LXR linux/arch/mips/kernel/stacktrace.c

   1/*
   2 * Stack trace management functions
   3 *
   4 *  Copyright (C) 2006 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
   5 */
   6#include <linux/sched.h>
   7#include <linux/stacktrace.h>
   8#include <linux/export.h>
   9#include <asm/stacktrace.h>
  10
  11/*
  12 * Save stack-backtrace addresses into a stack_trace buffer:
  13 */
  14static void save_raw_context_stack(struct stack_trace *trace,
  15        unsigned long reg29, int savesched)
  16{
  17        unsigned long *sp = (unsigned long *)reg29;
  18        unsigned long addr;
  19
  20        while (!kstack_end(sp)) {
  21                addr = *sp++;
  22                if (__kernel_text_address(addr) &&
  23                    (savesched || !in_sched_functions(addr))) {
  24                        if (trace->skip > 0)
  25                                trace->skip--;
  26                        else
  27                                trace->entries[trace->nr_entries++] = addr;
  28                        if (trace->nr_entries >= trace->max_entries)
  29                                break;
  30                }
  31        }
  32}
  33
  34static void save_context_stack(struct stack_trace *trace,
  35        struct task_struct *tsk, struct pt_regs *regs, int savesched)
  36{
  37        unsigned long sp = regs->regs[29];
  38#ifdef CONFIG_KALLSYMS
  39        unsigned long ra = regs->regs[31];
  40        unsigned long pc = regs->cp0_epc;
  41
  42        if (raw_show_trace || !__kernel_text_address(pc)) {
  43                unsigned long stack_page =
  44                        (unsigned long)task_stack_page(tsk);
  45                if (stack_page && sp >= stack_page &&
  46                    sp <= stack_page + THREAD_SIZE - 32)
  47                        save_raw_context_stack(trace, sp, savesched);
  48                return;
  49        }
  50        do {
  51                if (savesched || !in_sched_functions(pc)) {
  52                        if (trace->skip > 0)
  53                                trace->skip--;
  54                        else
  55                                trace->entries[trace->nr_entries++] = pc;
  56                        if (trace->nr_entries >= trace->max_entries)
  57                                break;
  58                }
  59                pc = unwind_stack(tsk, &sp, pc, &ra);
  60        } while (pc);
  61#else
  62        save_raw_context_stack(trace, sp, savesched);
  63#endif
  64}
  65
  66/*
  67 * Save stack-backtrace addresses into a stack_trace buffer.
  68 */
  69void save_stack_trace(struct stack_trace *trace)
  70{
  71        save_stack_trace_tsk(current, trace);
  72}
  73EXPORT_SYMBOL_GPL(save_stack_trace);
  74
  75void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  76{
  77        struct pt_regs dummyregs;
  78        struct pt_regs *regs = &dummyregs;
  79
  80        WARN_ON(trace->nr_entries || !trace->max_entries);
  81
  82        if (tsk != current) {
  83                regs->regs[29] = tsk->thread.reg29;
  84                regs->regs[31] = 0;
  85                regs->cp0_epc = tsk->thread.reg31;
  86        } else
  87                prepare_frametrace(regs);
  88        save_context_stack(trace, tsk, regs, tsk == current);
  89}
  90EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
  91