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/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 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n", buf,
 110             (unsigned long) VM_KERNEL_UNSLIDE(bt[2]), (unsigned long) VM_KERNEL_UNSLIDE(bt[3]),
 111             (unsigned long) VM_KERNEL_UNSLIDE(bt[4]), (unsigned long) VM_KERNEL_UNSLIDE(bt[5]),
 112             (unsigned long) VM_KERNEL_UNSLIDE(bt[6]), (unsigned long) VM_KERNEL_UNSLIDE(bt[7]),
 113             (unsigned long) VM_KERNEL_UNSLIDE(bt[8]));
 114         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2);
 115     }
 116     lck_mtx_unlock(sOSReportLock);
 117 }
 118
 119 static vm_offset_t minstackaddr = min_valid_stack_address();
 120 static vm_offset_t maxstackaddr = max_valid_stack_address();
 121
 122
 123 #if __x86_64__
 124 #define x86_64_RETURN_OFFSET 8
 125 static unsigned int
 126 x86_64_validate_raddr(vm_offset_t raddr)
 127 {
 128         return ((raddr > VM_MIN_KERNEL_AND_KEXT_ADDRESS) &&
 129             (raddr < VM_MAX_KERNEL_ADDRESS));
 130 }
 131 static unsigned int
 132 x86_64_validate_stackptr(vm_offset_t stackptr)
 133 {
 134         /* Existence and alignment check
 135          */
 136         if (!stackptr || (stackptr & 0x7) || !x86_64_validate_raddr(stackptr))
 137                 return 0;
 138
 139         /* Is a virtual->physical translation present?
 140          */
 141         if (!kvtophys(stackptr))
 142                 return 0;
 143
 144         /* Check if the return address lies on the same page;
 145          * If not, verify that a translation exists.
 146          */
 147         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < x86_64_RETURN_OFFSET) &&
 148             !kvtophys(stackptr + x86_64_RETURN_OFFSET))
 149                 return 0;
 150         return 1;
 151 }
 152 #endif
 153
 154 void
 155 OSPrintBacktrace(void)
 156 {
 157         void * btbuf[20];
 158         int tmp = OSBacktrace(btbuf, 20);
 159         int i;
 160         for(i=0;i<tmp;i++)
 161         {
 162                 kprintf("bt[%.2d] = %p\n", i, btbuf[i]);
 163         }
 164 }
 165
 166 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
 167 {
 168     unsigned frame;
 169
 170 #if   __x86_64__
 171 #define SANE_x86_64_FRAME_SIZE (kernel_stack_size >> 1)
 172     vm_offset_t stackptr, stackptr_prev, raddr;
 173     unsigned frame_index = 0;
 174 /* Obtain current frame pointer */
 175
 176     __asm__ volatile("movq %%rbp, %0" : "=m" (stackptr));
 177
 178     if (!x86_64_validate_stackptr(stackptr))
 179             goto pad;
 180
 181     raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 182
 183     if (!x86_64_validate_raddr(raddr))
 184             goto pad;
 185
 186     bt[frame_index++] = (void *) raddr;
 187
 188     for ( ; frame_index < maxAddrs; frame_index++) {
 189             stackptr_prev = stackptr;
 190             stackptr = *((vm_offset_t *) stackptr_prev);
 191
 192             if (!x86_64_validate_stackptr(stackptr))
 193                     break;
 194         /* Stack grows downwards */
 195             if (stackptr < stackptr_prev)
 196                     break;
 197
 198             if ((stackptr - stackptr_prev) > SANE_x86_64_FRAME_SIZE)
 199                     break;
 200
 201             raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
 202
 203             if (!x86_64_validate_raddr(raddr))
 204                     break;
 205
 206             bt[frame_index] = (void *) raddr;
 207     }
 208 pad:
 209     frame = frame_index;
 210
 211     for ( ; frame_index < maxAddrs; frame_index++)
 212             bt[frame_index] = (void *) 0;
 213 #else
 214 #error arch
 215 #endif
 216     return frame;
 217 }