Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[sfrench/cifs-2.6.git] / arch / x86 / kernel / dumpstack.c
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/ftrace.h>
14 #include <linux/kexec.h>
15 #include <linux/bug.h>
16 #include <linux/nmi.h>
17 #include <linux/sysfs.h>
18
19 #include <asm/stacktrace.h>
20
21 #include "dumpstack.h"
22
23 int panic_on_unrecovered_nmi;
24 int panic_on_io_nmi;
25 unsigned int code_bytes = 64;
26 int kstack_depth_to_print = 3 * STACKSLOTS_PER_LINE;
27 static int die_counter;
28
29 void printk_address(unsigned long address, int reliable)
30 {
31         printk(" [<%p>] %s%pS\n", (void *) address,
32                         reliable ? "" : "? ", (void *) address);
33 }
34
35 #ifdef CONFIG_FUNCTION_GRAPH_TRACER
36 static void
37 print_ftrace_graph_addr(unsigned long addr, void *data,
38                         const struct stacktrace_ops *ops,
39                         struct thread_info *tinfo, int *graph)
40 {
41         struct task_struct *task = tinfo->task;
42         unsigned long ret_addr;
43         int index = task->curr_ret_stack;
44
45         if (addr != (unsigned long)return_to_handler)
46                 return;
47
48         if (!task->ret_stack || index < *graph)
49                 return;
50
51         index -= *graph;
52         ret_addr = task->ret_stack[index].ret;
53
54         ops->address(data, ret_addr, 1);
55
56         (*graph)++;
57 }
58 #else
59 static inline void
60 print_ftrace_graph_addr(unsigned long addr, void *data,
61                         const struct stacktrace_ops *ops,
62                         struct thread_info *tinfo, int *graph)
63 { }
64 #endif
65
66 /*
67  * x86-64 can have up to three kernel stacks:
68  * process stack
69  * interrupt stack
70  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
71  */
72
73 static inline int valid_stack_ptr(struct thread_info *tinfo,
74                         void *p, unsigned int size, void *end)
75 {
76         void *t = tinfo;
77         if (end) {
78                 if (p < end && p >= (end-THREAD_SIZE))
79                         return 1;
80                 else
81                         return 0;
82         }
83         return p > t && p < t + THREAD_SIZE - size;
84 }
85
86 unsigned long
87 print_context_stack(struct thread_info *tinfo,
88                 unsigned long *stack, unsigned long bp,
89                 const struct stacktrace_ops *ops, void *data,
90                 unsigned long *end, int *graph)
91 {
92         struct stack_frame *frame = (struct stack_frame *)bp;
93
94         while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) {
95                 unsigned long addr;
96
97                 addr = *stack;
98                 if (__kernel_text_address(addr)) {
99                         if ((unsigned long) stack == bp + sizeof(long)) {
100                                 ops->address(data, addr, 1);
101                                 frame = frame->next_frame;
102                                 bp = (unsigned long) frame;
103                         } else {
104                                 ops->address(data, addr, 0);
105                         }
106                         print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
107                 }
108                 stack++;
109         }
110         return bp;
111 }
112 EXPORT_SYMBOL_GPL(print_context_stack);
113
114 unsigned long
115 print_context_stack_bp(struct thread_info *tinfo,
116                        unsigned long *stack, unsigned long bp,
117                        const struct stacktrace_ops *ops, void *data,
118                        unsigned long *end, int *graph)
119 {
120         struct stack_frame *frame = (struct stack_frame *)bp;
121         unsigned long *ret_addr = &frame->return_address;
122
123         while (valid_stack_ptr(tinfo, ret_addr, sizeof(*ret_addr), end)) {
124                 unsigned long addr = *ret_addr;
125
126                 if (__kernel_text_address(addr)) {
127                         ops->address(data, addr, 1);
128                         frame = frame->next_frame;
129                         ret_addr = &frame->return_address;
130                         print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
131                 }
132         }
133         return (unsigned long)frame;
134 }
135 EXPORT_SYMBOL_GPL(print_context_stack_bp);
136
137
138 static void
139 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
140 {
141         printk(data);
142         print_symbol(msg, symbol);
143         printk("\n");
144 }
145
146 static void print_trace_warning(void *data, char *msg)
147 {
148         printk("%s%s\n", (char *)data, msg);
149 }
150
151 static int print_trace_stack(void *data, char *name)
152 {
153         printk("%s <%s> ", (char *)data, name);
154         return 0;
155 }
156
157 /*
158  * Print one address/symbol entries per line.
159  */
160 static void print_trace_address(void *data, unsigned long addr, int reliable)
161 {
162         touch_nmi_watchdog();
163         printk(data);
164         printk_address(addr, reliable);
165 }
166
167 static const struct stacktrace_ops print_trace_ops = {
168         .warning                = print_trace_warning,
169         .warning_symbol         = print_trace_warning_symbol,
170         .stack                  = print_trace_stack,
171         .address                = print_trace_address,
172         .walk_stack             = print_context_stack,
173 };
174
175 void
176 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
177                 unsigned long *stack, unsigned long bp, char *log_lvl)
178 {
179         printk("%sCall Trace:\n", log_lvl);
180         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
181 }
182
183 void show_trace(struct task_struct *task, struct pt_regs *regs,
184                 unsigned long *stack, unsigned long bp)
185 {
186         show_trace_log_lvl(task, regs, stack, bp, "");
187 }
188
189 void show_stack(struct task_struct *task, unsigned long *sp)
190 {
191         show_stack_log_lvl(task, NULL, sp, 0, "");
192 }
193
194 /*
195  * The architecture-independent dump_stack generator
196  */
197 void dump_stack(void)
198 {
199         unsigned long bp = 0;
200         unsigned long stack;
201
202 #ifdef CONFIG_FRAME_POINTER
203         if (!bp)
204                 get_bp(bp);
205 #endif
206
207         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
208                 current->pid, current->comm, print_tainted(),
209                 init_utsname()->release,
210                 (int)strcspn(init_utsname()->version, " "),
211                 init_utsname()->version);
212         show_trace(NULL, NULL, &stack, bp);
213 }
214 EXPORT_SYMBOL(dump_stack);
215
216 static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;
217 static int die_owner = -1;
218 static unsigned int die_nest_count;
219
220 unsigned __kprobes long oops_begin(void)
221 {
222         int cpu;
223         unsigned long flags;
224
225         /* notify the hw-branch tracer so it may disable tracing and
226            add the last trace to the trace buffer -
227            the earlier this happens, the more useful the trace. */
228         trace_hw_branch_oops();
229
230         oops_enter();
231
232         /* racy, but better than risking deadlock. */
233         raw_local_irq_save(flags);
234         cpu = smp_processor_id();
235         if (!arch_spin_trylock(&die_lock)) {
236                 if (cpu == die_owner)
237                         /* nested oops. should stop eventually */;
238                 else
239                         arch_spin_lock(&die_lock);
240         }
241         die_nest_count++;
242         die_owner = cpu;
243         console_verbose();
244         bust_spinlocks(1);
245         return flags;
246 }
247
248 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
249 {
250         if (regs && kexec_should_crash(current))
251                 crash_kexec(regs);
252
253         bust_spinlocks(0);
254         die_owner = -1;
255         add_taint(TAINT_DIE);
256         die_nest_count--;
257         if (!die_nest_count)
258                 /* Nest count reaches zero, release the lock. */
259                 arch_spin_unlock(&die_lock);
260         raw_local_irq_restore(flags);
261         oops_exit();
262
263         if (!signr)
264                 return;
265         if (in_interrupt())
266                 panic("Fatal exception in interrupt");
267         if (panic_on_oops)
268                 panic("Fatal exception");
269         do_exit(signr);
270 }
271
272 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
273 {
274 #ifdef CONFIG_X86_32
275         unsigned short ss;
276         unsigned long sp;
277 #endif
278         printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
279 #ifdef CONFIG_PREEMPT
280         printk("PREEMPT ");
281 #endif
282 #ifdef CONFIG_SMP
283         printk("SMP ");
284 #endif
285 #ifdef CONFIG_DEBUG_PAGEALLOC
286         printk("DEBUG_PAGEALLOC");
287 #endif
288         printk("\n");
289         sysfs_printk_last_file();
290         if (notify_die(DIE_OOPS, str, regs, err,
291                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
292                 return 1;
293
294         show_registers(regs);
295 #ifdef CONFIG_X86_32
296         if (user_mode_vm(regs)) {
297                 sp = regs->sp;
298                 ss = regs->ss & 0xffff;
299         } else {
300                 sp = kernel_stack_pointer(regs);
301                 savesegment(ss, ss);
302         }
303         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
304         print_symbol("%s", regs->ip);
305         printk(" SS:ESP %04x:%08lx\n", ss, sp);
306 #else
307         /* Executive summary in case the oops scrolled away */
308         printk(KERN_ALERT "RIP ");
309         printk_address(regs->ip, 1);
310         printk(" RSP <%016lx>\n", regs->sp);
311 #endif
312         return 0;
313 }
314
315 /*
316  * This is gone through when something in the kernel has done something bad
317  * and is about to be terminated:
318  */
319 void die(const char *str, struct pt_regs *regs, long err)
320 {
321         unsigned long flags = oops_begin();
322         int sig = SIGSEGV;
323
324         if (!user_mode_vm(regs))
325                 report_bug(regs->ip, regs);
326
327         if (__die(str, regs, err))
328                 sig = 0;
329         oops_end(flags, regs, sig);
330 }
331
332 void notrace __kprobes
333 die_nmi(char *str, struct pt_regs *regs, int do_panic)
334 {
335         unsigned long flags;
336
337         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
338                 return;
339
340         /*
341          * We are in trouble anyway, lets at least try
342          * to get a message out.
343          */
344         flags = oops_begin();
345         printk(KERN_EMERG "%s", str);
346         printk(" on CPU%d, ip %08lx, registers:\n",
347                 smp_processor_id(), regs->ip);
348         show_registers(regs);
349         oops_end(flags, regs, 0);
350         if (do_panic || panic_on_oops)
351                 panic("Non maskable interrupt");
352         nmi_exit();
353         local_irq_enable();
354         do_exit(SIGBUS);
355 }
356
357 static int __init oops_setup(char *s)
358 {
359         if (!s)
360                 return -EINVAL;
361         if (!strcmp(s, "panic"))
362                 panic_on_oops = 1;
363         return 0;
364 }
365 early_param("oops", oops_setup);
366
367 static int __init kstack_setup(char *s)
368 {
369         if (!s)
370                 return -EINVAL;
371         kstack_depth_to_print = simple_strtoul(s, NULL, 0);
372         return 0;
373 }
374 early_param("kstack", kstack_setup);
375
376 static int __init code_bytes_setup(char *s)
377 {
378         code_bytes = simple_strtoul(s, NULL, 0);
379         if (code_bytes > 8192)
380                 code_bytes = 8192;
381
382         return 1;
383 }
384 __setup("code_bytes=", code_bytes_setup);