]> git.proxmox.com Git - mirror_ubuntu-artful-kernel.git/blame - arch/x86/kernel/dumpstack_64.c
x86: Fetch stack from regs when possible in dump_trace()
[mirror_ubuntu-artful-kernel.git] / arch / x86 / kernel / dumpstack_64.c
CommitLineData
6fcbede3
AH
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>
6fcbede3
AH
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>
b8030906 13#include <linux/sysfs.h>
6fcbede3
AH
14#include <linux/bug.h>
15#include <linux/nmi.h>
16
17#include <asm/stacktrace.h>
18
6fcbede3 19
b8030906
IM
20#define N_EXCEPTION_STACKS_END \
21 (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
0406ca6d
FW
22
23static char x86_stack_ids[][8] = {
b8030906
IM
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",
6fcbede3 29#if DEBUG_STKSZ > EXCEPTION_STKSZ
b8030906
IM
30 [ N_EXCEPTION_STACKS ...
31 N_EXCEPTION_STACKS_END ] = "#DB[?]"
6fcbede3 32#endif
b8030906 33};
0406ca6d 34
0406ca6d 35static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
b8030906 36 unsigned *usedp, char **idp)
0406ca6d 37{
6fcbede3
AH
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;
0406ca6d 66 *idp = x86_stack_ids[k];
6fcbede3
AH
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;
0406ca6d
FW
86 x86_stack_ids[j][4] = '1' +
87 (j - N_EXCEPTION_STACKS);
6fcbede3
AH
88 } while (stack < end - EXCEPTION_STKSZ);
89 if (*usedp & (1U << j))
90 break;
91 *usedp |= 1U << j;
0406ca6d 92 *idp = x86_stack_ids[j];
6fcbede3
AH
93 return (unsigned long *)end;
94 }
95#endif
96 }
97 return NULL;
98}
99
af2d8289
FW
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
107/*
108 * We are returning from the irq stack and go to the previous one.
109 * If the previous stack is also in the irq stack, then bp in the first
110 * frame of the irq stack points to the previous, interrupted one.
111 * Otherwise we have another level of indirection: We first save
112 * the bp of the previous stack, then we switch the stack to the irq one
113 * and save a new bp that links to the previous one.
114 * (See save_args())
115 */
116static inline unsigned long
117fixup_bp_irq_link(unsigned long bp, unsigned long *stack,
118 unsigned long *irq_stack, unsigned long *irq_stack_end)
119{
120#ifdef CONFIG_FRAME_POINTER
121 struct stack_frame *frame = (struct stack_frame *)bp;
29044ad1 122 unsigned long next;
af2d8289 123
29044ad1
FW
124 if (!in_irq_stack(stack, irq_stack, irq_stack_end)) {
125 if (!probe_kernel_address(&frame->next_frame, next))
126 return next;
127 else
128 WARN_ONCE(1, "Perf: bad frame pointer = %p in "
129 "callchain\n", &frame->next_frame);
130 }
af2d8289
FW
131#endif
132 return bp;
133}
134
6fcbede3
AH
135/*
136 * x86-64 can have up to three kernel stacks:
137 * process stack
138 * interrupt stack
139 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
140 */
141
e8e999cf
NK
142void dump_trace(struct task_struct *task, struct pt_regs *regs,
143 unsigned long *stack, unsigned long bp,
6fcbede3
AH
144 const struct stacktrace_ops *ops, void *data)
145{
146 const unsigned cpu = get_cpu();
26f80bd6
BG
147 unsigned long *irq_stack_end =
148 (unsigned long *)per_cpu(irq_stack_ptr, cpu);
6fcbede3
AH
149 unsigned used = 0;
150 struct thread_info *tinfo;
7ee991fb 151 int graph = 0;
2e5aa682 152 unsigned long dummy;
6fcbede3
AH
153
154 if (!task)
155 task = current;
156
157 if (!stack) {
47ce11a2
FW
158 if (regs)
159 stack = (unsigned long *)regs->sp;
160 else if (task && task != current)
6fcbede3 161 stack = (unsigned long *)task->thread.sp;
47ce11a2
FW
162 else
163 stack = &dummy;
6fcbede3
AH
164 }
165
e8e999cf
NK
166 if (!bp)
167 bp = stack_frame(task, regs);
6fcbede3
AH
168 /*
169 * Print function call entries in all stacks, starting at the
170 * current stack address. If the stacks consist of nested
171 * exceptions
172 */
173 tinfo = task_thread_info(task);
174 for (;;) {
175 char *id;
176 unsigned long *estack_end;
177 estack_end = in_exception_stack(cpu, (unsigned long)stack,
178 &used, &id);
179
180 if (estack_end) {
181 if (ops->stack(data, id) < 0)
182 break;
183
61c1917f
FW
184 bp = ops->walk_stack(tinfo, stack, bp, ops,
185 data, estack_end, &graph);
6fcbede3
AH
186 ops->stack(data, "<EOE>");
187 /*
188 * We link to the next stack via the
189 * second-to-last pointer (index -2 to end) in the
190 * exception stack:
191 */
192 stack = (unsigned long *) estack_end[-2];
193 continue;
194 }
26f80bd6
BG
195 if (irq_stack_end) {
196 unsigned long *irq_stack;
197 irq_stack = irq_stack_end -
198 (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
6fcbede3 199
af2d8289 200 if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
6fcbede3
AH
201 if (ops->stack(data, "IRQ") < 0)
202 break;
61e67fb9 203 bp = ops->walk_stack(tinfo, stack, bp,
26f80bd6 204 ops, data, irq_stack_end, &graph);
6fcbede3
AH
205 /*
206 * We link to the next stack (which would be
207 * the process stack normally) the last
208 * pointer (index -1 to end) in the IRQ stack:
209 */
26f80bd6 210 stack = (unsigned long *) (irq_stack_end[-1]);
af2d8289
FW
211 bp = fixup_bp_irq_link(bp, stack, irq_stack,
212 irq_stack_end);
26f80bd6 213 irq_stack_end = NULL;
6fcbede3
AH
214 ops->stack(data, "EOI");
215 continue;
216 }
217 }
218 break;
219 }
220
221 /*
222 * This handles the process stack:
223 */
61e67fb9 224 bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
6fcbede3
AH
225 put_cpu();
226}
227EXPORT_SYMBOL(dump_trace);
228
878719e8 229void
6fcbede3 230show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
e8e999cf 231 unsigned long *sp, unsigned long bp, char *log_lvl)
6fcbede3 232{
67f2de0b
IM
233 unsigned long *irq_stack_end;
234 unsigned long *irq_stack;
6fcbede3 235 unsigned long *stack;
67f2de0b 236 int cpu;
6fcbede3 237 int i;
67f2de0b
IM
238
239 preempt_disable();
240 cpu = smp_processor_id();
241
242 irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
243 irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
6fcbede3
AH
244
245 /*
67f2de0b
IM
246 * Debugging aid: "show_stack(NULL, NULL);" prints the
247 * back trace for this cpu:
6fcbede3 248 */
6fcbede3
AH
249 if (sp == NULL) {
250 if (task)
251 sp = (unsigned long *)task->thread.sp;
252 else
253 sp = (unsigned long *)&sp;
254 }
255
256 stack = sp;
257 for (i = 0; i < kstack_depth_to_print; i++) {
26f80bd6
BG
258 if (stack >= irq_stack && stack <= irq_stack_end) {
259 if (stack == irq_stack_end) {
260 stack = (unsigned long *) (irq_stack_end[-1]);
e4072a9a 261 printk(KERN_CONT " <EOI> ");
6fcbede3
AH
262 }
263 } else {
264 if (((long) stack & (THREAD_SIZE-1)) == 0)
265 break;
266 }
8a541665 267 if (i && ((i % STACKSLOTS_PER_LINE) == 0))
e4072a9a
JS
268 printk(KERN_CONT "\n");
269 printk(KERN_CONT " %016lx", *stack++);
6fcbede3
AH
270 touch_nmi_watchdog();
271 }
67f2de0b
IM
272 preempt_enable();
273
e4072a9a 274 printk(KERN_CONT "\n");
e8e999cf 275 show_trace_log_lvl(task, regs, sp, bp, log_lvl);
6fcbede3
AH
276}
277
6fcbede3
AH
278void show_registers(struct pt_regs *regs)
279{
280 int i;
281 unsigned long sp;
282 const int cpu = smp_processor_id();
c6f5e0ac 283 struct task_struct *cur = current;
6fcbede3
AH
284
285 sp = regs->sp;
286 printk("CPU %d ", cpu);
f266d7f5 287 print_modules();
6fcbede3
AH
288 __show_regs(regs, 1);
289 printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
290 cur->comm, cur->pid, task_thread_info(cur), cur);
291
292 /*
293 * When in-kernel, we also print out the stack and code at the
294 * time of the fault..
295 */
296 if (!user_mode(regs)) {
297 unsigned int code_prologue = code_bytes * 43 / 64;
298 unsigned int code_len = code_bytes;
299 unsigned char c;
300 u8 *ip;
301
ca0a8164 302 printk(KERN_EMERG "Stack:\n");
6fcbede3 303 show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
e8e999cf 304 0, KERN_EMERG);
6fcbede3
AH
305
306 printk(KERN_EMERG "Code: ");
307
308 ip = (u8 *)regs->ip - code_prologue;
309 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
8a541665 310 /* try starting at IP */
6fcbede3
AH
311 ip = (u8 *)regs->ip;
312 code_len = code_len - code_prologue + 1;
313 }
314 for (i = 0; i < code_len; i++, ip++) {
315 if (ip < (u8 *)PAGE_OFFSET ||
316 probe_kernel_address(ip, c)) {
317 printk(" Bad RIP value.");
318 break;
319 }
320 if (ip == (u8 *)regs->ip)
321 printk("<%02x> ", c);
322 else
323 printk("%02x ", c);
324 }
325 }
326 printk("\n");
327}
328
329int is_valid_bugaddr(unsigned long ip)
330{
331 unsigned short ud2;
332
333 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
334 return 0;
335
336 return ud2 == 0x0b0f;
337}