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

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