- 根目录:
- arch
- arm64
- kernel
- traps.c
/*
* 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 <http://www.gnu.org/licenses/>.
*/
#include <linux/bug.h>
#include <linux/signal.h>
#include <linux/personality.h>
#include <linux/kallsyms.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/kexec.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/syscalls.h>
#include <asm/atomic.h>
#include <asm/bug.h>
#include <asm/debug-monitors.h>
#include <asm/esr.h>
#include <asm/insn.h>
#include <asm/traps.h>
#include <asm/stacktrace.h>
#include <asm/exception.h>
#include <asm/system_misc.h>
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, bool compat)
{
unsigned long first;
mm_segment_t fs;
int i;
unsigned int width = compat ? 4 : 8;
/*
* 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 < (32 / width)
&& p < top; i++, p += width) {
if (p >= bottom && p < top) {
unsigned long val;
if (width == 8) {
if (__get_user(val, (unsigned long *)p) == 0)
sprintf(str + i * 17, " %016lx", val);
else
sprintf(str + i * 17, " ????????????????");
} else {
if (__get_user(val, (unsigned int *)p) == 0)
sprintf(str + i * 9, " %08lx", 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)
{
/*
* Note that 'where' can have a physical address, but it's not handled.
*/
print_ip_sym(where);
}
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;
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_stack_pointer;
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);
}
pr_emerg("Call trace:\n");
while (1) {
unsigned long where = frame.pc;
unsigned long stack;
int ret;
dump_backtrace_entry(where);
ret = unwind_frame(&frame);
if (ret < 0)
break;
stack = frame.sp;
if (in_exception_text(where))
dump_mem("", "Exception stack", stack,
stack + sizeof(struct pt_regs), false);
}
}
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
#define S_SMP " SMP"
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),
compat_user_mode(regs));
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, LOCKDEP_NOW_UNRELIABLE);
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)) {
current->thread.fault_address = 0;
current->thread.fault_code = err;
force_sig_info(info->si_signo, info, current);
} else {
die(str, regs, err);
}
}
static LIST_HEAD(undef_hook);
static DEFINE_RAW_SPINLOCK(undef_lock);
void register_undef_hook(struct undef_hook *hook)
{
unsigned long flags;
raw_spin_lock_irqsave(&undef_lock, flags);
list_add(&hook->node, &undef_hook);
raw_spin_unlock_irqrestore(&undef_lock, flags);
}
void unregister_undef_hook(struct undef_hook *hook)
{
unsigned long flags;
raw_spin_lock_irqsave(&undef_lock, flags);
list_del(&hook->node);
raw_spin_unlock_irqrestore(&undef_lock, flags);
}
static int call_undef_hook(struct pt_regs *regs)
{
struct undef_hook *hook;
unsigned long flags;
u32 instr;
int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
void __user *pc = (void __user *)instruction_pointer(regs);
if (!user_mode(regs))
return 1;
if (compat_thumb_mode(regs)) {
/* 16-bit Thumb instruction */
if (get_user(instr, (u16 __user *)pc))
goto exit;
instr = le16_to_cpu(instr);
if (aarch32_insn_is_wide(instr)) {
u32 instr2;
if (get_user(instr2, (u16 __user *)(pc + 2)))
goto exit;
instr2 = le16_to_cpu(instr2);
instr = (instr << 16) | instr2;
}
} else {
/* 32-bit ARM instruction */
if (get_user(instr, (u32 __user *)pc))
goto exit;
instr = le32_to_cpu(instr);
}
raw_spin_lock_irqsave(&undef_lock, flags);
list_for_each_entry(hook, &undef_hook, node)
if ((instr & hook->instr_mask) == hook->instr_val &&
(regs->pstate & hook->pstate_mask) == hook->pstate_val)
fn = hook->fn;
raw_spin_unlock_irqrestore(&undef_lock, flags);
exit:
return fn ? fn(regs, instr) : 1;
}
asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
{
siginfo_t info;
void __user *pc = (void __user *)instruction_pointer(regs);
/* check for AArch32 breakpoint instructions */
if (!aarch32_break_handler(regs))
return;
if (call_undef_hook(regs) == 0)
return;
if (unhandled_signal(current, SIGILL) && show_unhandled_signals_ratelimited()) {
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_ratelimited()) {
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();
}
static const char *esr_class_str[] = {
[0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
[ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
[ESR_ELx_EC_WFx] = "WFI/WFE",
[ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
[ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
[ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
[ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
[ESR_ELx_EC_FP_ASIMD] = "ASIMD",
[ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
[ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
[ESR_ELx_EC_ILL] = "PSTATE.IL",
[ESR_ELx_EC_SVC32] = "SVC (AArch32)",
[ESR_ELx_EC_HVC32] = "HVC (AArch32)",
[ESR_ELx_EC_SMC32] = "SMC (AArch32)",
[ESR_ELx_EC_SVC64] = "SVC (AArch64)",
[ESR_ELx_EC_HVC64] = "HVC (AArch64)",
[ESR_ELx_EC_SMC64] = "SMC (AArch64)",
[ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
[ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
[ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
[ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
[ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
[ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
[ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
[ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
[ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
[ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
[ESR_ELx_EC_SERROR] = "SError",
[ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
[ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
[ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
[ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
[ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
[ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
[ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
[ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
[ESR_ELx_EC_BRK64] = "BRK (AArch64)",
};
const char *esr_get_class_string(u32 esr)
{
return esr_class_str[esr >> ESR_ELx_EC_SHIFT];
}
/*
* bad_mode handles the impossible case in the exception vector.
*/
asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
{
siginfo_t info;
void __user *pc = (void __user *)instruction_pointer(regs);
console_verbose();
pr_crit("Bad mode in %s handler detected, code 0x%08x -- %s\n",
handler[reason], esr, esr_get_class_string(esr));
__show_regs(regs);
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLOPC;
info.si_addr = pc;
arm64_notify_die("Oops - bad mode", regs, &info, 0);
}
void __pte_error(const char *file, int line, unsigned long val)
{
pr_crit("%s:%d: bad pte %016lx.\n", file, line, val);
}
void __pmd_error(const char *file, int line, unsigned long val)
{
pr_crit("%s:%d: bad pmd %016lx.\n", file, line, val);
}
void __pud_error(const char *file, int line, unsigned long val)
{
pr_crit("%s:%d: bad pud %016lx.\n", file, line, val);
}
void __pgd_error(const char *file, int line, unsigned long val)
{
pr_crit("%s:%d: bad pgd %016lx.\n", file, line, val);
}
/* GENERIC_BUG traps */
int is_valid_bugaddr(unsigned long addr)
{
/*
* bug_handler() only called for BRK #BUG_BRK_IMM.
* So the answer is trivial -- any spurious instances with no
* bug table entry will be rejected by report_bug() and passed
* back to the debug-monitors code and handled as a fatal
* unexpected debug exception.
*/
return 1;
}
static int bug_handler(struct pt_regs *regs, unsigned int esr)
{
if (user_mode(regs))
return DBG_HOOK_ERROR;
switch (report_bug(regs->pc, regs)) {
case BUG_TRAP_TYPE_BUG:
die("Oops - BUG", regs, 0);
break;
case BUG_TRAP_TYPE_WARN:
/* Ideally, report_bug() should backtrace for us... but no. */
dump_backtrace(regs, NULL);
break;
default:
/* unknown/unrecognised bug trap type */
return DBG_HOOK_ERROR;
}
/* If thread survives, skip over the BUG instruction and continue: */
regs->pc += AARCH64_INSN_SIZE; /* skip BRK and resume */
return DBG_HOOK_HANDLED;
}
static struct break_hook bug_break_hook = {
.esr_val = 0xf2000000 | BUG_BRK_IMM,
.esr_mask = 0xffffffff,
.fn = bug_handler,
};
/*
* Initial handler for AArch64 BRK exceptions
* This handler only used until debug_traps_init().
*/
int __init early_brk64(unsigned long addr, unsigned int esr,
struct pt_regs *regs)
{
return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
}
/* This registration must happen early, before debug_traps_init(). */
void __init trap_init(void)
{
register_break_hook(&bug_break_hook);
}