arch/csky/kernel/stacktrace.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd. */
   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 *fp, *stack_start, *stack_end;
  18         unsigned long addr;
  19         int skip = trace->skip;
  20         int savesched;
  21         int graph_idx = 0;
  22
  23         if (tsk == current) {
  24                 asm volatile("mov %0, r8\n":"=r"(fp));
  25                 savesched = 1;
  26         } else {
  27                 fp = (unsigned long *)thread_saved_fp(tsk);
  28                 savesched = 0;
  29         }
  30
  31         addr = (unsigned long) fp & THREAD_MASK;
  32         stack_start = (unsigned long *) addr;
  33         stack_end = (unsigned long *) (addr + THREAD_SIZE);
  34
  35         while (fp > stack_start && fp < stack_end) {
  36                 unsigned long lpp, fpp;
  37
  38                 fpp = fp[0];
  39                 lpp = fp[1];
  40                 if (!__kernel_text_address(lpp))
  41                         break;
  42                 else
  43                         lpp = ftrace_graph_ret_addr(tsk, &graph_idx, lpp, NULL);
  44
  45                 if (savesched || !in_sched_functions(lpp)) {
  46                         if (skip) {
  47                                 skip--;
  48                         } else {
  49                                 trace->entries[trace->nr_entries++] = lpp;
  50                                 if (trace->nr_entries >= trace->max_entries)
  51                                         break;
  52                         }
  53                 }
  54                 fp = (unsigned long *)fpp;
  55         }
  56 }
  57 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);