1 /* 2 * Stack trace management functions 3 * 4 * Copyright IBM Corp. 2006 5 * Author(s): Heiko Carstens <[email protected]> 6 */ 7 8 #include <linux/sched.h> 9 #include <linux/stacktrace.h> 10 #include <linux/kallsyms.h> 11 #include <linux/module.h> 12 13 static unsigned long save_context_stack(struct stack_trace *trace, 14 unsigned long sp, 15 unsigned long low, 16 unsigned long high, 17 int nosched) 18 { 19 struct stack_frame *sf; 20 struct pt_regs *regs; 21 unsigned long addr; 22 23 while(1) { 24 if (sp < low || sp > high) 25 return sp; 26 sf = (struct stack_frame *)sp; 27 while(1) { 28 addr = sf->gprs[8]; 29 if (!trace->skip) 30 trace->entries[trace->nr_entries++] = addr; 31 else 32 trace->skip--; 33 if (trace->nr_entries >= trace->max_entries) 34 return sp; 35 low = sp; 36 sp = sf->back_chain; 37 if (!sp) 38 break; 39 if (sp <= low || sp > high - sizeof(*sf)) 40 return sp; 41 sf = (struct stack_frame *)sp; 42 } 43 /* Zero backchain detected, check for interrupt frame. */ 44 sp = (unsigned long)(sf + 1); 45 if (sp <= low || sp > high - sizeof(*regs)) 46 return sp; 47 regs = (struct pt_regs *)sp; 48 addr = regs->psw.addr; 49 if (!nosched || !in_sched_functions(addr)) { 50 if (!trace->skip) 51 trace->entries[trace->nr_entries++] = addr; 52 else 53 trace->skip--; 54 } 55 if (trace->nr_entries >= trace->max_entries) 56 return sp; 57 low = sp; 58 sp = regs->gprs[15]; 59 } 60 } 61 62 static void __save_stack_trace(struct stack_trace *trace, unsigned long sp) 63 { 64 unsigned long new_sp, frame_size; 65 66 frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs); 67 new_sp = save_context_stack(trace, sp, 68 S390_lowcore.panic_stack + frame_size - PAGE_SIZE, 69 S390_lowcore.panic_stack + frame_size, 0); 70 new_sp = save_context_stack(trace, new_sp, 71 S390_lowcore.async_stack + frame_size - ASYNC_SIZE, 72 S390_lowcore.async_stack + frame_size, 0); 73 save_context_stack(trace, new_sp, 74 S390_lowcore.thread_info, 75 S390_lowcore.thread_info + THREAD_SIZE, 0); 76 } 77 78 void save_stack_trace(struct stack_trace *trace) 79 { 80 unsigned long sp; 81 82 sp = current_stack_pointer(); 83 __save_stack_trace(trace, sp); 84 if (trace->nr_entries < trace->max_entries) 85 trace->entries[trace->nr_entries++] = ULONG_MAX; 86 } 87 EXPORT_SYMBOL_GPL(save_stack_trace); 88 89 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 90 { 91 unsigned long sp, low, high; 92 93 sp = tsk->thread.ksp; 94 if (tsk == current) 95 sp = current_stack_pointer(); 96 low = (unsigned long) task_stack_page(tsk); 97 high = (unsigned long) task_pt_regs(tsk); 98 save_context_stack(trace, sp, low, high, 1); 99 if (trace->nr_entries < trace->max_entries) 100 trace->entries[trace->nr_entries++] = ULONG_MAX; 101 } 102 EXPORT_SYMBOL_GPL(save_stack_trace_tsk); 103 104 void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace) 105 { 106 unsigned long sp; 107 108 sp = kernel_stack_pointer(regs); 109 __save_stack_trace(trace, sp); 110 if (trace->nr_entries < trace->max_entries) 111 trace->entries[trace->nr_entries++] = ULONG_MAX; 112 } 113 EXPORT_SYMBOL_GPL(save_stack_trace_regs); 114