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
  47 extern int etext;
  48 __BEGIN_DECLS
  49 // From osmfk/kern/thread.h but considered to be private
  50 extern vm_offset_t min_valid_stack_address(void);
  51 extern vm_offset_t max_valid_stack_address(void);
  52
  53 // From osfmk/kern/printf.c
  54 extern boolean_t doprnt_hide_pointers;
  55
  56 // From osfmk/kmod.c
  57 extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt, boolean_t doUnslide);
  58
  59 extern addr64_t kvtophys(vm_offset_t va);
  60 #if __arm__
  61 extern int copyinframe(vm_address_t fp, char *frame);
  62 #elif defined(__arm64__)
  63 extern int copyinframe(vm_address_t fp, char *frame, boolean_t is64bit);
  64 #endif
  65
  66 __END_DECLS
  67
  68 extern lck_grp_t *IOLockGroup;
  69
  70 static lck_mtx_t *sOSReportLock = lck_mtx_alloc_init(IOLockGroup, LCK_ATTR_NULL);
  71
  72 /* Use kernel_debug() to log a backtrace */
  73 void
  74 trace_backtrace(uint32_t debugid, uint32_t debugid2, uintptr_t size, uintptr_t data) {
  75         void *bt[16];
  76         const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  77         unsigned i;
  78         int found = 0;
  79
  80         OSBacktrace(bt, cnt);
  81
  82         /* find first non-kernel frame */
  83         for (i = 3; i < cnt && bt[i]; i++) {
  84                 if (bt[i] > (void*)&etext) {
  85                         found = 1;
  86                         break;
  87                 }
  88         }
  89         /*
  90          * if there are non-kernel frames, only log these
  91          * otherwise, log everything but the first two
  92          */
  93         if (!found) i=2;
  94
  95 #define safe_bt(a) (uintptr_t)(a<cnt ? bt[a] : 0)
  96         kernel_debug(debugid, data, size, safe_bt(i), safe_bt(i+1), 0);
  97         kernel_debug(debugid2, safe_bt(i+2), safe_bt(i+3), safe_bt(i+4), safe_bt(i+5), 0);
  98 }
  99
 100 /* Report a message with a 4 entry backtrace - very slow */
 101 void
 102 OSReportWithBacktrace(const char *str, ...)
 103 {
 104     char buf[128];
 105     void *bt[9] = {};
 106     const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
 107     va_list listp;
 108
 109     // Ignore the our and our callers stackframes, skipping frames 0 & 1
 110     (void) OSBacktrace(bt, cnt);
 111
 112     va_start(listp, str);
 113     vsnprintf(buf, sizeof(buf), str, listp);
 114     va_end(listp);
 115
 116     lck_mtx_lock(sOSReportLock);
 117     {
 118         boolean_t old_doprnt_hide_pointers = doprnt_hide_pointers;
 119         doprnt_hide_pointers = FALSE;
 120         printf("%s\nBacktrace 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n", buf,
 121             (unsigned long) VM_KERNEL_UNSLIDE(bt[2]), (unsigned long) VM_KERNEL_UNSLIDE(bt[3]),
 122             (unsigned long) VM_KERNEL_UNSLIDE(bt[4]), (unsigned long) VM_KERNEL_UNSLIDE(bt[5]),
 123             (unsigned long) VM_KERNEL_UNSLIDE(bt[6]), (unsigned long) VM_KERNEL_UNSLIDE(bt[7]),
 124             (unsigned long) VM_KERNEL_UNSLIDE(bt[8]));
 125         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2, TRUE);
 126         doprnt_hide_pointers = old_doprnt_hide_pointers;
 127     }
 128     lck_mtx_unlock(sOSReportLock);
 129 }
 130
 131 static vm_offset_t minstackaddr = min_valid_stack_address();
 132 static vm_offset_t maxstackaddr = max_valid_stack_address();
 133
 134
 135 #if __x86_64__
 136 #define x86_64_RETURN_OFFSET 8
 137 static unsigned int
 138 x86_64_validate_raddr(vm_offset_t raddr)
 139 {
 140         return ((raddr > VM_MIN_KERNEL_AND_KEXT_ADDRESS) &&
 141             (raddr < VM_MAX_KERNEL_ADDRESS));
 142 }
 143 static unsigned int
 144 x86_64_validate_stackptr(vm_offset_t stackptr)
 145 {
 146         /* Existence and alignment check
 147          */
 148         if (!stackptr || (stackptr & 0x7) || !x86_64_validate_raddr(stackptr))
 149                 return 0;
 150
 151         /* Is a virtual->physical translation present?
 152          */
 153         if (!kvtophys(stackptr))
 154                 return 0;
 155
 156         /* Check if the return address lies on the same page;
 157          * If not, verify that a translation exists.
 158          */
 159         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < x86_64_RETURN_OFFSET) &&
 160             !kvtophys(stackptr + x86_64_RETURN_OFFSET))
 161                 return 0;
 162         return 1;
 163 }
 164 #endif
 165
 166 void
 167 OSPrintBacktrace(void)
 168 {
 169         void * btbuf[20];
 170         int tmp = OSBacktrace(btbuf, 20);
 171         int i;
 172         for(i=0;i<tmp;i++)
 173         {
 174                 kprintf("bt[%.2d] = %p\n", i, btbuf[i]);
 175         }
 176 }
 177
 178 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
 179 {
 180     unsigned frame;
 181     if (!current_thread()) return 0;
 182
 183 #if   __x86_64__
 184 #define SANE_x86_64_FRAME_SIZE (kernel_stack_size >> 1)
 185     vm_offset_t stackptr, stackptr_prev, raddr;
 186     unsigned frame_index = 0;
 187 /* Obtain current frame pointer */
 188
 189     __asm__ volatile("movq %%rbp, %0" : "=m" (stackptr));
 190
 191     if (!x86_64_validate_stackptr(stackptr))
 192             goto pad;
 193
 194     raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 195
 196     if (!x86_64_validate_raddr(raddr))
 197             goto pad;
 198
 199     bt[frame_index++] = (void *) raddr;
 200
 201     for ( ; frame_index < maxAddrs; frame_index++) {
 202             stackptr_prev = stackptr;
 203             stackptr = *((vm_offset_t *) stackptr_prev);
 204
 205             if (!x86_64_validate_stackptr(stackptr))
 206                     break;
 207         /* Stack grows downwards */
 208             if (stackptr < stackptr_prev)
 209                     break;
 210
 211             if ((stackptr - stackptr_prev) > SANE_x86_64_FRAME_SIZE)
 212                     break;
 213
 214             raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 215
 216             if (!x86_64_validate_raddr(raddr))
 217                     break;
 218
 219             bt[frame_index] = (void *) raddr;
 220     }
 221 pad:
 222     frame = frame_index;
 223
 224     for ( ; frame_index < maxAddrs; frame_index++)
 225             bt[frame_index] = (void *) 0;
 226 #elif __arm__ || __arm64__
 227     uint32_t i = 0;
 228     uintptr_t frameb[2];
 229     uintptr_t fp = 0;
 230
 231     // get the current frame pointer for this thread
 232 #if defined(__arm__)
 233 #define OSBacktraceFrameAlignOK(x) (((x) & 0x3) == 0)
 234     __asm__ volatile("mov %0,r7" : "=r" (fp));
 235 #elif defined(__arm64__)
 236 #define OSBacktraceFrameAlignOK(x) (((x) & 0xf) == 0)
 237     __asm__ volatile("mov %0, fp" : "=r" (fp));
 238 #else
 239 #error Unknown architecture.
 240 #endif
 241
 242     // now crawl up the stack recording the link value of each frame
 243     do {
 244       // check bounds
 245       if ((fp == 0) || (!OSBacktraceFrameAlignOK(fp)) || (fp > VM_MAX_KERNEL_ADDRESS) || (fp < VM_MIN_KERNEL_AND_KEXT_ADDRESS)) {
 246         break;
 247       }
 248       // safely read frame
 249 #ifdef __arm64__
 250       if (copyinframe(fp, (char*)frameb, TRUE) != 0) {
 251 #else
 252       if (copyinframe(fp, (char*)frameb) != 0) {
 253 #endif
 254         break;
 255       }
 256
 257       // No need to use copyin as this is always a kernel address, see check above
 258       bt[i] = (void*)frameb[1];        // link register
 259       fp = frameb[0];
 260     } while (++i < maxAddrs);
 261     frame= i;
 262 #else
 263 #error arch
 264 #endif
 265     return frame;
 266 }