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