xref: /openbmc/linux/arch/x86/kernel/dumpstack_32.c (revision d7b6d709)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Copyright (C) 1991, 1992  Linus Torvalds
4  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
5  */
6 #include <linux/sched/debug.h>
7 #include <linux/kallsyms.h>
8 #include <linux/kprobes.h>
9 #include <linux/uaccess.h>
10 #include <linux/hardirq.h>
11 #include <linux/kdebug.h>
12 #include <linux/export.h>
13 #include <linux/ptrace.h>
14 #include <linux/kexec.h>
15 #include <linux/sysfs.h>
16 #include <linux/bug.h>
17 #include <linux/nmi.h>
18 
19 #include <asm/stacktrace.h>
20 
stack_type_name(enum stack_type type)21 const char *stack_type_name(enum stack_type type)
22 {
23 	if (type == STACK_TYPE_IRQ)
24 		return "IRQ";
25 
26 	if (type == STACK_TYPE_SOFTIRQ)
27 		return "SOFTIRQ";
28 
29 	if (type == STACK_TYPE_ENTRY)
30 		return "ENTRY_TRAMPOLINE";
31 
32 	if (type == STACK_TYPE_EXCEPTION)
33 		return "#DF";
34 
35 	return NULL;
36 }
37 
in_hardirq_stack(unsigned long * stack,struct stack_info * info)38 static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
39 {
40 	unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.hardirq_stack_ptr);
41 	unsigned long *end   = begin + (THREAD_SIZE / sizeof(long));
42 
43 	/*
44 	 * This is a software stack, so 'end' can be a valid stack pointer.
45 	 * It just means the stack is empty.
46 	 */
47 	if (stack < begin || stack > end)
48 		return false;
49 
50 	info->type	= STACK_TYPE_IRQ;
51 	info->begin	= begin;
52 	info->end	= end;
53 
54 	/*
55 	 * See irq_32.c -- the next stack pointer is stored at the beginning of
56 	 * the stack.
57 	 */
58 	info->next_sp	= (unsigned long *)*begin;
59 
60 	return true;
61 }
62 
in_softirq_stack(unsigned long * stack,struct stack_info * info)63 static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
64 {
65 	unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.softirq_stack_ptr);
66 	unsigned long *end   = begin + (THREAD_SIZE / sizeof(long));
67 
68 	/*
69 	 * This is a software stack, so 'end' can be a valid stack pointer.
70 	 * It just means the stack is empty.
71 	 */
72 	if (stack < begin || stack > end)
73 		return false;
74 
75 	info->type	= STACK_TYPE_SOFTIRQ;
76 	info->begin	= begin;
77 	info->end	= end;
78 
79 	/*
80 	 * The next stack pointer is stored at the beginning of the stack.
81 	 * See irq_32.c.
82 	 */
83 	info->next_sp	= (unsigned long *)*begin;
84 
85 	return true;
86 }
87 
in_doublefault_stack(unsigned long * stack,struct stack_info * info)88 static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info)
89 {
90 	struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id());
91 	struct doublefault_stack *ss = &cea->doublefault_stack;
92 
93 	void *begin = ss->stack;
94 	void *end = begin + sizeof(ss->stack);
95 
96 	if ((void *)stack < begin || (void *)stack >= end)
97 		return false;
98 
99 	info->type	= STACK_TYPE_EXCEPTION;
100 	info->begin	= begin;
101 	info->end	= end;
102 	info->next_sp	= (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp);
103 
104 	return true;
105 }
106 
107 
get_stack_info(unsigned long * stack,struct task_struct * task,struct stack_info * info,unsigned long * visit_mask)108 int get_stack_info(unsigned long *stack, struct task_struct *task,
109 		   struct stack_info *info, unsigned long *visit_mask)
110 {
111 	if (!stack)
112 		goto unknown;
113 
114 	task = task ? : current;
115 
116 	if (in_task_stack(stack, task, info))
117 		goto recursion_check;
118 
119 	if (task != current)
120 		goto unknown;
121 
122 	if (in_entry_stack(stack, info))
123 		goto recursion_check;
124 
125 	if (in_hardirq_stack(stack, info))
126 		goto recursion_check;
127 
128 	if (in_softirq_stack(stack, info))
129 		goto recursion_check;
130 
131 	if (in_doublefault_stack(stack, info))
132 		goto recursion_check;
133 
134 	goto unknown;
135 
136 recursion_check:
137 	/*
138 	 * Make sure we don't iterate through any given stack more than once.
139 	 * If it comes up a second time then there's something wrong going on:
140 	 * just break out and report an unknown stack type.
141 	 */
142 	if (visit_mask) {
143 		if (*visit_mask & (1UL << info->type)) {
144 			printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
145 			goto unknown;
146 		}
147 		*visit_mask |= 1UL << info->type;
148 	}
149 
150 	return 0;
151 
152 unknown:
153 	info->type = STACK_TYPE_UNKNOWN;
154 	return -EINVAL;
155 }
156