arch/x86/kernel/dumpstack_32.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/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>
  16
  17 #include <asm/stacktrace.h>
  18
  19 static void *is_irq_stack(void *p, void *irq)
  20 {
  21         if (p < irq || p >= (irq + THREAD_SIZE))
  22                 return NULL;
  23         return irq + THREAD_SIZE;
  24 }
  25
  26
  27 static void *is_hardirq_stack(unsigned long *stack, int cpu)
  28 {
  29         void *irq = per_cpu(hardirq_stack, cpu);
  30
  31         return is_irq_stack(stack, irq);
  32 }
  33
  34 static void *is_softirq_stack(unsigned long *stack, int cpu)
  35 {
  36         void *irq = per_cpu(softirq_stack, cpu);
  37
  38         return is_irq_stack(stack, irq);
  39 }
  40
  41 void dump_trace(struct task_struct *task, struct pt_regs *regs,
  42                 unsigned long *stack, unsigned long bp,
  43                 const struct stacktrace_ops *ops, void *data)
  44 {
  45         const unsigned cpu = get_cpu();
  46         int graph = 0;
  47         u32 *prev_esp;
  48
  49         if (!task)
  50                 task = current;
  51
  52         if (!stack) {
  53                 unsigned long dummy;
  54
  55                 stack = &dummy;
  56                 if (task != current)
  57                         stack = (unsigned long *)task->thread.sp;
  58         }
  59
  60         if (!bp)
  61                 bp = stack_frame(task, regs);
  62
  63         for (;;) {
  64                 struct thread_info *context;
  65                 void *end_stack;
  66
  67                 end_stack = is_hardirq_stack(stack, cpu);
  68                 if (!end_stack)
  69                         end_stack = is_softirq_stack(stack, cpu);
  70
  71                 context = task_thread_info(task);
  72                 bp = ops->walk_stack(context, stack, bp, ops, data,
  73                                      end_stack, &graph);
  74
  75                 /* Stop if not on irq stack */
  76                 if (!end_stack)
  77                         break;
  78
  79                 /* The previous esp is saved on the bottom of the stack */
  80                 prev_esp = (u32 *)(end_stack - THREAD_SIZE);
  81                 stack = (unsigned long *)*prev_esp;
  82                 if (!stack)
  83                         break;
  84
  85                 if (ops->stack(data, "IRQ") < 0)
  86                         break;
  87                 touch_nmi_watchdog();
  88         }
  89         put_cpu();
  90 }
  91 EXPORT_SYMBOL(dump_trace);
  92
  93 void
  94 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
  95                    unsigned long *sp, unsigned long bp, char *log_lvl)
  96 {
  97         unsigned long *stack;
  98         int i;
  99
 100         if (sp == NULL) {
 101                 if (task)
 102                         sp = (unsigned long *)task->thread.sp;
 103                 else
 104                         sp = (unsigned long *)&sp;
 105         }
 106
 107         stack = sp;
 108         for (i = 0; i < kstack_depth_to_print; i++) {
 109                 if (kstack_end(stack))
 110                         break;
 111                 if (i && ((i % STACKSLOTS_PER_LINE) == 0))
 112                         pr_cont("\n");
 113                 pr_cont(" %08lx", *stack++);
 114                 touch_nmi_watchdog();
 115         }
 116         pr_cont("\n");
 117         show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 118 }
 119
 120
 121 void show_regs(struct pt_regs *regs)
 122 {
 123         int i;
 124
 125         show_regs_print_info(KERN_EMERG);
 126         __show_regs(regs, !user_mode_vm(regs));
 127
 128         /*
 129          * When in-kernel, we also print out the stack and code at the
 130          * time of the fault..
 131          */
 132         if (!user_mode_vm(regs)) {
 133                 unsigned int code_prologue = code_bytes * 43 / 64;
 134                 unsigned int code_len = code_bytes;
 135                 unsigned char c;
 136                 u8 *ip;
 137
 138                 pr_emerg("Stack:\n");
 139                 show_stack_log_lvl(NULL, regs, &regs->sp, 0, KERN_EMERG);
 140
 141                 pr_emerg("Code:");
 142
 143                 ip = (u8 *)regs->ip - code_prologue;
 144                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 145                         /* try starting at IP */
 146                         ip = (u8 *)regs->ip;
 147                         code_len = code_len - code_prologue + 1;
 148                 }
 149                 for (i = 0; i < code_len; i++, ip++) {
 150                         if (ip < (u8 *)PAGE_OFFSET ||
 151                                         probe_kernel_address(ip, c)) {
 152                                 pr_cont("  Bad EIP value.");
 153                                 break;
 154                         }
 155                         if (ip == (u8 *)regs->ip)
 156                                 pr_cont(" <%02x>", c);
 157                         else
 158                                 pr_cont(" %02x", c);
 159                 }
 160         }
 161         pr_cont("\n");
 162 }
 163
 164 int is_valid_bugaddr(unsigned long ip)
 165 {
 166         unsigned short ud2;
 167
 168         if (ip < PAGE_OFFSET)
 169                 return 0;
 170         if (probe_kernel_address((unsigned short *)ip, ud2))
 171                 return 0;
 172
 173         return ud2 == 0x0b0f;
 174 }