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
  32 #include <sys/cdefs.h>
  33
  34 #include <stdarg.h>
  35 #include <mach/mach_types.h>
  36 #include <mach/kmod.h>
  37 #include <kern/lock.h>
  38
  39 #include <libkern/libkern.h>    // From bsd's libkern directory
  40 #include <mach/vm_param.h>
  41
  42 #include <sys/kdebug.h>
  43 extern int etext;
  44 __BEGIN_DECLS
  45 // From osmfk/kern/thread.h but considered to be private
  46 extern vm_offset_t min_valid_stack_address(void);
  47 extern vm_offset_t max_valid_stack_address(void);
  48
  49 // From osfmk/kmod.c
  50 extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt);
  51
  52 extern addr64_t kvtophys(vm_offset_t va);
  53 #if __arm__
  54 extern int copyinframe(vm_address_t fp, uint32_t *frame);
  55 #endif
  56
  57 __END_DECLS
  58
  59 static mutex_t *sOSReportLock = mutex_alloc(0);
  60
  61 /* Use kernel_debug() to log a backtrace */
  62 void
  63 trace_backtrace(unsigned int debugid, unsigned int debugid2, int size, int data) {
  64         void *bt[16];
  65         const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  66         unsigned i;
  67         int found = 0;
  68
  69         OSBacktrace(bt, cnt);
  70
  71         /* find first non-kernel frame */
  72         for (i = 3; i < cnt && bt[i]; i++) {
  73                 if (bt[i] > (void*)&etext) {
  74                         found = 1;
  75                         break;
  76                 }
  77         }
  78         /*
  79          * if there are non-kernel frames, only log these
  80          * otherwise, log everything but the first two
  81          */
  82         if (!found) i=2;
  83
  84 #define safe_bt(a) (int)(a<cnt ? bt[a] : 0)
  85         kernel_debug(debugid, data, size, safe_bt(i), safe_bt(i+1), 0);
  86         kernel_debug(debugid2, safe_bt(i+2), safe_bt(i+3), safe_bt(i+4), safe_bt(i+5), 0);
  87 }
  88
  89 /* Report a message with a 4 entry backtrace - very slow */
  90 void
  91 OSReportWithBacktrace(const char *str, ...)
  92 {
  93     char buf[128];
  94     void *bt[9];
  95     const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
  96     va_list listp;
  97
  98     // Ignore the our and our callers stackframes, skipping frames 0 & 1
  99     (void) OSBacktrace(bt, cnt);
 100
 101     va_start(listp, str);
 102     vsnprintf(buf, sizeof(buf), str, listp);
 103     va_end(listp);
 104
 105     mutex_lock(sOSReportLock);
 106     {
 107         printf("%s\nBacktrace %p %p %p %p %p %p %p\n",
 108                 buf, bt[2], bt[3], bt[4], bt[5], bt[6], bt[7], bt[8]);
 109         kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2);
 110     }
 111     mutex_unlock(sOSReportLock);
 112 }
 113
 114 static vm_offset_t minstackaddr = min_valid_stack_address();
 115 static vm_offset_t maxstackaddr = max_valid_stack_address();
 116
 117 #if __i386__
 118 #define i386_RETURN_OFFSET 4
 119
 120 static unsigned int
 121 i386_validate_stackptr(vm_offset_t stackptr)
 122 {
 123         /* Existence and alignment check
 124          */
 125         if (!stackptr || (stackptr & 0x3))
 126                 return 0;
 127
 128         /* Is a virtual->physical translation present?
 129          */
 130         if (!kvtophys(stackptr))
 131                 return 0;
 132
 133         /* Check if the return address lies on the same page;
 134          * If not, verify that a translation exists.
 135          */
 136         if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < i386_RETURN_OFFSET) &&
 137             !kvtophys(stackptr + i386_RETURN_OFFSET))
 138                 return 0;
 139         return 1;
 140 }
 141
 142 static unsigned int
 143 i386_validate_raddr(vm_offset_t raddr)
 144 {
 145         return ((raddr > VM_MIN_KERNEL_ADDRESS) &&
 146             (raddr < VM_MAX_KERNEL_ADDRESS));
 147 }
 148 #endif
 149
 150 unsigned OSBacktrace(void **bt, unsigned maxAddrs)
 151 {
 152     unsigned frame;
 153
 154 #if __ppc__
 155     vm_offset_t stackptr, stackptr_prev;
 156     const vm_offset_t * const mem = (vm_offset_t *) 0;
 157     unsigned i = 0;
 158
 159     __asm__ volatile("mflr %0" : "=r" (stackptr));
 160     bt[i++] = (void *) stackptr;
 161
 162     __asm__ volatile("mr %0,r1" : "=r" (stackptr));
 163     for ( ; i < maxAddrs; i++) {
 164         // Validate we have a reasonable stackptr
 165         if ( !(minstackaddr <= stackptr && stackptr < maxstackaddr)
 166         || (stackptr & 3))
 167             break;
 168
 169         stackptr_prev = stackptr;
 170         stackptr = mem[stackptr_prev >> 2];
 171         if ((stackptr_prev ^ stackptr) > 8 * 1024)      // Sanity check
 172             break;
 173
 174         vm_offset_t addr = mem[(stackptr >> 2) + 2];
 175         if ((addr & 3) || (addr < 0x8000))      // More sanity checks
 176             break;
 177         bt[i] = (void *) addr;
 178     }
 179     frame = i;
 180
 181     for ( ; i < maxAddrs; i++)
 182             bt[i] = (void *) 0;
 183 #elif __i386__
 184 #define SANE_i386_FRAME_SIZE 8*1024
 185     vm_offset_t stackptr, stackptr_prev, raddr;
 186     unsigned frame_index = 0;
 187 /* Obtain current frame pointer */
 188     __asm__ volatile("movl %%ebp, %0" : "=m" (stackptr));
 189
 190     if (!i386_validate_stackptr(stackptr))
 191             goto pad;
 192
 193     raddr = *((vm_offset_t *) (stackptr + i386_RETURN_OFFSET));
 194
 195     if (!i386_validate_raddr(raddr))
 196             goto pad;
 197
 198     bt[frame_index++] = (void *) raddr;
 199
 200     for ( ; frame_index < maxAddrs; frame_index++) {
 201             stackptr_prev = stackptr;
 202             stackptr = *((vm_offset_t *) stackptr_prev);
 203
 204             if (!i386_validate_stackptr(stackptr))
 205                     break;
 206         /* Stack grows downwards */
 207             if (stackptr < stackptr_prev)
 208                     break;
 209
 210             if ((stackptr_prev ^ stackptr) > SANE_i386_FRAME_SIZE)
 211                     break;
 212
 213             raddr = *((vm_offset_t *) (stackptr + i386_RETURN_OFFSET));
 214
 215             if (!i386_validate_raddr(raddr))
 216                     break;
 217
 218             bt[frame_index] = (void *) raddr;
 219     }
 220 pad:
 221     frame = frame_index;
 222
 223     for ( ; frame_index < maxAddrs; frame_index++)
 224             bt[frame_index] = (void *) 0;
 225 #elif __arm__
 226     uint32_t i= 0;
 227     uint32_t frameb[2];
 228     uint32_t fp= 0;
 229
 230     // get the current frame pointer for this thread
 231     __asm__ volatile("mov %0,r7" : "=r" (fp));
 232
 233     // now crawl up the stack recording the link value of each frame
 234     do {
 235       // check bounds
 236       if ((fp == 0) || ((fp & 3) != 0) || (fp > VM_MAX_KERNEL_ADDRESS) || (fp < VM_MIN_KERNEL_ADDRESS)) {
 237         break;
 238       }
 239       // safely read frame
 240       if (copyinframe(fp, frameb) != 0) {
 241         break;
 242       }
 243
 244       // No need to use copyin as this is always a kernel address, see check above
 245       bt[i] = (void*)frameb[1];        // link register
 246       fp = frameb[0];
 247     } while (++i < maxAddrs);
 248     frame= i;
 249 #else
 250 #error arch
 251 #endif
 252     return frame;
 253 }