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/export.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         task = task ? : current;
  50         stack = stack ? : get_stack_pointer(task, regs);
  51         bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
  52
  53         for (;;) {
  54                 void *end_stack;
  55
  56                 end_stack = is_hardirq_stack(stack, cpu);
  57                 if (!end_stack)
  58                         end_stack = is_softirq_stack(stack, cpu);
  59
  60                 bp = ops->walk_stack(task, stack, bp, ops, data,
  61                                      end_stack, &graph);
  62
  63                 /* Stop if not on irq stack */
  64                 if (!end_stack)
  65                         break;
  66
  67                 /* The previous esp is saved on the bottom of the stack */
  68                 prev_esp = (u32 *)(end_stack - THREAD_SIZE);
  69                 stack = (unsigned long *)*prev_esp;
  70                 if (!stack)
  71                         break;
  72
  73                 if (ops->stack(data, "IRQ") < 0)
  74                         break;
  75                 touch_nmi_watchdog();
  76         }
  77         put_cpu();
  78 }
  79 EXPORT_SYMBOL(dump_trace);
  80
  81 void
  82 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
  83                    unsigned long *sp, unsigned long bp, char *log_lvl)
  84 {
  85         unsigned long *stack;
  86         int i;
  87
  88         sp = sp ? : get_stack_pointer(task, regs);
  89
  90         stack = sp;
  91         for (i = 0; i < kstack_depth_to_print; i++) {
  92                 if (kstack_end(stack))
  93                         break;
  94                 if ((i % STACKSLOTS_PER_LINE) == 0) {
  95                         if (i != 0)
  96                                 pr_cont("\n");
  97                         printk("%s %08lx", log_lvl, *stack++);
  98                 } else
  99                         pr_cont(" %08lx", *stack++);
 100                 touch_nmi_watchdog();
 101         }
 102         pr_cont("\n");
 103         show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 104 }
 105
 106
 107 void show_regs(struct pt_regs *regs)
 108 {
 109         int i;
 110
 111         show_regs_print_info(KERN_EMERG);
 112         __show_regs(regs, !user_mode(regs));
 113
 114         /*
 115          * When in-kernel, we also print out the stack and code at the
 116          * time of the fault..
 117          */
 118         if (!user_mode(regs)) {
 119                 unsigned int code_prologue = code_bytes * 43 / 64;
 120                 unsigned int code_len = code_bytes;
 121                 unsigned char c;
 122                 u8 *ip;
 123
 124                 pr_emerg("Stack:\n");
 125                 show_stack_log_lvl(NULL, regs, NULL, 0, KERN_EMERG);
 126
 127                 pr_emerg("Code:");
 128
 129                 ip = (u8 *)regs->ip - code_prologue;
 130                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 131                         /* try starting at IP */
 132                         ip = (u8 *)regs->ip;
 133                         code_len = code_len - code_prologue + 1;
 134                 }
 135                 for (i = 0; i < code_len; i++, ip++) {
 136                         if (ip < (u8 *)PAGE_OFFSET ||
 137                                         probe_kernel_address(ip, c)) {
 138                                 pr_cont("  Bad EIP value.");
 139                                 break;
 140                         }
 141                         if (ip == (u8 *)regs->ip)
 142                                 pr_cont(" <%02x>", c);
 143                         else
 144                                 pr_cont(" %02x", c);
 145                 }
 146         }
 147         pr_cont("\n");
 148 }
 149
 150 int is_valid_bugaddr(unsigned long ip)
 151 {
 152         unsigned short ud2;
 153
 154         if (ip < PAGE_OFFSET)
 155                 return 0;
 156         if (probe_kernel_address((unsigned short *)ip, ud2))
 157                 return 0;
 158
 159         return ud2 == 0x0b0f;
 160 }