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 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
35void 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}
161EXPORT_SYMBOL(show_stack);
162
163void 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}
175EXPORT_SYMBOL(dump_stack);
176