summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/dumpstack_64.c
blob: 36cf1a49822746da21d2950c9324c1669555e3d4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
 */
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/export.h>
#include <linux/ptrace.h>
#include <linux/kexec.h>
#include <linux/sysfs.h>
#include <linux/bug.h>
#include <linux/nmi.h>

#include <asm/stacktrace.h>

static char *exception_stack_names[N_EXCEPTION_STACKS] = {
		[ DOUBLEFAULT_STACK-1	]	= "#DF",
		[ NMI_STACK-1		]	= "NMI",
		[ DEBUG_STACK-1		]	= "#DB",
		[ MCE_STACK-1		]	= "#MC",
};

static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
	[0 ... N_EXCEPTION_STACKS - 1]		= EXCEPTION_STKSZ,
	[DEBUG_STACK - 1]			= DEBUG_STKSZ
};

void stack_type_str(enum stack_type type, const char **begin, const char **end)
{
	BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);

	switch (type) {
	case STACK_TYPE_IRQ:
		*begin = "IRQ";
		*end   = "EOI";
		break;
	case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
		*begin = exception_stack_names[type - STACK_TYPE_EXCEPTION];
		*end   = "EOE";
		break;
	default:
		*begin = NULL;
		*end   = NULL;
	}
}

static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
{
	unsigned long *begin, *end;
	struct pt_regs *regs;
	unsigned k;

	BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);

	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
		end   = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
		begin = end - (exception_stack_sizes[k] / sizeof(long));
		regs  = (struct pt_regs *)end - 1;

		if (stack < begin || stack >= end)
			continue;

		info->type	= STACK_TYPE_EXCEPTION + k;
		info->begin	= begin;
		info->end	= end;
		info->next_sp	= (unsigned long *)regs->sp;

		return true;
	}

	return false;
}

static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
{
	unsigned long *end   = (unsigned long *)this_cpu_read(irq_stack_ptr);
	unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));

	/*
	 * This is a software stack, so 'end' can be a valid stack pointer.
	 * It just means the stack is empty.
	 */
	if (stack < begin || stack > end)
		return false;

	info->type	= STACK_TYPE_IRQ;
	info->begin	= begin;
	info->end	= end;

	/*
	 * The next stack pointer is the first thing pushed by the entry code
	 * after switching to the irq stack.
	 */
	info->next_sp = (unsigned long *)*(end - 1);

	return true;
}

int get_stack_info(unsigned long *stack, struct task_struct *task,
		   struct stack_info *info, unsigned long *visit_mask)
{
	if (!stack)
		goto unknown;

	task = task ? : current;

	if (in_task_stack(stack, task, info))
		goto recursion_check;

	if (task != current)
		goto unknown;

	if (in_exception_stack(stack, info))
		goto recursion_check;

	if (in_irq_stack(stack, info))
		goto recursion_check;

	goto unknown;

recursion_check:
	/*
	 * Make sure we don't iterate through any given stack more than once.
	 * If it comes up a second time then there's something wrong going on:
	 * just break out and report an unknown stack type.
	 */
	if (visit_mask) {
		if (*visit_mask & (1UL << info->type))
			goto unknown;
		*visit_mask |= 1UL << info->type;
	}

	return 0;

unknown:
	info->type = STACK_TYPE_UNKNOWN;
	return -EINVAL;
}

void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
			unsigned long *sp, char *log_lvl)
{
	unsigned long *irq_stack_end;
	unsigned long *irq_stack;
	unsigned long *stack;
	int i;

	if (!try_get_task_stack(task))
		return;

	irq_stack_end = (unsigned long *)this_cpu_read(irq_stack_ptr);
	irq_stack     = irq_stack_end - (IRQ_STACK_SIZE / sizeof(long));

	sp = sp ? : get_stack_pointer(task, regs);

	stack = sp;
	for (i = 0; i < kstack_depth_to_print; i++) {
		unsigned long word;

		if (stack >= irq_stack && stack <= irq_stack_end) {
			if (stack == irq_stack_end) {
				stack = (unsigned long *) (irq_stack_end[-1]);
				pr_cont(" <EOI> ");
			}
		} else {
		if (kstack_end(stack))
			break;
		}

		if (probe_kernel_address(stack, word))
			break;

		if ((i % STACKSLOTS_PER_LINE) == 0) {
			if (i != 0)
				pr_cont("\n");
			printk("%s %016lx", log_lvl, word);
		} else
			pr_cont(" %016lx", word);

		stack++;
		touch_nmi_watchdog();
	}

	pr_cont("\n");
	show_trace_log_lvl(task, regs, sp, log_lvl);

	put_task_stack(task);
}

void show_regs(struct pt_regs *regs)
{
	int i;

	show_regs_print_info(KERN_DEFAULT);
	__show_regs(regs, 1);

	/*
	 * When in-kernel, we also print out the stack and code at the
	 * time of the fault..
	 */
	if (!user_mode(regs)) {
		unsigned int code_prologue = code_bytes * 43 / 64;
		unsigned int code_len = code_bytes;
		unsigned char c;
		u8 *ip;

		printk(KERN_DEFAULT "Stack:\n");
		show_stack_log_lvl(current, regs, NULL, KERN_DEFAULT);

		printk(KERN_DEFAULT "Code: ");

		ip = (u8 *)regs->ip - code_prologue;
		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
			/* try starting at IP */
			ip = (u8 *)regs->ip;
			code_len = code_len - code_prologue + 1;
		}
		for (i = 0; i < code_len; i++, ip++) {
			if (ip < (u8 *)PAGE_OFFSET ||
					probe_kernel_address(ip, c)) {
				pr_cont(" Bad RIP value.");
				break;
			}
			if (ip == (u8 *)regs->ip)
				pr_cont("<%02x> ", c);
			else
				pr_cont("%02x ", c);
		}
	}
	pr_cont("\n");
}

int is_valid_bugaddr(unsigned long ip)
{
	unsigned short ud2;

	if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
		return 0;

	return ud2 == 0x0b0f;
}