xref: /openbmc/linux/arch/x86/kernel/dumpstack_32.c (revision b8bb76713ec50df2f11efee386e16f93d51e1076)
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/utsname.h>
9 #include <linux/hardirq.h>
10 #include <linux/kdebug.h>
11 #include <linux/module.h>
12 #include <linux/ptrace.h>
13 #include <linux/kexec.h>
14 #include <linux/bug.h>
15 #include <linux/nmi.h>
16 #include <linux/sysfs.h>
17 
18 #include <asm/stacktrace.h>
19 
20 #include "dumpstack.h"
21 
22 void dump_trace(struct task_struct *task, struct pt_regs *regs,
23 		unsigned long *stack, unsigned long bp,
24 		const struct stacktrace_ops *ops, void *data)
25 {
26 	int graph = 0;
27 
28 	if (!task)
29 		task = current;
30 
31 	if (!stack) {
32 		unsigned long dummy;
33 		stack = &dummy;
34 		if (task && task != current)
35 			stack = (unsigned long *)task->thread.sp;
36 	}
37 
38 #ifdef CONFIG_FRAME_POINTER
39 	if (!bp) {
40 		if (task == current) {
41 			/* Grab bp right from our regs */
42 			get_bp(bp);
43 		} else {
44 			/* bp is the last reg pushed by switch_to */
45 			bp = *(unsigned long *) task->thread.sp;
46 		}
47 	}
48 #endif
49 
50 	for (;;) {
51 		struct thread_info *context;
52 
53 		context = (struct thread_info *)
54 			((unsigned long)stack & (~(THREAD_SIZE - 1)));
55 		bp = print_context_stack(context, stack, bp, ops,
56 					 data, NULL, &graph);
57 
58 		stack = (unsigned long *)context->previous_esp;
59 		if (!stack)
60 			break;
61 		if (ops->stack(data, "IRQ") < 0)
62 			break;
63 		touch_nmi_watchdog();
64 	}
65 }
66 EXPORT_SYMBOL(dump_trace);
67 
68 void
69 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
70 		unsigned long *sp, unsigned long bp, char *log_lvl)
71 {
72 	unsigned long *stack;
73 	int i;
74 
75 	if (sp == NULL) {
76 		if (task)
77 			sp = (unsigned long *)task->thread.sp;
78 		else
79 			sp = (unsigned long *)&sp;
80 	}
81 
82 	stack = sp;
83 	for (i = 0; i < kstack_depth_to_print; i++) {
84 		if (kstack_end(stack))
85 			break;
86 		if (i && ((i % STACKSLOTS_PER_LINE) == 0))
87 			printk("\n%s", log_lvl);
88 		printk(" %08lx", *stack++);
89 		touch_nmi_watchdog();
90 	}
91 	printk("\n");
92 	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
93 }
94 
95 
96 void show_registers(struct pt_regs *regs)
97 {
98 	int i;
99 
100 	print_modules();
101 	__show_regs(regs, 0);
102 
103 	printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)\n",
104 		TASK_COMM_LEN, current->comm, task_pid_nr(current),
105 		current_thread_info(), current, task_thread_info(current));
106 	/*
107 	 * When in-kernel, we also print out the stack and code at the
108 	 * time of the fault..
109 	 */
110 	if (!user_mode_vm(regs)) {
111 		unsigned int code_prologue = code_bytes * 43 / 64;
112 		unsigned int code_len = code_bytes;
113 		unsigned char c;
114 		u8 *ip;
115 
116 		printk(KERN_EMERG "Stack:\n");
117 		show_stack_log_lvl(NULL, regs, &regs->sp,
118 				0, KERN_EMERG);
119 
120 		printk(KERN_EMERG "Code: ");
121 
122 		ip = (u8 *)regs->ip - code_prologue;
123 		if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
124 			/* try starting at IP */
125 			ip = (u8 *)regs->ip;
126 			code_len = code_len - code_prologue + 1;
127 		}
128 		for (i = 0; i < code_len; i++, ip++) {
129 			if (ip < (u8 *)PAGE_OFFSET ||
130 					probe_kernel_address(ip, c)) {
131 				printk(" Bad EIP value.");
132 				break;
133 			}
134 			if (ip == (u8 *)regs->ip)
135 				printk("<%02x> ", c);
136 			else
137 				printk("%02x ", c);
138 		}
139 	}
140 	printk("\n");
141 }
142 
143 int is_valid_bugaddr(unsigned long ip)
144 {
145 	unsigned short ud2;
146 
147 	if (ip < PAGE_OFFSET)
148 		return 0;
149 	if (probe_kernel_address((unsigned short *)ip, ud2))
150 		return 0;
151 
152 	return ud2 == 0x0b0f;
153 }
154 
155