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/utsname.h>
   9 #include <linux/hardirq.h>
  10 #include <linux/kdebug.h>
  11 #include <linux/module.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/kexec.h>
  14 #include <linux/bug.h>
  15 #include <linux/nmi.h>
  16 #include <linux/sysfs.h>
  17
  18 #include <asm/stacktrace.h>
  19
  20 #include "dumpstack.h"
  21
  22
  23 static char x86_stack_ids[][8] = {
  24                 [DEBUG_STACK - 1] = "#DB",
  25                 [NMI_STACK - 1] = "NMI",
  26                 [DOUBLEFAULT_STACK - 1] = "#DF",
  27                 [STACKFAULT_STACK - 1] = "#SS",
  28                 [MCE_STACK - 1] = "#MC",
  29 #if DEBUG_STKSZ > EXCEPTION_STKSZ
  30                 [N_EXCEPTION_STACKS ...
  31                         N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]"
  32 #endif
  33         };
  34
  35 int x86_is_stack_id(int id, char *name)
  36 {
  37         return x86_stack_ids[id - 1] == name;
  38 }
  39
  40 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
  41                                         unsigned *usedp, char **idp)
  42 {
  43         unsigned k;
  44
  45         /*
  46          * Iterate over all exception stacks, and figure out whether
  47          * 'stack' is in one of them:
  48          */
  49         for (k = 0; k < N_EXCEPTION_STACKS; k++) {
  50                 unsigned long end = per_cpu(orig_ist, cpu).ist[k];
  51                 /*
  52                  * Is 'stack' above this exception frame's end?
  53                  * If yes then skip to the next frame.
  54                  */
  55                 if (stack >= end)
  56                         continue;
  57                 /*
  58                  * Is 'stack' above this exception frame's start address?
  59                  * If yes then we found the right frame.
  60                  */
  61                 if (stack >= end - EXCEPTION_STKSZ) {
  62                         /*
  63                          * Make sure we only iterate through an exception
  64                          * stack once. If it comes up for the second time
  65                          * then there's something wrong going on - just
  66                          * break out and return NULL:
  67                          */
  68                         if (*usedp & (1U << k))
  69                                 break;
  70                         *usedp |= 1U << k;
  71                         *idp = x86_stack_ids[k];
  72                         return (unsigned long *)end;
  73                 }
  74                 /*
  75                  * If this is a debug stack, and if it has a larger size than
  76                  * the usual exception stacks, then 'stack' might still
  77                  * be within the lower portion of the debug stack:
  78                  */
  79 #if DEBUG_STKSZ > EXCEPTION_STKSZ
  80                 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
  81                         unsigned j = N_EXCEPTION_STACKS - 1;
  82
  83                         /*
  84                          * Black magic. A large debug stack is composed of
  85                          * multiple exception stack entries, which we
  86                          * iterate through now. Dont look:
  87                          */
  88                         do {
  89                                 ++j;
  90                                 end -= EXCEPTION_STKSZ;
  91                                 x86_stack_ids[j][4] = '1' +
  92                                                 (j - N_EXCEPTION_STACKS);
  93                         } while (stack < end - EXCEPTION_STKSZ);
  94                         if (*usedp & (1U << j))
  95                                 break;
  96                         *usedp |= 1U << j;
  97                         *idp = x86_stack_ids[j];
  98                         return (unsigned long *)end;
  99                 }
 100 #endif
 101         }
 102         return NULL;
 103 }
 104
 105 /*
 106  * x86-64 can have up to three kernel stacks:
 107  * process stack
 108  * interrupt stack
 109  * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
 110  */
 111
 112 void dump_trace(struct task_struct *task, struct pt_regs *regs,
 113                 unsigned long *stack, unsigned long bp,
 114                 const struct stacktrace_ops *ops, void *data)
 115 {
 116         const unsigned cpu = get_cpu();
 117         unsigned long *irq_stack_end =
 118                 (unsigned long *)per_cpu(irq_stack_ptr, cpu);
 119         unsigned used = 0;
 120         struct thread_info *tinfo;
 121         int graph = 0;
 122
 123         if (!task)
 124                 task = current;
 125
 126         if (!stack) {
 127                 unsigned long dummy;
 128                 stack = &dummy;
 129                 if (task && task != current)
 130                         stack = (unsigned long *)task->thread.sp;
 131         }
 132
 133 #ifdef CONFIG_FRAME_POINTER
 134         if (!bp) {
 135                 if (task == current) {
 136                         /* Grab bp right from our regs */
 137                         get_bp(bp);
 138                 } else {
 139                         /* bp is the last reg pushed by switch_to */
 140                         bp = *(unsigned long *) task->thread.sp;
 141                 }
 142         }
 143 #endif
 144
 145         /*
 146          * Print function call entries in all stacks, starting at the
 147          * current stack address. If the stacks consist of nested
 148          * exceptions
 149          */
 150         tinfo = task_thread_info(task);
 151         for (;;) {
 152                 char *id;
 153                 unsigned long *estack_end;
 154                 estack_end = in_exception_stack(cpu, (unsigned long)stack,
 155                                                 &used, &id);
 156
 157                 if (estack_end) {
 158                         if (ops->stack(data, id) < 0)
 159                                 break;
 160
 161                         bp = print_context_stack(tinfo, stack, bp, ops,
 162                                                  data, estack_end, &graph);
 163                         ops->stack(data, "<EOE>");
 164                         /*
 165                          * We link to the next stack via the
 166                          * second-to-last pointer (index -2 to end) in the
 167                          * exception stack:
 168                          */
 169                         stack = (unsigned long *) estack_end[-2];
 170                         continue;
 171                 }
 172                 if (irq_stack_end) {
 173                         unsigned long *irq_stack;
 174                         irq_stack = irq_stack_end -
 175                                 (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
 176
 177                         if (stack >= irq_stack && stack < irq_stack_end) {
 178                                 if (ops->stack(data, "IRQ") < 0)
 179                                         break;
 180                                 bp = print_context_stack(tinfo, stack, bp,
 181                                         ops, data, irq_stack_end, &graph);
 182                                 /*
 183                                  * We link to the next stack (which would be
 184                                  * the process stack normally) the last
 185                                  * pointer (index -1 to end) in the IRQ stack:
 186                                  */
 187                                 stack = (unsigned long *) (irq_stack_end[-1]);
 188                                 irq_stack_end = NULL;
 189                                 ops->stack(data, "EOI");
 190                                 continue;
 191                         }
 192                 }
 193                 break;
 194         }
 195
 196         /*
 197          * This handles the process stack:
 198          */
 199         bp = print_context_stack(tinfo, stack, bp, ops, data, NULL, &graph);
 200         put_cpu();
 201 }
 202 EXPORT_SYMBOL(dump_trace);
 203
 204 void
 205 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 206                 unsigned long *sp, unsigned long bp, char *log_lvl)
 207 {
 208         unsigned long *stack;
 209         int i;
 210         const int cpu = smp_processor_id();
 211         unsigned long *irq_stack_end =
 212                 (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
 213         unsigned long *irq_stack =
 214                 (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
 215
 216         /*
 217          * debugging aid: "show_stack(NULL, NULL);" prints the
 218          * back trace for this cpu.
 219          */
 220
 221         if (sp == NULL) {
 222                 if (task)
 223                         sp = (unsigned long *)task->thread.sp;
 224                 else
 225                         sp = (unsigned long *)&sp;
 226         }
 227
 228         stack = sp;
 229         for (i = 0; i < kstack_depth_to_print; i++) {
 230                 if (stack >= irq_stack && stack <= irq_stack_end) {
 231                         if (stack == irq_stack_end) {
 232                                 stack = (unsigned long *) (irq_stack_end[-1]);
 233                                 printk(" <EOI> ");
 234                         }
 235                 } else {
 236                 if (((long) stack & (THREAD_SIZE-1)) == 0)
 237                         break;
 238                 }
 239                 if (i && ((i % STACKSLOTS_PER_LINE) == 0))
 240                         printk("\n%s", log_lvl);
 241                 printk(" %016lx", *stack++);
 242                 touch_nmi_watchdog();
 243         }
 244         printk("\n");
 245         show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 246 }
 247
 248 void show_registers(struct pt_regs *regs)
 249 {
 250         int i;
 251         unsigned long sp;
 252         const int cpu = smp_processor_id();
 253         struct task_struct *cur = current;
 254
 255         sp = regs->sp;
 256         printk("CPU %d ", cpu);
 257         __show_regs(regs, 1);
 258         printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
 259                 cur->comm, cur->pid, task_thread_info(cur), cur);
 260
 261         /*
 262          * When in-kernel, we also print out the stack and code at the
 263          * time of the fault..
 264          */
 265         if (!user_mode(regs)) {
 266                 unsigned int code_prologue = code_bytes * 43 / 64;
 267                 unsigned int code_len = code_bytes;
 268                 unsigned char c;
 269                 u8 *ip;
 270
 271                 printk(KERN_EMERG "Stack:\n");
 272                 show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
 273                                 regs->bp, KERN_EMERG);
 274
 275                 printk(KERN_EMERG "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                                 printk(" Bad RIP value.");
 287                                 break;
 288                         }
 289                         if (ip == (u8 *)regs->ip)
 290                                 printk("<%02x> ", c);
 291                         else
 292                                 printk("%02x ", c);
 293                 }
 294         }
 295         printk("\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 }
 307