LXR linux/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
   9void save_stack_trace(struct stack_trace *trace)
  10{
  11        save_stack_trace_tsk(current, trace);
  12}
  13EXPORT_SYMBOL_GPL(save_stack_trace);
  14
  15void 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}
  57EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
  58