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  */
  16 static 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
  35 static 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  */
  68 void save_stack_trace(struct stack_trace *trace)
  69 {
  70         save_stack_trace_tsk(current, trace);
  71 }
  72 EXPORT_SYMBOL_GPL(save_stack_trace);
  73
  74 void 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 }
  89 EXPORT_SYMBOL_GPL(save_stack_trace_tsk);