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
  41 __BEGIN_DECLS
  42 // From osmfk/kern/thread.h but considered to be private
  43 extern vm_offset_t min_valid_stack_address(void);
  44 extern vm_offset_t max_valid_stack_address(void);
  45
  46 // From osfmk/kmod.c
  47 extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt);
  48 __END_DECLS
  49
  50 static mutex_t *sOSReportLock = mutex_alloc(0);
  51
  52 /* Report a message with a 4 entry backtrace - very slow */
  53 void
  54 OSReportWithBacktrace(const char *str, ...)
  55 {
  56     char buf[128];
  57     void *bt[9];
  58     const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  59     va_list listp;
  60
  61     // Ignore the our and our callers stackframes, skipping frames 0 & 1
  62     (void) OSBacktrace(bt, cnt);
  63
  64     va_start(listp, str);
  65     vsnprintf(buf, sizeof(buf), str, listp);
  66     va_end(listp);
  67
  68     mutex_lock(sOSReportLock);
  69     {
  70         printf("%s\nBacktrace %p %p %p %p %p %p %p\n",
  71                 buf, bt[2], bt[3], bt[4], bt[5], bt[6], bt[7], bt[8]);
  72         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2);
  73     }
  74     mutex_unlock(sOSReportLock);
  75 }
  76
  77 static vm_offset_t minstackaddr = min_valid_stack_address();
  78 static vm_offset_t maxstackaddr = max_valid_stack_address();
  79
  80 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
  81 {
  82     unsigned frame;
  83
  84 #if __ppc__
  85     vm_offset_t stackptr, stackptr_prev;
  86     const vm_offset_t * const mem = (vm_offset_t *) 0;
  87     unsigned i = 0;
  88
  89     __asm__ volatile("mflr %0" : "=r" (stackptr));
  90     bt[i++] = (void *) stackptr;
  91
  92     __asm__ volatile("mr %0,r1" : "=r" (stackptr));
  93     for ( ; i < maxAddrs; i++) {
  94         // Validate we have a reasonable stackptr
  95         if ( !(minstackaddr <= stackptr && stackptr < maxstackaddr)
  96         || (stackptr & 3))
  97             break;
  98
  99         stackptr_prev = stackptr;
 100         stackptr = mem[stackptr_prev >> 2];
 101         if ((stackptr_prev ^ stackptr) > 8 * 1024)      // Sanity check
 102             break;
 103
 104         vm_offset_t addr = mem[(stackptr >> 2) + 2];
 105         if ((addr & 3) || (addr < 0x8000))      // More sanity checks
 106             break;
 107         bt[i] = (void *) addr;
 108     }
 109     frame = i;
 110
 111     for ( ; i < maxAddrs; i++)
 112             bt[i] = (void *) 0;
 113 #elif 0 && __i386__     // Note that this should be ported for i386
 114     // This function is not safe, we should get this code ported appropriately
 115     if (maxAddrs > 16) {
 116         for (frame = 16; frame < maxAddrs; frame++)
 117             bt[frame] = __builtin_return_address(frame);
 118         maxAddrs = 16;
 119     }
 120
 121     switch(maxAddrs) {
 122     case 15+1: bt[15] = __builtin_return_address(15);
 123     case 14+1: bt[14] = __builtin_return_address(14);
 124     case 13+1: bt[13] = __builtin_return_address(13);
 125     case 12+1: bt[12] = __builtin_return_address(12);
 126     case 11+1: bt[11] = __builtin_return_address(11);
 127     case 10+1: bt[10] = __builtin_return_address(10);
 128     case  9+1: bt[ 9] = __builtin_return_address( 9);
 129     case  8+1: bt[ 8] = __builtin_return_address( 8);
 130     case  7+1: bt[ 7] = __builtin_return_address( 7);
 131     case  6+1: bt[ 6] = __builtin_return_address( 6);
 132     case  5+1: bt[ 5] = __builtin_return_address( 5);
 133     case  4+1: bt[ 4] = __builtin_return_address( 4);
 134     case  3+1: bt[ 3] = __builtin_return_address( 3);
 135     case  2+1: bt[ 2] = __builtin_return_address( 2);
 136     case  1+1: bt[ 1] = __builtin_return_address( 1);
 137     case  0+1: bt[ 0] = __builtin_return_address( 0);
 138     case 0: default: break;
 139     }
 140
 141     frame = maxAddrs;
 142 #else
 143     // This function is not safe, we should get this code ported appropriately
 144     if (maxAddrs > 16) {
 145         for (frame = 16; frame < maxAddrs; frame++)
 146             bt[frame] = 0;
 147         maxAddrs = 16;
 148     }
 149
 150     switch (maxAddrs) {
 151     case 15+1: bt[15] = __builtin_return_address(15);
 152     case 14+1: bt[14] = __builtin_return_address(14);
 153     case 13+1: bt[13] = __builtin_return_address(13);
 154     case 12+1: bt[12] = __builtin_return_address(12);
 155     case 11+1: bt[11] = __builtin_return_address(11);
 156     case 10+1: bt[10] = __builtin_return_address(10);
 157     case  9+1: bt[ 9] = __builtin_return_address( 9);
 158     case  8+1: bt[ 8] = __builtin_return_address( 8);
 159     case  7+1: bt[ 7] = __builtin_return_address( 7);
 160     case  6+1: bt[ 6] = __builtin_return_address( 6);
 161     case  5+1: bt[ 5] = __builtin_return_address( 5);
 162     case  4+1: bt[ 4] = __builtin_return_address( 4);
 163     case  3+1: bt[ 3] = __builtin_return_address( 3);
 164     case  2+1: bt[ 2] = __builtin_return_address( 2);
 165     case  1+1: bt[ 1] = __builtin_return_address( 1);
 166     case  0+1: bt[ 0] = __builtin_return_address( 0);
 167     case    0:
 168     default  :
 169         break;
 170     }
 171
 172     frame = maxAddrs;
 173 #endif
 174
 175     return frame;
 176 }