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 {
  76         void *bt[16];
  77         const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  78         unsigned i;
  79         int found = 0;
  80
  81         OSBacktrace(bt, cnt);
  82
  83         /* find first non-kernel frame */
  84         for (i = 3; i < cnt && bt[i]; i++) {
  85                 if (bt[i] > (void*)&etext) {
  86                         found = 1;
  87                         break;
  88                 }
  89         }
  90         /*
  91          * if there are non-kernel frames, only log these
  92          * otherwise, log everything but the first two
  93          */
  94         if (!found) {
  95                 i = 2;
  96         }
  97
  98 #define safe_bt(a) (uintptr_t)(a<cnt ? bt[a] : 0)
  99         kernel_debug(debugid, data, size, safe_bt(i), safe_bt(i + 1), 0);
 100         kernel_debug(debugid2, safe_bt(i + 2), safe_bt(i + 3), safe_bt(i + 4), safe_bt(i + 5), 0);
 101 }
 102
 103 /* Report a message with a 4 entry backtrace - very slow */
 104 void
 105 OSReportWithBacktrace(const char *str, ...)
 106 {
 107         char buf[128];
 108         void *bt[9] = {};
 109         const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
 110         va_list listp;
 111
 112         // Ignore the our and our callers stackframes, skipping frames 0 & 1
 113         (void) OSBacktrace(bt, cnt);
 114
 115         va_start(listp, str);
 116         vsnprintf(buf, sizeof(buf), str, listp);
 117         va_end(listp);
 118
 119         lck_mtx_lock(sOSReportLock);
 120         {
 121                 boolean_t old_doprnt_hide_pointers = doprnt_hide_pointers;
 122                 doprnt_hide_pointers = FALSE;
 123                 printf("%s\nBacktrace 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n", buf,
 124                     (unsigned long) VM_KERNEL_UNSLIDE(bt[2]), (unsigned long) VM_KERNEL_UNSLIDE(bt[3]),
 125                     (unsigned long) VM_KERNEL_UNSLIDE(bt[4]), (unsigned long) VM_KERNEL_UNSLIDE(bt[5]),
 126                     (unsigned long) VM_KERNEL_UNSLIDE(bt[6]), (unsigned long) VM_KERNEL_UNSLIDE(bt[7]),
 127                     (unsigned long) VM_KERNEL_UNSLIDE(bt[8]));
 128                 kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2, TRUE);
 129                 doprnt_hide_pointers = old_doprnt_hide_pointers;
 130         }
 131         lck_mtx_unlock(sOSReportLock);
 132 }
 133
 134 static vm_offset_t minstackaddr = min_valid_stack_address();
 135 static vm_offset_t maxstackaddr = max_valid_stack_address();
 136
 137
 138 #if __x86_64__
 139 #define x86_64_RETURN_OFFSET 8
 140 static unsigned int
 141 x86_64_validate_raddr(vm_offset_t raddr)
 142 {
 143         return (raddr > VM_MIN_KERNEL_AND_KEXT_ADDRESS) &&
 144                (raddr < VM_MAX_KERNEL_ADDRESS);
 145 }
 146 static unsigned int
 147 x86_64_validate_stackptr(vm_offset_t stackptr)
 148 {
 149         /* Existence and alignment check
 150          */
 151         if (!stackptr || (stackptr & 0x7) || !x86_64_validate_raddr(stackptr)) {
 152                 return 0;
 153         }
 154
 155         /* Is a virtual->physical translation present?
 156          */
 157         if (!kvtophys(stackptr)) {
 158                 return 0;
 159         }
 160
 161         /* Check if the return address lies on the same page;
 162          * If not, verify that a translation exists.
 163          */
 164         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < x86_64_RETURN_OFFSET) &&
 165             !kvtophys(stackptr + x86_64_RETURN_OFFSET)) {
 166                 return 0;
 167         }
 168         return 1;
 169 }
 170 #endif
 171
 172 void
 173 OSPrintBacktrace(void)
 174 {
 175         void * btbuf[20];
 176         int tmp = OSBacktrace(btbuf, 20);
 177         int i;
 178         for (i = 0; i < tmp; i++) {
 179                 kprintf("bt[%.2d] = %p\n", i, btbuf[i]);
 180         }
 181 }
 182
 183 unsigned
 184 OSBacktrace(void **bt, unsigned maxAddrs)
 185 {
 186         unsigned frame;
 187         if (!current_thread()) {
 188                 return 0;
 189         }
 190
 191 #if   __x86_64__
 192 #define SANE_x86_64_FRAME_SIZE (kernel_stack_size >> 1)
 193         vm_offset_t stackptr, stackptr_prev, raddr;
 194         unsigned frame_index = 0;
 195 /* Obtain current frame pointer */
 196
 197         __asm__ volatile ("movq %%rbp, %0" : "=m" (stackptr));
 198
 199         if (!x86_64_validate_stackptr(stackptr)) {
 200                 goto pad;
 201         }
 202
 203         raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 204
 205         if (!x86_64_validate_raddr(raddr)) {
 206                 goto pad;
 207         }
 208
 209         bt[frame_index++] = (void *) raddr;
 210
 211         for (; frame_index < maxAddrs; frame_index++) {
 212                 stackptr_prev = stackptr;
 213                 stackptr = *((vm_offset_t *) stackptr_prev);
 214
 215                 if (!x86_64_validate_stackptr(stackptr)) {
 216                         break;
 217                 }
 218                 /* Stack grows downwards */
 219                 if (stackptr < stackptr_prev) {
 220                         break;
 221                 }
 222
 223                 if ((stackptr - stackptr_prev) > SANE_x86_64_FRAME_SIZE) {
 224                         break;
 225                 }
 226
 227                 raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 228
 229                 if (!x86_64_validate_raddr(raddr)) {
 230                         break;
 231                 }
 232
 233                 bt[frame_index] = (void *) raddr;
 234         }
 235 pad:
 236         frame = frame_index;
 237
 238         for (; frame_index < maxAddrs; frame_index++) {
 239                 bt[frame_index] = (void *) 0;
 240         }
 241 #elif __arm__ || __arm64__
 242         uint32_t i = 0;
 243         uintptr_t frameb[2];
 244         uintptr_t fp = 0;
 245
 246         // get the current frame pointer for this thread
 247 #if defined(__arm__)
 248 #define OSBacktraceFrameAlignOK(x) (((x) & 0x3) == 0)
 249         __asm__ volatile ("mov %0,r7" : "=r" (fp));
 250 #elif defined(__arm64__)
 251 #define OSBacktraceFrameAlignOK(x) (((x) & 0xf) == 0)
 252         __asm__ volatile ("mov %0, fp" : "=r" (fp));
 253 #else
 254 #error Unknown architecture.
 255 #endif
 256
 257         // now crawl up the stack recording the link value of each frame
 258         do {
 259                 // check bounds
 260                 if ((fp == 0) || (!OSBacktraceFrameAlignOK(fp)) || (fp > VM_MAX_KERNEL_ADDRESS) || (fp < VM_MIN_KERNEL_AND_KEXT_ADDRESS)) {
 261                         break;
 262                 }
 263                 // safely read frame
 264 #ifdef __arm64__
 265                 if (copyinframe(fp, (char*)frameb, TRUE) != 0) {
 266 #else
 267                 if (copyinframe(fp, (char*)frameb) != 0) {
 268 #endif
 269                         break;
 270                 }
 271
 272                 // No need to use copyin as this is always a kernel address, see check above
 273                 bt[i] = (void*)frameb[1]; // link register
 274                 fp = frameb[0];
 275         } while (++i < maxAddrs);
 276         frame = i;
 277 #else
 278 #error arch
 279 #endif
 280         return frame;
 281 }