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; 66 67 orig_sp = sp; 68 new_sp = save_context_stack(trace, orig_sp, 69 S390_lowcore.panic_stack - PAGE_SIZE, 70 S390_lowcore.panic_stack, 1); 71 if (new_sp != orig_sp) 72 return; 73 new_sp = save_context_stack(trace, new_sp, 74 S390_lowcore.async_stack - ASYNC_SIZE, 75 S390_lowcore.async_stack, 1); 76 if (new_sp != orig_sp) 77 return; 78 save_context_stack(trace, new_sp, 79 S390_lowcore.thread_info, 80 S390_lowcore.thread_info + THREAD_SIZE, 1); 81 } 82 EXPORT_SYMBOL_GPL(save_stack_trace); 83 84 void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace) 85 { 86 unsigned long sp, low, high; 87 88 sp = tsk->thread.ksp; 89 low = (unsigned long) task_stack_page(tsk); 90 high = (unsigned long) task_pt_regs(tsk); 91 save_context_stack(trace, sp, low, high, 0); 92 if (trace->nr_entries < trace->max_entries) 93 trace->entries[trace->nr_entries++] = ULONG_MAX; 94 } 95 EXPORT_SYMBOL_GPL(save_stack_trace_tsk); 96