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 <asm/stacktrace.h>
  11
  12 /*
  13  * Save stack-backtrace addresses into a stack_trace buffer:
  14  */
  15 static void save_raw_context_stack(struct stack_trace *trace,
  16         unsigned long reg29)
  17 {
  18         unsigned long *sp = (unsigned long *)reg29;
  19         unsigned long addr;
  20
  21         while (!kstack_end(sp)) {
  22                 addr = *sp++;
  23                 if (__kernel_text_address(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
  34 static void save_context_stack(struct stack_trace *trace, 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(current);
  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(current, &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  */
  66 void save_stack_trace(struct stack_trace *trace)
  67 {
  68         struct pt_regs dummyregs;
  69         struct pt_regs *regs = &dummyregs;
  70
  71         WARN_ON(trace->nr_entries || !trace->max_entries);
  72
  73         prepare_frametrace(regs);
  74         save_context_stack(trace, regs);
  75 }
  76 EXPORT_SYMBOL_GPL(save_stack_trace);