1 /* 2 * Stack trace management functions 3 * 4 * Copyright (C) 2006 Atsushi Nemoto <[email protected]> 5 */ 6 #include <linux/sched.h> 7 #include <linux/sched/debug.h> 8 #include <linux/stacktrace.h> 9 #include <linux/export.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, int savesched) 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 (savesched || !in_sched_functions(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, int savesched) 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, savesched); 49 return; 50 } 51 do { 52 if (savesched || !in_sched_functions(pc)) { 53 if (trace->skip > 0) 54 trace->skip--; 55 else 56 trace->entries[trace->nr_entries++] = pc; 57 if (trace->nr_entries >= trace->max_entries) 58 break; 59 } 60 pc = unwind_stack(tsk, &sp, pc, &ra); 61 } while (pc); 62 #else 63 save_raw_context_stack(trace, sp, savesched); 64 #endif 65 } 66 67 /* 68 * Save stack-backtrace addresses into a stack_trace buffer. 69 */ 70 void save_stack_trace(struct stack_trace *trace) 71 { 72 save_stack_trace_tsk(current, trace); 73 } 74 EXPORT_SYMBOL_GPL(save_stack_trace); 75 76 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 77 { 78 struct pt_regs dummyregs; 79 struct pt_regs *regs = &dummyregs; 80 81 WARN_ON(trace->nr_entries || !trace->max_entries); 82 83 if (tsk != current) { 84 regs->regs[29] = tsk->thread.reg29; 85 regs->regs[31] = 0; 86 regs->cp0_epc = tsk->thread.reg31; 87 } else 88 prepare_frametrace(regs); 89 save_context_stack(trace, tsk, regs, tsk == current); 90 } 91 EXPORT_SYMBOL_GPL(save_stack_trace_tsk); 92