libkern/gen/OSDebug.cpp

   1 /*
   2  * Copyright (c) 2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_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
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30
  31 // NOTE:  This file is only c++ so I can get static initialisers going
  32 #include <libkern/OSDebug.h>
  33
  34 #include <sys/cdefs.h>
  35
  36 #include <stdarg.h>
  37 #include <mach/mach_types.h>
  38 #include <mach/kmod.h>
  39 #include <kern/lock.h>
  40
  41 #include <libkern/libkern.h>    // From bsd's libkern directory
  42
  43 __BEGIN_DECLS
  44 // From osmfk/kern/thread.h but considered to be private
  45 extern vm_offset_t min_valid_stack_address(void);
  46 extern vm_offset_t max_valid_stack_address(void);
  47
  48 // From osfmk/kmod.c
  49 extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt);
  50 __END_DECLS
  51
  52 static mutex_t *sOSReportLock = mutex_alloc(0);
  53
  54 /* Report a message with a 4 entry backtrace - very slow */
  55 void
  56 OSReportWithBacktrace(const char *str, ...)
  57 {
  58     char buf[128];
  59     void *bt[9];
  60     const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  61     va_list listp;
  62
  63     // Ignore the our and our callers stackframes, skipping frames 0 & 1
  64     (void) OSBacktrace(bt, cnt);
  65
  66     va_start(listp, str);
  67     vsnprintf(buf, sizeof(buf), str, listp);
  68     va_end(listp);
  69
  70     mutex_lock(sOSReportLock);
  71     {
  72         printf("%s\nBacktrace %p %p %p %p %p %p %p\n",
  73                 buf, bt[2], bt[3], bt[4], bt[5], bt[6], bt[7], bt[8]);
  74         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2);
  75     }
  76     mutex_unlock(sOSReportLock);
  77 }
  78
  79 static vm_offset_t minstackaddr = min_valid_stack_address();
  80 static vm_offset_t maxstackaddr = max_valid_stack_address();
  81
  82 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
  83 {
  84     unsigned frame;
  85
  86 #if __ppc__
  87     vm_offset_t stackptr, stackptr_prev;
  88     const vm_offset_t * const mem = (vm_offset_t *) 0;
  89     unsigned i = 0;
  90
  91     __asm__ volatile("mflr %0" : "=r" (stackptr));
  92     bt[i++] = (void *) stackptr;
  93
  94     __asm__ volatile("mr %0,r1" : "=r" (stackptr));
  95     for ( ; i < maxAddrs; i++) {
  96         // Validate we have a reasonable stackptr
  97         if ( !(minstackaddr <= stackptr && stackptr < maxstackaddr)
  98         || (stackptr & 3))
  99             break;
 100
 101         stackptr_prev = stackptr;
 102         stackptr = mem[stackptr_prev >> 2];
 103         if ((stackptr_prev ^ stackptr) > 8 * 1024)      // Sanity check
 104             break;
 105
 106         vm_offset_t addr = mem[(stackptr >> 2) + 2];
 107         if ((addr & 3) || (addr < 0x8000))      // More sanity checks
 108             break;
 109         bt[i] = (void *) addr;
 110     }
 111     frame = i;
 112
 113     for ( ; i < maxAddrs; i++)
 114             bt[i] = (void *) 0;
 115 #elif 0 && __i386__     // Note that this should be ported for i386
 116     // This function is not safe, we should get this code ported appropriately
 117     if (maxAddrs > 16) {
 118         for (frame = 16; frame < maxAddrs; frame++)
 119             bt[frame] = __builtin_return_address(frame);
 120         maxAddrs = 16;
 121     }
 122
 123     switch(maxAddrs) {
 124     case 15+1: bt[15] = __builtin_return_address(15);
 125     case 14+1: bt[14] = __builtin_return_address(14);
 126     case 13+1: bt[13] = __builtin_return_address(13);
 127     case 12+1: bt[12] = __builtin_return_address(12);
 128     case 11+1: bt[11] = __builtin_return_address(11);
 129     case 10+1: bt[10] = __builtin_return_address(10);
 130     case  9+1: bt[ 9] = __builtin_return_address( 9);
 131     case  8+1: bt[ 8] = __builtin_return_address( 8);
 132     case  7+1: bt[ 7] = __builtin_return_address( 7);
 133     case  6+1: bt[ 6] = __builtin_return_address( 6);
 134     case  5+1: bt[ 5] = __builtin_return_address( 5);
 135     case  4+1: bt[ 4] = __builtin_return_address( 4);
 136     case  3+1: bt[ 3] = __builtin_return_address( 3);
 137     case  2+1: bt[ 2] = __builtin_return_address( 2);
 138     case  1+1: bt[ 1] = __builtin_return_address( 1);
 139     case  0+1: bt[ 0] = __builtin_return_address( 0);
 140     case 0: default: break;
 141     }
 142
 143     frame = maxAddrs;
 144 #else
 145     // This function is not safe, we should get this code ported appropriately
 146     if (maxAddrs > 16) {
 147         for (frame = 16; frame < maxAddrs; frame++)
 148             bt[frame] = 0;
 149         maxAddrs = 16;
 150     }
 151
 152     switch (maxAddrs) {
 153     case 15+1: bt[15] = __builtin_return_address(15);
 154     case 14+1: bt[14] = __builtin_return_address(14);
 155     case 13+1: bt[13] = __builtin_return_address(13);
 156     case 12+1: bt[12] = __builtin_return_address(12);
 157     case 11+1: bt[11] = __builtin_return_address(11);
 158     case 10+1: bt[10] = __builtin_return_address(10);
 159     case  9+1: bt[ 9] = __builtin_return_address( 9);
 160     case  8+1: bt[ 8] = __builtin_return_address( 8);
 161     case  7+1: bt[ 7] = __builtin_return_address( 7);
 162     case  6+1: bt[ 6] = __builtin_return_address( 6);
 163     case  5+1: bt[ 5] = __builtin_return_address( 5);
 164     case  4+1: bt[ 4] = __builtin_return_address( 4);
 165     case  3+1: bt[ 3] = __builtin_return_address( 3);
 166     case  2+1: bt[ 2] = __builtin_return_address( 2);
 167     case  1+1: bt[ 1] = __builtin_return_address( 1);
 168     case  0+1: bt[ 0] = __builtin_return_address( 0);
 169     case    0:
 170     default  :
 171         break;
 172     }
 173
 174     frame = maxAddrs;
 175 #endif
 176
 177     return frame;
 178 }