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, 35 struct task_struct *task, struct pt_regs *regs) 36 { 37 unsigned long sp = regs->regs[29]; 38 #ifdef CONFIG_KALLSYMS 39 unsigned long ra = regs->regs[31]; 40 unsigned long pc = regs->cp0_epc; 41 42 if (raw_show_trace || !__kernel_text_address(pc)) { 43 unsigned long stack_page = 44 (unsigned long)task_stack_page(task); 45 if (stack_page && sp >= stack_page && 46 sp <= stack_page + THREAD_SIZE - 32) 47 save_raw_context_stack(trace, sp); 48 return; 49 } 50 do { 51 if (trace->skip > 0) 52 trace->skip--; 53 else 54 trace->entries[trace->nr_entries++] = pc; 55 if (trace->nr_entries >= trace->max_entries) 56 break; 57 pc = unwind_stack(task, &sp, pc, &ra); 58 } while (pc); 59 #else 60 save_raw_context_stack(trace, sp); 61 #endif 62 } 63 64 /* 65 * Save stack-backtrace addresses into a stack_trace buffer. 66 */ 67 void save_stack_trace(struct stack_trace *trace, struct task_struct *task) 68 { 69 struct pt_regs dummyregs; 70 struct pt_regs *regs = &dummyregs; 71 72 WARN_ON(trace->nr_entries || !trace->max_entries); 73 74 if (task && task != current) { 75 regs->regs[29] = task->thread.reg29; 76 regs->regs[31] = 0; 77 regs->cp0_epc = task->thread.reg31; 78 } else { 79 if (!task) 80 task = current; 81 prepare_frametrace(regs); 82 } 83 84 save_context_stack(trace, task, regs); 85 } 86