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 [ MCE_STACK-1 ] = "#MC",
28 #if DEBUG_STKSZ > EXCEPTION_STKSZ
29 [ N_EXCEPTION_STACKS ...
30 N_EXCEPTION_STACKS_END ] = "#DB[?]"
34 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
35 unsigned *usedp, char **idp)
40 * Iterate over all exception stacks, and figure out whether
41 * 'stack' is in one of them:
43 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
44 unsigned long end = per_cpu(orig_ist, cpu).ist[k];
46 * Is 'stack' above this exception frame's end?
47 * If yes then skip to the next frame.
52 * Is 'stack' above this exception frame's start address?
53 * If yes then we found the right frame.
55 if (stack >= end - EXCEPTION_STKSZ) {
57 * Make sure we only iterate through an exception
58 * stack once. If it comes up for the second time
59 * then there's something wrong going on - just
60 * break out and return NULL:
62 if (*usedp & (1U << k))
65 *idp = x86_stack_ids[k];
66 return (unsigned long *)end;
69 * If this is a debug stack, and if it has a larger size than
70 * the usual exception stacks, then 'stack' might still
71 * be within the lower portion of the debug stack:
73 #if DEBUG_STKSZ > EXCEPTION_STKSZ
74 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
75 unsigned j = N_EXCEPTION_STACKS - 1;
78 * Black magic. A large debug stack is composed of
79 * multiple exception stack entries, which we
80 * iterate through now. Dont look:
84 end -= EXCEPTION_STKSZ;
85 x86_stack_ids[j][4] = '1' +
86 (j - N_EXCEPTION_STACKS);
87 } while (stack < end - EXCEPTION_STKSZ);
88 if (*usedp & (1U << j))
91 *idp = x86_stack_ids[j];
92 return (unsigned long *)end;
100 in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
101 unsigned long *irq_stack_end)
103 return (stack >= irq_stack && stack < irq_stack_end);
107 * x86-64 can have up to three kernel stacks:
110 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
113 void dump_trace(struct task_struct *task, struct pt_regs *regs,
114 unsigned long *stack, unsigned long bp,
115 const struct stacktrace_ops *ops, void *data)
117 const unsigned cpu = get_cpu();
118 unsigned long *irq_stack_end =
119 (unsigned long *)per_cpu(irq_stack_ptr, cpu);
121 struct thread_info *tinfo;
130 stack = (unsigned long *)regs->sp;
131 else if (task != current)
132 stack = (unsigned long *)task->thread.sp;
138 bp = stack_frame(task, regs);
140 * Print function call entries in all stacks, starting at the
141 * current stack address. If the stacks consist of nested
144 tinfo = task_thread_info(task);
147 unsigned long *estack_end;
148 estack_end = in_exception_stack(cpu, (unsigned long)stack,
152 if (ops->stack(data, id) < 0)
155 bp = ops->walk_stack(tinfo, stack, bp, ops,
156 data, estack_end, &graph);
157 ops->stack(data, "<EOE>");
159 * We link to the next stack via the
160 * second-to-last pointer (index -2 to end) in the
163 stack = (unsigned long *) estack_end[-2];
167 unsigned long *irq_stack;
168 irq_stack = irq_stack_end -
169 (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
171 if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
172 if (ops->stack(data, "IRQ") < 0)
174 bp = ops->walk_stack(tinfo, stack, bp,
175 ops, data, irq_stack_end, &graph);
177 * We link to the next stack (which would be
178 * the process stack normally) the last
179 * pointer (index -1 to end) in the IRQ stack:
181 stack = (unsigned long *) (irq_stack_end[-1]);
182 irq_stack_end = NULL;
183 ops->stack(data, "EOI");
191 * This handles the process stack:
193 bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
196 EXPORT_SYMBOL(dump_trace);
199 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
200 unsigned long *sp, unsigned long bp, char *log_lvl)
202 unsigned long *irq_stack_end;
203 unsigned long *irq_stack;
204 unsigned long *stack;
209 cpu = smp_processor_id();
211 irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
212 irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
215 * Debugging aid: "show_stack(NULL, NULL);" prints the
216 * back trace for this cpu:
220 sp = (unsigned long *)task->thread.sp;
222 sp = (unsigned long *)&sp;
226 for (i = 0; i < kstack_depth_to_print; i++) {
227 if (stack >= irq_stack && stack <= irq_stack_end) {
228 if (stack == irq_stack_end) {
229 stack = (unsigned long *) (irq_stack_end[-1]);
233 if (((long) stack & (THREAD_SIZE-1)) == 0)
236 if (i && ((i % STACKSLOTS_PER_LINE) == 0))
238 pr_cont(" %016lx", *stack++);
239 touch_nmi_watchdog();
244 show_trace_log_lvl(task, regs, sp, bp, log_lvl);
247 void show_regs(struct pt_regs *regs)
253 show_regs_print_info(KERN_DEFAULT);
254 __show_regs(regs, 1);
257 * When in-kernel, we also print out the stack and code at the
258 * time of the fault..
260 if (!user_mode(regs)) {
261 unsigned int code_prologue = code_bytes * 43 / 64;
262 unsigned int code_len = code_bytes;
266 printk(KERN_DEFAULT "Stack:\n");
267 show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
270 printk(KERN_DEFAULT "Code: ");
272 ip = (u8 *)regs->ip - code_prologue;
273 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
274 /* try starting at IP */
276 code_len = code_len - code_prologue + 1;
278 for (i = 0; i < code_len; i++, ip++) {
279 if (ip < (u8 *)PAGE_OFFSET ||
280 probe_kernel_address(ip, c)) {
281 pr_cont(" Bad RIP value.");
284 if (ip == (u8 *)regs->ip)
285 pr_cont("<%02x> ", c);
293 int is_valid_bugaddr(unsigned long ip)
297 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
300 return ud2 == 0x0b0f;