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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/stacktrace.h>
20
21static char *exception_stack_names[N_EXCEPTION_STACKS] = {
22 [ DOUBLEFAULT_STACK-1 ] = "#DF",
23 [ NMI_STACK-1 ] = "NMI",
24 [ DEBUG_STACK-1 ] = "#DB",
25 [ MCE_STACK-1 ] = "#MC",
26};
27
28static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
29 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
30 [DEBUG_STACK - 1] = DEBUG_STKSZ
31};
32
33const char *stack_type_name(enum stack_type type)
34{
35 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
36
37 if (type == STACK_TYPE_IRQ)
38 return "IRQ";
39
40 if (type == STACK_TYPE_ENTRY) {
41 /*
42 * On 64-bit, we have a generic entry stack that we
43 * use for all the kernel entry points, including
44 * SYSENTER.
45 */
46 return "ENTRY_TRAMPOLINE";
47 }
48
49 if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
50 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
51
52 return NULL;
53}
54
55static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
56{
57 unsigned long *begin, *end;
58 struct pt_regs *regs;
59 unsigned k;
60
61 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
62
63 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
64 end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
65 begin = end - (exception_stack_sizes[k] / sizeof(long));
66 regs = (struct pt_regs *)end - 1;
67
68 if (stack <= begin || stack >= end)
69 continue;
70
71 info->type = STACK_TYPE_EXCEPTION + k;
72 info->begin = begin;
73 info->end = end;
74 info->next_sp = (unsigned long *)regs->sp;
75
76 return true;
77 }
78
79 return false;
80}
81
82static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
83{
84 unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
85 unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
86
87 /*
88 * This is a software stack, so 'end' can be a valid stack pointer.
89 * It just means the stack is empty.
90 */
91 if (stack <= begin || stack > end)
92 return false;
93
94 info->type = STACK_TYPE_IRQ;
95 info->begin = begin;
96 info->end = end;
97
98 /*
99 * The next stack pointer is the first thing pushed by the entry code
100 * after switching to the irq stack.
101 */
102 info->next_sp = (unsigned long *)*(end - 1);
103
104 return true;
105}
106
107int get_stack_info(unsigned long *stack, struct task_struct *task,
108 struct stack_info *info, unsigned long *visit_mask)
109{
110 if (!stack)
111 goto unknown;
112
113 task = task ? : current;
114
115 if (in_task_stack(stack, task, info))
116 goto recursion_check;
117
118 if (task != current)
119 goto unknown;
120
121 if (in_exception_stack(stack, info))
122 goto recursion_check;
123
124 if (in_irq_stack(stack, info))
125 goto recursion_check;
126
127 if (in_entry_stack(stack, info))
128 goto recursion_check;
129
130 goto unknown;
131
132recursion_check:
133 /*
134 * Make sure we don't iterate through any given stack more than once.
135 * If it comes up a second time then there's something wrong going on:
136 * just break out and report an unknown stack type.
137 */
138 if (visit_mask) {
139 if (*visit_mask & (1UL << info->type)) {
140 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
141 goto unknown;
142 }
143 *visit_mask |= 1UL << info->type;
144 }
145
146 return 0;
147
148unknown:
149 info->type = STACK_TYPE_UNKNOWN;
150 return -EINVAL;
151}
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#define N_EXCEPTION_STACKS_END \
21 (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
22
23static char x86_stack_ids[][8] = {
24 [ DEBUG_STACK-1 ] = "#DB",
25 [ NMI_STACK-1 ] = "NMI",
26 [ DOUBLEFAULT_STACK-1 ] = "#DF",
27 [ STACKFAULT_STACK-1 ] = "#SS",
28 [ MCE_STACK-1 ] = "#MC",
29#if DEBUG_STKSZ > EXCEPTION_STKSZ
30 [ N_EXCEPTION_STACKS ...
31 N_EXCEPTION_STACKS_END ] = "#DB[?]"
32#endif
33};
34
35static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
36 unsigned *usedp, char **idp)
37{
38 unsigned k;
39
40 /*
41 * Iterate over all exception stacks, and figure out whether
42 * 'stack' is in one of them:
43 */
44 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
45 unsigned long end = per_cpu(orig_ist, cpu).ist[k];
46 /*
47 * Is 'stack' above this exception frame's end?
48 * If yes then skip to the next frame.
49 */
50 if (stack >= end)
51 continue;
52 /*
53 * Is 'stack' above this exception frame's start address?
54 * If yes then we found the right frame.
55 */
56 if (stack >= end - EXCEPTION_STKSZ) {
57 /*
58 * Make sure we only iterate through an exception
59 * stack once. If it comes up for the second time
60 * then there's something wrong going on - just
61 * break out and return NULL:
62 */
63 if (*usedp & (1U << k))
64 break;
65 *usedp |= 1U << k;
66 *idp = x86_stack_ids[k];
67 return (unsigned long *)end;
68 }
69 /*
70 * If this is a debug stack, and if it has a larger size than
71 * the usual exception stacks, then 'stack' might still
72 * be within the lower portion of the debug stack:
73 */
74#if DEBUG_STKSZ > EXCEPTION_STKSZ
75 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
76 unsigned j = N_EXCEPTION_STACKS - 1;
77
78 /*
79 * Black magic. A large debug stack is composed of
80 * multiple exception stack entries, which we
81 * iterate through now. Dont look:
82 */
83 do {
84 ++j;
85 end -= EXCEPTION_STKSZ;
86 x86_stack_ids[j][4] = '1' +
87 (j - N_EXCEPTION_STACKS);
88 } while (stack < end - EXCEPTION_STKSZ);
89 if (*usedp & (1U << j))
90 break;
91 *usedp |= 1U << j;
92 *idp = x86_stack_ids[j];
93 return (unsigned long *)end;
94 }
95#endif
96 }
97 return NULL;
98}
99
100static inline int
101in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
102 unsigned long *irq_stack_end)
103{
104 return (stack >= irq_stack && stack < irq_stack_end);
105}
106
107static const unsigned long irq_stack_size =
108 (IRQ_STACK_SIZE - 64) / sizeof(unsigned long);
109
110enum stack_type {
111 STACK_IS_UNKNOWN,
112 STACK_IS_NORMAL,
113 STACK_IS_EXCEPTION,
114 STACK_IS_IRQ,
115};
116
117static enum stack_type
118analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
119 unsigned long **stack_end, unsigned long *irq_stack,
120 unsigned *used, char **id)
121{
122 unsigned long addr;
123
124 addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
125 if ((unsigned long)task_stack_page(task) == addr)
126 return STACK_IS_NORMAL;
127
128 *stack_end = in_exception_stack(cpu, (unsigned long)stack,
129 used, id);
130 if (*stack_end)
131 return STACK_IS_EXCEPTION;
132
133 if (!irq_stack)
134 return STACK_IS_NORMAL;
135
136 *stack_end = irq_stack;
137 irq_stack = irq_stack - irq_stack_size;
138
139 if (in_irq_stack(stack, irq_stack, *stack_end))
140 return STACK_IS_IRQ;
141
142 return STACK_IS_UNKNOWN;
143}
144
145/*
146 * x86-64 can have up to three kernel stacks:
147 * process stack
148 * interrupt stack
149 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
150 */
151
152void dump_trace(struct task_struct *task, struct pt_regs *regs,
153 unsigned long *stack, unsigned long bp,
154 const struct stacktrace_ops *ops, void *data)
155{
156 const unsigned cpu = get_cpu();
157 struct thread_info *tinfo;
158 unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
159 unsigned long dummy;
160 unsigned used = 0;
161 int graph = 0;
162 int done = 0;
163
164 if (!task)
165 task = current;
166
167 if (!stack) {
168 if (regs)
169 stack = (unsigned long *)regs->sp;
170 else if (task != current)
171 stack = (unsigned long *)task->thread.sp;
172 else
173 stack = &dummy;
174 }
175
176 if (!bp)
177 bp = stack_frame(task, regs);
178 /*
179 * Print function call entries in all stacks, starting at the
180 * current stack address. If the stacks consist of nested
181 * exceptions
182 */
183 tinfo = task_thread_info(task);
184 while (!done) {
185 unsigned long *stack_end;
186 enum stack_type stype;
187 char *id;
188
189 stype = analyze_stack(cpu, task, stack, &stack_end,
190 irq_stack, &used, &id);
191
192 /* Default finish unless specified to continue */
193 done = 1;
194
195 switch (stype) {
196
197 /* Break out early if we are on the thread stack */
198 case STACK_IS_NORMAL:
199 break;
200
201 case STACK_IS_EXCEPTION:
202
203 if (ops->stack(data, id) < 0)
204 break;
205
206 bp = ops->walk_stack(tinfo, stack, bp, ops,
207 data, stack_end, &graph);
208 ops->stack(data, "<EOE>");
209 /*
210 * We link to the next stack via the
211 * second-to-last pointer (index -2 to end) in the
212 * exception stack:
213 */
214 stack = (unsigned long *) stack_end[-2];
215 done = 0;
216 break;
217
218 case STACK_IS_IRQ:
219
220 if (ops->stack(data, "IRQ") < 0)
221 break;
222 bp = ops->walk_stack(tinfo, stack, bp,
223 ops, data, stack_end, &graph);
224 /*
225 * We link to the next stack (which would be
226 * the process stack normally) the last
227 * pointer (index -1 to end) in the IRQ stack:
228 */
229 stack = (unsigned long *) (stack_end[-1]);
230 irq_stack = NULL;
231 ops->stack(data, "EOI");
232 done = 0;
233 break;
234
235 case STACK_IS_UNKNOWN:
236 ops->stack(data, "UNK");
237 break;
238 }
239 }
240
241 /*
242 * This handles the process stack:
243 */
244 bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
245 put_cpu();
246}
247EXPORT_SYMBOL(dump_trace);
248
249void
250show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
251 unsigned long *sp, unsigned long bp, char *log_lvl)
252{
253 unsigned long *irq_stack_end;
254 unsigned long *irq_stack;
255 unsigned long *stack;
256 int cpu;
257 int i;
258
259 preempt_disable();
260 cpu = smp_processor_id();
261
262 irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
263 irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
264
265 /*
266 * Debugging aid: "show_stack(NULL, NULL);" prints the
267 * back trace for this cpu:
268 */
269 if (sp == NULL) {
270 if (task)
271 sp = (unsigned long *)task->thread.sp;
272 else
273 sp = (unsigned long *)&sp;
274 }
275
276 stack = sp;
277 for (i = 0; i < kstack_depth_to_print; i++) {
278 if (stack >= irq_stack && stack <= irq_stack_end) {
279 if (stack == irq_stack_end) {
280 stack = (unsigned long *) (irq_stack_end[-1]);
281 pr_cont(" <EOI> ");
282 }
283 } else {
284 if (((long) stack & (THREAD_SIZE-1)) == 0)
285 break;
286 }
287 if (i && ((i % STACKSLOTS_PER_LINE) == 0))
288 pr_cont("\n");
289 pr_cont(" %016lx", *stack++);
290 touch_nmi_watchdog();
291 }
292 preempt_enable();
293
294 pr_cont("\n");
295 show_trace_log_lvl(task, regs, sp, bp, log_lvl);
296}
297
298void show_regs(struct pt_regs *regs)
299{
300 int i;
301 unsigned long sp;
302
303 sp = regs->sp;
304 show_regs_print_info(KERN_DEFAULT);
305 __show_regs(regs, 1);
306
307 /*
308 * When in-kernel, we also print out the stack and code at the
309 * time of the fault..
310 */
311 if (!user_mode(regs)) {
312 unsigned int code_prologue = code_bytes * 43 / 64;
313 unsigned int code_len = code_bytes;
314 unsigned char c;
315 u8 *ip;
316
317 printk(KERN_DEFAULT "Stack:\n");
318 show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
319 0, KERN_DEFAULT);
320
321 printk(KERN_DEFAULT "Code: ");
322
323 ip = (u8 *)regs->ip - code_prologue;
324 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
325 /* try starting at IP */
326 ip = (u8 *)regs->ip;
327 code_len = code_len - code_prologue + 1;
328 }
329 for (i = 0; i < code_len; i++, ip++) {
330 if (ip < (u8 *)PAGE_OFFSET ||
331 probe_kernel_address(ip, c)) {
332 pr_cont(" Bad RIP value.");
333 break;
334 }
335 if (ip == (u8 *)regs->ip)
336 pr_cont("<%02x> ", c);
337 else
338 pr_cont("%02x ", c);
339 }
340 }
341 pr_cont("\n");
342}
343
344int is_valid_bugaddr(unsigned long ip)
345{
346 unsigned short ud2;
347
348 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
349 return 0;
350
351 return ud2 == 0x0b0f;
352}