2 * Based on arch/arm/kernel/traps.c
4 * Copyright (C) 1995-2009 Russell King
5 * Copyright (C) 2012 ARM Ltd.
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
20 #include <linux/bug.h>
21 #include <linux/signal.h>
22 #include <linux/personality.h>
23 #include <linux/kallsyms.h>
24 #include <linux/spinlock.h>
25 #include <linux/uaccess.h>
26 #include <linux/hardirq.h>
27 #include <linux/kdebug.h>
28 #include <linux/module.h>
29 #include <linux/kexec.h>
30 #include <linux/delay.h>
31 #include <linux/init.h>
32 #include <linux/sched.h>
33 #include <linux/syscalls.h>
35 #include <asm/atomic.h>
37 #include <asm/debug-monitors.h>
40 #include <asm/traps.h>
41 #include <asm/stack_pointer.h>
42 #include <asm/stacktrace.h>
43 #include <asm/exception.h>
44 #include <asm/system_misc.h>
45 #include <asm/sysreg.h>
47 static const char *handler[]= {
54 int show_unhandled_signals = 1;
57 * Dump out the contents of some kernel memory nicely...
59 static void dump_mem(const char *lvl, const char *str, unsigned long bottom,
67 * We need to switch to kernel mode so that we can use __get_user
68 * to safely read from kernel space.
73 printk("%s%s(0x%016lx to 0x%016lx)\n", lvl, str, bottom, top);
75 for (first = bottom & ~31; first < top; first += 32) {
77 char str[sizeof(" 12345678") * 8 + 1];
79 memset(str, ' ', sizeof(str));
80 str[sizeof(str) - 1] = '\0';
82 for (p = first, i = 0; i < (32 / 8)
83 && p < top; i++, p += 8) {
84 if (p >= bottom && p < top) {
87 if (__get_user(val, (unsigned long *)p) == 0)
88 sprintf(str + i * 17, " %016lx", val);
90 sprintf(str + i * 17, " ????????????????");
93 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
99 static void dump_backtrace_entry(unsigned long where)
102 * Note that 'where' can have a physical address, but it's not handled.
107 static void __dump_instr(const char *lvl, struct pt_regs *regs)
109 unsigned long addr = instruction_pointer(regs);
110 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
113 for (i = -4; i < 1; i++) {
114 unsigned int val, bad;
116 bad = __get_user(val, &((u32 *)addr)[i]);
119 p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
121 p += sprintf(p, "bad PC value");
125 printk("%sCode: %s\n", lvl, str);
128 static void dump_instr(const char *lvl, struct pt_regs *regs)
130 if (!user_mode(regs)) {
131 mm_segment_t fs = get_fs();
133 __dump_instr(lvl, regs);
136 __dump_instr(lvl, regs);
140 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
142 struct stackframe frame;
143 unsigned long irq_stack_ptr;
146 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
151 if (!try_get_task_stack(tsk))
155 * Switching between stacks is valid when tracing current and in
156 * non-preemptible context.
158 if (tsk == current && !preemptible())
159 irq_stack_ptr = IRQ_STACK_PTR(smp_processor_id());
163 if (tsk == current) {
164 frame.fp = (unsigned long)__builtin_frame_address(0);
165 frame.sp = current_stack_pointer;
166 frame.pc = (unsigned long)dump_backtrace;
169 * task blocked in __switch_to
171 frame.fp = thread_saved_fp(tsk);
172 frame.sp = thread_saved_sp(tsk);
173 frame.pc = thread_saved_pc(tsk);
175 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
176 frame.graph = tsk->curr_ret_stack;
180 printk("Call trace:\n");
182 unsigned long where = frame.pc;
186 /* skip until specified stack frame */
188 dump_backtrace_entry(where);
189 } else if (frame.fp == regs->regs[29]) {
192 * Mostly, this is the case where this function is
193 * called in panic/abort. As exception handler's
194 * stack frame does not contain the corresponding pc
195 * at which an exception has taken place, use regs->pc
198 dump_backtrace_entry(regs->pc);
200 ret = unwind_frame(tsk, &frame);
204 if (in_exception_text(where)) {
206 * If we switched to the irq_stack before calling this
207 * exception handler, then the pt_regs will be on the
208 * task stack. The easiest way to tell is if the large
209 * pt_regs would overlap with the end of the irq_stack.
211 if (stack < irq_stack_ptr &&
212 (stack + sizeof(struct pt_regs)) > irq_stack_ptr)
213 stack = IRQ_STACK_TO_TASK_STACK(irq_stack_ptr);
215 dump_mem("", "Exception stack", stack,
216 stack + sizeof(struct pt_regs));
223 void show_stack(struct task_struct *tsk, unsigned long *sp)
225 dump_backtrace(NULL, tsk);
229 #ifdef CONFIG_PREEMPT
230 #define S_PREEMPT " PREEMPT"
236 static int __die(const char *str, int err, struct pt_regs *regs)
238 struct task_struct *tsk = current;
239 static int die_counter;
242 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP "\n",
243 str, err, ++die_counter);
245 /* trap and error numbers are mostly meaningless on ARM */
246 ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
247 if (ret == NOTIFY_STOP)
252 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
253 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk),
256 if (!user_mode(regs)) {
257 dump_mem(KERN_EMERG, "Stack: ", regs->sp,
258 THREAD_SIZE + (unsigned long)task_stack_page(tsk));
259 dump_backtrace(regs, tsk);
260 dump_instr(KERN_EMERG, regs);
266 static DEFINE_RAW_SPINLOCK(die_lock);
269 * This function is protected against re-entrancy.
271 void die(const char *str, struct pt_regs *regs, int err)
277 raw_spin_lock_irq(&die_lock);
280 ret = __die(str, err, regs);
282 if (regs && kexec_should_crash(current))
286 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
287 raw_spin_unlock_irq(&die_lock);
291 panic("Fatal exception in interrupt");
293 panic("Fatal exception");
294 if (ret != NOTIFY_STOP)
298 void arm64_notify_die(const char *str, struct pt_regs *regs,
299 struct siginfo *info, int err)
301 if (user_mode(regs)) {
302 current->thread.fault_address = 0;
303 current->thread.fault_code = err;
304 force_sig_info(info->si_signo, info, current);
310 static LIST_HEAD(undef_hook);
311 static DEFINE_RAW_SPINLOCK(undef_lock);
313 void register_undef_hook(struct undef_hook *hook)
317 raw_spin_lock_irqsave(&undef_lock, flags);
318 list_add(&hook->node, &undef_hook);
319 raw_spin_unlock_irqrestore(&undef_lock, flags);
322 void unregister_undef_hook(struct undef_hook *hook)
326 raw_spin_lock_irqsave(&undef_lock, flags);
327 list_del(&hook->node);
328 raw_spin_unlock_irqrestore(&undef_lock, flags);
331 static int call_undef_hook(struct pt_regs *regs)
333 struct undef_hook *hook;
336 int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
337 void __user *pc = (void __user *)instruction_pointer(regs);
339 if (!user_mode(regs))
342 if (compat_thumb_mode(regs)) {
343 /* 16-bit Thumb instruction */
344 if (get_user(instr, (u16 __user *)pc))
346 instr = le16_to_cpu(instr);
347 if (aarch32_insn_is_wide(instr)) {
350 if (get_user(instr2, (u16 __user *)(pc + 2)))
352 instr2 = le16_to_cpu(instr2);
353 instr = (instr << 16) | instr2;
356 /* 32-bit ARM instruction */
357 if (get_user(instr, (u32 __user *)pc))
359 instr = le32_to_cpu(instr);
362 raw_spin_lock_irqsave(&undef_lock, flags);
363 list_for_each_entry(hook, &undef_hook, node)
364 if ((instr & hook->instr_mask) == hook->instr_val &&
365 (regs->pstate & hook->pstate_mask) == hook->pstate_val)
368 raw_spin_unlock_irqrestore(&undef_lock, flags);
370 return fn ? fn(regs, instr) : 1;
373 static void force_signal_inject(int signal, int code, struct pt_regs *regs,
374 unsigned long address)
377 void __user *pc = (void __user *)instruction_pointer(regs);
382 desc = "undefined instruction";
385 desc = "illegal memory access";
392 if (unhandled_signal(current, signal) &&
393 show_unhandled_signals_ratelimited()) {
394 pr_info("%s[%d]: %s: pc=%p\n",
395 current->comm, task_pid_nr(current), desc, pc);
396 dump_instr(KERN_INFO, regs);
399 info.si_signo = signal;
404 arm64_notify_die(desc, regs, &info, 0);
408 * Set up process info to signal segmentation fault - called on access error.
410 void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
414 down_read(¤t->mm->mmap_sem);
415 if (find_vma(current->mm, addr) == NULL)
419 up_read(¤t->mm->mmap_sem);
421 force_signal_inject(SIGSEGV, code, regs, addr);
424 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
426 /* check for AArch32 breakpoint instructions */
427 if (!aarch32_break_handler(regs))
430 if (call_undef_hook(regs) == 0)
433 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
436 int cpu_enable_cache_maint_trap(void *__unused)
438 config_sctlr_el1(SCTLR_EL1_UCI, 0);
442 #define __user_cache_maint(insn, address, res) \
443 if (untagged_addr(address) >= user_addr_max()) { \
446 uaccess_ttbr0_enable(); \
448 "1: " insn ", %1\n" \
451 " .pushsection .fixup,\"ax\"\n" \
453 "3: mov %w0, %w2\n" \
456 _ASM_EXTABLE(1b, 3b) \
458 : "r" (address), "i" (-EFAULT)); \
459 uaccess_ttbr0_disable(); \
462 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
464 unsigned long address;
465 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
466 int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
469 address = (rt == 31) ? 0 : regs->regs[rt];
472 case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */
473 __user_cache_maint("dc civac", address, ret);
475 case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */
476 __user_cache_maint("dc civac", address, ret);
478 case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */
479 __user_cache_maint("dc civac", address, ret);
481 case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */
482 __user_cache_maint("ic ivau", address, ret);
485 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
490 arm64_notify_segfault(regs, address);
495 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
497 int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
499 regs->regs[rt] = arm64_ftr_reg_ctrel0.sys_val;
504 unsigned int esr_mask;
505 unsigned int esr_val;
506 void (*handler)(unsigned int esr, struct pt_regs *regs);
509 static struct sys64_hook sys64_hooks[] = {
511 .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
512 .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
513 .handler = user_cache_maint_handler,
516 /* Trap read access to CTR_EL0 */
517 .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
518 .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
519 .handler = ctr_read_handler,
524 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
526 struct sys64_hook *hook;
528 for (hook = sys64_hooks; hook->handler; hook++)
529 if ((hook->esr_mask & esr) == hook->esr_val) {
530 hook->handler(esr, regs);
534 force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
537 long compat_arm_syscall(struct pt_regs *regs);
539 asmlinkage long do_ni_syscall(struct pt_regs *regs)
543 if (is_compat_task()) {
544 ret = compat_arm_syscall(regs);
550 if (show_unhandled_signals_ratelimited()) {
551 pr_info("%s[%d]: syscall %d\n", current->comm,
552 task_pid_nr(current), (int)regs->syscallno);
553 dump_instr("", regs);
558 return sys_ni_syscall();
561 static const char *esr_class_str[] = {
562 [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
563 [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
564 [ESR_ELx_EC_WFx] = "WFI/WFE",
565 [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
566 [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
567 [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
568 [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
569 [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
570 [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
571 [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
572 [ESR_ELx_EC_ILL] = "PSTATE.IL",
573 [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
574 [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
575 [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
576 [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
577 [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
578 [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
579 [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
580 [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
581 [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
582 [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
583 [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
584 [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
585 [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
586 [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
587 [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
588 [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
589 [ESR_ELx_EC_SERROR] = "SError",
590 [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
591 [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
592 [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
593 [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
594 [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
595 [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
596 [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
597 [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
598 [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
601 const char *esr_get_class_string(u32 esr)
603 return esr_class_str[ESR_ELx_EC(esr)];
607 * bad_mode handles the impossible case in the exception vector.
609 asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
612 void __user *pc = (void __user *)instruction_pointer(regs);
615 pr_crit("Bad mode in %s handler detected on CPU%d, code 0x%08x -- %s\n",
616 handler[reason], smp_processor_id(), esr,
617 esr_get_class_string(esr));
620 info.si_signo = SIGILL;
622 info.si_code = ILL_ILLOPC;
625 arm64_notify_die("Oops - bad mode", regs, &info, 0);
628 void __pte_error(const char *file, int line, unsigned long val)
630 pr_err("%s:%d: bad pte %016lx.\n", file, line, val);
633 void __pmd_error(const char *file, int line, unsigned long val)
635 pr_err("%s:%d: bad pmd %016lx.\n", file, line, val);
638 void __pud_error(const char *file, int line, unsigned long val)
640 pr_err("%s:%d: bad pud %016lx.\n", file, line, val);
643 void __pgd_error(const char *file, int line, unsigned long val)
645 pr_err("%s:%d: bad pgd %016lx.\n", file, line, val);
648 /* GENERIC_BUG traps */
650 int is_valid_bugaddr(unsigned long addr)
653 * bug_handler() only called for BRK #BUG_BRK_IMM.
654 * So the answer is trivial -- any spurious instances with no
655 * bug table entry will be rejected by report_bug() and passed
656 * back to the debug-monitors code and handled as a fatal
657 * unexpected debug exception.
662 static int bug_handler(struct pt_regs *regs, unsigned int esr)
665 return DBG_HOOK_ERROR;
667 switch (report_bug(regs->pc, regs)) {
668 case BUG_TRAP_TYPE_BUG:
669 die("Oops - BUG", regs, 0);
672 case BUG_TRAP_TYPE_WARN:
673 /* Ideally, report_bug() should backtrace for us... but no. */
674 dump_backtrace(regs, NULL);
678 /* unknown/unrecognised bug trap type */
679 return DBG_HOOK_ERROR;
682 /* If thread survives, skip over the BUG instruction and continue: */
683 regs->pc += AARCH64_INSN_SIZE; /* skip BRK and resume */
684 return DBG_HOOK_HANDLED;
687 static struct break_hook bug_break_hook = {
688 .esr_val = 0xf2000000 | BUG_BRK_IMM,
689 .esr_mask = 0xffffffff,
694 * Initial handler for AArch64 BRK exceptions
695 * This handler only used until debug_traps_init().
697 int __init early_brk64(unsigned long addr, unsigned int esr,
698 struct pt_regs *regs)
700 return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
703 /* This registration must happen early, before debug_traps_init(). */
704 void __init trap_init(void)
706 register_break_hook(&bug_break_hook);