1/* 2 * Stack trace utility 3 * 4 * Copyright 2008 Christoph Hellwig, IBM Corp. 5 * 6 * 7 * This program is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 */ 12 13#include <linux/module.h> 14#include <linux/sched.h> 15#include <linux/stacktrace.h> 16#include <asm/ptrace.h> 17#include <asm/processor.h> 18 19/* 20 * Save stack-backtrace addresses into a stack_trace buffer. 21 */ 22static void save_context_stack(struct stack_trace *trace, unsigned long sp, 23 struct task_struct *tsk, int savesched) 24{ 25 for (;;) { 26 unsigned long *stack = (unsigned long *) sp; 27 unsigned long newsp, ip; 28 29 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) 30 return; 31 32 newsp = stack[0]; 33 ip = stack[STACK_FRAME_LR_SAVE]; 34 35 if (savesched || !in_sched_functions(ip)) { 36 if (!trace->skip) 37 trace->entries[trace->nr_entries++] = ip; 38 else 39 trace->skip--; 40 } 41 42 if (trace->nr_entries >= trace->max_entries) 43 return; 44 45 sp = newsp; 46 } 47} 48 49void save_stack_trace(struct stack_trace *trace) 50{ 51 unsigned long sp; 52 53 asm("mr %0,1" : "=r" (sp)); 54 55 save_context_stack(trace, sp, current, 1); 56} 57EXPORT_SYMBOL_GPL(save_stack_trace); 58 59void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 60{ 61 save_context_stack(trace, tsk->thread.ksp, tsk, 0); 62} 63EXPORT_SYMBOL_GPL(save_stack_trace_tsk); 64