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 <linux/sched/debug.h>
14
15 #include <asm/trace.h>
16
17 /*
18 * Checks to see if the address pointed to is either a
19 * 16-bit CALL instruction, or a 32-bit CALL instruction
20 */
is_bfin_call(unsigned short * addr)21 static bool is_bfin_call(unsigned short *addr)
22 {
23 unsigned int opcode;
24
25 if (!get_instruction(&opcode, addr))
26 return false;
27
28 if ((opcode >= 0x0060 && opcode <= 0x0067) ||
29 (opcode >= 0x0070 && opcode <= 0x0077) ||
30 (opcode >= 0xE3000000 && opcode <= 0xE3FFFFFF))
31 return true;
32
33 return false;
34
35 }
36
show_stack(struct task_struct * task,unsigned long * stack)37 void show_stack(struct task_struct *task, unsigned long *stack)
38 {
39 #ifdef CONFIG_PRINTK
40 unsigned int *addr, *endstack, *fp = 0, *frame;
41 unsigned short *ins_addr;
42 char buf[150];
43 unsigned int i, j, ret_addr, frame_no = 0;
44
45 /*
46 * If we have been passed a specific stack, use that one otherwise
47 * if we have been passed a task structure, use that, otherwise
48 * use the stack of where the variable "stack" exists
49 */
50
51 if (stack == NULL) {
52 if (task) {
53 /* We know this is a kernel stack, so this is the start/end */
54 stack = (unsigned long *)task->thread.ksp;
55 endstack = (unsigned int *)(((unsigned int)(stack) & ~(THREAD_SIZE - 1)) + THREAD_SIZE);
56 } else {
57 /* print out the existing stack info */
58 stack = (unsigned long *)&stack;
59 endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
60 }
61 } else
62 endstack = (unsigned int *)PAGE_ALIGN((unsigned int)stack);
63
64 printk(KERN_NOTICE "Stack info:\n");
65 decode_address(buf, (unsigned int)stack);
66 printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
67
68 if (!access_ok(VERIFY_READ, stack, (unsigned int)endstack - (unsigned int)stack)) {
69 printk(KERN_NOTICE "Invalid stack pointer\n");
70 return;
71 }
72
73 /* First thing is to look for a frame pointer */
74 for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
75 if (*addr & 0x1)
76 continue;
77 ins_addr = (unsigned short *)*addr;
78 ins_addr--;
79 if (is_bfin_call(ins_addr))
80 fp = addr - 1;
81
82 if (fp) {
83 /* Let's check to see if it is a frame pointer */
84 while (fp >= (addr - 1) && fp < endstack
85 && fp && ((unsigned int) fp & 0x3) == 0)
86 fp = (unsigned int *)*fp;
87 if (fp == 0 || fp == endstack) {
88 fp = addr - 1;
89 break;
90 }
91 fp = 0;
92 }
93 }
94 if (fp) {
95 frame = fp;
96 printk(KERN_NOTICE " FP: (0x%p)\n", fp);
97 } else
98 frame = 0;
99
100 /*
101 * Now that we think we know where things are, we
102 * walk the stack again, this time printing things out
103 * incase there is no frame pointer, we still look for
104 * valid return addresses
105 */
106
107 /* First time print out data, next time, print out symbols */
108 for (j = 0; j <= 1; j++) {
109 if (j)
110 printk(KERN_NOTICE "Return addresses in stack:\n");
111 else
112 printk(KERN_NOTICE " Memory from 0x%08lx to %p", ((long unsigned int)stack & ~0xF), endstack);
113
114 fp = frame;
115 frame_no = 0;
116
117 for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0;
118 addr < endstack; addr++, i++) {
119
120 ret_addr = 0;
121 if (!j && i % 8 == 0)
122 printk(KERN_NOTICE "%p:", addr);
123
124 /* if it is an odd address, or zero, just skip it */
125 if (*addr & 0x1 || !*addr)
126 goto print;
127
128 ins_addr = (unsigned short *)*addr;
129
130 /* Go back one instruction, and see if it is a CALL */
131 ins_addr--;
132 ret_addr = is_bfin_call(ins_addr);
133 print:
134 if (!j && stack == (unsigned long *)addr)
135 printk("[%08x]", *addr);
136 else if (ret_addr)
137 if (j) {
138 decode_address(buf, (unsigned int)*addr);
139 if (frame == addr) {
140 printk(KERN_NOTICE " frame %2i : %s\n", frame_no, buf);
141 continue;
142 }
143 printk(KERN_NOTICE " address : %s\n", buf);
144 } else
145 printk("<%08x>", *addr);
146 else if (fp == addr) {
147 if (j)
148 frame = addr+1;
149 else
150 printk("(%08x)", *addr);
151
152 fp = (unsigned int *)*addr;
153 frame_no++;
154
155 } else if (!j)
156 printk(" %08x ", *addr);
157 }
158 if (!j)
159 printk("\n");
160 }
161 #endif
162 }
163 EXPORT_SYMBOL(show_stack);
164
dump_stack(void)165 void dump_stack(void)
166 {
167 unsigned long stack;
168 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
169 int tflags;
170 #endif
171 trace_buffer_save(tflags);
172 dump_bfin_trace_buffer();
173 dump_stack_print_info(KERN_DEFAULT);
174 show_stack(current, &stack);
175 trace_buffer_restore(tflags);
176 }
177 EXPORT_SYMBOL(dump_stack);
178