1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/arch/arm/kernel/traps.c
5 * Copyright (C) 1995-2009 Russell King
6 * Fragments that appear the same as linux/arch/i386/kernel/traps.c (C) Linus Torvalds
8 * 'traps.c' handles hardware exceptions after we have saved some state in
9 * 'linux/arch/arm/lib/traps.S'. Mostly a debugging aid, but will probably
10 * kill the offending process.
12 #include <linux/signal.h>
13 #include <linux/personality.h>
14 #include <linux/kallsyms.h>
15 #include <linux/spinlock.h>
16 #include <linux/uaccess.h>
17 #include <linux/hardirq.h>
18 #include <linux/kdebug.h>
19 #include <linux/kprobes.h>
20 #include <linux/module.h>
21 #include <linux/kexec.h>
22 #include <linux/bug.h>
23 #include <linux/delay.h>
24 #include <linux/init.h>
25 #include <linux/sched/signal.h>
26 #include <linux/sched/debug.h>
27 #include <linux/sched/task_stack.h>
28 #include <linux/irq.h>
30 #include <linux/atomic.h>
31 #include <asm/cacheflush.h>
32 #include <asm/exception.h>
33 #include <asm/spectre.h>
34 #include <asm/unistd.h>
35 #include <asm/traps.h>
36 #include <asm/ptrace.h>
37 #include <asm/unwind.h>
39 #include <asm/stacktrace.h>
40 #include <asm/system_misc.h>
41 #include <asm/opcodes.h>
44 static const char *handler[]= {
49 "undefined instruction",
54 #ifdef CONFIG_DEBUG_USER
55 unsigned int user_debug;
57 static int __init user_debug_setup(char *str)
59 get_option(&str, &user_debug);
62 __setup("user_debug=", user_debug_setup);
65 void dump_backtrace_entry(unsigned long where, unsigned long from,
66 unsigned long frame, const char *loglvl)
68 unsigned long end = frame + 4 + sizeof(struct pt_regs);
70 if (IS_ENABLED(CONFIG_UNWINDER_FRAME_POINTER) &&
71 IS_ENABLED(CONFIG_CC_IS_GCC) &&
72 end > ALIGN(frame, THREAD_SIZE)) {
74 * If we are walking past the end of the stack, it may be due
75 * to the fact that we are on an IRQ or overflow stack. In this
76 * case, we can load the address of the other stack from the
79 frame = ((unsigned long *)frame)[-2] - 4;
80 end = frame + 4 + sizeof(struct pt_regs);
83 #ifndef CONFIG_KALLSYMS
84 printk("%sFunction entered at [<%08lx>] from [<%08lx>]\n",
86 #elif defined CONFIG_BACKTRACE_VERBOSE
87 printk("%s[<%08lx>] (%ps) from [<%08lx>] (%pS)\n",
88 loglvl, where, (void *)where, from, (void *)from);
90 printk("%s %ps from %pS\n", loglvl, (void *)where, (void *)from);
93 if (in_entry_text(from) && end <= ALIGN(frame, THREAD_SIZE))
94 dump_mem(loglvl, "Exception stack", frame + 4, end);
97 void dump_backtrace_stm(u32 *stack, u32 instruction, const char *loglvl)
103 for (reg = 10, x = 0, p = str; reg >= 0; reg--) {
104 if (instruction & BIT(reg)) {
105 p += sprintf(p, " r%d:%08x", reg, *stack--);
109 printk("%s%s\n", loglvl, str);
114 printk("%s%s\n", loglvl, str);
117 #ifndef CONFIG_ARM_UNWIND
119 * Stack pointers should always be within the kernels view of
120 * physical memory. If it is not there, then we can't dump
121 * out any information relating to the stack.
123 static int verify_stack(unsigned long sp)
125 if (sp < PAGE_OFFSET ||
126 (!IS_ENABLED(CONFIG_VMAP_STACK) &&
127 sp > (unsigned long)high_memory && high_memory != NULL))
135 * Dump out the contents of some memory nicely...
137 void dump_mem(const char *lvl, const char *str, unsigned long bottom,
143 printk("%s%s(0x%08lx to 0x%08lx)\n", lvl, str, bottom, top);
145 for (first = bottom & ~31; first < top; first += 32) {
147 char str[sizeof(" 12345678") * 8 + 1];
149 memset(str, ' ', sizeof(str));
150 str[sizeof(str) - 1] = '\0';
152 for (p = first, i = 0; i < 8 && p < top; i++, p += 4) {
153 if (p >= bottom && p < top) {
155 if (!get_kernel_nofault(val, (unsigned long *)p))
156 sprintf(str + i * 9, " %08lx", val);
158 sprintf(str + i * 9, " ????????");
161 printk("%s%04lx:%s\n", lvl, first & 0xffff, str);
165 static void dump_instr(const char *lvl, struct pt_regs *regs)
167 unsigned long addr = instruction_pointer(regs);
168 const int thumb = thumb_mode(regs);
169 const int width = thumb ? 4 : 8;
170 char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
174 * Note that we now dump the code first, just in case the backtrace
178 for (i = -4; i < 1 + !!thumb; i++) {
179 unsigned int val, bad;
181 if (!user_mode(regs)) {
184 bad = get_kernel_nofault(val16, &((u16 *)addr)[i]);
187 bad = get_kernel_nofault(val, &((u32 *)addr)[i]);
191 bad = get_user(val, &((u16 *)addr)[i]);
193 bad = get_user(val, &((u32 *)addr)[i]);
197 p += sprintf(p, i == 0 ? "(%0*x) " : "%0*x ",
200 p += sprintf(p, "bad PC value");
204 printk("%sCode: %s\n", lvl, str);
207 #ifdef CONFIG_ARM_UNWIND
208 static inline void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
211 unwind_backtrace(regs, tsk, loglvl);
214 static void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
217 unsigned int fp, mode;
220 printk("%sBacktrace: ", loglvl);
226 fp = frame_pointer(regs);
227 mode = processor_mode(regs);
228 } else if (tsk != current) {
229 fp = thread_saved_fp(tsk);
232 asm("mov %0, fp" : "=r" (fp) : : "cc");
237 pr_cont("no frame pointer");
239 } else if (verify_stack(fp)) {
240 pr_cont("invalid frame pointer 0x%08x", fp);
242 } else if (fp < (unsigned long)end_of_stack(tsk))
243 pr_cont("frame pointer underflow");
247 c_backtrace(fp, mode, loglvl);
251 void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
253 dump_backtrace(NULL, tsk, loglvl);
257 #ifdef CONFIG_PREEMPT
258 #define S_PREEMPT " PREEMPT"
259 #elif defined(CONFIG_PREEMPT_RT)
260 #define S_PREEMPT " PREEMPT_RT"
269 #ifdef CONFIG_THUMB2_KERNEL
270 #define S_ISA " THUMB2"
275 static int __die(const char *str, int err, struct pt_regs *regs)
277 struct task_struct *tsk = current;
278 static int die_counter;
281 pr_emerg("Internal error: %s: %x [#%d]" S_PREEMPT S_SMP S_ISA "\n",
282 str, err, ++die_counter);
284 /* trap and error numbers are mostly meaningless on ARM */
285 ret = notify_die(DIE_OOPS, str, regs, err, tsk->thread.trap_no, SIGSEGV);
286 if (ret == NOTIFY_STOP)
291 __show_regs_alloc_free(regs);
292 pr_emerg("Process %.*s (pid: %d, stack limit = 0x%p)\n",
293 TASK_COMM_LEN, tsk->comm, task_pid_nr(tsk), end_of_stack(tsk));
295 if (!user_mode(regs) || in_interrupt()) {
296 dump_mem(KERN_EMERG, "Stack: ", regs->ARM_sp,
297 ALIGN(regs->ARM_sp - THREAD_SIZE, THREAD_ALIGN)
299 dump_backtrace(regs, tsk, KERN_EMERG);
300 dump_instr(KERN_EMERG, regs);
306 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
307 static int die_owner = -1;
308 static unsigned int die_nest_count;
310 static unsigned long oops_begin(void)
317 /* racy, but better than risking deadlock. */
318 raw_local_irq_save(flags);
319 cpu = smp_processor_id();
320 if (!arch_spin_trylock(&die_lock)) {
321 if (cpu == die_owner)
322 /* nested oops. should stop eventually */;
324 arch_spin_lock(&die_lock);
333 static void oops_end(unsigned long flags, struct pt_regs *regs, int signr)
335 if (regs && kexec_should_crash(current))
340 add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
343 /* Nest count reaches zero, release the lock. */
344 arch_spin_unlock(&die_lock);
345 raw_local_irq_restore(flags);
349 panic("Fatal exception in interrupt");
351 panic("Fatal exception");
353 make_task_dead(signr);
357 * This function is protected against re-entrancy.
359 void die(const char *str, struct pt_regs *regs, int err)
361 enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;
362 unsigned long flags = oops_begin();
365 if (!user_mode(regs))
366 bug_type = report_bug(regs->ARM_pc, regs);
367 if (bug_type != BUG_TRAP_TYPE_NONE)
370 if (__die(str, err, regs))
373 oops_end(flags, regs, sig);
376 void arm_notify_die(const char *str, struct pt_regs *regs,
377 int signo, int si_code, void __user *addr,
378 unsigned long err, unsigned long trap)
380 if (user_mode(regs)) {
381 current->thread.error_code = err;
382 current->thread.trap_no = trap;
384 force_sig_fault(signo, si_code, addr);
390 #ifdef CONFIG_GENERIC_BUG
392 int is_valid_bugaddr(unsigned long pc)
394 #ifdef CONFIG_THUMB2_KERNEL
396 u16 insn = __opcode_to_mem_thumb16(BUG_INSTR_VALUE);
399 u32 insn = __opcode_to_mem_arm(BUG_INSTR_VALUE);
402 if (get_kernel_nofault(bkpt, (void *)pc))
410 static LIST_HEAD(undef_hook);
411 static DEFINE_RAW_SPINLOCK(undef_lock);
413 void register_undef_hook(struct undef_hook *hook)
417 raw_spin_lock_irqsave(&undef_lock, flags);
418 list_add(&hook->node, &undef_hook);
419 raw_spin_unlock_irqrestore(&undef_lock, flags);
422 void unregister_undef_hook(struct undef_hook *hook)
426 raw_spin_lock_irqsave(&undef_lock, flags);
427 list_del(&hook->node);
428 raw_spin_unlock_irqrestore(&undef_lock, flags);
431 static nokprobe_inline
432 int call_undef_hook(struct pt_regs *regs, unsigned int instr)
434 struct undef_hook *hook;
436 int (*fn)(struct pt_regs *regs, unsigned int instr) = NULL;
438 raw_spin_lock_irqsave(&undef_lock, flags);
439 list_for_each_entry(hook, &undef_hook, node)
440 if ((instr & hook->instr_mask) == hook->instr_val &&
441 (regs->ARM_cpsr & hook->cpsr_mask) == hook->cpsr_val)
443 raw_spin_unlock_irqrestore(&undef_lock, flags);
445 return fn ? fn(regs, instr) : 1;
448 asmlinkage void do_undefinstr(struct pt_regs *regs)
453 pc = (void __user *)instruction_pointer(regs);
455 if (processor_mode(regs) == SVC_MODE) {
456 #ifdef CONFIG_THUMB2_KERNEL
457 if (thumb_mode(regs)) {
458 instr = __mem_to_opcode_thumb16(((u16 *)pc)[0]);
459 if (is_wide_instruction(instr)) {
461 inst2 = __mem_to_opcode_thumb16(((u16 *)pc)[1]);
462 instr = __opcode_thumb32_compose(instr, inst2);
466 instr = __mem_to_opcode_arm(*(u32 *) pc);
467 } else if (thumb_mode(regs)) {
468 if (get_user(instr, (u16 __user *)pc))
470 instr = __mem_to_opcode_thumb16(instr);
471 if (is_wide_instruction(instr)) {
473 if (get_user(instr2, (u16 __user *)pc+1))
475 instr2 = __mem_to_opcode_thumb16(instr2);
476 instr = __opcode_thumb32_compose(instr, instr2);
479 if (get_user(instr, (u32 __user *)pc))
481 instr = __mem_to_opcode_arm(instr);
484 if (call_undef_hook(regs, instr) == 0)
488 #ifdef CONFIG_DEBUG_USER
489 if (user_debug & UDBG_UNDEFINED) {
490 pr_info("%s (%d): undefined instruction: pc=%p\n",
491 current->comm, task_pid_nr(current), pc);
493 dump_instr(KERN_INFO, regs);
496 arm_notify_die("Oops - undefined instruction", regs,
497 SIGILL, ILL_ILLOPC, pc, 0, 6);
499 NOKPROBE_SYMBOL(do_undefinstr)
502 * Handle FIQ similarly to NMI on x86 systems.
504 * The runtime environment for NMIs is extremely restrictive
505 * (NMIs can pre-empt critical sections meaning almost all locking is
506 * forbidden) meaning this default FIQ handling must only be used in
507 * circumstances where non-maskability improves robustness, such as
508 * watchdog or debug logic.
510 * This handler is not appropriate for general purpose use in drivers
511 * platform code and can be overrideen using set_fiq_handler.
513 asmlinkage void __exception_irq_entry handle_fiq_as_nmi(struct pt_regs *regs)
515 struct pt_regs *old_regs = set_irq_regs(regs);
519 /* nop. FIQ handlers for special arch/arm features can be added here. */
523 set_irq_regs(old_regs);
527 * bad_mode handles the impossible case in the vectors. If you see one of
528 * these, then it's extremely serious, and could mean you have buggy hardware.
529 * It never returns, and never tries to sync. We hope that we can at least
530 * dump out some state information...
532 asmlinkage void bad_mode(struct pt_regs *regs, int reason)
536 pr_crit("Bad mode in %s handler detected\n", handler[reason]);
538 die("Oops - bad mode", regs, 0);
543 static int bad_syscall(int n, struct pt_regs *regs)
545 if ((current->personality & PER_MASK) != PER_LINUX) {
546 send_sig(SIGSEGV, current, 1);
550 #ifdef CONFIG_DEBUG_USER
551 if (user_debug & UDBG_SYSCALL) {
552 pr_err("[%d] %s: obsolete system call %08x.\n",
553 task_pid_nr(current), current->comm, n);
554 dump_instr(KERN_ERR, regs);
558 arm_notify_die("Oops - bad syscall", regs, SIGILL, ILL_ILLTRP,
559 (void __user *)instruction_pointer(regs) -
560 (thumb_mode(regs) ? 2 : 4),
567 __do_cache_op(unsigned long start, unsigned long end)
572 unsigned long chunk = min(PAGE_SIZE, end - start);
574 if (fatal_signal_pending(current))
577 ret = flush_icache_user_range(start, start + chunk);
583 } while (start < end);
589 do_cache_op(unsigned long start, unsigned long end, int flags)
591 if (end < start || flags)
594 if (!access_ok((void __user *)start, end - start))
597 return __do_cache_op(start, end);
601 * Handle all unrecognised system calls.
602 * 0x9f0000 - 0x9fffff are some more esoteric system calls
604 #define NR(x) ((__ARM_NR_##x) - __ARM_NR_BASE)
605 asmlinkage int arm_syscall(int no, struct pt_regs *regs)
607 if ((no >> 16) != (__ARM_NR_BASE>> 16))
608 return bad_syscall(no, regs);
610 switch (no & 0xffff) {
611 case 0: /* branch through 0 */
612 arm_notify_die("branch through zero", regs,
613 SIGSEGV, SEGV_MAPERR, NULL, 0, 0);
616 case NR(breakpoint): /* SWI BREAK_POINT */
617 regs->ARM_pc -= thumb_mode(regs) ? 2 : 4;
622 * Flush a region from virtual address 'r0' to virtual address 'r1'
623 * _exclusive_. There is no alignment requirement on either address;
624 * user space does not need to know the hardware cache layout.
626 * r2 contains flags. It should ALWAYS be passed as ZERO until it
627 * is defined to be something else. For now we ignore it, but may
628 * the fires of hell burn in your belly if you break this rule. ;)
630 * (at a later date, we may want to allow this call to not flush
631 * various aspects of the cache. Passing '0' will guarantee that
632 * everything necessary gets flushed to maintain consistency in
633 * the specified region).
636 return do_cache_op(regs->ARM_r0, regs->ARM_r1, regs->ARM_r2);
639 if (!(elf_hwcap & HWCAP_26BIT))
641 regs->ARM_cpsr &= ~MODE32_BIT;
645 if (!(elf_hwcap & HWCAP_26BIT))
647 regs->ARM_cpsr |= MODE32_BIT;
651 set_tls(regs->ARM_r0);
655 return current_thread_info()->tp_value[0];
658 /* Calls 9f00xx..9f07ff are defined to return -ENOSYS
659 if not implemented, rather than raising SIGILL. This
660 way the calling program can gracefully determine whether
661 a feature is supported. */
662 if ((no & 0xffff) <= 0x7ff)
666 #ifdef CONFIG_DEBUG_USER
668 * experience shows that these seem to indicate that
669 * something catastrophic has happened
671 if (user_debug & UDBG_SYSCALL) {
672 pr_err("[%d] %s: arm syscall %d\n",
673 task_pid_nr(current), current->comm, no);
674 dump_instr(KERN_ERR, regs);
675 if (user_mode(regs)) {
677 c_backtrace(frame_pointer(regs), processor_mode(regs), KERN_ERR);
681 arm_notify_die("Oops - bad syscall(2)", regs, SIGILL, ILL_ILLTRP,
682 (void __user *)instruction_pointer(regs) -
683 (thumb_mode(regs) ? 2 : 4),
688 #ifdef CONFIG_TLS_REG_EMUL
691 * We might be running on an ARMv6+ processor which should have the TLS
692 * register but for some reason we can't use it, or maybe an SMP system
693 * using a pre-ARMv6 processor (there are apparently a few prototypes like
694 * that in existence) and therefore access to that register must be
698 static int get_tp_trap(struct pt_regs *regs, unsigned int instr)
700 int reg = (instr >> 12) & 15;
703 regs->uregs[reg] = current_thread_info()->tp_value[0];
708 static struct undef_hook arm_mrc_hook = {
709 .instr_mask = 0x0fff0fff,
710 .instr_val = 0x0e1d0f70,
711 .cpsr_mask = PSR_T_BIT,
716 static int __init arm_mrc_hook_init(void)
718 register_undef_hook(&arm_mrc_hook);
722 late_initcall(arm_mrc_hook_init);
727 * A data abort trap was taken, but we did not handle the instruction.
728 * Try to abort the user program, or panic if it was the kernel.
731 baddataabort(int code, unsigned long instr, struct pt_regs *regs)
733 unsigned long addr = instruction_pointer(regs);
735 #ifdef CONFIG_DEBUG_USER
736 if (user_debug & UDBG_BADABORT) {
737 pr_err("8<--- cut here ---\n");
738 pr_err("[%d] %s: bad data abort: code %d instr 0x%08lx\n",
739 task_pid_nr(current), current->comm, code, instr);
740 dump_instr(KERN_ERR, regs);
741 show_pte(KERN_ERR, current->mm, addr);
745 arm_notify_die("unknown data abort code", regs,
746 SIGILL, ILL_ILLOPC, (void __user *)addr, instr, 0);
749 void __readwrite_bug(const char *fn)
751 pr_err("%s called, but not implemented\n", fn);
754 EXPORT_SYMBOL(__readwrite_bug);
756 void __pte_error(const char *file, int line, pte_t pte)
758 pr_err("%s:%d: bad pte %08llx.\n", file, line, (long long)pte_val(pte));
761 void __pmd_error(const char *file, int line, pmd_t pmd)
763 pr_err("%s:%d: bad pmd %08llx.\n", file, line, (long long)pmd_val(pmd));
766 void __pgd_error(const char *file, int line, pgd_t pgd)
768 pr_err("%s:%d: bad pgd %08llx.\n", file, line, (long long)pgd_val(pgd));
771 asmlinkage void __div0(void)
773 pr_err("Division by zero in kernel.\n");
776 EXPORT_SYMBOL(__div0);
782 /* if that doesn't kill us, halt */
783 panic("Oops failed to kill thread");
786 #ifdef CONFIG_KUSER_HELPERS
787 static void __init kuser_init(void *vectors)
789 extern char __kuser_helper_start[], __kuser_helper_end[];
790 int kuser_sz = __kuser_helper_end - __kuser_helper_start;
792 memcpy(vectors + 0x1000 - kuser_sz, __kuser_helper_start, kuser_sz);
795 * vectors + 0xfe0 = __kuser_get_tls
796 * vectors + 0xfe8 = hardware TLS instruction at 0xffff0fe8
798 if (tls_emu || has_tls_reg)
799 memcpy(vectors + 0xfe0, vectors + 0xfe8, 4);
802 static inline void __init kuser_init(void *vectors)
807 #ifndef CONFIG_CPU_V7M
808 static void copy_from_lma(void *vma, void *lma_start, void *lma_end)
810 memcpy(vma, lma_start, lma_end - lma_start);
813 static void flush_vectors(void *vma, size_t offset, size_t size)
815 unsigned long start = (unsigned long)vma + offset;
816 unsigned long end = start + size;
818 flush_icache_range(start, end);
821 #ifdef CONFIG_HARDEN_BRANCH_HISTORY
822 int spectre_bhb_update_vectors(unsigned int method)
824 extern char __vectors_bhb_bpiall_start[], __vectors_bhb_bpiall_end[];
825 extern char __vectors_bhb_loop8_start[], __vectors_bhb_loop8_end[];
826 void *vec_start, *vec_end;
828 if (system_state >= SYSTEM_FREEING_INITMEM) {
829 pr_err("CPU%u: Spectre BHB workaround too late - system vulnerable\n",
831 return SPECTRE_VULNERABLE;
835 case SPECTRE_V2_METHOD_LOOP8:
836 vec_start = __vectors_bhb_loop8_start;
837 vec_end = __vectors_bhb_loop8_end;
840 case SPECTRE_V2_METHOD_BPIALL:
841 vec_start = __vectors_bhb_bpiall_start;
842 vec_end = __vectors_bhb_bpiall_end;
846 pr_err("CPU%u: unknown Spectre BHB state %d\n",
847 smp_processor_id(), method);
848 return SPECTRE_VULNERABLE;
851 copy_from_lma(vectors_page, vec_start, vec_end);
852 flush_vectors(vectors_page, 0, vec_end - vec_start);
854 return SPECTRE_MITIGATED;
858 void __init early_trap_init(void *vectors_base)
860 extern char __stubs_start[], __stubs_end[];
861 extern char __vectors_start[], __vectors_end[];
864 vectors_page = vectors_base;
867 * Poison the vectors page with an undefined instruction. This
868 * instruction is chosen to be undefined for both ARM and Thumb
869 * ISAs. The Thumb version is an undefined instruction with a
870 * branch back to the undefined instruction.
872 for (i = 0; i < PAGE_SIZE / sizeof(u32); i++)
873 ((u32 *)vectors_base)[i] = 0xe7fddef1;
876 * Copy the vectors, stubs and kuser helpers (in entry-armv.S)
877 * into the vector page, mapped at 0xffff0000, and ensure these
878 * are visible to the instruction stream.
880 copy_from_lma(vectors_base, __vectors_start, __vectors_end);
881 copy_from_lma(vectors_base + 0x1000, __stubs_start, __stubs_end);
883 kuser_init(vectors_base);
885 flush_vectors(vectors_base, 0, PAGE_SIZE * 2);
887 #else /* ifndef CONFIG_CPU_V7M */
888 void __init early_trap_init(void *vectors_base)
891 * on V7-M there is no need to copy the vector table to a dedicated
892 * memory area. The address is configurable and so a table in the kernel
898 #ifdef CONFIG_VMAP_STACK
900 DECLARE_PER_CPU(u8 *, irq_stack_ptr);
902 asmlinkage DEFINE_PER_CPU(u8 *, overflow_stack_ptr);
904 static int __init allocate_overflow_stacks(void)
909 for_each_possible_cpu(cpu) {
910 stack = (u8 *)__get_free_page(GFP_KERNEL);
913 per_cpu(overflow_stack_ptr, cpu) = &stack[OVERFLOW_STACK_SIZE];
917 early_initcall(allocate_overflow_stacks);
919 asmlinkage void handle_bad_stack(struct pt_regs *regs)
921 unsigned long tsk_stk = (unsigned long)current->stack;
922 #ifdef CONFIG_IRQSTACKS
923 unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
925 unsigned long ovf_stk = (unsigned long)this_cpu_read(overflow_stack_ptr);
928 pr_emerg("Insufficient stack space to handle exception!");
930 pr_emerg("Task stack: [0x%08lx..0x%08lx]\n",
931 tsk_stk, tsk_stk + THREAD_SIZE);
932 #ifdef CONFIG_IRQSTACKS
933 pr_emerg("IRQ stack: [0x%08lx..0x%08lx]\n",
934 irq_stk - THREAD_SIZE, irq_stk);
936 pr_emerg("Overflow stack: [0x%08lx..0x%08lx]\n",
937 ovf_stk - OVERFLOW_STACK_SIZE, ovf_stk);
939 die("kernel stack overflow", regs, 0);
942 #ifndef CONFIG_ARM_LPAE
944 * Normally, we rely on the logic in do_translation_fault() to update stale PMD
945 * entries covering the vmalloc space in a task's page tables when it first
946 * accesses the region in question. Unfortunately, this is not sufficient when
947 * the task stack resides in the vmalloc region, as do_translation_fault() is a
948 * C function that needs a stack to run.
950 * So we need to ensure that these PMD entries are up to date *before* the MM
951 * switch. As we already have some logic in the MM switch path that takes care
952 * of this, let's trigger it by bumping the counter every time the core vmalloc
953 * code modifies a PMD entry in the vmalloc region. Use release semantics on
954 * the store so that other CPUs observing the counter's new value are
955 * guaranteed to see the updated page table entries as well.
957 void arch_sync_kernel_mappings(unsigned long start, unsigned long end)
959 if (start < VMALLOC_END && end > VMALLOC_START)
960 atomic_inc_return_release(&init_mm.context.vmalloc_seq);