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 #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/kmod.c
  53 extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt);
  54
  55 extern addr64_t kvtophys(vm_offset_t va);
  56
  57 __END_DECLS
  58
  59 extern lck_grp_t *IOLockGroup;
  60
  61 static lck_mtx_t *sOSReportLock = lck_mtx_alloc_init(IOLockGroup, LCK_ATTR_NULL);
  62
  63 /* Use kernel_debug() to log a backtrace */
  64 void
  65 trace_backtrace(uint32_t debugid, uint32_t debugid2, uintptr_t size, uintptr_t data) {
  66         void *bt[16];
  67         const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  68         unsigned i;
  69         int found = 0;
  70
  71         OSBacktrace(bt, cnt);
  72
  73         /* find first non-kernel frame */
  74         for (i = 3; i < cnt && bt[i]; i++) {
  75                 if (bt[i] > (void*)&etext) {
  76                         found = 1;
  77                         break;
  78                 }
  79         }
  80         /*
  81          * if there are non-kernel frames, only log these
  82          * otherwise, log everything but the first two
  83          */
  84         if (!found) i=2;
  85
  86 #define safe_bt(a) (uintptr_t)(a<cnt ? bt[a] : 0)
  87         kernel_debug(debugid, data, size, safe_bt(i), safe_bt(i+1), 0);
  88         kernel_debug(debugid2, safe_bt(i+2), safe_bt(i+3), safe_bt(i+4), safe_bt(i+5), 0);
  89 }
  90
  91 /* Report a message with a 4 entry backtrace - very slow */
  92 void
  93 OSReportWithBacktrace(const char *str, ...)
  94 {
  95     char buf[128];
  96     void *bt[9];
  97     const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  98     va_list listp;
  99
 100     // Ignore the our and our callers stackframes, skipping frames 0 & 1
 101     (void) OSBacktrace(bt, cnt);
 102
 103     va_start(listp, str);
 104     vsnprintf(buf, sizeof(buf), str, listp);
 105     va_end(listp);
 106
 107     lck_mtx_lock(sOSReportLock);
 108     {
 109         printf("%s\nBacktrace %p %p %p %p %p %p %p\n",
 110             buf, bt[2], bt[3], bt[4], bt[5], bt[6], bt[7], bt[8]);
 111         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2);
 112     }
 113     lck_mtx_unlock(sOSReportLock);
 114 }
 115
 116 static vm_offset_t minstackaddr = min_valid_stack_address();
 117 static vm_offset_t maxstackaddr = max_valid_stack_address();
 118
 119 #if __i386__
 120 #define i386_RETURN_OFFSET 4
 121
 122 static unsigned int
 123 i386_validate_stackptr(vm_offset_t stackptr)
 124 {
 125         /* Existence and alignment check
 126          */
 127         if (!stackptr || (stackptr & 0x3))
 128                 return 0;
 129
 130         /* Is a virtual->physical translation present?
 131          */
 132         if (!kvtophys(stackptr))
 133                 return 0;
 134
 135         /* Check if the return address lies on the same page;
 136          * If not, verify that a translation exists.
 137          */
 138         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < i386_RETURN_OFFSET) &&
 139             !kvtophys(stackptr + i386_RETURN_OFFSET))
 140                 return 0;
 141         return 1;
 142 }
 143
 144 static unsigned int
 145 i386_validate_raddr(vm_offset_t raddr)
 146 {
 147         return ((raddr > VM_MIN_KERNEL_AND_KEXT_ADDRESS) &&
 148             (raddr < VM_MAX_KERNEL_ADDRESS));
 149 }
 150 #endif
 151
 152 #if __x86_64__
 153 #define x86_64_RETURN_OFFSET 8
 154 static unsigned int
 155 x86_64_validate_raddr(vm_offset_t raddr)
 156 {
 157         return ((raddr > VM_MIN_KERNEL_AND_KEXT_ADDRESS) &&
 158             (raddr < VM_MAX_KERNEL_ADDRESS));
 159 }
 160 static unsigned int
 161 x86_64_validate_stackptr(vm_offset_t stackptr)
 162 {
 163         /* Existence and alignment check
 164          */
 165         if (!stackptr || (stackptr & 0x7) || !x86_64_validate_raddr(stackptr))
 166                 return 0;
 167
 168         /* Is a virtual->physical translation present?
 169          */
 170         if (!kvtophys(stackptr))
 171                 return 0;
 172
 173         /* Check if the return address lies on the same page;
 174          * If not, verify that a translation exists.
 175          */
 176         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < x86_64_RETURN_OFFSET) &&
 177             !kvtophys(stackptr + x86_64_RETURN_OFFSET))
 178                 return 0;
 179         return 1;
 180 }
 181 #endif
 182
 183 void
 184 OSPrintBacktrace(void)
 185 {
 186         void * btbuf[20];
 187         int tmp = OSBacktrace(btbuf, 20);
 188         int i;
 189         for(i=0;i<tmp;i++)
 190         {
 191                 kprintf("bt[%.2d] = %p\n", i, btbuf[i]);
 192         }
 193 }
 194
 195 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
 196 {
 197     unsigned frame;
 198
 199 #if __i386__
 200 #define SANE_i386_FRAME_SIZE (kernel_stack_size >> 1)
 201     vm_offset_t stackptr, stackptr_prev, raddr;
 202     unsigned frame_index = 0;
 203 /* Obtain current frame pointer */
 204     __asm__ volatile("movl %%ebp, %0" : "=m" (stackptr));
 205
 206     if (!i386_validate_stackptr(stackptr))
 207             goto pad;
 208
 209     raddr = *((vm_offset_t *) (stackptr + i386_RETURN_OFFSET));
 210
 211     if (!i386_validate_raddr(raddr))
 212             goto pad;
 213
 214     bt[frame_index++] = (void *) raddr;
 215
 216     for ( ; frame_index < maxAddrs; frame_index++) {
 217             stackptr_prev = stackptr;
 218             stackptr = *((vm_offset_t *) stackptr_prev);
 219
 220             if (!i386_validate_stackptr(stackptr))
 221                     break;
 222         /* Stack grows downwards */
 223             if (stackptr < stackptr_prev)
 224                     break;
 225
 226             if ((stackptr - stackptr_prev) > SANE_i386_FRAME_SIZE)
 227                     break;
 228
 229             raddr = *((vm_offset_t *) (stackptr + i386_RETURN_OFFSET));
 230
 231             if (!i386_validate_raddr(raddr))
 232                     break;
 233
 234             bt[frame_index] = (void *) raddr;
 235     }
 236 pad:
 237     frame = frame_index;
 238
 239     for ( ; frame_index < maxAddrs; frame_index++)
 240             bt[frame_index] = (void *) 0;
 241 #elif __x86_64__
 242 #define SANE_x86_64_FRAME_SIZE (kernel_stack_size >> 1)
 243     vm_offset_t stackptr, stackptr_prev, raddr;
 244     unsigned frame_index = 0;
 245 /* Obtain current frame pointer */
 246
 247     __asm__ volatile("movq %%rbp, %0" : "=m" (stackptr));
 248
 249     if (!x86_64_validate_stackptr(stackptr))
 250             goto pad;
 251
 252     raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 253
 254     if (!x86_64_validate_raddr(raddr))
 255             goto pad;
 256
 257     bt[frame_index++] = (void *) raddr;
 258
 259     for ( ; frame_index < maxAddrs; frame_index++) {
 260             stackptr_prev = stackptr;
 261             stackptr = *((vm_offset_t *) stackptr_prev);
 262
 263             if (!x86_64_validate_stackptr(stackptr))
 264                     break;
 265         /* Stack grows downwards */
 266             if (stackptr < stackptr_prev)
 267                     break;
 268
 269             if ((stackptr - stackptr_prev) > SANE_x86_64_FRAME_SIZE)
 270                     break;
 271
 272             raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 273
 274             if (!x86_64_validate_raddr(raddr))
 275                     break;
 276
 277             bt[frame_index] = (void *) raddr;
 278     }
 279 pad:
 280     frame = frame_index;
 281
 282     for ( ; frame_index < maxAddrs; frame_index++)
 283             bt[frame_index] = (void *) 0;
 284 #else
 285 #error arch
 286 #endif
 287     return frame;
 288 }