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)
  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                        if (trace->skip > 0)
  24                                trace->skip--;
  25                        else
  26                                trace->entries[trace->nr_entries++] = addr;
  27                        if (trace->nr_entries >= trace->max_entries)
  28                                break;
  29                }
  30        }
  31}
  32
  33static void save_context_stack(struct stack_trace *trace,
  34        struct task_struct *tsk, struct pt_regs *regs)
  35{
  36        unsigned long sp = regs->regs[29];
  37#ifdef CONFIG_KALLSYMS
  38        unsigned long ra = regs->regs[31];
  39        unsigned long pc = regs->cp0_epc;
  40
  41        if (raw_show_trace || !__kernel_text_address(pc)) {
  42                unsigned long stack_page =
  43                        (unsigned long)task_stack_page(tsk);
  44                if (stack_page && sp >= stack_page &&
  45                    sp <= stack_page + THREAD_SIZE - 32)
  46                        save_raw_context_stack(trace, sp);
  47                return;
  48        }
  49        do {
  50                if (trace->skip > 0)
  51                        trace->skip--;
  52                else
  53                        trace->entries[trace->nr_entries++] = pc;
  54                if (trace->nr_entries >= trace->max_entries)
  55                        break;
  56                pc = unwind_stack(tsk, &sp, pc, &ra);
  57        } while (pc);
  58#else
  59        save_raw_context_stack(trace, sp);
  60#endif
  61}
  62
  63/*
  64 * Save stack-backtrace addresses into a stack_trace buffer.
  65 */
  66void save_stack_trace(struct stack_trace *trace)
  67{
  68        save_stack_trace_tsk(current, trace);
  69}
  70EXPORT_SYMBOL_GPL(save_stack_trace);
  71
  72void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
  73{
  74        struct pt_regs dummyregs;
  75        struct pt_regs *regs = &dummyregs;
  76
  77        WARN_ON(trace->nr_entries || !trace->max_entries);
  78
  79        if (tsk != current) {
  80                regs->regs[29] = tsk->thread.reg29;
  81                regs->regs[31] = 0;
  82                regs->cp0_epc = tsk->thread.reg31;
  83        } else
  84                prepare_frametrace(regs);
  85        save_context_stack(trace, tsk, regs);
  86}
  87EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
  88