *)kgdbts_break_test, + BREAK_INSTR_SIZE); + init_simple_test(); + ts.tst = plant_and_detach_test; + ts.name = "plant_and_detach_test"; + /* Activate test with initial breakpoint */ + if (!is_early) + kgdb_breakpoint(); + probe_kernel_read(after, (char *)kgdbts_break_test, + BREAK_INSTR_SIZE); + if (memcmp(before, after, BREAK_INSTR_SIZE)) { + printk(KERN_CRIT "kgdbts: ERROR kgdb corrupted memory\n"); + panic("kgdb memory corruption"); + } + + /* complete the detach test */ + if (!is_early) + kgdbts_break_test(); +} + +static void run_breakpoint_test(int is_hw_breakpoint) +{ + test_complete = 0; + init_simple_test(); + if (is_hw_breakpoint) { + ts.tst = hw_breakpoint_test; + ts.name = "hw_breakpoint_test"; + } else { + ts.tst = sw_breakpoint_test; + ts.name = "sw_breakpoint_test"; + } + /* Activate test with initial breakpoint */ + kgdb_breakpoint(); + /* run code with the break point in it */ + kgdbts_break_test(); + kgdb_breakpoint(); + + if (test_complete) + return; + + printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name); +} + +static void run_hw_break_test(int is_write_test) +{ + test_complete = 0; + init_simple_test(); + if (is_write_test) { + ts.tst = hw_write_break_test; + ts.name = "hw_write_break_test"; + } else { + ts.tst = hw_access_break_test; + ts.name = "hw_access_break_test"; + } + /* Activate test with initial breakpoint */ + kgdb_breakpoint(); + hw_break_val_access(); + if (is_write_test) { + if (test_complete == 2) + printk(KERN_ERR "kgdbts: ERROR %s broke on access\n", + ts.name); + hw_break_val_write(); + } + kgdb_breakpoint(); + + if (test_complete == 1) + return; + + printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name); +} + +static void run_nmi_sleep_test(int nmi_sleep) +{ + unsigned long flags; + + init_simple_test(); + ts.tst = nmi_sleep_test; + ts.name = "nmi_sleep_test"; + /* Activate test with initial breakpoint */ + kgdb_breakpoint(); + local_irq_save(flags); + mdelay(nmi_sleep*1000); + touch_nmi_watchdog(); + local_irq_restore(flags); + if (test_complete != 2) + printk(KERN_ERR "kgdbts: ERROR nmi_test did not hit nmi\n"); + kgdb_breakpoint(); + if (test_complete == 1) + return; + + printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name); +} + +static void run_bad_read_test(void) +{ + init_simple_test(); + ts.tst = bad_read_test; + ts.name = "bad_read_test"; + /* Activate test with initial breakpoint */ + kgdb_breakpoint(); +} + +static void run_do_fork_test(void) +{ + init_simple_test(); + ts.tst = do_fork_test; + ts.name = "do_fork_test"; + /* Activate test with initial breakpoint */ + kgdb_breakpoint(); +} + +static void run_sys_open_test(void) +{ + init_simple_test(); + ts.tst = sys_open_test; + ts.name = "sys_open_test"; + /* Activate test with initial breakpoint */ + kgdb_breakpoint(); +} + +static void run_singlestep_break_test(void) +{ + init_simple_test(); + ts.tst = singlestep_break_test; + ts.name = "singlestep_breakpoint_test"; + /* Activate test with initial breakpoint */ + kgdb_breakpoint(); + kgdbts_break_test(); + kgdbts_break_test(); +} + +static void kgdbts_run_tests(void) +{ + char *ptr; + int fork_test = 0; + int sys_open_test = 0; + int nmi_sleep = 0; + + ptr = strstr(config, "F"); + if (ptr) + fork_test = simple_strtol(ptr+1, NULL, 10); + ptr = strstr(config, "S"); + if (ptr) + sys_open_test = simple_strtol(ptr+1, NULL, 10); + ptr = strstr(config, "N"); + if (ptr) + nmi_sleep = simple_strtol(ptr+1, NULL, 10); + + /* required internal KGDB tests */ + v1printk("kgdbts:RUN plant and detach test\n"); + run_plant_and_detach_test(0); + v1printk("kgdbts:RUN sw breakpoint test\n"); + run_breakpoint_test(0); + v1printk("kgdbts:RUN bad memory access test\n"); + run_bad_read_test(); + v1printk("kgdbts:RUN singlestep breakpoint test\n"); + run_singlestep_break_test(); + + /* ===Optional tests=== */ + + /* All HW break point tests */ + if (arch_kgdb_ops.flags & KGDB_HW_BREAKPOINT) { + v1printk("kgdbts:RUN hw breakpoint test\n"); + run_breakpoint_test(1); + v1printk("kgdbts:RUN hw write breakpoint test\n"); + run_hw_break_test(1); + v1printk("kgdbts:RUN access write breakpoint test\n"); + run_hw_break_test(0); + } + + if (nmi_sleep) { + v1printk("kgdbts:RUN NMI sleep %i seconds test\n", nmi_sleep); + run_nmi_sleep_test(nmi_sleep); + } + + /* If the do_fork test is run it will be the last test that is + * executed because a kernel thread will be spawned at the very + * end to unregister the debug hooks. + */ + if (fork_test) { + repeat_test = fork_test; + printk(KERN_INFO "kgdbts:RUN do_fork for %i breakpoints\n", + repeat_test); + kthread_run(kgdbts_unreg_thread, 0, "kgdbts_unreg"); + run_do_fork_test(); + return; + } + + /* If the sys_open test is run it will be the last test that is + * executed because a kernel thread will be spawned at the very + * end to unregister the debug hooks. + */ + if (sys_open_test) { + repeat_test = sys_open_test; + printk(KERN_INFO "kgdbts:RUN sys_open for %i breakpoints\n", + repeat_test); + kthread_run(kgdbts_unreg_thread, 0, "kgdbts_unreg"); + run_sys_open_test(); + return; + } + /* Shutdown and unregister */ + kgdb_unregister_io_module(&kgdbts_io_ops); + configured = 0; +} + +static int kgdbts_option_setup(char *opt) +{ + if (strlen(opt) > MAX_CONFIG_LEN) { + printk(KERN_ERR "kgdbts: config string too long\n"); + return -ENOSPC; + } + strcpy(config, opt); + + verbose = 0; + if (strstr(config, "V1")) + verbose = 1; + if (strstr(config, "V2")) + verbose = 2; + + return 0; +} + +__setup("kgdbts=", kgdbts_option_setup); + +static int configure_kgdbts(void) +{ + int err = 0; + + if (!strlen(config) || isspace(config[0])) + goto noconfig; + err = kgdbts_option_setup(config); + if (err) + goto noconfig; + + final_ack = 0; + run_plant_and_detach_test(1); + + err = kgdb_register_io_module(&kgdbts_io_ops); + if (err) { + configured = 0; + return err; + } + configured = 1; + kgdbts_run_tests(); + + return err; + +noconfig: + config[0] = 0; + configured = 0; + + return err; +} + +static int __init init_kgdbts(void) +{ + /* Already configured? */ + if (configured == 1) + return 0; + + return configure_kgdbts(); +} + +static void cleanup_kgdbts(void) +{ + if (configured == 1) + kgdb_unregister_io_module(&kgdbts_io_ops); +} + +static int kgdbts_get_char(void) +{ + int val = 0; + + if (ts.run_test) + val = ts.run_test(1, 0); + + return val; +} + +static void kgdbts_put_char(u8 chr) +{ + if (ts.run_test) + ts.run_test(0, chr); +} + +static int param_set_kgdbts_var(const char *kmessage, struct kernel_param *kp) +{ + int len = strlen(kmessage); + + if (len >= MAX_CONFIG_LEN) { + printk(KERN_ERR "kgdbts: config string too long\n"); + return -ENOSPC; + } + + /* Only copy in the string if the init function has not run yet */ + if (configured < 0) { + strcpy(config, kmessage); + return 0; + } + + if (kgdb_connected) { + printk(KERN_ERR + "kgdbts: Cannot reconfigure while KGDB is connected.\n"); + + return -EBUSY; + } + + strcpy(config, kmessage); + /* Chop out \n char as a result of echo */ + if (config[len - 1] == '\n') + config[len - 1] = '\0'; + + if (configured == 1) + cleanup_kgdbts(); + + /* Go and configure with the new params. */ + return configure_kgdbts(); +} + +static void kgdbts_pre_exp_handler(void) +{ + /* Increment the module count when the debugger is active */ + if (!kgdb_connected) + try_module_get(THIS_MODULE); +} + +static void kgdbts_post_exp_handler(void) +{ + /* decrement the module count when the debugger detaches */ + if (!kgdb_connected) + module_put(THIS_MODULE); +} + +static struct kgdb_io kgdbts_io_ops = { + .name = "kgdbts", + .read_char = kgdbts_get_char, + .write_char = kgdbts_put_char, + .pre_exception = kgdbts_pre_exp_handler, + .post_exception = kgdbts_post_exp_handler, +}; + +module_init(init_kgdbts); +module_exit(cleanup_kgdbts); +module_param_call(kgdbts, param_set_kgdbts_var, param_get_string, &kps, 0644); +MODULE_PARM_DESC(kgdbts, "[F#|S#][N#]"); +MODULE_DESCRIPTION("KGDB Test Suite"); +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Wind River Systems, Inc."); + diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb index 9631ba3baaf3..aaabcddcda5a 100644 --- a/lib/Kconfig.kgdb +++ b/lib/Kconfig.kgdb @@ -25,3 +25,16 @@ config KGDB_SERIAL_CONSOLE help Share a serial console with kgdb. Sysrq-g must be used to break in initially. + +config KGDB_TESTS + bool "KGDB: internal test suite" + depends on KGDB + default n + help + This is a kgdb I/O module specifically designed to test + kgdb's internal functions. This kgdb I/O module is + intended to for the development of new kgdb stubs + as well as regression testing the kgdb internals. + See the drivers/misc/kgdbts.c for the details about + the tests. The most basic of this I/O module is to boot + a kernel boot arguments "kgdbwait kgdbts=V1F100" -- cgit v1.2.3 From 4a1b5502d426df09b9ba1cbcc74fd09702a74cd8 Mon Sep 17 00:00:00 2001 From: Andrew Morton Date: Fri, 7 Mar 2008 15:51:16 -0800 Subject: kgdb: Kconfig fix ERROR: "uart_parse_options" [drivers/serial/serial_core.ko] undefined! Cc: Jason Wessel Signed-off-by: Andrew Morton Signed-off-by: Ingo Molnar --- drivers/serial/serial_core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index 4d7eecbead9b..c32c1ca75f63 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1771,7 +1771,7 @@ static int uart_read_proc(char *page, char **start, off_t off, } #endif -#ifdef CONFIG_SERIAL_CORE_CONSOLE +#if defined(CONFIG_SERIAL_CORE_CONSOLE) || defined(CONFIG_CONSOLE_POLL) /* * uart_console_write - write a console message to a serial port * @port: the port to write the message -- cgit v1.2.3 From e3e2aaf7dc0d82a055e084cfd48b9257c0c66b68 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 20 Mar 2008 13:43:45 -0500 Subject: kgdb: add documentation Add in the kgdb documentation for kgdb. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- Documentation/DocBook/Makefile | 2 +- Documentation/DocBook/kgdb.tmpl | 435 ++++++++++++++++++++++++++++++++++++++++ MAINTAINERS | 6 + include/linux/kgdb.h | 52 +++-- 4 files changed, 473 insertions(+), 22 deletions(-) create mode 100644 Documentation/DocBook/kgdb.tmpl diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index 300e1707893f..e471bc466a7e 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -9,7 +9,7 @@ DOCBOOKS := wanbook.xml z8530book.xml mcabook.xml videobook.xml \ kernel-hacking.xml kernel-locking.xml deviceiobook.xml \ procfs-guide.xml writing_usb_driver.xml networking.xml \ - kernel-api.xml filesystems.xml lsm.xml usb.xml \ + kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \ genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl new file mode 100644 index 000000000000..95e5f84cbf56 --- /dev/null +++ b/Documentation/DocBook/kgdb.tmpl @@ -0,0 +1,435 @@ + + + + + + Using kgdb and the kgdb Internals + + + + Jason + Wessel + +
+ jason.wessel@windriver.com +
+ + + + + + + Tom + Rini + +
+ trini@kernel.crashing.org +
+ + + + + + + Amit S. + Kale + +
+ amitkale@linsyssoft.com +
+ + + + + + 2008 + Wind River Systems, Inc. + + + 2004-2005 + MontaVista Software, Inc. + + + 2004 + Amit S. Kale + + + + + This file is licensed under the terms of the GNU General Public License + version 2. This program is licensed "as is" without any warranty of any + kind, whether express or implied. + + + + + + + + Introduction + + kgdb is a source level debugger for linux kernel. It is used along + with gdb to debug a linux kernel. The expectation is that gdb can + be used to "break in" to the kernel to inspect memory, variables + and look through a cal stack information similar to what an + application developer would use gdb for. It is possible to place + breakpoints in kernel code and perform some limited execution + stepping. + + + Two machines are required for using kgdb. One of these machines is a + development machine and the other is a test machine. The kernel + to be debugged runs on the test machine. The development machine + runs an instance of gdb against the vmlinux file which contains + the symbols (not boot image such as bzImage, zImage, uImage...). + In gdb the developer specifies the connection parameters and + connects to kgdb. Depending on which kgdb I/O modules exist in + the kernel for a given architecture, it may be possible to debug + the test machine's kernel with the development machine using a + rs232 or ethernet connection. + + + + Compiling a kernel + + To enable CONFIG_KGDB, look under the "Kernel debugging" + and then select "KGDB: kernel debugging with remote gdb". + + + Next you should choose one of more I/O drivers to interconnect debugging + host and debugged target. Early boot debugging requires a KGDB + I/O driver that supports early debugging and the driver must be + built into the kernel directly. Kgdb I/O driver configuration + takes place via kernel or module parameters, see following + chapter. + + + The kgdb test compile options are described in the kgdb test suite chapter. + + + + + Enable kgdb for debugging + + In order to use kgdb you must activate it by passing configuration + information to one of the kgdb I/O drivers. If you do not pass any + configuration information kgdb will not do anything at all. Kgdb + will only actively hook up to the kernel trap hooks if a kgdb I/O + driver is loaded and configured. If you unconfigure a kgdb I/O + driver, kgdb will unregister all the kernel hook points. + + + All drivers can be reconfigured at run time, if + CONFIG_SYSFS and CONFIG_MODULES + are enabled, by echo'ing a new config string to + /sys/module/<driver>/parameter/<option>. + The driver can be unconfigured by passing an empty string. You cannot + change the configuration while the debugger is attached. Make sure + to detach the debugger with the detach command + prior to trying unconfigure a kgdb I/O driver. + + + Kernel parameter: kgdbwait + + The Kernel command line option kgdbwait makes + kgdb wait for a debugger connection during booting of a kernel. You + can only use this option you compiled a kgdb I/O driver into the + kernel and you specified the I/O driver configuration as a kernel + command line option. The kgdbwait parameter should always follow the + configuration parameter for the kgdb I/O driver in the kernel + command line else the I/O driver will not be configured prior to + asking the kernel to use it to wait. + + + The kernel will stop and wait as early as the I/O driver and + architecture will allow when you use this option. If you build the + kgdb I/O driver as a kernel module kgdbwait will not do anything. + + + + Kernel parameter: kgdboc + + The kgdboc driver was originally an abbreviation meant to stand for + "kgdb over console". Kgdboc is designed to work with a single + serial port as example, and it was meant to cover the circumstance + where you wanted to use a serial console as your primary console as + well as using it to perform kernel debugging. + + + Using kgdboc + + You can configure kgdboc via sysfs or a module or kernel boot line + parameter depending on if you build with CONFIG_KGDBOC as a module + or built-in. + + From the module load or build-in + kgdboc=<tty-device>,[baud] + + The example here would be if your console port was typically ttyS0, you would use something like kgdboc=ttyS0,115200 or on the ARM Versatile AB you would likely use kgdboc=ttyAMA0,115200 + + + From sysfs + echo ttyS0 > /sys/module/kgdboc/parameters/kgdboc + + + + + NOTE: Kgdboc does not support interrupting the target via the + gdb remote protocol. You must manually send a sysrq-g unless you + have a proxy that splits console output to a terminal problem and + has a separate port for the debugger to connect to that sends the + sysrq-g for you. + + When using kgdboc with no debugger proxy, you can end up + connecting the debugger for one of two entry points. If an + exception occurs after you have loaded kgdboc a message should print + on the console stating it is waiting for the debugger. In case you + disconnect your terminal program and then connect the debugger in + its place. If you want to interrupt the target system and forcibly + enter a debug session you have to issue a Sysrq sequence and then + type the letter g. Then you disconnect the + terminal session and connect gdb. Your options if you don't like + this are to hack gdb to send the sysrq-g for you as well as on the + initial connect, or to use a debugger proxy that allows an + unmodified gdb to do the debugging. + + + + kgdboc internals + + The kgdboc driver is actually a very thin driver that relies on the + underlying low level to the hardware driver having "polling hooks" + which the to which the tty driver is attached. In the initial + implementation of kgdboc it the serial_core was changed to expose a + low level uart hook for doing polled mode reading and writing of a + single character while in an atomic context. When kgdb makes an I/O + request to the debugger, kgdboc invokes a call back in the serial + core which in turn uses the call back in the uart driver. It is + certainly possible to extend kgdboc to work with non-uart based + consoles in the future. + + + When using kgdboc with a uart, the uart driver must implement two callbacks in the struct uart_ops. Example from drivers/8250.c: +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif + + Any implementation specifics around creating a polling driver use the + #ifdef CONFIG_CONSOLE_POLL, as shown above. + Keep in mind that polling hooks have to be implemented in such a way + that they can be called from an atomic context and have to restore + the state of the uart chip on return such that the system can return + to normal when the debugger detaches. You need to be very careful + with any kind of lock you consider, because failing here is most + going to mean pressing the reset button. + + + + + Kernel parameter: kgdbcon + + Kgdb supports using the gdb serial protocol to send console messages + to the debugger when the debugger is connected and running. There + are two ways to activate this feature. + + Activate with the kernel command line option: + kgdbcon + + Use sysfs before configuring an io driver + + echo 1 > /sys/module/kgdb/parameters/kgdb_use_con + + + NOTE: If you do this after you configure the kgdb I/O driver, the + setting will not take effect until the next point the I/O is + reconfigured. + + + + + + IMPORTANT NOTE: Using this option with kgdb over the console + (kgdboc) or kgdb over ethernet (kgdboe) is not supported. + + + + + Connecting gdb + + If you are using kgdboc, you need to have used kgdbwait as a boot + argument, issued a sysrq-g, or the system you are going to debug + has already taken an exception and is waiting for the debugger to + attach before you can connect gdb. + + + If you are not using different kgdb I/O driver other than kgdboc, + you should be able to connect and the target will automatically + respond. + + + Example (using a serial port): + + + % gdb ./vmlinux + (gdb) set remotebaud 115200 + (gdb) target remote /dev/ttyS0 + + + Example (kgdb to a terminal server): + + + % gdb ./vmlinux + (gdb) target remote udp:192.168.2.2:6443 + + + Example (kgdb over ethernet): + + + % gdb ./vmlinux + (gdb) target remote udp:192.168.2.2:6443 + + + Once connected, you can debug a kernel the way you would debug an + application program. + + + If you are having problems connecting or something is going + seriously wrong while debugging, it will most often be the case + that you want to enable gdb to be verbose about its target + communications. You do this prior to issuing the target + remote command by typing in: set remote debug 1 + + + + kgdb Test Suite + + When kgdb is enabled in the kernel config you can also elect to + enable the config parameter KGDB_TESTS. Turning this on will + enable a special kgdb I/O module which is designed to test the + kgdb internal functions. + + + The kgdb tests are mainly intended for developers to test the kgdb + internals as well as a tool for developing a new kgdb architecture + specific implementation. These tests are not really for end users + of the Linux kernel. The primary source of documentation would be + to look in the drivers/misc/kgdbts.c file. + + + The kgdb test suite can also be configured at compile time to run + the core set of tests by setting the kernel config parameter + KGDB_TESTS_ON_BOOT. This particular option is aimed at automated + regression testing and does not require modifying the kernel boot + config arguments. If this is turned on, the kgdb test suite can + be disabled by specifying "kgdbts=" as a kernel boot argument. + + + + Architecture Specifics + + Kgdb is organized into three basic components: + + kgdb core + + The kgdb core is found in kernel/kgdb.c. It contains: + + All the logic to implement the gdb serial protocol + A generic OS exception handler which includes sync'ing the processors into a stopped state on an multi cpu system. + The API to talk to the kgdb I/O drivers + The API to make calls to the arch specific kgdb implementation + The logic to perform safe memory reads and writes to memory while using the debugger + A full implementation for software breakpoints unless overridden by the arch + + + + kgdb arch specific implementation + + This implementation is generally found in arch/*/kernel/kgdb.c. + As an example, arch/x86/kernel/kgdb.c contains the specifics to + implement HW breakpoint as well as the initialization to + dynamically register and unregister for the trap handlers on + this architecture. The arch specific portion implements: + + contains an arch specific trap catcher which + invokes kgdb_handle_exception() to start kgdb about doing its + work + translation to and from gdb specific packet format to pt_regs + Registration and unregistration of architecture specific trap hooks + Any special exception handling and cleanup + NMI exception handling and cleanup + (optional)HW breakpoints + + + + kgdb I/O driver + + Each kgdb I/O driver has to provide an configuration + initialization, and cleanup handler for when it + unloads/unconfigures. Any given kgdb I/O driver has to operate + very closely with the hardware and must do it in such a way that + does not enable interrupts or change other parts of the system + context without completely restoring them. Every kgdb I/O + driver must provide a read and write character interface. The + kgdb core will repeatedly "poll" a kgdb I/O driver for characters + when it needs input. The I/O driver is expected to return + immediately if there is no data available. Doing so allows for + the future possibility to touch watch dog hardware in such a way + as to have a target system not reset when these are enabled. + + + + + + If you are intent on adding kgdb architecture specific support + for a new architecture, the architecture should define + HAVE_ARCH_KGDB in the architecture specific + Kconfig file. This will enable kgdb for the architecture, and + at that point you must create an architecture specific kgdb + implementation. + + + There are a few flags which must be set on every architecture in + their <asm/kgdb.h> file. These are: + + + + NUMREGBYTES: The size in bytes of all of the registers, so + that we can ensure they will all fit into a packet. + + + BUFMAX: The size in bytes of the buffer GDB will read into. + This must be larger than NUMREGBYTES. + + + CACHE_FLUSH_IS_SAFE: Set to 1 if it is always safe to call + flush_cache_range or flush_icache_range. On some architectures, + these functions may not be safe to call on SMP since we keep other + CPUs in a holding pattern. + + + + + + There are also the following functions for the common backend, + found in kernel/kgdb.c, that must be supplied by the + architecture-specific backend unless marked as (optional), in + which case a default function maybe used if the architecture + does not need to provide a specific implementation. + +!Iinclude/linux/kgdb.h + + + Credits + + The following people have contributed to this document: + + Amit Kaleamitkale@linsyssoft.com + Tom Rinitrini@kernel.crashing.org + Jason Wesseljason.wessel@windriver.com + + + + + diff --git a/MAINTAINERS b/MAINTAINERS index e46775868019..3eceebb48c92 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2319,6 +2319,12 @@ L: linux-kernel@vger.kernel.org L: kexec@lists.infradead.org S: Maintained +KGDB +P: Jason Wessel +M: jason.wessel@windriver.com +L: kgdb-bugreport@lists.sourceforge.net +S: Maintained + KPROBES P: Ananth N Mavinakayanahalli M: ananth@in.ibm.com diff --git a/include/linux/kgdb.h b/include/linux/kgdb.h index b0985b79b638..9757b1a6d9dc 100644 --- a/include/linux/kgdb.h +++ b/include/linux/kgdb.h @@ -22,31 +22,34 @@ struct pt_regs; -/* - * kgdb_skipexception - Bail out of KGDB when we've been triggered. +/** + * kgdb_skipexception - (optional) exit kgdb_handle_exception early * @exception: Exception vector number * @regs: Current &struct pt_regs. * - * On some architectures we need to skip a breakpoint exception when - * it occurs after a breakpoint has been removed. + * On some architectures it is required to skip a breakpoint + * exception when it occurs after a breakpoint has been removed. + * This can be implemented in the architecture specific portion of + * for kgdb. */ extern int kgdb_skipexception(int exception, struct pt_regs *regs); -/* - * kgdb_post_primary_code - Save error vector/code numbers. +/** + * kgdb_post_primary_code - (optional) Save error vector/code numbers. * @regs: Original pt_regs. * @e_vector: Original error vector. * @err_code: Original error code. * - * This is needed on architectures which support SMP and KGDB. - * This function is called after all the secondary cpus have been put - * to a know spin state and the primary CPU has control over KGDB. + * This is usually needed on architectures which support SMP and + * KGDB. This function is called after all the secondary cpus have + * been put to a know spin state and the primary CPU has control over + * KGDB. */ extern void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code); -/* - * kgdb_disable_hw_debug - Disable hardware debugging while we in kgdb. +/** + * kgdb_disable_hw_debug - (optional) Disable hardware debugging hook * @regs: Current &struct pt_regs. * * This function will be called if the particular architecture must @@ -59,7 +62,14 @@ struct tasklet_struct; struct task_struct; struct uart_port; -/* To enter the debugger explicitly. */ +/** + * kgdb_breakpoint - compiled in breakpoint + * + * This will be impelmented a static inline per architecture. This + * function is called by the kgdb core to execute an architecture + * specific trap to cause kgdb to enter the exception processing. + * + */ void kgdb_breakpoint(void); extern int kgdb_connected; @@ -102,7 +112,7 @@ struct kgdb_bkpt { * Functions each KGDB-supporting architecture must provide: */ -/* +/** * kgdb_arch_init - Perform any architecture specific initalization. * * This function will handle the initalization of any architecture @@ -110,7 +120,7 @@ struct kgdb_bkpt { */ extern int kgdb_arch_init(void); -/* +/** * kgdb_arch_exit - Perform any architecture specific uninitalization. * * This function will handle the uninitalization of any architecture @@ -118,7 +128,7 @@ extern int kgdb_arch_init(void); */ extern void kgdb_arch_exit(void); -/* +/** * pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs * @gdb_regs: A pointer to hold the registers in the order GDB wants. * @regs: The &struct pt_regs of the current process. @@ -128,7 +138,7 @@ extern void kgdb_arch_exit(void); */ extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs); -/* +/** * sleeping_thread_to_gdb_regs - Convert ptrace regs to GDB regs * @gdb_regs: A pointer to hold the registers in the order GDB wants. * @p: The &struct task_struct of the desired process. @@ -143,7 +153,7 @@ extern void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs); extern void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p); -/* +/** * gdb_regs_to_pt_regs - Convert GDB regs to ptrace regs. * @gdb_regs: A pointer to hold the registers we've received from GDB. * @regs: A pointer to a &struct pt_regs to hold these values in. @@ -153,7 +163,7 @@ sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p); */ extern void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs); -/* +/** * kgdb_arch_handle_exception - Handle architecture specific GDB packets. * @vector: The error vector of the exception that happened. * @signo: The signal number of the exception that happened. @@ -175,7 +185,7 @@ kgdb_arch_handle_exception(int vector, int signo, int err_code, char *remcom_out_buffer, struct pt_regs *regs); -/* +/** * kgdb_roundup_cpus - Get other CPUs into a holding pattern * @flags: Current IRQ state * @@ -198,7 +208,7 @@ extern int kgdb_validate_break_address(unsigned long addr); extern int kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr); extern int kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle); -/* +/** * struct kgdb_arch - Describe architecture specific values. * @gdb_bpt_instr: The instruction to trigger a breakpoint. * @flags: Flags for the breakpoint, currently just %KGDB_HW_BREAKPOINT. @@ -227,7 +237,7 @@ struct kgdb_arch { void (*correct_hw_break)(void); }; -/* +/** * struct kgdb_io - Describe the interface for an I/O driver to talk with KGDB. * @name: Name of the I/O driver. * @read_char: Pointer to a function that will return one char. -- cgit v1.2.3 From 974460c5bfd9f6c38aa3dda189a63f9fc351035f Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Thu, 20 Mar 2008 13:43:44 -0500 Subject: kgdb: allow static kgdbts boot configuration This patch adds in the ability to compile the kgdb internal test string into the kernel so as to run the tests at boot without changing the kernel boot arguments. This patch also changes all the error paths to invoke WARN_ON(1) which will emit the line number of the file and dump the kernel stack when an error occurs. You can disable the tests in a kernel that is built this way using "kgdbts=" Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- drivers/misc/kgdbts.c | 41 ++++++++++++++++++++++++----------------- lib/Kconfig.kgdb | 18 ++++++++++++++++++ 2 files changed, 42 insertions(+), 17 deletions(-) diff --git a/drivers/misc/kgdbts.c b/drivers/misc/kgdbts.c index cbc4822b5847..6d6286c4eeac 100644 --- a/drivers/misc/kgdbts.c +++ b/drivers/misc/kgdbts.c @@ -112,6 +112,10 @@ printk(KERN_INFO a); \ touch_nmi_watchdog(); \ } while (0) +#define eprintk(a...) do { \ + printk(KERN_ERR a); \ + WARN_ON(1); \ + } while (0) #define MAX_CONFIG_LEN 40 static const char hexchars[] = "0123456789abcdef"; @@ -145,7 +149,11 @@ static struct pt_regs kgdbts_regs; /* -1 = init not run yet, 0 = unconfigured, 1 = configured. */ static int configured = -1; +#ifdef CONFIG_KGDB_TESTS_BOOT_STRING +static char config[MAX_CONFIG_LEN] = CONFIG_KGDB_TESTS_BOOT_STRING; +#else static char config[MAX_CONFIG_LEN]; +#endif static struct kparam_string kps = { .string = config, .maxlen = MAX_CONFIG_LEN, @@ -289,7 +297,7 @@ static int check_and_rewind_pc(char *put_str, char *arg) #endif if (strcmp(arg, "silent") && instruction_pointer(&kgdbts_regs) + offset != addr) { - printk(KERN_ERR "kgdbts: BP mismatch %lx expected %lx\n", + eprintk("kgdbts: BP mismatch %lx expected %lx\n", instruction_pointer(&kgdbts_regs) + offset, addr); return 1; } @@ -313,7 +321,7 @@ static int check_single_step(char *put_str, char *arg) v2printk("Singlestep stopped at IP: %lx\n", instruction_pointer(&kgdbts_regs)); if (instruction_pointer(&kgdbts_regs) == addr) { - printk(KERN_ERR "kgdbts: SingleStep failed at %lx\n", + eprintk("kgdbts: SingleStep failed at %lx\n", instruction_pointer(&kgdbts_regs)); return 1; } @@ -378,7 +386,7 @@ static void emul_sstep_get(char *arg) break_helper("z0", 0, sstep_addr); break; default: - printk(KERN_ERR "kgdbts: ERROR failed sstep get emulation\n"); + eprintk("kgdbts: ERROR failed sstep get emulation\n"); } sstep_state++; } @@ -404,26 +412,26 @@ static int emul_sstep_put(char *put_str, char *arg) break; case 2: if (strncmp(put_str, "$OK", 3)) { - printk(KERN_ERR "kgdbts: failed sstep break set\n"); + eprintk("kgdbts: failed sstep break set\n"); return 1; } break; case 3: if (strncmp(put_str, "$T0", 3)) { - printk(KERN_ERR "kgdbts: failed continue sstep\n"); + eprintk("kgdbts: failed continue sstep\n"); return 1; } break; case 4: if (strncmp(put_str, "$OK", 3)) { - printk(KERN_ERR "kgdbts: failed sstep break unset\n"); + eprintk("kgdbts: failed sstep break unset\n"); return 1; } /* Single step is complete so continue on! */ sstep_state = 0; return 0; default: - printk(KERN_ERR "kgdbts: ERROR failed sstep put emulation\n"); + eprintk("kgdbts: ERROR failed sstep put emulation\n"); } /* Continue on the same test line until emulation is complete */ @@ -668,8 +676,7 @@ static int run_simple_test(int is_get_char, int chr) } if (get_buf[get_buf_cnt] == '\0') { - printk(KERN_ERR - "kgdbts: ERROR GET: end of buffer on '%s' at %i\n", + eprintk("kgdbts: ERROR GET: EOB on '%s' at %i\n", ts.name, ts.idx); get_buf_cnt = 0; fill_get_buf("D"); @@ -684,13 +691,13 @@ static int run_simple_test(int is_get_char, int chr) */ if (ts.tst[ts.idx].get[0] == '\0' && ts.tst[ts.idx].put[0] == '\0') { - printk(KERN_ERR "kgdbts: ERROR: beyond end of test on" + eprintk("kgdbts: ERROR: beyond end of test on" " '%s' line %i\n", ts.name, ts.idx); return 0; } if (put_buf_cnt >= BUFMAX) { - printk(KERN_ERR "kgdbts: ERROR: put buffer overflow on" + eprintk("kgdbts: ERROR: put buffer overflow on" " '%s' line %i\n", ts.name, ts.idx); put_buf_cnt = 0; return 0; @@ -708,7 +715,7 @@ static int run_simple_test(int is_get_char, int chr) v2printk("put%i: %s\n", ts.idx, put_buf); /* Trigger check here */ if (ts.validate_put && ts.validate_put(put_buf)) { - printk(KERN_ERR "kgdbts: ERROR PUT: end of test " + eprintk("kgdbts: ERROR PUT: end of test " "buffer on '%s' line %i expected %s got %s\n", ts.name, ts.idx, ts.tst[ts.idx].put, put_buf); } @@ -772,7 +779,7 @@ static void run_breakpoint_test(int is_hw_breakpoint) if (test_complete) return; - printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name); + eprintk("kgdbts: ERROR %s test failed\n", ts.name); } static void run_hw_break_test(int is_write_test) @@ -791,7 +798,7 @@ static void run_hw_break_test(int is_write_test) hw_break_val_access(); if (is_write_test) { if (test_complete == 2) - printk(KERN_ERR "kgdbts: ERROR %s broke on access\n", + eprintk("kgdbts: ERROR %s broke on access\n", ts.name); hw_break_val_write(); } @@ -800,7 +807,7 @@ static void run_hw_break_test(int is_write_test) if (test_complete == 1) return; - printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name); + eprintk("kgdbts: ERROR %s test failed\n", ts.name); } static void run_nmi_sleep_test(int nmi_sleep) @@ -817,12 +824,12 @@ static void run_nmi_sleep_test(int nmi_sleep) touch_nmi_watchdog(); local_irq_restore(flags); if (test_complete != 2) - printk(KERN_ERR "kgdbts: ERROR nmi_test did not hit nmi\n"); + eprintk("kgdbts: ERROR nmi_test did not hit nmi\n"); kgdb_breakpoint(); if (test_complete == 1) return; - printk(KERN_ERR "kgdbts: ERROR %s test failed\n", ts.name); + eprintk("kgdbts: ERROR %s test failed\n", ts.name); } static void run_bad_read_test(void) diff --git a/lib/Kconfig.kgdb b/lib/Kconfig.kgdb index aaabcddcda5a..f2e01ac5ab09 100644 --- a/lib/Kconfig.kgdb +++ b/lib/Kconfig.kgdb @@ -38,3 +38,21 @@ config KGDB_TESTS See the drivers/misc/kgdbts.c for the details about the tests. The most basic of this I/O module is to boot a kernel boot arguments "kgdbwait kgdbts=V1F100" + +config KGDB_TESTS_ON_BOOT + bool "KGDB: Run tests on boot" + depends on KGDB_TESTS + default n + help + Run the kgdb tests on boot up automatically without the need + to pass in a kernel parameter + +config KGDB_TESTS_BOOT_STRING + string "KGDB: which internal kgdb tests to run" + depends on KGDB_TESTS_ON_BOOT + default "V1F100" + help + This is the command string to send the kgdb test suite on + boot. See the drivers/misc/kgdbts.c for detailed + information about other strings you could use beyond the + default of V1F100. -- cgit v1.2.3 From 225a4424ade24e913c081d5a4c4bd71a0fe2e0ac Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Tue, 1 Apr 2008 16:55:26 -0500 Subject: kgdb: documentation fixes Minor cleanups to kgdb docs. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- Documentation/DocBook/kgdb.tmpl | 104 ++++++++++++++++++++++------------------ 1 file changed, 58 insertions(+), 46 deletions(-) diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl index 95e5f84cbf56..97618bed4d65 100644 --- a/Documentation/DocBook/kgdb.tmpl +++ b/Documentation/DocBook/kgdb.tmpl @@ -152,9 +152,10 @@ The kgdboc driver was originally an abbreviation meant to stand for "kgdb over console". Kgdboc is designed to work with a single - serial port as example, and it was meant to cover the circumstance + serial port. It was meant to cover the circumstance where you wanted to use a serial console as your primary console as - well as using it to perform kernel debugging. + well as using it to perform kernel debugging. Of course you can + also use kgdboc without assigning a console to the same port. Using kgdboc @@ -195,37 +196,6 @@ unmodified gdb to do the debugging. - - kgdboc internals - - The kgdboc driver is actually a very thin driver that relies on the - underlying low level to the hardware driver having "polling hooks" - which the to which the tty driver is attached. In the initial - implementation of kgdboc it the serial_core was changed to expose a - low level uart hook for doing polled mode reading and writing of a - single character while in an atomic context. When kgdb makes an I/O - request to the debugger, kgdboc invokes a call back in the serial - core which in turn uses the call back in the uart driver. It is - certainly possible to extend kgdboc to work with non-uart based - consoles in the future. - - - When using kgdboc with a uart, the uart driver must implement two callbacks in the struct uart_ops. Example from drivers/8250.c: -#ifdef CONFIG_CONSOLE_POLL - .poll_get_char = serial8250_get_poll_char, - .poll_put_char = serial8250_put_poll_char, -#endif - - Any implementation specifics around creating a polling driver use the - #ifdef CONFIG_CONSOLE_POLL, as shown above. - Keep in mind that polling hooks have to be implemented in such a way - that they can be called from an atomic context and have to restore - the state of the uart chip on return such that the system can return - to normal when the debugger detaches. You need to be very careful - with any kind of lock you consider, because failing here is most - going to mean pressing the reset button. - - Kernel parameter: kgdbcon @@ -327,6 +297,8 @@ + KGDB Internals + Architecture Specifics Kgdb is organized into three basic components: @@ -365,18 +337,23 @@ kgdb I/O driver - Each kgdb I/O driver has to provide an configuration - initialization, and cleanup handler for when it - unloads/unconfigures. Any given kgdb I/O driver has to operate - very closely with the hardware and must do it in such a way that - does not enable interrupts or change other parts of the system - context without completely restoring them. Every kgdb I/O - driver must provide a read and write character interface. The - kgdb core will repeatedly "poll" a kgdb I/O driver for characters - when it needs input. The I/O driver is expected to return - immediately if there is no data available. Doing so allows for - the future possibility to touch watch dog hardware in such a way - as to have a target system not reset when these are enabled. + Each kgdb I/O driver has to provide an implemenation for the following: + + configuration via builtin or module + dynamic configuration and kgdb hook registration calls + read and write character interface + A cleanup handler for unconfiguring from the kgdb core + (optional) Early debug methodology + + Any given kgdb I/O driver has to operate very closely with the + hardware and must do it in such a way that does not enable + interrupts or change other parts of the system context without + completely restoring them. The kgdb core will repeatedly "poll" + a kgdb I/O driver for characters when it needs input. The I/O + driver is expected to return immediately if there is no data + available. Doing so allows for the future possibility to touch + watch dog hardware in such a way as to have a target system not + reset when these are enabled. @@ -419,6 +396,38 @@ does not need to provide a specific implementation. !Iinclude/linux/kgdb.h + + + kgdboc internals + + The kgdboc driver is actually a very thin driver that relies on the + underlying low level to the hardware driver having "polling hooks" + which the to which the tty driver is attached. In the initial + implementation of kgdboc it the serial_core was changed to expose a + low level uart hook for doing polled mode reading and writing of a + single character while in an atomic context. When kgdb makes an I/O + request to the debugger, kgdboc invokes a call back in the serial + core which in turn uses the call back in the uart driver. It is + certainly possible to extend kgdboc to work with non-uart based + consoles in the future. + + + When using kgdboc with a uart, the uart driver must implement two callbacks in the struct uart_ops. Example from drivers/8250.c: +#ifdef CONFIG_CONSOLE_POLL + .poll_get_char = serial8250_get_poll_char, + .poll_put_char = serial8250_put_poll_char, +#endif + + Any implementation specifics around creating a polling driver use the + #ifdef CONFIG_CONSOLE_POLL, as shown above. + Keep in mind that polling hooks have to be implemented in such a way + that they can be called from an atomic context and have to restore + the state of the uart chip on return such that the system can return + to normal when the debugger detaches. You need to be very careful + with any kind of lock you consider, because failing here is most + going to mean pressing the reset button. + + Credits @@ -427,8 +436,11 @@ Amit Kaleamitkale@linsyssoft.com Tom Rinitrini@kernel.crashing.org - Jason Wesseljason.wessel@windriver.com + In March 2008 this document was completely rewritten by: + + Jason Wesseljason.wessel@windriver.com + -- cgit v1.2.3 From 56fb70932964927597ce30bbd820471633c72adc Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Tue, 1 Apr 2008 16:55:27 -0500 Subject: kgdb: fix SMP NMI kgdb_handle_exception exit race Fix the problem of protecting the kgdb handle_exception exit which had an NMI race condition, while trying to restore normal system operation. There was a small window after the master processor sets cpu_in_debug to zero but before it has set kgdb_active to zero where a non-master processor in an SMP system could receive an NMI and re-enter the kgdb_wait() loop. As long as the master processor sets the cpu_in_debug before sending the cpu roundup the cpu_in_debug variable can also be used to guard against the race condition. The kgdb_wait() function no longer needs to check kgdb_active because it is done in the arch specific code and handled along with the nmi traps at the low level. This also allows kgdb_wait() to exit correctly if it was entered for some unknown reason due to a spurious NMI that could not be handled by the arch specific code. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- kernel/kgdb.c | 27 ++++++++------------------- 1 file changed, 8 insertions(+), 19 deletions(-) diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 85b7e5b934a7..4d1b3c232377 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -561,18 +561,6 @@ static void kgdb_wait(struct pt_regs *regs) smp_wmb(); atomic_set(&cpu_in_kgdb[cpu], 1); - /* - * The primary CPU must be active to enter here, but this is - * guard in case the primary CPU had not been selected if - * this was an entry via nmi. - */ - while (atomic_read(&kgdb_active) == -1) - cpu_relax(); - - /* Wait till primary CPU goes completely into the debugger. */ - while (!atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) - cpu_relax(); - /* Wait till primary CPU is done with debugging */ while (atomic_read(&passive_cpu_wait[cpu])) cpu_relax(); @@ -1447,18 +1435,18 @@ acquirelock: atomic_set(&passive_cpu_wait[i], 1); } -#ifdef CONFIG_SMP - /* Signal the other CPUs to enter kgdb_wait() */ - if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup) - kgdb_roundup_cpus(flags); -#endif - /* * spin_lock code is good enough as a barrier so we don't * need one here: */ atomic_set(&cpu_in_kgdb[ks->cpu], 1); +#ifdef CONFIG_SMP + /* Signal the other CPUs to enter kgdb_wait() */ + if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup) + kgdb_roundup_cpus(flags); +#endif + /* * Wait for the other CPUs to be notified and be waiting for us: */ @@ -1514,7 +1502,8 @@ int kgdb_nmicallback(int cpu, void *regs) { #ifdef CONFIG_SMP if (!atomic_read(&cpu_in_kgdb[cpu]) && - atomic_read(&kgdb_active) != cpu) { + atomic_read(&kgdb_active) != cpu && + atomic_read(&cpu_in_kgdb[atomic_read(&kgdb_active)])) { kgdb_wait((struct pt_regs *)regs); return 0; } -- cgit v1.2.3 From 1a9a3e76dde191f82f7a8a66059dcbb4a9f63ff3 Mon Sep 17 00:00:00 2001 From: Jason Wessel Date: Tue, 1 Apr 2008 16:55:28 -0500 Subject: kgdb: always use icache flush for sw breakpoints On the ppc 4xx architecture the instruction cache must be flushed as well as the data cache. This patch just makes it generic for all architectures where CACHE_FLUSH_IS_SAFE is set to 1. Signed-off-by: Jason Wessel Signed-off-by: Ingo Molnar --- kernel/kgdb.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 4d1b3c232377..1bd0ec1c80b2 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -591,9 +591,9 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) if (current->mm && current->mm->mmap_cache) { flush_cache_range(current->mm->mmap_cache, addr, addr + BREAK_INSTR_SIZE); - } else { - flush_icache_range(addr, addr + BREAK_INSTR_SIZE); } + /* Force flush instruction cache if it was outside the mm */ + flush_icache_range(addr, addr + BREAK_INSTR_SIZE); } /* -- cgit v1.2.3