diff options
| -rw-r--r-- | arch/powerpc/Kconfig | 3 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/thread_info.h | 4 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/uprobes.h | 54 | ||||
| -rw-r--r-- | arch/powerpc/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/powerpc/kernel/signal.c | 6 | ||||
| -rw-r--r-- | arch/powerpc/kernel/uprobes.c | 184 |
6 files changed, 251 insertions, 1 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 352f416269ce..98e513b62709 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -239,6 +239,9 @@ config PPC_OF_PLATFORM_PCI config ARCH_SUPPORTS_DEBUG_PAGEALLOC def_bool y +config ARCH_SUPPORTS_UPROBES + def_bool y + config PPC_ADV_DEBUG_REGS bool depends on 40x || BOOKE diff --git a/arch/powerpc/include/asm/thread_info.h b/arch/powerpc/include/asm/thread_info.h index faf93529cbf0..e942203cd4a8 100644 --- a/arch/powerpc/include/asm/thread_info.h +++ b/arch/powerpc/include/asm/thread_info.h @@ -102,6 +102,7 @@ static inline struct thread_info *current_thread_info(void) #define TIF_RESTOREALL 11 /* Restore all regs (implies NOERROR) */ #define TIF_NOERROR 12 /* Force successful syscall return */ #define TIF_NOTIFY_RESUME 13 /* callback before returning to user */ +#define TIF_UPROBE 14 /* breakpointed or single-stepping */ #define TIF_SYSCALL_TRACEPOINT 15 /* syscall tracepoint instrumentation */ /* as above, but as bit values */ @@ -118,12 +119,13 @@ static inline struct thread_info *current_thread_info(void) #define _TIF_RESTOREALL (1<<TIF_RESTOREALL) #define _TIF_NOERROR (1<<TIF_NOERROR) #define _TIF_NOTIFY_RESUME (1<<TIF_NOTIFY_RESUME) +#define _TIF_UPROBE (1<<TIF_UPROBE) #define _TIF_SYSCALL_TRACEPOINT (1<<TIF_SYSCALL_TRACEPOINT) #define _TIF_SYSCALL_T_OR_A (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | \ _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT) #define _TIF_USER_WORK_MASK (_TIF_SIGPENDING | _TIF_NEED_RESCHED | \ - _TIF_NOTIFY_RESUME) + _TIF_NOTIFY_RESUME | _TIF_UPROBE) #define _TIF_PERSYSCALL_MASK (_TIF_RESTOREALL|_TIF_NOERROR) /* Bits in local_flags */ diff --git a/arch/powerpc/include/asm/uprobes.h b/arch/powerpc/include/asm/uprobes.h new file mode 100644 index 000000000000..13ba5077b59b --- /dev/null +++ b/arch/powerpc/include/asm/uprobes.h @@ -0,0 +1,54 @@ +#ifndef _ASM_UPROBES_H +#define _ASM_UPROBES_H +/* + * User-space Probes (UProbes) for powerpc + * + * 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 of the License, 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. + * + * 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. + * + * Copyright IBM Corporation, 2007-2012 + * + * Adapted from the x86 port by Ananth N Mavinakayanahalli <ananth@in.ibm.com> + */ + +#include <linux/notifier.h> +#include <asm/probes.h> + +typedef opcode_t uprobe_opcode_t; + +#define MAX_UINSN_BYTES 4 +#define UPROBE_XOL_SLOT_BYTES (MAX_UINSN_BYTES) + +/* The following alias is needed for reference from arch-agnostic code */ +#define UPROBE_SWBP_INSN BREAKPOINT_INSTRUCTION +#define UPROBE_SWBP_INSN_SIZE 4 /* swbp insn size in bytes */ + +struct arch_uprobe { + union { + u8 insn[MAX_UINSN_BYTES]; + u32 ainsn; + }; +}; + +struct arch_uprobe_task { + unsigned long saved_trap_nr; +}; + +extern int arch_uprobe_analyze_insn(struct arch_uprobe *aup, struct mm_struct *mm, unsigned long addr); +extern int arch_uprobe_pre_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs); +extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk); +extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data); +extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs); +#endif /* _ASM_UPROBES_H */ diff --git a/arch/powerpc/kernel/Makefile b/arch/powerpc/kernel/Makefile index bb282dd81612..cde12f8a4ebc 100644 --- a/arch/powerpc/kernel/Makefile +++ b/arch/powerpc/kernel/Makefile @@ -96,6 +96,7 @@ obj-$(CONFIG_MODULES) += ppc_ksyms.o obj-$(CONFIG_BOOTX_TEXT) += btext.o obj-$(CONFIG_SMP) += smp.o obj-$(CONFIG_KPROBES) += kprobes.o +obj-$(CONFIG_UPROBES) += uprobes.o obj-$(CONFIG_PPC_UDBG_16550) += legacy_serial.o udbg_16550.o obj-$(CONFIG_STACKTRACE) += stacktrace.o obj-$(CONFIG_SWIOTLB) += dma-swiotlb.o diff --git a/arch/powerpc/kernel/signal.c b/arch/powerpc/kernel/signal.c index 5c023c9cf16e..29be2712e560 100644 --- a/arch/powerpc/kernel/signal.c +++ b/arch/powerpc/kernel/signal.c @@ -11,6 +11,7 @@ #include <linux/tracehook.h> #include <linux/signal.h> +#include <linux/uprobes.h> #include <linux/key.h> #include <asm/hw_breakpoint.h> #include <asm/uaccess.h> @@ -157,6 +158,11 @@ static int do_signal(struct pt_regs *regs) void do_notify_resume(struct pt_regs *regs, unsigned long thread_info_flags) { + if (thread_info_flags & _TIF_UPROBE) { + clear_thread_flag(TIF_UPROBE); + uprobe_notify_resume(regs); + } + if (thread_info_flags & _TIF_SIGPENDING) do_signal(regs); diff --git a/arch/powerpc/kernel/uprobes.c b/arch/powerpc/kernel/uprobes.c new file mode 100644 index 000000000000..d2d46d1014f8 --- /dev/null +++ b/arch/powerpc/kernel/uprobes.c @@ -0,0 +1,184 @@ +/* + * User-space Probes (UProbes) for powerpc + * + * 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 of the License, 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. + * + * 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. + * + * Copyright IBM Corporation, 2007-2012 + * + * Adapted from the x86 port by Ananth N Mavinakayanahalli <ananth@in.ibm.com> + */ +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/ptrace.h> +#include <linux/uprobes.h> +#include <linux/uaccess.h> +#include <linux/kdebug.h> + +#include <asm/sstep.h> + +#define UPROBE_TRAP_NR UINT_MAX + +/** + * arch_uprobe_analyze_insn + * @mm: the probed address space. + * @arch_uprobe: the probepoint information. + * @addr: vaddr to probe. + * Return 0 on success or a -ve number on error. + */ +int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, + struct mm_struct *mm, unsigned long addr) +{ + if (addr & 0x03) + return -EINVAL; + + /* + * We currently don't support a uprobe on an already + * existing breakpoint instruction underneath + */ + if (is_trap(auprobe->ainsn)) + return -ENOTSUPP; + return 0; +} + +/* + * arch_uprobe_pre_xol - prepare to execute out of line. + * @auprobe: the probepoint information. + * @regs: reflects the saved user state of current task. + */ +int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct arch_uprobe_task *autask = ¤t->utask->autask; + + autask->saved_trap_nr = current->thread.trap_nr; + current->thread.trap_nr = UPROBE_TRAP_NR; + regs->nip = current->utask->xol_vaddr; + return 0; +} + +/** + * uprobe_get_swbp_addr - compute address of swbp given post-swbp regs + * @regs: Reflects the saved state of the task after it has hit a breakpoint + * instruction. + * Return the address of the breakpoint instruction. + */ +unsigned long uprobe_get_swbp_addr(struct pt_regs *regs) +{ + return instruction_pointer(regs); +} + +/* + * If xol insn itself traps and generates a signal (SIGILL/SIGSEGV/etc), + * then detect the case where a singlestepped instruction jumps back to its + * own address. It is assumed that anything like do_page_fault/do_trap/etc + * sets thread.trap_nr != UINT_MAX. + * + * arch_uprobe_pre_xol/arch_uprobe_post_xol save/restore thread.trap_nr, + * arch_uprobe_xol_was_trapped() simply checks that ->trap_nr is not equal to + * UPROBE_TRAP_NR == UINT_MAX set by arch_uprobe_pre_xol(). + */ +bool arch_uprobe_xol_was_trapped(struct task_struct *t) +{ + if (t->thread.trap_nr != UPROBE_TRAP_NR) + return true; + + return false; +} + +/* + * Called after single-stepping. To avoid the SMP problems that can + * occur when we temporarily put back the original opcode to + * single-step, we single-stepped a copy of the instruction. + * + * This function prepares to resume execution after the single-step. + */ +int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR); + + current->thread.trap_nr = utask->autask.saved_trap_nr; + + /* + * On powerpc, except for loads and stores, most instructions + * including ones that alter code flow (branches, calls, returns) + * are emulated in the kernel. We get here only if the emulation + * support doesn't exist and have to fix-up the next instruction + * to be executed. + */ + regs->nip = utask->vaddr + MAX_UINSN_BYTES; + return 0; +} + +/* callback routine for handling exceptions. */ +int arch_uprobe_exception_notify(struct notifier_block *self, + unsigned long val, void *data) +{ + struct die_args *args = data; + struct pt_regs *regs = args->regs; + + /* regs == NULL is a kernel bug */ + if (WARN_ON(!regs)) + return NOTIFY_DONE; + + /* We are only interested in userspace traps */ + if (!user_mode(regs)) + return NOTIFY_DONE; + + switch (val) { + case DIE_BPT: + if (uprobe_pre_sstep_notifier(regs)) + return NOTIFY_STOP; + break; + case DIE_SSTEP: + if (uprobe_post_sstep_notifier(regs)) + return NOTIFY_STOP; + default: + break; + } + return NOTIFY_DONE; +} + +/* + * This function gets called when XOL instruction either gets trapped or + * the thread has a fatal signal, so reset the instruction pointer to its + * probed address. + */ +void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + struct uprobe_task *utask = current->utask; + + current->thread.trap_nr = utask->autask.saved_trap_nr; + instruction_pointer_set(regs, utask->vaddr); +} + +/* + * See if the instruction can be emulated. + * Returns true if instruction was emulated, false otherwise. + */ +bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs) +{ + int ret; + + /* + * emulate_step() returns 1 if the insn was successfully emulated. + * For all other cases, we need to single-step in hardware. + */ + ret = emulate_step(regs, auprobe->ainsn); + if (ret > 0) + return true; + + return false; +} |