arch/nds32/kernel/stacktrace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4 #include <linux/sched/debug.h>
   5 #include <linux/sched/task_stack.h>
   6 #include <linux/stacktrace.h>
   7 #include <linux/ftrace.h>
   8
   9 void save_stack_trace(struct stack_trace *trace)
  10 {
  11         save_stack_trace_tsk(current, trace);
  12 }
  13 EXPORT_SYMBOL_GPL(save_stack_trace);
  14
  15 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  16 {
  17         unsigned long *fpn;
  18         int skip = trace->skip;
  19         int savesched;
  20         int graph_idx = 0;
  21
  22         if (tsk == current) {
  23                 __asm__ __volatile__("\tori\t%0, $fp, #0\n":"=r"(fpn));
  24                 savesched = 1;
  25         } else {
  26                 fpn = (unsigned long *)thread_saved_fp(tsk);
  27                 savesched = 0;
  28         }
  29
  30         while (!kstack_end(fpn) && !((unsigned long)fpn & 0x3)
  31                && (fpn >= (unsigned long *)TASK_SIZE)) {
  32                 unsigned long lpp, fpp;
  33
  34                 lpp = fpn[LP_OFFSET];
  35                 fpp = fpn[FP_OFFSET];
  36                 if (!__kernel_text_address(lpp))
  37                         break;
  38                 else
  39                         lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL);
  40
  41                 if (savesched || !in_sched_functions(lpp)) {
  42                         if (skip) {
  43                                 skip--;
  44                         } else {
  45                                 trace->entries[trace->nr_entries++] = lpp;
  46                                 if (trace->nr_entries >= trace->max_entries)
  47                                         break;
  48                         }
  49                 }
  50                 fpn = (unsigned long *)fpp;
  51         }
  52 }
  53 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);