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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198// SPDX-License-Identifier: GPL-2.0-only#include <linux/export.h>#include <linux/kprobes.h>#include <linux/sched.h>#include <linux/sched/debug.h>#include <linux/stacktrace.h>
#include <asm/sections.h>#include <asm/stacktrace.h>#include <asm/traps.h>
#include "reboot.h"
#if defined(CONFIG_FRAME_POINTER) && !defined(CONFIG_ARM_UNWIND)/* * Unwind the current stack frame and store the new register values in the * structure passed as argument. Unwinding is equivalent to a function return, * hence the new PC value rather than LR should be used for backtrace. * * With framepointer enabled, a simple function prologue looks like this: * mov ip, sp * stmdb sp!, {fp, ip, lr, pc} * sub fp, ip, #4 * * A simple function epilogue looks like this: * ldm sp, {fp, sp, pc} * * When compiled with clang, pc and sp are not pushed. A simple function * prologue looks like this when built with clang: * * stmdb {..., fp, lr} * add fp, sp, #x * sub sp, sp, #y * * A simple function epilogue looks like this when built with clang: * * sub sp, fp, #x * ldm {..., fp, pc} * * * Note that with framepointer enabled, even the leaf functions have the same * prologue and epilogue, therefore we can ignore the LR value in this case. */
extern unsigned long call_with_stack_end;
static int frame_pointer_check(struct stackframe *frame){ unsigned long high, low; unsigned long fp = frame->fp; unsigned long pc = frame->pc;
/* * call_with_stack() is the only place we allow SP to jump from one * stack to another, with FP and SP pointing to different stacks, * skipping the FP boundary check at this point. */ if (pc >= (unsigned long)&call_with_stack && pc < (unsigned long)&call_with_stack_end) return 0;
/* only go to a higher address on the stack */ low = frame->sp; high = ALIGN(low, THREAD_SIZE);
/* check current frame pointer is within bounds */#ifdef CONFIG_CC_IS_CLANG if (fp < low + 4 || fp > high - 4) return -EINVAL;#else if (fp < low + 12 || fp > high - 4) return -EINVAL;#endif
return 0;}
int notrace unwind_frame(struct stackframe *frame){ unsigned long fp = frame->fp;
if (frame_pointer_check(frame)) return -EINVAL;
/* * When we unwind through an exception stack, include the saved PC * value into the stack trace. */ if (frame->ex_frame) { struct pt_regs *regs = (struct pt_regs *)frame->sp;
/* * We check that 'regs + sizeof(struct pt_regs)' (that is, * ®s[1]) does not exceed the bottom of the stack to avoid * accessing data outside the task's stack. This may happen * when frame->ex_frame is a false positive. */ if ((unsigned long)®s[1] > ALIGN(frame->sp, THREAD_SIZE)) return -EINVAL;
frame->pc = regs->ARM_pc; frame->ex_frame = false; return 0; }
/* restore the registers from the stack frame */#ifdef CONFIG_CC_IS_CLANG frame->sp = frame->fp; frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp)); frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 4));#else frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 12)); frame->sp = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 8)); frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp - 4));#endif#ifdef CONFIG_KRETPROBES if (is_kretprobe_trampoline(frame->pc)) frame->pc = kretprobe_find_ret_addr(frame->tsk, (void *)frame->fp, &frame->kr_cur);#endif
if (in_entry_text(frame->pc)) frame->ex_frame = true;
return 0;}#endif
void notrace walk_stackframe(struct stackframe *frame, bool (*fn)(void *, unsigned long), void *data){ while (1) { int ret;
if (!fn(data, frame->pc)) break; ret = unwind_frame(frame); if (ret < 0) break; }}EXPORT_SYMBOL(walk_stackframe);
#ifdef CONFIG_STACKTRACEstatic void start_stack_trace(struct stackframe *frame, struct task_struct *task, unsigned long fp, unsigned long sp, unsigned long lr, unsigned long pc){ frame->fp = fp; frame->sp = sp; frame->lr = lr; frame->pc = pc;#ifdef CONFIG_KRETPROBES frame->kr_cur = NULL; frame->tsk = task;#endif#ifdef CONFIG_UNWINDER_FRAME_POINTER frame->ex_frame = in_entry_text(frame->pc);#endif}
void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie, struct task_struct *task, struct pt_regs *regs){ struct stackframe frame;
if (regs) { start_stack_trace(&frame, NULL, regs->ARM_fp, regs->ARM_sp, regs->ARM_lr, regs->ARM_pc); } else if (task != current) {#ifdef CONFIG_SMP /* * What guarantees do we have here that 'tsk' is not * running on another CPU? For now, ignore it as we * can't guarantee we won't explode. */ return;#else start_stack_trace(&frame, task, thread_saved_fp(task), thread_saved_sp(task), 0, thread_saved_pc(task));#endif } else {here: start_stack_trace(&frame, task, (unsigned long)__builtin_frame_address(0), current_stack_pointer, (unsigned long)__builtin_return_address(0), (unsigned long)&&here); /* skip this function */ if (unwind_frame(&frame)) return; }
walk_stackframe(&frame, consume_entry, cookie);}#endif