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         regs = &dummyregs;
  22
  23         if (task == current) {
  24                 regs->regs[3] = (unsigned long)__builtin_frame_address(0);
  25                 regs->csr_era = (unsigned long)__builtin_return_address(0);
  26         } else {
  27                 regs->regs[3] = thread_saved_fp(task);
  28                 regs->csr_era = thread_saved_ra(task);
  29         }
  30
  31         regs->regs[1] = 0;
  32         for (unwind_start(&state, task, regs);
  33               !unwind_done(&state); unwind_next_frame(&state)) {
  34                 addr = unwind_get_return_address(&state);
  35                 if (!addr || !consume_entry(cookie, addr))
  36                         break;
  37         }
  38 }
  39
  40 static int
  41 copy_stack_frame(unsigned long fp, struct stack_frame *frame)
  42 {
  43         int ret = 1;
  44         unsigned long err;
  45         unsigned long __user *user_frame_tail;
  46
  47         user_frame_tail = (unsigned long *)(fp - sizeof(struct stack_frame));
  48         if (!access_ok(user_frame_tail, sizeof(*frame)))
  49                 return 0;
  50
  51         pagefault_disable();
  52         err = (__copy_from_user_inatomic(frame, user_frame_tail, sizeof(*frame)));
  53         if (err || (unsigned long)user_frame_tail >= frame->fp)
  54                 ret = 0;
  55         pagefault_enable();
  56
  57         return ret;
  58 }
  59
  60 void arch_stack_walk_user(stack_trace_consume_fn consume_entry, void *cookie,
  61                           const struct pt_regs *regs)
  62 {
  63         unsigned long fp = regs->regs[22];
  64
  65         while (fp && !((unsigned long)fp & 0xf)) {
  66                 struct stack_frame frame;
  67
  68                 frame.fp = 0;
  69                 frame.ra = 0;
  70                 if (!copy_stack_frame(fp, &frame))
  71                         break;
  72                 if (!frame.ra)
  73                         break;
  74                 if (!consume_entry(cookie, frame.ra))
  75                         break;
  76                 fp = frame.fp;
  77         }
  78 }