Merge branch 'linus' into tracing/hw-breakpoints
[linux-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 #include <linux/ftrace.h>
19
20 #include <asm/stacktrace.h>
21
22 #include "dumpstack.h"
23
24 int panic_on_unrecovered_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
113
114 static void
115 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
116 {
117         printk(data);
118         print_symbol(msg, symbol);
119         printk("\n");
120 }
121
122 static void print_trace_warning(void *data, char *msg)
123 {
124         printk("%s%s\n", (char *)data, msg);
125 }
126
127 static int print_trace_stack(void *data, char *name)
128 {
129         printk("%s <%s> ", (char *)data, name);
130         return 0;
131 }
132
133 /*
134  * Print one address/symbol entries per line.
135  */
136 static void print_trace_address(void *data, unsigned long addr, int reliable)
137 {
138         touch_nmi_watchdog();
139         printk(data);
140         printk_address(addr, reliable);
141 }
142
143 static const struct stacktrace_ops print_trace_ops = {
144         .warning = print_trace_warning,
145         .warning_symbol = print_trace_warning_symbol,
146         .stack = print_trace_stack,
147         .address = print_trace_address,
148 };
149
150 void
151 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
152                 unsigned long *stack, unsigned long bp, char *log_lvl)
153 {
154         printk("%sCall Trace:\n", log_lvl);
155         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
156 }
157
158 void show_trace(struct task_struct *task, struct pt_regs *regs,
159                 unsigned long *stack, unsigned long bp)
160 {
161         show_trace_log_lvl(task, regs, stack, bp, "");
162 }
163
164 void show_stack(struct task_struct *task, unsigned long *sp)
165 {
166         show_stack_log_lvl(task, NULL, sp, 0, "");
167 }
168
169 /*
170  * The architecture-independent dump_stack generator
171  */
172 void dump_stack(void)
173 {
174         unsigned long bp = 0;
175         unsigned long stack;
176
177 #ifdef CONFIG_FRAME_POINTER
178         if (!bp)
179                 get_bp(bp);
180 #endif
181
182         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
183                 current->pid, current->comm, print_tainted(),
184                 init_utsname()->release,
185                 (int)strcspn(init_utsname()->version, " "),
186                 init_utsname()->version);
187         show_trace(NULL, NULL, &stack, bp);
188 }
189 EXPORT_SYMBOL(dump_stack);
190
191 static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;
192 static int die_owner = -1;
193 static unsigned int die_nest_count;
194
195 unsigned __kprobes long oops_begin(void)
196 {
197         int cpu;
198         unsigned long flags;
199
200         /* notify the hw-branch tracer so it may disable tracing and
201            add the last trace to the trace buffer -
202            the earlier this happens, the more useful the trace. */
203         trace_hw_branch_oops();
204
205         oops_enter();
206
207         /* racy, but better than risking deadlock. */
208         raw_local_irq_save(flags);
209         cpu = smp_processor_id();
210         if (!__raw_spin_trylock(&die_lock)) {
211                 if (cpu == die_owner)
212                         /* nested oops. should stop eventually */;
213                 else
214                         __raw_spin_lock(&die_lock);
215         }
216         die_nest_count++;
217         die_owner = cpu;
218         console_verbose();
219         bust_spinlocks(1);
220         return flags;
221 }
222
223 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
224 {
225         if (regs && kexec_should_crash(current))
226                 crash_kexec(regs);
227
228         bust_spinlocks(0);
229         die_owner = -1;
230         add_taint(TAINT_DIE);
231         die_nest_count--;
232         if (!die_nest_count)
233                 /* Nest count reaches zero, release the lock. */
234                 __raw_spin_unlock(&die_lock);
235         raw_local_irq_restore(flags);
236         oops_exit();
237
238         if (!signr)
239                 return;
240         if (in_interrupt())
241                 panic("Fatal exception in interrupt");
242         if (panic_on_oops)
243                 panic("Fatal exception");
244         do_exit(signr);
245 }
246
247 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
248 {
249 #ifdef CONFIG_X86_32
250         unsigned short ss;
251         unsigned long sp;
252 #endif
253         printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
254 #ifdef CONFIG_PREEMPT
255         printk("PREEMPT ");
256 #endif
257 #ifdef CONFIG_SMP
258         printk("SMP ");
259 #endif
260 #ifdef CONFIG_DEBUG_PAGEALLOC
261         printk("DEBUG_PAGEALLOC");
262 #endif
263         printk("\n");
264         sysfs_printk_last_file();
265         if (notify_die(DIE_OOPS, str, regs, err,
266                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
267                 return 1;
268
269         show_registers(regs);
270 #ifdef CONFIG_X86_32
271         sp = (unsigned long) (&regs->sp);
272         savesegment(ss, ss);
273         if (user_mode(regs)) {
274                 sp = regs->sp;
275                 ss = regs->ss & 0xffff;
276         }
277         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
278         print_symbol("%s", regs->ip);
279         printk(" SS:ESP %04x:%08lx\n", ss, sp);
280 #else
281         /* Executive summary in case the oops scrolled away */
282         printk(KERN_ALERT "RIP ");
283         printk_address(regs->ip, 1);
284         printk(" RSP <%016lx>\n", regs->sp);
285 #endif
286         return 0;
287 }
288
289 /*
290  * This is gone through when something in the kernel has done something bad
291  * and is about to be terminated:
292  */
293 void die(const char *str, struct pt_regs *regs, long err)
294 {
295         unsigned long flags = oops_begin();
296         int sig = SIGSEGV;
297
298         if (!user_mode_vm(regs))
299                 report_bug(regs->ip, regs);
300
301         if (__die(str, regs, err))
302                 sig = 0;
303         oops_end(flags, regs, sig);
304 }
305
306 void notrace __kprobes
307 die_nmi(char *str, struct pt_regs *regs, int do_panic)
308 {
309         unsigned long flags;
310
311         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
312                 return;
313
314         /*
315          * We are in trouble anyway, lets at least try
316          * to get a message out.
317          */
318         flags = oops_begin();
319         printk(KERN_EMERG "%s", str);
320         printk(" on CPU%d, ip %08lx, registers:\n",
321                 smp_processor_id(), regs->ip);
322         show_registers(regs);
323         oops_end(flags, regs, 0);
324         if (do_panic || panic_on_oops)
325                 panic("Non maskable interrupt");
326         nmi_exit();
327         local_irq_enable();
328         do_exit(SIGBUS);
329 }
330
331 static int __init oops_setup(char *s)
332 {
333         if (!s)
334                 return -EINVAL;
335         if (!strcmp(s, "panic"))
336                 panic_on_oops = 1;
337         return 0;
338 }
339 early_param("oops", oops_setup);
340
341 static int __init kstack_setup(char *s)
342 {
343         if (!s)
344                 return -EINVAL;
345         kstack_depth_to_print = simple_strtoul(s, NULL, 0);
346         return 0;
347 }
348 early_param("kstack", kstack_setup);
349
350 static int __init code_bytes_setup(char *s)
351 {
352         code_bytes = simple_strtoul(s, NULL, 0);
353         if (code_bytes > 8192)
354                 code_bytes = 8192;
355
356         return 1;
357 }
358 __setup("code_bytes=", code_bytes_setup);