| Heiko Carstens | 5bdc9b4 | 2006-07-03 00:24:41 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * arch/s390/kernel/stacktrace.c |
| 3 | * |
| 4 | * Stack trace management functions |
| 5 | * |
| 6 | * Copyright (C) IBM Corp. 2006 |
| 7 | * Author(s): Heiko Carstens <heiko.carstens@de.ibm.com> |
| 8 | */ |
| 9 | |
| 10 | #include <linux/sched.h> |
| 11 | #include <linux/stacktrace.h> |
| 12 | #include <linux/kallsyms.h> |
| 13 | |
| 14 | static inline unsigned long save_context_stack(struct stack_trace *trace, |
| 15 | unsigned int *skip, |
| 16 | unsigned long sp, |
| 17 | unsigned long low, |
| 18 | unsigned long high) |
| 19 | { |
| 20 | struct stack_frame *sf; |
| 21 | struct pt_regs *regs; |
| 22 | unsigned long addr; |
| 23 | |
| 24 | while(1) { |
| 25 | sp &= PSW_ADDR_INSN; |
| 26 | if (sp < low || sp > high) |
| 27 | return sp; |
| 28 | sf = (struct stack_frame *)sp; |
| 29 | while(1) { |
| 30 | addr = sf->gprs[8] & PSW_ADDR_INSN; |
| 31 | if (!(*skip)) |
| 32 | trace->entries[trace->nr_entries++] = addr; |
| 33 | else |
| 34 | (*skip)--; |
| 35 | if (trace->nr_entries >= trace->max_entries) |
| 36 | return sp; |
| 37 | low = sp; |
| 38 | sp = sf->back_chain & PSW_ADDR_INSN; |
| 39 | if (!sp) |
| 40 | break; |
| 41 | if (sp <= low || sp > high - sizeof(*sf)) |
| 42 | return sp; |
| 43 | sf = (struct stack_frame *)sp; |
| 44 | } |
| 45 | /* Zero backchain detected, check for interrupt frame. */ |
| 46 | sp = (unsigned long)(sf + 1); |
| 47 | if (sp <= low || sp > high - sizeof(*regs)) |
| 48 | return sp; |
| 49 | regs = (struct pt_regs *)sp; |
| 50 | addr = regs->psw.addr & PSW_ADDR_INSN; |
| 51 | if (!(*skip)) |
| 52 | trace->entries[trace->nr_entries++] = addr; |
| 53 | else |
| 54 | (*skip)--; |
| 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 | struct task_struct *task, int all_contexts, |
| 64 | unsigned int skip) |
| 65 | { |
| 66 | register unsigned long sp asm ("15"); |
| 67 | unsigned long orig_sp; |
| 68 | |
| 69 | sp &= PSW_ADDR_INSN; |
| 70 | orig_sp = sp; |
| 71 | |
| 72 | sp = save_context_stack(trace, &skip, sp, |
| 73 | S390_lowcore.panic_stack - PAGE_SIZE, |
| 74 | S390_lowcore.panic_stack); |
| 75 | if ((sp != orig_sp) && !all_contexts) |
| 76 | return; |
| 77 | sp = save_context_stack(trace, &skip, sp, |
| 78 | S390_lowcore.async_stack - ASYNC_SIZE, |
| 79 | S390_lowcore.async_stack); |
| 80 | if ((sp != orig_sp) && !all_contexts) |
| 81 | return; |
| 82 | if (task) |
| 83 | save_context_stack(trace, &skip, sp, |
| 84 | (unsigned long) task_stack_page(task), |
| 85 | (unsigned long) task_stack_page(task) + THREAD_SIZE); |
| 86 | else |
| 87 | save_context_stack(trace, &skip, sp, S390_lowcore.thread_info, |
| 88 | S390_lowcore.thread_info + THREAD_SIZE); |
| 89 | return; |
| 90 | } |