1 /* 2 * Stack trace management functions 3 * 4 * Copyright IBM Corp. 2006 5 * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com> 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 savesched) 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 (savesched || !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 void save_stack_trace(struct stack_trace *trace) 63 { 64 register unsigned long sp asm ("15"); 65 unsigned long orig_sp, new_sp, frame_size; 66 67 frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs); 68 orig_sp = sp; 69 new_sp = save_context_stack(trace, orig_sp, 70 S390_lowcore.panic_stack + frame_size - PAGE_SIZE, 71 S390_lowcore.panic_stack + frame_size, 1); 72 if (new_sp != orig_sp) 73 return; 74 new_sp = save_context_stack(trace, new_sp, 75 S390_lowcore.async_stack + frame_size - ASYNC_SIZE, 76 S390_lowcore.async_stack + frame_size, 1); 77 if (new_sp != orig_sp) 78 return; 79 save_context_stack(trace, new_sp, 80 S390_lowcore.thread_info, 81 S390_lowcore.thread_info + THREAD_SIZE, 1); 82 if (trace->nr_entries < trace->max_entries) 83 trace->entries[trace->nr_entries++] = ULONG_MAX; 84 } 85 EXPORT_SYMBOL_GPL(save_stack_trace); 86 87 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 88 { 89 unsigned long sp, low, high; 90 91 sp = tsk->thread.ksp; 92 if (tsk == current) { 93 /* Get current stack pointer. */ 94 asm volatile("la %0,0(15)" : "=a" (sp)); 95 } 96 low = (unsigned long) task_stack_page(tsk); 97 high = (unsigned long) task_pt_regs(tsk); 98 save_context_stack(trace, sp, low, high, 0); 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