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