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review.evervolv.com / android_kernel_htc_msm8960 / 2a12c4632db1c0c548a7023e63869b27c7789a92 / . / arch / blackfin / kernel / dumpstack.c
blob: e81392c9d1db9d9b8f158c78234f63d55814a97c [file] [log] [blame]
Robin Getz2a12c462010-03-11 16:24:18 +0000[diff] [blame^]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 */
19static bool is_bfin_call(unsigned short *addr)
20{
21 unsigned short opcode = 0, *ins_addr;
22 ins_addr = (unsigned short *)addr;
23
24 if (!get_instruction(&opcode, ins_addr))
25 return false;
26
27 if ((opcode >= 0x0060 && opcode <= 0x0067) ||
28 (opcode >= 0x0070 && opcode <= 0x0077))
29 return true;
30
31 ins_addr--;
32 if (!get_instruction(&opcode, ins_addr))
33 return false;
34
35 if (opcode >= 0xE300 && opcode <= 0xE3FF)
36 return true;
37
38 return false;
39
40}
41
42void show_stack(struct task_struct *task, unsigned long *stack)
43{
44#ifdef CONFIG_PRINTK
45 unsigned int *addr, *endstack, *fp = 0, *frame;
46 unsigned short *ins_addr;
47 char buf[150];
48 unsigned int i, j, ret_addr, frame_no = 0;
49
50 /*
51 * If we have been passed a specific stack, use that one otherwise
52 * if we have been passed a task structure, use that, otherwise
53 * use the stack of where the variable "stack" exists
54 */
55
56 if (stack == NULL) {
57 if (task) {
58 /* We know this is a kernel stack, so this is the start/end */
59 stack = (unsigned long *)task->thread.ksp;
60 endstack = (unsigned int *)(((unsigned int)(stack) & ~(THREAD_SIZE - 1)) + THREAD_SIZE);
61 } else {
62 /* print out the existing stack info */
63 stack = (unsigned long *)&stack;
64 endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
65 }
66 } else
67 endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
68
69 printk(KERN_NOTICE "Stack info:\n");
70 decode_address(buf, (unsigned int)stack);
71 printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
72
73 if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) {
74 printk(KERN_NOTICE "Invalid stack pointer\n");
75 return;
76 }
77
78 /* First thing is to look for a frame pointer */
79 for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
80 if (*addr & 0x1)
81 continue;
82 ins_addr = (unsigned short *)*addr;
83 ins_addr--;
84 if (is_bfin_call(ins_addr))
85 fp = addr - 1;
86
87 if (fp) {
88 /* Let's check to see if it is a frame pointer */
89 while (fp >= (addr - 1) && fp < endstack
90 && fp && ((unsigned int) fp & 0x3) == 0)
91 fp = (unsigned int *)*fp;
92 if (fp == 0 || fp == endstack) {
93 fp = addr - 1;
94 break;
95 }
96 fp = 0;
97 }
98 }
99 if (fp) {
100 frame = fp;
101 printk(KERN_NOTICE " FP: (0x%p)\n", fp);
102 } else
103 frame = 0;
104
105 /*
106 * Now that we think we know where things are, we
107 * walk the stack again, this time printing things out
108 * incase there is no frame pointer, we still look for
109 * valid return addresses
110 */
111
112 /* First time print out data, next time, print out symbols */
113 for (j = 0; j <= 1; j++) {
114 if (j)
115 printk(KERN_NOTICE "Return addresses in stack:\n");
116 else
117 printk(KERN_NOTICE " Memory from 0x%08lx to %p", ((long unsigned int)stack & ~0xF), endstack);
118
119 fp = frame;
120 frame_no = 0;
121
122 for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0;
123 addr < endstack; addr++, i++) {
124
125 ret_addr = 0;
126 if (!j && i % 8 == 0)
127 printk(KERN_NOTICE "%p:", addr);
128
129 /* if it is an odd address, or zero, just skip it */
130 if (*addr & 0x1 || !*addr)
131 goto print;
132
133 ins_addr = (unsigned short *)*addr;
134
135 /* Go back one instruction, and see if it is a CALL */
136 ins_addr--;
137 ret_addr = is_bfin_call(ins_addr);
138 print:
139 if (!j && stack == (unsigned long *)addr)
140 printk("[%08x]", *addr);
141 else if (ret_addr)
142 if (j) {
143 decode_address(buf, (unsigned int)*addr);
144 if (frame == addr) {
145 printk(KERN_NOTICE " frame %2i : %s\n", frame_no, buf);
146 continue;
147 }
148 printk(KERN_NOTICE " address : %s\n", buf);
149 } else
150 printk("<%08x>", *addr);
151 else if (fp == addr) {
152 if (j)
153 frame = addr+1;
154 else
155 printk("(%08x)", *addr);
156
157 fp = (unsigned int *)*addr;
158 frame_no++;
159
160 } else if (!j)
161 printk(" %08x ", *addr);
162 }
163 if (!j)
164 printk("\n");
165 }
166#endif
167}
168EXPORT_SYMBOL(show_stack);
169
170void dump_stack(void)
171{
172 unsigned long stack;
173#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
174 int tflags;
175#endif
176 trace_buffer_save(tflags);
177 dump_bfin_trace_buffer();
178 show_stack(current, &stack);
179 trace_buffer_restore(tflags);
180}
181EXPORT_SYMBOL(dump_stack);