arch/loongarch/kernel/stacktrace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Stack trace management functions
   4  *
   5  * Copyright (C) 2022 Loongson Technology Corporation Limited
   6  */
   7 #include <linux/sched.h>
   8 #include <linux/stacktrace.h>
   9 #include <linux/uaccess.h>
  10
  11 #include <asm/stacktrace.h>
  12 #include <asm/unwind.h>
  13
  14 void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
  15                      struct task_struct *task, struct pt_regs *regs)
  16 {
  17         unsigned long addr;
  18         struct pt_regs dummyregs;
  19         struct unwind_state state;
  20
  21         if (!regs) {
  22                 regs = &dummyregs;
  23
  24                 if (task == current) {
  25                         regs->regs[3] = (unsigned long)__builtin_frame_address(0);
  26                         regs->csr_era = (unsigned long)__builtin_return_address(0);
  27                 } else {
  28                         regs->regs[3] = thread_saved_fp(task);
  29                         regs->csr_era = thread_saved_ra(task);
  30                 }
  31                 regs->regs[1] = 0;
  32         }
  33
  34         for (unwind_start(&state, task, regs);
  35              !unwind_done(&state); unwind_next_frame(&state)) {
  36                 addr = unwind_get_return_address(&state);
  37                 if (!addr || !consume_entry(cookie, addr))
  38                         break;
  39         }
  40 }
  41
  42 static int
  43 copy_stack_frame(unsigned long fp, struct stack_frame *frame)
  44 {
  45         int ret = 1;
  46         unsigned long err;
  47         unsigned long __user *user_frame_tail;
  48
  49         user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
  50         if (!access_ok(user_frame_tail, sizeof(*frame)))
  51                 return 0;
  52
  53         pagefault_disable();
  54         err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame)));
  55         if (err || (unsigned long)user_frame_tail >= frame->fp)
  56                 ret = 0;
  57         pagefault_enable();
  58
  59         return ret;
  60 }
  61
  62 void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
  63                           const struct pt_regs *regs)
  64 {
  65         unsigned long fp = regs->regs[22];
  66
  67         while (fp && !((unsigned long)fp & 0xf)) {
  68                 struct stack_frame frame;
  69
  70                 frame.fp = 0;
  71                 frame.ra = 0;
  72                 if (!copy_stack_frame(fp, &frame))
  73                         break;
  74                 if (!frame.ra)
  75                         break;
  76                 if (!consume_entry(cookie, frame.ra))
  77                         break;
  78                 fp = frame.fp;
  79         }
  80 }