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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/cpu_entry_area.h>
20#include <asm/stacktrace.h>
21
22static const char * const exception_stack_names[] = {
23 [ ESTACK_DF ] = "#DF",
24 [ ESTACK_NMI ] = "NMI",
25 [ ESTACK_DB ] = "#DB",
26 [ ESTACK_MCE ] = "#MC",
27};
28
29const char *stack_type_name(enum stack_type type)
30{
31 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
32
33 if (type == STACK_TYPE_IRQ)
34 return "IRQ";
35
36 if (type == STACK_TYPE_ENTRY) {
37 /*
38 * On 64-bit, we have a generic entry stack that we
39 * use for all the kernel entry points, including
40 * SYSENTER.
41 */
42 return "ENTRY_TRAMPOLINE";
43 }
44
45 if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
46 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
47
48 return NULL;
49}
50
51/**
52 * struct estack_pages - Page descriptor for exception stacks
53 * @offs: Offset from the start of the exception stack area
54 * @size: Size of the exception stack
55 * @type: Type to store in the stack_info struct
56 */
57struct estack_pages {
58 u32 offs;
59 u16 size;
60 u16 type;
61};
62
63#define EPAGERANGE(st) \
64 [PFN_DOWN(CEA_ESTACK_OFFS(st)) ... \
65 PFN_DOWN(CEA_ESTACK_OFFS(st) + CEA_ESTACK_SIZE(st) - 1)] = { \
66 .offs = CEA_ESTACK_OFFS(st), \
67 .size = CEA_ESTACK_SIZE(st), \
68 .type = STACK_TYPE_EXCEPTION + ESTACK_ ##st, }
69
70/*
71 * Array of exception stack page descriptors. If the stack is larger than
72 * PAGE_SIZE, all pages covering a particular stack will have the same
73 * info. The guard pages including the not mapped DB2 stack are zeroed
74 * out.
75 */
76static const
77struct estack_pages estack_pages[CEA_ESTACK_PAGES] ____cacheline_aligned = {
78 EPAGERANGE(DF),
79 EPAGERANGE(NMI),
80 EPAGERANGE(DB),
81 EPAGERANGE(MCE),
82};
83
84static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
85{
86 unsigned long begin, end, stk = (unsigned long)stack;
87 const struct estack_pages *ep;
88 struct pt_regs *regs;
89 unsigned int k;
90
91 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
92
93 begin = (unsigned long)__this_cpu_read(cea_exception_stacks);
94 /*
95 * Handle the case where stack trace is collected _before_
96 * cea_exception_stacks had been initialized.
97 */
98 if (!begin)
99 return false;
100
101 end = begin + sizeof(struct cea_exception_stacks);
102 /* Bail if @stack is outside the exception stack area. */
103 if (stk < begin || stk >= end)
104 return false;
105
106 /* Calc page offset from start of exception stacks */
107 k = (stk - begin) >> PAGE_SHIFT;
108 /* Lookup the page descriptor */
109 ep = &estack_pages[k];
110 /* Guard page? */
111 if (!ep->size)
112 return false;
113
114 begin += (unsigned long)ep->offs;
115 end = begin + (unsigned long)ep->size;
116 regs = (struct pt_regs *)end - 1;
117
118 info->type = ep->type;
119 info->begin = (unsigned long *)begin;
120 info->end = (unsigned long *)end;
121 info->next_sp = (unsigned long *)regs->sp;
122 return true;
123}
124
125static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
126{
127 unsigned long *end = (unsigned long *)this_cpu_read(hardirq_stack_ptr);
128 unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
129
130 /*
131 * This is a software stack, so 'end' can be a valid stack pointer.
132 * It just means the stack is empty.
133 */
134 if (stack < begin || stack >= end)
135 return false;
136
137 info->type = STACK_TYPE_IRQ;
138 info->begin = begin;
139 info->end = end;
140
141 /*
142 * The next stack pointer is the first thing pushed by the entry code
143 * after switching to the irq stack.
144 */
145 info->next_sp = (unsigned long *)*(end - 1);
146
147 return true;
148}
149
150int get_stack_info(unsigned long *stack, struct task_struct *task,
151 struct stack_info *info, unsigned long *visit_mask)
152{
153 if (!stack)
154 goto unknown;
155
156 task = task ? : current;
157
158 if (in_task_stack(stack, task, info))
159 goto recursion_check;
160
161 if (task != current)
162 goto unknown;
163
164 if (in_exception_stack(stack, info))
165 goto recursion_check;
166
167 if (in_irq_stack(stack, info))
168 goto recursion_check;
169
170 if (in_entry_stack(stack, info))
171 goto recursion_check;
172
173 goto unknown;
174
175recursion_check:
176 /*
177 * Make sure we don't iterate through any given stack more than once.
178 * If it comes up a second time then there's something wrong going on:
179 * just break out and report an unknown stack type.
180 */
181 if (visit_mask) {
182 if (*visit_mask & (1UL << info->type)) {
183 if (task == current)
184 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
185 goto unknown;
186 }
187 *visit_mask |= 1UL << info->type;
188 }
189
190 return 0;
191
192unknown:
193 info->type = STACK_TYPE_UNKNOWN;
194 return -EINVAL;
195}
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/export.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
19static char *exception_stack_names[N_EXCEPTION_STACKS] = {
20 [ DOUBLEFAULT_STACK-1 ] = "#DF",
21 [ NMI_STACK-1 ] = "NMI",
22 [ DEBUG_STACK-1 ] = "#DB",
23 [ MCE_STACK-1 ] = "#MC",
24};
25
26static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
27 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
28 [DEBUG_STACK - 1] = DEBUG_STKSZ
29};
30
31const char *stack_type_name(enum stack_type type)
32{
33 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
34
35 if (type == STACK_TYPE_IRQ)
36 return "IRQ";
37
38 if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
39 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
40
41 return NULL;
42}
43
44static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
45{
46 unsigned long *begin, *end;
47 struct pt_regs *regs;
48 unsigned k;
49
50 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
51
52 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
53 end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
54 begin = end - (exception_stack_sizes[k] / sizeof(long));
55 regs = (struct pt_regs *)end - 1;
56
57 if (stack < begin || stack >= end)
58 continue;
59
60 info->type = STACK_TYPE_EXCEPTION + k;
61 info->begin = begin;
62 info->end = end;
63 info->next_sp = (unsigned long *)regs->sp;
64
65 return true;
66 }
67
68 return false;
69}
70
71static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
72{
73 unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
74 unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
75
76 /*
77 * This is a software stack, so 'end' can be a valid stack pointer.
78 * It just means the stack is empty.
79 */
80 if (stack < begin || stack > end)
81 return false;
82
83 info->type = STACK_TYPE_IRQ;
84 info->begin = begin;
85 info->end = end;
86
87 /*
88 * The next stack pointer is the first thing pushed by the entry code
89 * after switching to the irq stack.
90 */
91 info->next_sp = (unsigned long *)*(end - 1);
92
93 return true;
94}
95
96int get_stack_info(unsigned long *stack, struct task_struct *task,
97 struct stack_info *info, unsigned long *visit_mask)
98{
99 if (!stack)
100 goto unknown;
101
102 task = task ? : current;
103
104 if (in_task_stack(stack, task, info))
105 goto recursion_check;
106
107 if (task != current)
108 goto unknown;
109
110 if (in_exception_stack(stack, info))
111 goto recursion_check;
112
113 if (in_irq_stack(stack, info))
114 goto recursion_check;
115
116 goto unknown;
117
118recursion_check:
119 /*
120 * Make sure we don't iterate through any given stack more than once.
121 * If it comes up a second time then there's something wrong going on:
122 * just break out and report an unknown stack type.
123 */
124 if (visit_mask) {
125 if (*visit_mask & (1UL << info->type)) {
126 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
127 goto unknown;
128 }
129 *visit_mask |= 1UL << info->type;
130 }
131
132 return 0;
133
134unknown:
135 info->type = STACK_TYPE_UNKNOWN;
136 return -EINVAL;
137}
138
139void show_regs(struct pt_regs *regs)
140{
141 int i;
142
143 show_regs_print_info(KERN_DEFAULT);
144 __show_regs(regs, 1);
145
146 /*
147 * When in-kernel, we also print out the stack and code at the
148 * time of the fault..
149 */
150 if (!user_mode(regs)) {
151 unsigned int code_prologue = code_bytes * 43 / 64;
152 unsigned int code_len = code_bytes;
153 unsigned char c;
154 u8 *ip;
155
156 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
157
158 printk(KERN_DEFAULT "Code: ");
159
160 ip = (u8 *)regs->ip - code_prologue;
161 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
162 /* try starting at IP */
163 ip = (u8 *)regs->ip;
164 code_len = code_len - code_prologue + 1;
165 }
166 for (i = 0; i < code_len; i++, ip++) {
167 if (ip < (u8 *)PAGE_OFFSET ||
168 probe_kernel_address(ip, c)) {
169 pr_cont(" Bad RIP value.");
170 break;
171 }
172 if (ip == (u8 *)regs->ip)
173 pr_cont("<%02x> ", c);
174 else
175 pr_cont("%02x ", c);
176 }
177 }
178 pr_cont("\n");
179}
180
181int is_valid_bugaddr(unsigned long ip)
182{
183 unsigned short ud2;
184
185 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
186 return 0;
187
188 return ud2 == 0x0b0f;
189}