arch/x86/kernel/dumpstack_64.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 char *exception_stack_names[N_EXCEPTION_STACKS] = {
  20                 [ DOUBLEFAULT_STACK-1   ]       = "#DF",
  21                 [ NMI_STACK-1           ]       = "NMI",
  22                 [ DEBUG_STACK-1         ]       = "#DB",
  23                 [ MCE_STACK-1           ]       = "#MC",
  24 };
  25
  26 static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
  27         [0 ... N_EXCEPTION_STACKS - 1]          = EXCEPTION_STKSZ,
  28         [DEBUG_STACK - 1]                       = DEBUG_STKSZ
  29 };
  30
  31 const char *stack_type_name(enum stack_type type)
  32 {
  33         BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
  34
  35         if (type == STACK_TYPE_IRQ)
  36                 return "IRQ";
  37
  38         if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
  39                 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
  40
  41         return NULL;
  42 }
  43
  44 static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
  45 {
  46         unsigned long *begin, *end;
  47         struct pt_regs *regs;
  48         unsigned k;
  49
  50         BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
  51
  52         for (k = 0; k < N_EXCEPTION_STACKS; k++) {
  53                 end   = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
  54                 begin = end - (exception_stack_sizes[k] / sizeof(long));
  55                 regs  = (struct pt_regs *)end - 1;
  56
  57                 if (stack < begin || stack >= end)
  58                         continue;
  59
  60                 info->type      = STACK_TYPE_EXCEPTION + k;
  61                 info->begin     = begin;
  62                 info->end       = end;
  63                 info->next_sp   = (unsigned long *)regs->sp;
  64
  65                 return true;
  66         }
  67
  68         return false;
  69 }
  70
  71 static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
  72 {
  73         unsigned long *end   = (unsigned long *)this_cpu_read(irq_stack_ptr);
  74         unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
  75
  76         /*
  77          * This is a software stack, so 'end' can be a valid stack pointer.
  78          * It just means the stack is empty.
  79          */
  80         if (stack < begin || stack > end)
  81                 return false;
  82
  83         info->type      = STACK_TYPE_IRQ;
  84         info->begin     = begin;
  85         info->end       = end;
  86
  87         /*
  88          * The next stack pointer is the first thing pushed by the entry code
  89          * after switching to the irq stack.
  90          */
  91         info->next_sp = (unsigned long *)*(end - 1);
  92
  93         return true;
  94 }
  95
  96 int get_stack_info(unsigned long *stack, struct task_struct *task,
  97                    struct stack_info *info, unsigned long *visit_mask)
  98 {
  99         if (!stack)
 100                 goto unknown;
 101
 102         task = task ? : current;
 103
 104         if (in_task_stack(stack, task, info))
 105                 goto recursion_check;
 106
 107         if (task != current)
 108                 goto unknown;
 109
 110         if (in_exception_stack(stack, info))
 111                 goto recursion_check;
 112
 113         if (in_irq_stack(stack, info))
 114                 goto recursion_check;
 115
 116         goto unknown;
 117
 118 recursion_check:
 119         /*
 120          * Make sure we don't iterate through any given stack more than once.
 121          * If it comes up a second time then there's something wrong going on:
 122          * just break out and report an unknown stack type.
 123          */
 124         if (visit_mask) {
 125                 if (*visit_mask & (1UL << info->type)) {
 126                         printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
 127                         goto unknown;
 128                 }
 129                 *visit_mask |= 1UL << info->type;
 130         }
 131
 132         return 0;
 133
 134 unknown:
 135         info->type = STACK_TYPE_UNKNOWN;
 136         return -EINVAL;
 137 }
 138
 139 void show_regs(struct pt_regs *regs)
 140 {
 141         int i;
 142
 143         show_regs_print_info(KERN_DEFAULT);
 144         __show_regs(regs, 1);
 145
 146         /*
 147          * When in-kernel, we also print out the stack and code at the
 148          * time of the fault..
 149          */
 150         if (!user_mode(regs)) {
 151                 unsigned int code_prologue = code_bytes * 43 / 64;
 152                 unsigned int code_len = code_bytes;
 153                 unsigned char c;
 154                 u8 *ip;
 155
 156                 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
 157
 158                 printk(KERN_DEFAULT "Code: ");
 159
 160                 ip = (u8 *)regs->ip - code_prologue;
 161                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 162                         /* try starting at IP */
 163                         ip = (u8 *)regs->ip;
 164                         code_len = code_len - code_prologue + 1;
 165                 }
 166                 for (i = 0; i < code_len; i++, ip++) {
 167                         if (ip < (u8 *)PAGE_OFFSET ||
 168                                         probe_kernel_address(ip, c)) {
 169                                 pr_cont(" Bad RIP value.");
 170                                 break;
 171                         }
 172                         if (ip == (u8 *)regs->ip)
 173                                 pr_cont("<%02x> ", c);
 174                         else
 175                                 pr_cont("%02x ", c);
 176                 }
 177         }
 178         pr_cont("\n");
 179 }
 180
 181 int is_valid_bugaddr(unsigned long ip)
 182 {
 183         unsigned short ud2;
 184
 185         if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
 186                 return 0;
 187
 188         return ud2 == 0x0b0f;
 189 }