From 60ffc30d5652810dd34ea2eec41504222f5d5791 Mon Sep 17 00:00:00 2001 From: Catalin Marinas Date: Mon, 5 Mar 2012 11:49:27 +0000 Subject: arm64: Exception handling The patch contains the exception entry code (kernel/entry.S), pt_regs structure and related accessors, undefined instruction trapping and stack tracing. AArch64 Linux kernel (including kernel threads) runs in EL1 mode using the SP1 stack. The vectors don't have a fixed address, only alignment (2^11) requirements. Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Acked-by: Tony Lindgren Acked-by: Nicolas Pitre Acked-by: Olof Johansson Acked-by: Santosh Shilimkar Acked-by: Arnd Bergmann --- arch/arm64/kernel/traps.c | 348 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 348 insertions(+) create mode 100644 arch/arm64/kernel/traps.c (limited to 'arch/arm64/kernel/traps.c') diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c new file mode 100644 index 000000000000..3883f842434f --- /dev/null +++ b/arch/arm64/kernel/traps.c @@ -0,0 +1,348 @@ +/* + * Based on arch/arm/kernel/traps.c + * + * Copyright (C) 1995-2009 Russell King + * Copyright (C) 2012 ARM Ltd. + * + * 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, see . + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#include +#include +#include + +static const char *handler[]= { + "Synchronous Abort", + "IRQ", + "FIQ", + "Error" +}; + +int show_unhandled_signals = 1; + +/* + * Dump out the contents of some memory nicely... + */ +static void dump_mem(const char *lvl, const char *str, unsigned long bottom, + unsigned long top) +{ + unsigned long first; + mm_segment_t fs; + int i; + + /* + * We need to switch to kernel mode so that we can use __get_user + * to safely read from kernel space. Note that we now dump the + * code first, just in case the backtrace kills us. + */ + fs = get_fs(); + set_fs(KERNEL_DS); + + printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top); + + for (first = bottom & ~31; first < top; first += 32) { + unsigned long p; + char str[sizeof(" 12345678") * 8 + 1]; + + memset(str, ' ', sizeof(str)); + str[sizeof(str) - 1] = '\0'; + + for (p = first, i = 0; i < 8 && p < top; i++, p += 4) { + if (p >= bottom && p < top) { + unsigned int val; + if (__get_user(val, (unsigned int *)p) == 0) + sprintf(str + i * 9, " %08x", val); + else + sprintf(str + i * 9, " ????????"); + } + } + printk("%s%04lx:%s\n", lvl, first & 0xffff, str); + } + + set_fs(fs); +} + +static void dump_backtrace_entry(unsigned long where, unsigned long stack) +{ + print_ip_sym(where); + if (in_exception_text(where)) + dump_mem("", "Exception stack", stack, + stack + sizeof(struct pt_regs)); +} + +static void dump_instr(const char *lvl, struct pt_regs *regs) +{ + unsigned long addr = instruction_pointer(regs); + mm_segment_t fs; + char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str; + int i; + + /* + * We need to switch to kernel mode so that we can use __get_user + * to safely read from kernel space. Note that we now dump the + * code first, just in case the backtrace kills us. + */ + fs = get_fs(); + set_fs(KERNEL_DS); + + for (i = -4; i < 1; i++) { + unsigned int val, bad; + + bad = __get_user(val, &((u32 *)addr)[i]); + + if (!bad) + p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val); + else { + p += sprintf(p, "bad PC value"); + break; + } + } + printk("%sCode: %s\n", lvl, str); + + set_fs(fs); +} + +static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk) +{ + struct stackframe frame; + const register unsigned long current_sp asm ("sp"); + + pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk); + + if (!tsk) + tsk = current; + + if (regs) { + frame.fp = regs->regs[29]; + frame.sp = regs->sp; + frame.pc = regs->pc; + } else if (tsk == current) { + frame.fp = (unsigned long)__builtin_frame_address(0); + frame.sp = current_sp; + frame.pc = (unsigned long)dump_backtrace; + } else { + /* + * task blocked in __switch_to + */ + frame.fp = thread_saved_fp(tsk); + frame.sp = thread_saved_sp(tsk); + frame.pc = thread_saved_pc(tsk); + } + + printk("Call trace:\n"); + while (1) { + unsigned long where = frame.pc; + int ret; + + ret = unwind_frame(&frame); + if (ret < 0) + break; + dump_backtrace_entry(where, frame.sp); + } +} + +void dump_stack(void) +{ + dump_backtrace(NULL, NULL); +} + +EXPORT_SYMBOL(dump_stack); + +void show_stack(struct task_struct *tsk, unsigned long *sp) +{ + dump_backtrace(NULL, tsk); + barrier(); +} + +#ifdef CONFIG_PREEMPT +#define S_PREEMPT " PREEMPT" +#else +#define S_PREEMPT "" +#endif +#ifdef CONFIG_SMP +#define S_SMP " SMP" +#else +#define S_SMP "" +#endif + +static int __die(const char *str, int err, struct thread_info *thread, + struct pt_regs *regs) +{ + struct task_struct *tsk = thread->task; + static int die_counter; + int ret; + + pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n", + str, err, ++die_counter); + + /* trap and error numbers are mostly meaningless on ARM */ + ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV); + if (ret == NOTIFY_STOP) + return ret; + + print_modules(); + __show_regs(regs); + pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n", + TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), thread + 1); + + if (!user_mode(regs) || in_interrupt()) { + dump_mem(KERN_EMERG, "Stack: ", regs->sp, + THREAD_SIZE + (unsigned long)task_stack_page(tsk)); + dump_backtrace(regs, tsk); + dump_instr(KERN_EMERG, regs); + } + + return ret; +} + +static DEFINE_RAW_SPINLOCK(die_lock); + +/* + * This function is protected against re-entrancy. + */ +void die(const char *str, struct pt_regs *regs, int err) +{ + struct thread_info *thread = current_thread_info(); + int ret; + + oops_enter(); + + raw_spin_lock_irq(&die_lock); + console_verbose(); + bust_spinlocks(1); + ret = __die(str, err, thread, regs); + + if (regs && kexec_should_crash(thread->task)) + crash_kexec(regs); + + bust_spinlocks(0); + add_taint(TAINT_DIE); + raw_spin_unlock_irq(&die_lock); + oops_exit(); + + if (in_interrupt()) + panic("Fatal exception in interrupt"); + if (panic_on_oops) + panic("Fatal exception"); + if (ret != NOTIFY_STOP) + do_exit(SIGSEGV); +} + +void arm64_notify_die(const char *str, struct pt_regs *regs, + struct siginfo *info, int err) +{ + if (user_mode(regs)) + force_sig_info(info->si_signo, info, current); + else + die(str, regs, err); +} + +asmlinkage void __exception do_undefinstr(struct pt_regs *regs) +{ + siginfo_t info; + void __user *pc = (void __user *)instruction_pointer(regs); + +#ifdef CONFIG_COMPAT + /* check for AArch32 breakpoint instructions */ + if (compat_user_mode(regs) && aarch32_break_trap(regs) == 0) + return; +#endif + + if (show_unhandled_signals) { + pr_info("%s[%d]: undefined instruction: pc=%p\n", + current->comm, task_pid_nr(current), pc); + dump_instr(KERN_INFO, regs); + } + + info.si_signo = SIGILL; + info.si_errno = 0; + info.si_code = ILL_ILLOPC; + info.si_addr = pc; + + arm64_notify_die("Oops - undefined instruction", regs, &info, 0); +} + +long compat_arm_syscall(struct pt_regs *regs); + +asmlinkage long do_ni_syscall(struct pt_regs *regs) +{ +#ifdef CONFIG_COMPAT + long ret; + if (is_compat_task()) { + ret = compat_arm_syscall(regs); + if (ret != -ENOSYS) + return ret; + } +#endif + + if (show_unhandled_signals) { + pr_info("%s[%d]: syscall %d\n", current->comm, + task_pid_nr(current), (int)regs->syscallno); + dump_instr("", regs); + if (user_mode(regs)) + __show_regs(regs); + } + + return sys_ni_syscall(); +} + +/* + * bad_mode handles the impossible case in the exception vector. + */ +asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr) +{ + console_verbose(); + + pr_crit("Bad mode in %s handler detected, code 0x%08x\n", + handler[reason], esr); + + die("Oops - bad mode", regs, 0); + local_irq_disable(); + panic("bad mode"); +} + +void __pte_error(const char *file, int line, unsigned long val) +{ + printk("%s:%d: bad pte %016lx.\n", file, line, val); +} + +void __pmd_error(const char *file, int line, unsigned long val) +{ + printk("%s:%d: bad pmd %016lx.\n", file, line, val); +} + +void __pgd_error(const char *file, int line, unsigned long val) +{ + printk("%s:%d: bad pgd %016lx.\n", file, line, val); +} + +void __init trap_init(void) +{ + return; +} -- cgit v1.2.3