libkern/gen/OSDebug.cpp

   1 /*
   2  * Copyright (c) 2005-2012 Apple 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 #include <IOKit/IOLib.h>
  32
  33 #include <sys/cdefs.h>
  34
  35 #include <stdarg.h>
  36 #include <mach/mach_types.h>
  37 #include <mach/kmod.h>
  38 #include <kern/locks.h>
  39
  40 #include <libkern/libkern.h>    // From bsd's libkern directory
  41 #include <mach/vm_param.h>
  42
  43 #include <sys/kdebug.h>
  44 #include <kern/thread.h>
  45
  46 extern int etext;
  47 __BEGIN_DECLS
  48 // From osmfk/kern/thread.h but considered to be private
  49 extern vm_offset_t min_valid_stack_address(void);
  50 extern vm_offset_t max_valid_stack_address(void);
  51
  52 // From osfmk/kern/printf.c
  53 extern boolean_t doprnt_hide_pointers;
  54
  55 // From osfmk/kmod.c
  56 extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt, boolean_t doUnslide);
  57
  58 extern addr64_t kvtophys(vm_offset_t va);
  59
  60 __END_DECLS
  61
  62 extern lck_grp_t *IOLockGroup;
  63
  64 static lck_mtx_t *sOSReportLock = lck_mtx_alloc_init(IOLockGroup, LCK_ATTR_NULL);
  65
  66 /* Use kernel_debug() to log a backtrace */
  67 void
  68 trace_backtrace(uint32_t debugid, uint32_t debugid2, uintptr_t size, uintptr_t data) {
  69         void *bt[16];
  70         const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  71         unsigned i;
  72         int found = 0;
  73
  74         OSBacktrace(bt, cnt);
  75
  76         /* find first non-kernel frame */
  77         for (i = 3; i < cnt && bt[i]; i++) {
  78                 if (bt[i] > (void*)&etext) {
  79                         found = 1;
  80                         break;
  81                 }
  82         }
  83         /*
  84          * if there are non-kernel frames, only log these
  85          * otherwise, log everything but the first two
  86          */
  87         if (!found) i=2;
  88
  89 #define safe_bt(a) (uintptr_t)(a<cnt ? bt[a] : 0)
  90         kernel_debug(debugid, data, size, safe_bt(i), safe_bt(i+1), 0);
  91         kernel_debug(debugid2, safe_bt(i+2), safe_bt(i+3), safe_bt(i+4), safe_bt(i+5), 0);
  92 }
  93
  94 /* Report a message with a 4 entry backtrace - very slow */
  95 void
  96 OSReportWithBacktrace(const char *str, ...)
  97 {
  98     char buf[128];
  99     void *bt[9];
 100     const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
 101     va_list listp;
 102
 103     // Ignore the our and our callers stackframes, skipping frames 0 & 1
 104     (void) OSBacktrace(bt, cnt);
 105
 106     va_start(listp, str);
 107     vsnprintf(buf, sizeof(buf), str, listp);
 108     va_end(listp);
 109
 110     lck_mtx_lock(sOSReportLock);
 111     {
 112         boolean_t old_doprnt_hide_pointers = doprnt_hide_pointers;
 113         doprnt_hide_pointers = FALSE;
 114         printf("%s\nBacktrace 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n", buf,
 115             (unsigned long) VM_KERNEL_UNSLIDE(bt[2]), (unsigned long) VM_KERNEL_UNSLIDE(bt[3]),
 116             (unsigned long) VM_KERNEL_UNSLIDE(bt[4]), (unsigned long) VM_KERNEL_UNSLIDE(bt[5]),
 117             (unsigned long) VM_KERNEL_UNSLIDE(bt[6]), (unsigned long) VM_KERNEL_UNSLIDE(bt[7]),
 118             (unsigned long) VM_KERNEL_UNSLIDE(bt[8]));
 119         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2, TRUE);
 120         doprnt_hide_pointers = old_doprnt_hide_pointers;
 121     }
 122     lck_mtx_unlock(sOSReportLock);
 123 }
 124
 125 static vm_offset_t minstackaddr = min_valid_stack_address();
 126 static vm_offset_t maxstackaddr = max_valid_stack_address();
 127
 128
 129 #if __x86_64__
 130 #define x86_64_RETURN_OFFSET 8
 131 static unsigned int
 132 x86_64_validate_raddr(vm_offset_t raddr)
 133 {
 134         return ((raddr > VM_MIN_KERNEL_AND_KEXT_ADDRESS) &&
 135             (raddr < VM_MAX_KERNEL_ADDRESS));
 136 }
 137 static unsigned int
 138 x86_64_validate_stackptr(vm_offset_t stackptr)
 139 {
 140         /* Existence and alignment check
 141          */
 142         if (!stackptr || (stackptr & 0x7) || !x86_64_validate_raddr(stackptr))
 143                 return 0;
 144
 145         /* Is a virtual->physical translation present?
 146          */
 147         if (!kvtophys(stackptr))
 148                 return 0;
 149
 150         /* Check if the return address lies on the same page;
 151          * If not, verify that a translation exists.
 152          */
 153         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < x86_64_RETURN_OFFSET) &&
 154             !kvtophys(stackptr + x86_64_RETURN_OFFSET))
 155                 return 0;
 156         return 1;
 157 }
 158 #endif
 159
 160 void
 161 OSPrintBacktrace(void)
 162 {
 163         void * btbuf[20];
 164         int tmp = OSBacktrace(btbuf, 20);
 165         int i;
 166         for(i=0;i<tmp;i++)
 167         {
 168                 kprintf("bt[%.2d] = %p\n", i, btbuf[i]);
 169         }
 170 }
 171
 172 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
 173 {
 174     unsigned frame;
 175     if (!current_thread()) return 0;
 176
 177 #if   __x86_64__
 178 #define SANE_x86_64_FRAME_SIZE (kernel_stack_size >> 1)
 179     vm_offset_t stackptr, stackptr_prev, raddr;
 180     unsigned frame_index = 0;
 181 /* Obtain current frame pointer */
 182
 183     __asm__ volatile("movq %%rbp, %0" : "=m" (stackptr));
 184
 185     if (!x86_64_validate_stackptr(stackptr))
 186             goto pad;
 187
 188     raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 189
 190     if (!x86_64_validate_raddr(raddr))
 191             goto pad;
 192
 193     bt[frame_index++] = (void *) raddr;
 194
 195     for ( ; frame_index < maxAddrs; frame_index++) {
 196             stackptr_prev = stackptr;
 197             stackptr = *((vm_offset_t *) stackptr_prev);
 198
 199             if (!x86_64_validate_stackptr(stackptr))
 200                     break;
 201         /* Stack grows downwards */
 202             if (stackptr < stackptr_prev)
 203                     break;
 204
 205             if ((stackptr - stackptr_prev) > SANE_x86_64_FRAME_SIZE)
 206                     break;
 207
 208             raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 209
 210             if (!x86_64_validate_raddr(raddr))
 211                     break;
 212
 213             bt[frame_index] = (void *) raddr;
 214     }
 215 pad:
 216     frame = frame_index;
 217
 218     for ( ; frame_index < maxAddrs; frame_index++)
 219             bt[frame_index] = (void *) 0;
 220 #else
 221 #error arch
 222 #endif
 223     return frame;
 224 }