2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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>
17 #include <asm/stacktrace.h>
20 #define N_EXCEPTION_STACKS_END \
21 (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
23 static 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[?]"
35 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
36 unsigned *usedp, char **idp)
41 * Iterate over all exception stacks, and figure out whether
42 * 'stack' is in one of them:
44 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
45 unsigned long end = per_cpu(orig_ist, cpu).ist[k];
47 * Is 'stack' above this exception frame's end?
48 * If yes then skip to the next frame.
53 * Is 'stack' above this exception frame's start address?
54 * If yes then we found the right frame.
56 if (stack >= end - EXCEPTION_STKSZ) {
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:
63 if (*usedp & (1U << k))
66 *idp = x86_stack_ids[k];
67 return (unsigned long *)end;
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:
74 #if DEBUG_STKSZ > EXCEPTION_STKSZ
75 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
76 unsigned j = N_EXCEPTION_STACKS - 1;
79 * Black magic. A large debug stack is composed of
80 * multiple exception stack entries, which we
81 * iterate through now. Dont look:
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))
92 *idp = x86_stack_ids[j];
93 return (unsigned long *)end;
101 in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
102 unsigned long *irq_stack_end)
104 return (stack >= irq_stack && stack < irq_stack_end);
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.
116 static inline unsigned long
117 fixup_bp_irq_link(unsigned long bp, unsigned long *stack,
118 unsigned long *irq_stack, unsigned long *irq_stack_end)
120 #ifdef CONFIG_FRAME_POINTER
121 struct stack_frame *frame = (struct stack_frame *)bp;
124 if (!in_irq_stack(stack, irq_stack, irq_stack_end)) {
125 if (!probe_kernel_address(&frame->next_frame, next))
128 WARN_ONCE(1, "Perf: bad frame pointer = %p in "
129 "callchain\n", &frame->next_frame);
136 * x86-64 can have up to three kernel stacks:
139 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
142 void dump_trace(struct task_struct *task, struct pt_regs *regs,
143 unsigned long *stack, unsigned long bp,
144 const struct stacktrace_ops *ops, void *data)
146 const unsigned cpu = get_cpu();
147 unsigned long *irq_stack_end =
148 (unsigned long *)per_cpu(irq_stack_ptr, cpu);
150 struct thread_info *tinfo;
159 stack = (unsigned long *)regs->sp;
160 else if (task && task != current)
161 stack = (unsigned long *)task->thread.sp;
167 bp = stack_frame(task, regs);
169 * Print function call entries in all stacks, starting at the
170 * current stack address. If the stacks consist of nested
173 tinfo = task_thread_info(task);
176 unsigned long *estack_end;
177 estack_end = in_exception_stack(cpu, (unsigned long)stack,
181 if (ops->stack(data, id) < 0)
184 bp = ops->walk_stack(tinfo, stack, bp, ops,
185 data, estack_end, &graph);
186 ops->stack(data, "<EOE>");
188 * We link to the next stack via the
189 * second-to-last pointer (index -2 to end) in the
192 stack = (unsigned long *) estack_end[-2];
196 unsigned long *irq_stack;
197 irq_stack = irq_stack_end -
198 (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
200 if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
201 if (ops->stack(data, "IRQ") < 0)
203 bp = ops->walk_stack(tinfo, stack, bp,
204 ops, data, irq_stack_end, &graph);
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:
210 stack = (unsigned long *) (irq_stack_end[-1]);
211 bp = fixup_bp_irq_link(bp, stack, irq_stack,
213 irq_stack_end = NULL;
214 ops->stack(data, "EOI");
222 * This handles the process stack:
224 bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
227 EXPORT_SYMBOL(dump_trace);
230 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
231 unsigned long *sp, unsigned long bp, char *log_lvl)
233 unsigned long *irq_stack_end;
234 unsigned long *irq_stack;
235 unsigned long *stack;
240 cpu = smp_processor_id();
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);
246 * Debugging aid: "show_stack(NULL, NULL);" prints the
247 * back trace for this cpu:
251 sp = (unsigned long *)task->thread.sp;
253 sp = (unsigned long *)&sp;
257 for (i = 0; i < kstack_depth_to_print; i++) {
258 if (stack >= irq_stack && stack <= irq_stack_end) {
259 if (stack == irq_stack_end) {
260 stack = (unsigned long *) (irq_stack_end[-1]);
261 printk(KERN_CONT " <EOI> ");
264 if (((long) stack & (THREAD_SIZE-1)) == 0)
267 if (i && ((i % STACKSLOTS_PER_LINE) == 0))
268 printk(KERN_CONT "\n");
269 printk(KERN_CONT " %016lx", *stack++);
270 touch_nmi_watchdog();
274 printk(KERN_CONT "\n");
275 show_trace_log_lvl(task, regs, sp, bp, log_lvl);
278 void show_registers(struct pt_regs *regs)
282 const int cpu = smp_processor_id();
283 struct task_struct *cur = current;
286 printk("CPU %d ", cpu);
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);
293 * When in-kernel, we also print out the stack and code at the
294 * time of the fault..
296 if (!user_mode(regs)) {
297 unsigned int code_prologue = code_bytes * 43 / 64;
298 unsigned int code_len = code_bytes;
302 printk(KERN_EMERG "Stack:\n");
303 show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
306 printk(KERN_EMERG "Code: ");
308 ip = (u8 *)regs->ip - code_prologue;
309 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
310 /* try starting at IP */
312 code_len = code_len - code_prologue + 1;
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.");
320 if (ip == (u8 *)regs->ip)
321 printk("<%02x> ", c);
329 int is_valid_bugaddr(unsigned long ip)
333 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
336 return ud2 == 0x0b0f;