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/export.h> 14 #include <linux/sched.h> 15 #include <linux/sched/debug.h> 16 #include <linux/stacktrace.h> 17 #include <asm/ptrace.h> 18 #include <asm/processor.h> 19 20 /* 21 * Save stack-backtrace addresses into a stack_trace buffer. 22 */ 23 static void save_context_stack(struct stack_trace *trace, unsigned long sp, 24 struct task_struct *tsk, int savesched) 25 { 26 for (;;) { 27 unsigned long *stack = (unsigned long *) sp; 28 unsigned long newsp, ip; 29 30 if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD)) 31 return; 32 33 newsp = stack[0]; 34 ip = stack[STACK_FRAME_LR_SAVE]; 35 36 if (savesched || !in_sched_functions(ip)) { 37 if (!trace->skip) 38 trace->entries[trace->nr_entries++] = ip; 39 else 40 trace->skip--; 41 } 42 43 if (trace->nr_entries >= trace->max_entries) 44 return; 45 46 sp = newsp; 47 } 48 } 49 50 void save_stack_trace(struct stack_trace *trace) 51 { 52 unsigned long sp; 53 54 sp = current_stack_pointer(); 55 56 save_context_stack(trace, sp, current, 1); 57 } 58 EXPORT_SYMBOL_GPL(save_stack_trace); 59 60 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 61 { 62 unsigned long sp; 63 64 if (tsk == current) 65 sp = current_stack_pointer(); 66 else 67 sp = tsk->thread.ksp; 68 69 save_context_stack(trace, sp, tsk, 0); 70 } 71 EXPORT_SYMBOL_GPL(save_stack_trace_tsk); 72 73 void 74 save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) 75 { 76 save_context_stack(trace, regs->gpr[1], current, 0); 77 } 78 EXPORT_SYMBOL_GPL(save_stack_trace_regs); 79