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