dump_stack: consolidate dump_stack() implementations and unify their behaviors
[linux-3.10.git] / arch / blackfin / kernel / dumpstack.c
1 /* Provide basic stack dumping functions
2  *
3  * Copyright 2004-2009 Analog Devices Inc.
4  *
5  * Licensed under the GPL-2 or later
6  */
7
8 #include <linux/kernel.h>
9 #include <linux/thread_info.h>
10 #include <linux/mm.h>
11 #include <linux/uaccess.h>
12 #include <linux/module.h>
13 #include <asm/trace.h>
14
15 /*
16  * Checks to see if the address pointed to is either a
17  * 16-bit CALL instruction, or a 32-bit CALL instruction
18  */
19 static bool is_bfin_call(unsigned short *addr)
20 {
21         unsigned int opcode;
22
23         if (!get_instruction(&opcode, addr))
24                 return false;
25
26         if ((opcode >= 0x0060 && opcode <= 0x0067) ||
27             (opcode >= 0x0070 && opcode <= 0x0077) ||
28             (opcode >= 0xE3000000 && opcode <= 0xE3FFFFFF))
29                 return true;
30
31         return false;
32
33 }
34
35 void show_stack(struct task_struct *task, unsigned long *stack)
36 {
37 #ifdef CONFIG_PRINTK
38         unsigned int *addr, *endstack, *fp = 0, *frame;
39         unsigned short *ins_addr;
40         char buf[150];
41         unsigned int i, j, ret_addr, frame_no = 0;
42
43         /*
44          * If we have been passed a specific stack, use that one otherwise
45          *    if we have been passed a task structure, use that, otherwise
46          *    use the stack of where the variable "stack" exists
47          */
48
49         if (stack == NULL) {
50                 if (task) {
51                         /* We know this is a kernel stack, so this is the start/end */
52                         stack = (unsigned long *)task->thread.ksp;
53                         endstack = (unsigned int *)(((unsigned int)(stack) & ~(THREAD_SIZE - 1)) + THREAD_SIZE);
54                 } else {
55                         /* print out the existing stack info */
56                         stack = (unsigned long *)&stack;
57                         endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
58                 }
59         } else
60                 endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
61
62         printk(KERN_NOTICE "Stack info:\n");
63         decode_address(buf, (unsigned int)stack);
64         printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
65
66         if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) {
67                 printk(KERN_NOTICE "Invalid stack pointer\n");
68                 return;
69         }
70
71         /* First thing is to look for a frame pointer */
72         for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
73                 if (*addr & 0x1)
74                         continue;
75                 ins_addr = (unsigned short *)*addr;
76                 ins_addr--;
77                 if (is_bfin_call(ins_addr))
78                         fp = addr - 1;
79
80                 if (fp) {
81                         /* Let's check to see if it is a frame pointer */
82                         while (fp >= (addr - 1) && fp < endstack
83                                && fp && ((unsigned int) fp & 0x3) == 0)
84                                 fp = (unsigned int *)*fp;
85                         if (fp == 0 || fp == endstack) {
86                                 fp = addr - 1;
87                                 break;
88                         }
89                         fp = 0;
90                 }
91         }
92         if (fp) {
93                 frame = fp;
94                 printk(KERN_NOTICE " FP: (0x%p)\n", fp);
95         } else
96                 frame = 0;
97
98         /*
99          * Now that we think we know where things are, we
100          * walk the stack again, this time printing things out
101          * incase there is no frame pointer, we still look for
102          * valid return addresses
103          */
104
105         /* First time print out data, next time, print out symbols */
106         for (j = 0; j <= 1; j++) {
107                 if (j)
108                         printk(KERN_NOTICE "Return addresses in stack:\n");
109                 else
110                         printk(KERN_NOTICE " Memory from 0x%08lx to %p", ((long unsigned int)stack & ~0xF), endstack);
111
112                 fp = frame;
113                 frame_no = 0;
114
115                 for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0;
116                      addr < endstack; addr++, i++) {
117
118                         ret_addr = 0;
119                         if (!j && i % 8 == 0)
120                                 printk(KERN_NOTICE "%p:", addr);
121
122                         /* if it is an odd address, or zero, just skip it */
123                         if (*addr & 0x1 || !*addr)
124                                 goto print;
125
126                         ins_addr = (unsigned short *)*addr;
127
128                         /* Go back one instruction, and see if it is a CALL */
129                         ins_addr--;
130                         ret_addr = is_bfin_call(ins_addr);
131  print:
132                         if (!j && stack == (unsigned long *)addr)
133                                 printk("[%08x]", *addr);
134                         else if (ret_addr)
135                                 if (j) {
136                                         decode_address(buf, (unsigned int)*addr);
137                                         if (frame == addr) {
138                                                 printk(KERN_NOTICE "   frame %2i : %s\n", frame_no, buf);
139                                                 continue;
140                                         }
141                                         printk(KERN_NOTICE "    address : %s\n", buf);
142                                 } else
143                                         printk("<%08x>", *addr);
144                         else if (fp == addr) {
145                                 if (j)
146                                         frame = addr+1;
147                                 else
148                                         printk("(%08x)", *addr);
149
150                                 fp = (unsigned int *)*addr;
151                                 frame_no++;
152
153                         } else if (!j)
154                                 printk(" %08x ", *addr);
155                 }
156                 if (!j)
157                         printk("\n");
158         }
159 #endif
160 }
161 EXPORT_SYMBOL(show_stack);
162
163 void dump_stack(void)
164 {
165         unsigned long stack;
166 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
167         int tflags;
168 #endif
169         trace_buffer_save(tflags);
170         dump_bfin_trace_buffer();
171         dump_stack_print_info(KERN_DEFAULT);
172         show_stack(current, &stack);
173         trace_buffer_restore(tflags);
174 }
175 EXPORT_SYMBOL(dump_stack);