xref: /openbmc/linux/arch/x86/kernel/dumpstack_32.c (revision 9cdb81c7)
1 /*
2  *  Copyright (C) 1991, 1992  Linus Torvalds
3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
4  */
5 #include <linux/kallsyms.h>
6 #include <linux/kprobes.h>
7 #include <linux/uaccess.h>
8 #include <linux/hardirq.h>
9 #include <linux/kdebug.h>
10 #include <linux/module.h>
11 #include <linux/ptrace.h>
12 #include <linux/kexec.h>
13 #include <linux/sysfs.h>
14 #include <linux/bug.h>
15 #include <linux/nmi.h>
16 
17 #include <asm/stacktrace.h>
18 
19 
20 void dump_trace(struct task_struct *task, struct pt_regs *regs,
21 		unsigned long *stack, unsigned long bp,
22 		const struct stacktrace_ops *ops, void *data)
23 {
24 	int graph = 0;
25 
26 	if (!task)
27 		task = current;
28 
29 	if (!stack) {
30 		unsigned long dummy;
31 
32 		stack = &dummy;
33 		if (task && task != current)
34 			stack = (unsigned long *)task->thread.sp;
35 	}
36 
37 	if (!bp)
38 		bp = stack_frame(task, regs);
39 
40 	for (;;) {
41 		struct thread_info *context;
42 
43 		context = (struct thread_info *)
44 			((unsigned long)stack & (~(THREAD_SIZE - 1)));
45 		bp = ops->walk_stack(context, stack, bp, ops, data, NULL, &graph);
46 
47 		stack = (unsigned long *)context->previous_esp;
48 		if (!stack)
49 			break;
50 		if (ops->stack(data, "IRQ") < 0)
51 			break;
52 		touch_nmi_watchdog();
53 	}
54 }
55 EXPORT_SYMBOL(dump_trace);
56 
57 void
58 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
59 		   unsigned long *sp, unsigned long bp, char *log_lvl)
60 {
61 	unsigned long *stack;
62 	int i;
63 
64 	if (sp == NULL) {
65 		if (task)
66 			sp = (unsigned long *)task->thread.sp;
67 		else
68 			sp = (unsigned long *)&sp;
69 	}
70 
71 	stack = sp;
72 	for (i = 0; i < kstack_depth_to_print; i++) {
73 		if (kstack_end(stack))
74 			break;
75 		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
76 			printk(KERN_CONT "\n");
77 		printk(KERN_CONT " %08lx", *stack++);
78 		touch_nmi_watchdog();
79 	}
80 	printk(KERN_CONT "\n");
81 	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
82 }
83 
84 
85 void show_registers(struct pt_regs *regs)
86 {
87 	int i;
88 
89 	print_modules();
90 	__show_regs(regs, !user_mode_vm(regs));
91 
92 	printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)\n",
93 		TASK_COMM_LEN, current->comm, task_pid_nr(current),
94 		current_thread_info(), current, task_thread_info(current));
95 	/*
96 	 * When in-kernel, we also print out the stack and code at the
97 	 * time of the fault..
98 	 */
99 	if (!user_mode_vm(regs)) {
100 		unsigned int code_prologue = code_bytes * 43 / 64;
101 		unsigned int code_len = code_bytes;
102 		unsigned char c;
103 		u8 *ip;
104 
105 		printk(KERN_EMERG "Stack:\n");
106 		show_stack_log_lvl(NULL, regs, &regs->sp, 0, KERN_EMERG);
107 
108 		printk(KERN_EMERG "Code: ");
109 
110 		ip = (u8 *)regs->ip - code_prologue;
111 		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
112 			/* try starting at IP */
113 			ip = (u8 *)regs->ip;
114 			code_len = code_len - code_prologue + 1;
115 		}
116 		for (i = 0; i < code_len; i++, ip++) {
117 			if (ip < (u8 *)PAGE_OFFSET ||
118 					probe_kernel_address(ip, c)) {
119 				printk(KERN_CONT " Bad EIP value.");
120 				break;
121 			}
122 			if (ip == (u8 *)regs->ip)
123 				printk(KERN_CONT "<%02x> ", c);
124 			else
125 				printk(KERN_CONT "%02x ", c);
126 		}
127 	}
128 	printk(KERN_CONT "\n");
129 }
130 
131 int is_valid_bugaddr(unsigned long ip)
132 {
133 	unsigned short ud2;
134 
135 	if (ip < PAGE_OFFSET)
136 		return 0;
137 	if (probe_kernel_address((unsigned short *)ip, ud2))
138 		return 0;
139 
140 	return ud2 == 0x0b0f;
141 }
142