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 void stack_type_str(enum stack_type type, const char **begin, const char **end)
  32 {
  33         BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
  34
  35         switch (type) {
  36         case STACK_TYPE_IRQ:
  37                 *begin = "IRQ";
  38                 *end   = "EOI";
  39                 break;
  40         case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
  41                 *begin = exception_stack_names[type - STACK_TYPE_EXCEPTION];
  42                 *end   = "EOE";
  43                 break;
  44         default:
  45                 *begin = NULL;
  46                 *end   = NULL;
  47         }
  48 }
  49
  50 static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
  51 {
  52         unsigned long *begin, *end;
  53         struct pt_regs *regs;
  54         unsigned k;
  55
  56         BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
  57
  58         for (k = 0; k < N_EXCEPTION_STACKS; k++) {
  59                 end   = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
  60                 begin = end - (exception_stack_sizes[k] / sizeof(long));
  61                 regs  = (struct pt_regs *)end - 1;
  62
  63                 if (stack < begin || stack >= end)
  64                         continue;
  65
  66                 info->type      = STACK_TYPE_EXCEPTION + k;
  67                 info->begin     = begin;
  68                 info->end       = end;
  69                 info->next_sp   = (unsigned long *)regs->sp;
  70
  71                 return true;
  72         }
  73
  74         return false;
  75 }
  76
  77 static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
  78 {
  79         unsigned long *end   = (unsigned long *)this_cpu_read(irq_stack_ptr);
  80         unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
  81
  82         /*
  83          * This is a software stack, so 'end' can be a valid stack pointer.
  84          * It just means the stack is empty.
  85          */
  86         if (stack < begin || stack > end)
  87                 return false;
  88
  89         info->type      = STACK_TYPE_IRQ;
  90         info->begin     = begin;
  91         info->end       = end;
  92
  93         /*
  94          * The next stack pointer is the first thing pushed by the entry code
  95          * after switching to the irq stack.
  96          */
  97         info->next_sp = (unsigned long *)*(end - 1);
  98
  99         return true;
 100 }
 101
 102 int get_stack_info(unsigned long *stack, struct task_struct *task,
 103                    struct stack_info *info, unsigned long *visit_mask)
 104 {
 105         if (!stack)
 106                 goto unknown;
 107
 108         task = task ? : current;
 109
 110         if (in_task_stack(stack, task, info))
 111                 goto recursion_check;
 112
 113         if (task != current)
 114                 goto unknown;
 115
 116         if (in_exception_stack(stack, info))
 117                 goto recursion_check;
 118
 119         if (in_irq_stack(stack, info))
 120                 goto recursion_check;
 121
 122         goto unknown;
 123
 124 recursion_check:
 125         /*
 126          * Make sure we don't iterate through any given stack more than once.
 127          * If it comes up a second time then there's something wrong going on:
 128          * just break out and report an unknown stack type.
 129          */
 130         if (visit_mask) {
 131                 if (*visit_mask & (1UL << info->type))
 132                         goto unknown;
 133                 *visit_mask |= 1UL << info->type;
 134         }
 135
 136         return 0;
 137
 138 unknown:
 139         info->type = STACK_TYPE_UNKNOWN;
 140         return -EINVAL;
 141 }
 142
 143 /*
 144  * x86-64 can have up to three kernel stacks:
 145  * process stack
 146  * interrupt stack
 147  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
 148  */
 149
 150 void dump_trace(struct task_struct *task, struct pt_regs *regs,
 151                 unsigned long *stack, unsigned long bp,
 152                 const struct stacktrace_ops *ops, void *data)
 153 {
 154         unsigned long visit_mask = 0;
 155         struct stack_info info;
 156         int graph = 0;
 157         int done = 0;
 158
 159         task = task ? : current;
 160         stack = stack ? : get_stack_pointer(task, regs);
 161         bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
 162
 163         /*
 164          * Print function call entries in all stacks, starting at the
 165          * current stack address. If the stacks consist of nested
 166          * exceptions
 167          */
 168         while (!done) {
 169                 const char *begin_str, *end_str;
 170
 171                 get_stack_info(stack, task, &info, &visit_mask);
 172
 173                 /* Default finish unless specified to continue */
 174                 done = 1;
 175
 176                 switch (info.type) {
 177
 178                 /* Break out early if we are on the thread stack */
 179                 case STACK_TYPE_TASK:
 180                         break;
 181
 182                 case STACK_TYPE_IRQ:
 183                 case STACK_TYPE_EXCEPTION ... STACK_TYPE_EXCEPTION_LAST:
 184
 185                         stack_type_str(info.type, &begin_str, &end_str);
 186
 187                         if (ops->stack(data, begin_str) < 0)
 188                                 break;
 189
 190                         bp = ops->walk_stack(task, stack, bp, ops,
 191                                              data, &info, &graph);
 192
 193                         ops->stack(data, end_str);
 194
 195                         stack = info.next_sp;
 196                         done = 0;
 197                         break;
 198
 199                 default:
 200                         ops->stack(data, "UNK");
 201                         break;
 202                 }
 203         }
 204
 205         /*
 206          * This handles the process stack:
 207          */
 208         bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
 209 }
 210 EXPORT_SYMBOL(dump_trace);
 211
 212 void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 213                         unsigned long *sp, char *log_lvl)
 214 {
 215         unsigned long *irq_stack_end;
 216         unsigned long *irq_stack;
 217         unsigned long *stack;
 218         int i;
 219
 220         if (!try_get_task_stack(task))
 221                 return;
 222
 223         irq_stack_end = (unsigned long *)this_cpu_read(irq_stack_ptr);
 224         irq_stack     = irq_stack_end - (IRQ_STACK_SIZE / sizeof(long));
 225
 226         sp = sp ? : get_stack_pointer(task, regs);
 227
 228         stack = sp;
 229         for (i = 0; i < kstack_depth_to_print; i++) {
 230                 unsigned long word;
 231
 232                 if (stack >= irq_stack && stack <= irq_stack_end) {
 233                         if (stack == irq_stack_end) {
 234                                 stack = (unsigned long *) (irq_stack_end[-1]);
 235                                 pr_cont(" <EOI> ");
 236                         }
 237                 } else {
 238                 if (kstack_end(stack))
 239                         break;
 240                 }
 241
 242                 if (probe_kernel_address(stack, word))
 243                         break;
 244
 245                 if ((i % STACKSLOTS_PER_LINE) == 0) {
 246                         if (i != 0)
 247                                 pr_cont("\n");
 248                         printk("%s %016lx", log_lvl, word);
 249                 } else
 250                         pr_cont(" %016lx", word);
 251
 252                 stack++;
 253                 touch_nmi_watchdog();
 254         }
 255
 256         pr_cont("\n");
 257         show_trace_log_lvl(task, regs, sp, log_lvl);
 258
 259         put_task_stack(task);
 260 }
 261
 262 void show_regs(struct pt_regs *regs)
 263 {
 264         int i;
 265
 266         show_regs_print_info(KERN_DEFAULT);
 267         __show_regs(regs, 1);
 268
 269         /*
 270          * When in-kernel, we also print out the stack and code at the
 271          * time of the fault..
 272          */
 273         if (!user_mode(regs)) {
 274                 unsigned int code_prologue = code_bytes * 43 / 64;
 275                 unsigned int code_len = code_bytes;
 276                 unsigned char c;
 277                 u8 *ip;
 278
 279                 printk(KERN_DEFAULT "Stack:\n");
 280                 show_stack_log_lvl(current, regs, NULL, KERN_DEFAULT);
 281
 282                 printk(KERN_DEFAULT "Code: ");
 283
 284                 ip = (u8 *)regs->ip - code_prologue;
 285                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 286                         /* try starting at IP */
 287                         ip = (u8 *)regs->ip;
 288                         code_len = code_len - code_prologue + 1;
 289                 }
 290                 for (i = 0; i < code_len; i++, ip++) {
 291                         if (ip < (u8 *)PAGE_OFFSET ||
 292                                         probe_kernel_address(ip, c)) {
 293                                 pr_cont(" Bad RIP value.");
 294                                 break;
 295                         }
 296                         if (ip == (u8 *)regs->ip)
 297                                 pr_cont("<%02x> ", c);
 298                         else
 299                                 pr_cont("%02x ", c);
 300                 }
 301         }
 302         pr_cont("\n");
 303 }
 304
 305 int is_valid_bugaddr(unsigned long ip)
 306 {
 307         unsigned short ud2;
 308
 309         if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
 310                 return 0;
 311
 312         return ud2 == 0x0b0f;
 313 }