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/sched/debug.h>
   6 #include <linux/kallsyms.h>
   7 #include <linux/kprobes.h>
   8 #include <linux/uaccess.h>
   9 #include <linux/hardirq.h>
  10 #include <linux/kdebug.h>
  11 #include <linux/export.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/kexec.h>
  14 #include <linux/sysfs.h>
  15 #include <linux/bug.h>
  16 #include <linux/nmi.h>
  17
  18 #include <asm/stacktrace.h>
  19
  20 static char *exception_stack_names[N_EXCEPTION_STACKS] = {
  21                 [ DOUBLEFAULT_STACK-1   ]       = "#DF",
  22                 [ NMI_STACK-1           ]       = "NMI",
  23                 [ DEBUG_STACK-1         ]       = "#DB",
  24                 [ MCE_STACK-1           ]       = "#MC",
  25 };
  26
  27 static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
  28         [0 ... N_EXCEPTION_STACKS - 1]          = EXCEPTION_STKSZ,
  29         [DEBUG_STACK - 1]                       = DEBUG_STKSZ
  30 };
  31
  32 const char *stack_type_name(enum stack_type type)
  33 {
  34         BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
  35
  36         if (type == STACK_TYPE_IRQ)
  37                 return "IRQ";
  38
  39         if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
  40                 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
  41
  42         return NULL;
  43 }
  44
  45 static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
  46 {
  47         unsigned long *begin, *end;
  48         struct pt_regs *regs;
  49         unsigned k;
  50
  51         BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
  52
  53         for (k = 0; k < N_EXCEPTION_STACKS; k++) {
  54                 end   = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
  55                 begin = end - (exception_stack_sizes[k] / sizeof(long));
  56                 regs  = (struct pt_regs *)end - 1;
  57
  58                 if (stack < begin || stack >= end)
  59                         continue;
  60
  61                 info->type      = STACK_TYPE_EXCEPTION + k;
  62                 info->begin     = begin;
  63                 info->end       = end;
  64                 info->next_sp   = (unsigned long *)regs->sp;
  65
  66                 return true;
  67         }
  68
  69         return false;
  70 }
  71
  72 static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
  73 {
  74         unsigned long *end   = (unsigned long *)this_cpu_read(irq_stack_ptr);
  75         unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
  76
  77         /*
  78          * This is a software stack, so 'end' can be a valid stack pointer.
  79          * It just means the stack is empty.
  80          */
  81         if (stack < begin || stack > end)
  82                 return false;
  83
  84         info->type      = STACK_TYPE_IRQ;
  85         info->begin     = begin;
  86         info->end       = end;
  87
  88         /*
  89          * The next stack pointer is the first thing pushed by the entry code
  90          * after switching to the irq stack.
  91          */
  92         info->next_sp = (unsigned long *)*(end - 1);
  93
  94         return true;
  95 }
  96
  97 int get_stack_info(unsigned long *stack, struct task_struct *task,
  98                    struct stack_info *info, unsigned long *visit_mask)
  99 {
 100         if (!stack)
 101                 goto unknown;
 102
 103         task = task ? : current;
 104
 105         if (in_task_stack(stack, task, info))
 106                 goto recursion_check;
 107
 108         if (task != current)
 109                 goto unknown;
 110
 111         if (in_exception_stack(stack, info))
 112                 goto recursion_check;
 113
 114         if (in_irq_stack(stack, info))
 115                 goto recursion_check;
 116
 117         goto unknown;
 118
 119 recursion_check:
 120         /*
 121          * Make sure we don't iterate through any given stack more than once.
 122          * If it comes up a second time then there's something wrong going on:
 123          * just break out and report an unknown stack type.
 124          */
 125         if (visit_mask) {
 126                 if (*visit_mask & (1UL << info->type)) {
 127                         printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
 128                         goto unknown;
 129                 }
 130                 *visit_mask |= 1UL << info->type;
 131         }
 132
 133         return 0;
 134
 135 unknown:
 136         info->type = STACK_TYPE_UNKNOWN;
 137         return -EINVAL;
 138 }
 139
 140 void show_regs(struct pt_regs *regs)
 141 {
 142         int i;
 143
 144         show_regs_print_info(KERN_DEFAULT);
 145         __show_regs(regs, 1);
 146
 147         /*
 148          * When in-kernel, we also print out the stack and code at the
 149          * time of the fault..
 150          */
 151         if (!user_mode(regs)) {
 152                 unsigned int code_prologue = code_bytes * 43 / 64;
 153                 unsigned int code_len = code_bytes;
 154                 unsigned char c;
 155                 u8 *ip;
 156
 157                 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
 158
 159                 printk(KERN_DEFAULT "Code: ");
 160
 161                 ip = (u8 *)regs->ip - code_prologue;
 162                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 163                         /* try starting at IP */
 164                         ip = (u8 *)regs->ip;
 165                         code_len = code_len - code_prologue + 1;
 166                 }
 167                 for (i = 0; i < code_len; i++, ip++) {
 168                         if (ip < (u8 *)PAGE_OFFSET ||
 169                                         probe_kernel_address(ip, c)) {
 170                                 pr_cont(" Bad RIP value.");
 171                                 break;
 172                         }
 173                         if (ip == (u8 *)regs->ip)
 174                                 pr_cont("<%02x> ", c);
 175                         else
 176                                 pr_cont("%02x ", c);
 177                 }
 178         }
 179         pr_cont("\n");
 180 }