libkern/gen/OSDebug.cpp

   1 /*
   2  * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 // NOTE:  This file is only c++ so I can get static initialisers going
  30 #include <libkern/OSDebug.h>
  31
  32 #include <sys/cdefs.h>
  33
  34 #include <stdarg.h>
  35 #include <mach/mach_types.h>
  36 #include <mach/kmod.h>
  37 #include <kern/lock.h>
  38
  39 #include <libkern/libkern.h>    // From bsd's libkern directory
  40 #include <mach/vm_param.h>
  41
  42 #include <sys/kdebug.h>
  43 extern int etext;
  44 __BEGIN_DECLS
  45 // From osmfk/kern/thread.h but considered to be private
  46 extern vm_offset_t min_valid_stack_address(void);
  47 extern vm_offset_t max_valid_stack_address(void);
  48
  49 // From osfmk/kmod.c
  50 extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt);
  51
  52 extern addr64_t kvtophys(vm_offset_t va);
  53
  54 __END_DECLS
  55
  56 static mutex_t *sOSReportLock = mutex_alloc(0);
  57
  58 /* Use kernel_debug() to log a backtrace */
  59 void
  60 trace_backtrace(unsigned int debugid, unsigned int debugid2, int size, int data) {
  61         void *bt[16];
  62         const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  63         unsigned i;
  64         int found = 0;
  65
  66         OSBacktrace(bt, cnt);
  67
  68         /* find first non-kernel frame */
  69         for (i = 3; i < cnt && bt[i]; i++) {
  70                 if (bt[i] > (void*)&etext) {
  71                         found = 1;
  72                         break;
  73                 }
  74         }
  75         /*
  76          * if there are non-kernel frames, only log these
  77          * otherwise, log everything but the first two
  78          */
  79         if (!found) i=2;
  80
  81 #define safe_bt(a) (int)(a<cnt ? bt[a] : 0)
  82         kernel_debug(debugid, data, size, safe_bt(i), safe_bt(i+1), 0);
  83         kernel_debug(debugid2, safe_bt(i+2), safe_bt(i+3), safe_bt(i+4), safe_bt(i+5), 0);
  84 }
  85
  86 /* Report a message with a 4 entry backtrace - very slow */
  87 void
  88 OSReportWithBacktrace(const char *str, ...)
  89 {
  90     char buf[128];
  91     void *bt[9];
  92     const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  93     va_list listp;
  94
  95     // Ignore the our and our callers stackframes, skipping frames 0 & 1
  96     (void) OSBacktrace(bt, cnt);
  97
  98     va_start(listp, str);
  99     vsnprintf(buf, sizeof(buf), str, listp);
 100     va_end(listp);
 101
 102     mutex_lock(sOSReportLock);
 103     {
 104         printf("%s\nBacktrace %p %p %p %p %p %p %p\n",
 105                 buf, bt[2], bt[3], bt[4], bt[5], bt[6], bt[7], bt[8]);
 106         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2);
 107     }
 108     mutex_unlock(sOSReportLock);
 109 }
 110
 111 static vm_offset_t minstackaddr = min_valid_stack_address();
 112 static vm_offset_t maxstackaddr = max_valid_stack_address();
 113
 114 #if __i386__
 115 #define i386_RETURN_OFFSET 4
 116
 117 static unsigned int
 118 i386_validate_stackptr(vm_offset_t stackptr)
 119 {
 120         /* Existence and alignment check
 121          */
 122         if (!stackptr || (stackptr & 0x3))
 123                 return 0;
 124
 125         /* Is a virtual->physical translation present?
 126          */
 127         if (!kvtophys(stackptr))
 128                 return 0;
 129
 130         /* Check if the return address lies on the same page;
 131          * If not, verify that a translation exists.
 132          */
 133         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < i386_RETURN_OFFSET) &&
 134             !kvtophys(stackptr + i386_RETURN_OFFSET))
 135                 return 0;
 136         return 1;
 137 }
 138
 139 static unsigned int
 140 i386_validate_raddr(vm_offset_t raddr)
 141 {
 142         return ((raddr > VM_MIN_KERNEL_ADDRESS) &&
 143             (raddr < VM_MAX_KERNEL_ADDRESS));
 144 }
 145 #endif
 146
 147 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
 148 {
 149     unsigned frame;
 150
 151 #if __ppc__
 152     vm_offset_t stackptr, stackptr_prev;
 153     const vm_offset_t * const mem = (vm_offset_t *) 0;
 154     unsigned i = 0;
 155
 156     __asm__ volatile("mflr %0" : "=r" (stackptr));
 157     bt[i++] = (void *) stackptr;
 158
 159     __asm__ volatile("mr %0,r1" : "=r" (stackptr));
 160     for ( ; i < maxAddrs; i++) {
 161         // Validate we have a reasonable stackptr
 162         if ( !(minstackaddr <= stackptr && stackptr < maxstackaddr)
 163         || (stackptr & 3))
 164             break;
 165
 166         stackptr_prev = stackptr;
 167         stackptr = mem[stackptr_prev >> 2];
 168         if ((stackptr_prev ^ stackptr) > 8 * 1024)      // Sanity check
 169             break;
 170
 171         vm_offset_t addr = mem[(stackptr >> 2) + 2];
 172         if ((addr & 3) || (addr < 0x8000))      // More sanity checks
 173             break;
 174         bt[i] = (void *) addr;
 175     }
 176     frame = i;
 177
 178     for ( ; i < maxAddrs; i++)
 179             bt[i] = (void *) 0;
 180 #elif __i386__
 181 #define SANE_i386_FRAME_SIZE 8*1024
 182     vm_offset_t stackptr, stackptr_prev, raddr;
 183     unsigned frame_index = 0;
 184 /* Obtain current frame pointer */
 185     __asm__ volatile("movl %%ebp, %0" : "=m" (stackptr));
 186
 187     if (!i386_validate_stackptr(stackptr))
 188             goto pad;
 189
 190     raddr = *((vm_offset_t *) (stackptr + i386_RETURN_OFFSET));
 191
 192     if (!i386_validate_raddr(raddr))
 193             goto pad;
 194
 195     bt[frame_index++] = (void *) raddr;
 196
 197     for ( ; frame_index < maxAddrs; frame_index++) {
 198             stackptr_prev = stackptr;
 199             stackptr = *((vm_offset_t *) stackptr_prev);
 200
 201             if (!i386_validate_stackptr(stackptr))
 202                     break;
 203         /* Stack grows downwards */
 204             if (stackptr < stackptr_prev)
 205                     break;
 206
 207             if ((stackptr_prev ^ stackptr) > SANE_i386_FRAME_SIZE)
 208                     break;
 209
 210             raddr = *((vm_offset_t *) (stackptr + i386_RETURN_OFFSET));
 211
 212             if (!i386_validate_raddr(raddr))
 213                     break;
 214
 215             bt[frame_index] = (void *) raddr;
 216     }
 217 pad:
 218     frame = frame_index;
 219
 220     for ( ; frame_index < maxAddrs; frame_index++)
 221             bt[frame_index] = (void *) 0;
 222 #else
 223 #error arch
 224 #endif
 225     return frame;
 226 }