Merge master.kernel.org:/pub/scm/linux/kernel/git/jejb/scsi-rc-fixes-2.6
[linux-2.6] / arch / s390 / kernel / stacktrace.c
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 unsigned long save_context_stack(struct stack_trace *trace,
15                                         unsigned long sp,
16                                         unsigned long low,
17                                         unsigned long high)
18 {
19         struct stack_frame *sf;
20         struct pt_regs *regs;
21         unsigned long addr;
22
23         while(1) {
24                 sp &= PSW_ADDR_INSN;
25                 if (sp < low || sp > high)
26                         return sp;
27                 sf = (struct stack_frame *)sp;
28                 while(1) {
29                         addr = sf->gprs[8] & PSW_ADDR_INSN;
30                         if (!trace->skip)
31                                 trace->entries[trace->nr_entries++] = addr;
32                         else
33                                 trace->skip--;
34                         if (trace->nr_entries >= trace->max_entries)
35                                 return sp;
36                         low = sp;
37                         sp = sf->back_chain & PSW_ADDR_INSN;
38                         if (!sp)
39                                 break;
40                         if (sp <= low || sp > high - sizeof(*sf))
41                                 return sp;
42                         sf = (struct stack_frame *)sp;
43                 }
44                 /* Zero backchain detected, check for interrupt frame. */
45                 sp = (unsigned long)(sf + 1);
46                 if (sp <= low || sp > high - sizeof(*regs))
47                         return sp;
48                 regs = (struct pt_regs *)sp;
49                 addr = regs->psw.addr & PSW_ADDR_INSN;
50                 if (!trace->skip)
51                         trace->entries[trace->nr_entries++] = addr;
52                 else
53                         trace->skip--;
54                 if (trace->nr_entries >= trace->max_entries)
55                         return sp;
56                 low = sp;
57                 sp = regs->gprs[15];
58         }
59 }
60
61 void save_stack_trace(struct stack_trace *trace)
62 {
63         register unsigned long sp asm ("15");
64         unsigned long orig_sp, new_sp;
65
66         orig_sp = sp & PSW_ADDR_INSN;
67         new_sp = save_context_stack(trace, orig_sp,
68                                     S390_lowcore.panic_stack - PAGE_SIZE,
69                                     S390_lowcore.panic_stack);
70         if (new_sp != orig_sp)
71                 return;
72         new_sp = save_context_stack(trace, new_sp,
73                                     S390_lowcore.async_stack - ASYNC_SIZE,
74                                     S390_lowcore.async_stack);
75         if (new_sp != orig_sp)
76                 return;
77         save_context_stack(trace, new_sp,
78                            S390_lowcore.thread_info,
79                            S390_lowcore.thread_info + THREAD_SIZE);
80 }