osfmk/i386/panic_hooks.c

   1 /*
   2  * Copyright (c) 2014 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 #include "panic_hooks.h"
  30
  31 #include <kern/queue.h>
  32 #include <kern/locks.h>
  33 #include <kern/thread.h>
  34 #include <vm/WKdm_new.h>
  35 #include <pexpert/boot.h>
  36
  37 #include "pmap.h"
  38
  39 struct panic_hook {
  40         uint32_t                        magic1;
  41         queue_chain_t           chain;
  42         thread_t                        thread;
  43         panic_hook_fn_t         hook_fn;
  44         uint32_t                        magic2;
  45 };
  46
  47 typedef char check1_[sizeof(struct panic_hook)
  48                                          <= sizeof(panic_hook_t) ? 1 : -1];
  49 typedef char check2_[PAGE_SIZE == 4096 ? 1 : -1];
  50
  51 static hw_lock_data_t   panic_hooks_lock;
  52 static queue_head_t     panic_hooks;
  53 static uint8_t                  panic_dump_buf[8192];
  54
  55 #define PANIC_HOOK_MAGIC1               0x4A1C400C
  56 #define PANIC_HOOK_MAGIC2               0xC004C1A4
  57
  58 void panic_hooks_init(void)
  59 {
  60         hw_lock_init(&panic_hooks_lock);
  61         queue_init(&panic_hooks);
  62 }
  63
  64 void panic_hook(panic_hook_t *hook_, panic_hook_fn_t hook_fn)
  65 {
  66         struct panic_hook *hook = (struct panic_hook *)hook_;
  67
  68         hook->magic1    = PANIC_HOOK_MAGIC1;
  69         hook->magic2    = PANIC_HOOK_MAGIC2;
  70         hook->hook_fn   = hook_fn;
  71         hook->thread    = current_thread();
  72
  73         hw_lock_lock(&panic_hooks_lock);
  74         queue_enter(&panic_hooks, hook, struct panic_hook *, chain);
  75         hw_lock_unlock(&panic_hooks_lock);
  76 }
  77
  78 void panic_unhook(panic_hook_t *hook_)
  79 {
  80         struct panic_hook *hook = (struct panic_hook *)hook_;
  81
  82         hw_lock_lock(&panic_hooks_lock);
  83         queue_remove(&panic_hooks, hook, struct panic_hook *, chain);
  84         hw_lock_unlock(&panic_hooks_lock);
  85 }
  86
  87 void panic_check_hook(void)
  88 {
  89         struct panic_hook *hook;
  90         thread_t thread = current_thread();
  91         uint32_t count = 0;
  92
  93         queue_iterate(&panic_hooks, hook, struct panic_hook *, chain) {
  94                 if (++count > 1024
  95                         || !kvtophys((vm_offset_t)hook)
  96                         || !kvtophys((vm_offset_t)hook + sizeof (*hook) - 1)
  97                         || hook->magic1 != PANIC_HOOK_MAGIC1
  98                         || hook->magic2 != PANIC_HOOK_MAGIC2
  99                         || !kvtophys((vm_offset_t)hook->hook_fn))
 100                         return;
 101
 102                 if (hook->thread == thread) {
 103                         hook->hook_fn((panic_hook_t *)hook);
 104                         return;
 105                 }
 106         }
 107 }
 108
 109 /*
 110  * addr should be page aligned and len should be multiple of page
 111  * size.  This will currently only work if each page can be compressed
 112  * to no more than 4095 bytes.
 113  *
 114  * Remember the debug buffer isn't very big so don't try and dump too
 115  * much.
 116  */
 117 void panic_dump_mem(const void *addr, int len)
 118 {
 119         void *scratch = panic_dump_buf + 4096;
 120
 121         for (; len > 0; addr = (uint8_t *)addr + PAGE_SIZE, len -= PAGE_SIZE) {
 122                 if (!kvtophys((vm_offset_t)addr))
 123                         continue;
 124
 125                 // 4095 is multiple of 3 -- see below
 126                 int n = WKdm_compress_new((WK_word *)addr, (WK_word *)(void *)panic_dump_buf,
 127                                                                   scratch, 4095);
 128
 129                 if (n == -1)
 130                         return; // Give up
 131
 132                 kdb_log("%p: ", addr);
 133
 134                 // Dump out base64
 135                 static char base64_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 136                         "abcdefghijklmnopqrstuvwxyz0123456789+/";
 137
 138                 // Pad to multiple of 3
 139                 switch (n % 3) {
 140                 case 1:
 141                         panic_dump_buf[n++] = 0;
 142                 case 2:
 143                         panic_dump_buf[n++] = 0;
 144                 }
 145
 146                 uint8_t *p = panic_dump_buf;
 147                 while (n) {
 148                         uint8_t c;
 149
 150                         c = p[0] >> 2;
 151                         consdebug_log(base64_table[c]);
 152
 153                         c = (p[0] << 4 | p[1] >> 4) & 0x3f;
 154                         consdebug_log(base64_table[c]);
 155
 156                         c = (p[1] << 2 | p[2] >> 6) & 0x3f;
 157                         consdebug_log(base64_table[c]);
 158
 159                         c = p[2] & 0x3f;
 160                         consdebug_log(base64_table[c]);
 161
 162                         p += 3;
 163                         n -= 3;
 164                 }
 165
 166                 consdebug_log('\n');
 167         }
 168 }
 169
 170 bool panic_phys_range_before(const void *addr, uint64_t *pphys,
 171                                                          panic_phys_range_t *range)
 172 {
 173         *pphys = kvtophys((vm_offset_t)addr);
 174
 175         const boot_args *args = PE_state.bootArgs;
 176
 177         if (!kvtophys((vm_offset_t)args))
 178                 return FALSE;
 179
 180         const EfiMemoryRange *r = PHYSMAP_PTOV((uintptr_t)args->MemoryMap), *closest = NULL;
 181         const uint32_t size = args->MemoryMapDescriptorSize;
 182         const uint32_t count = args->MemoryMapSize / size;
 183
 184         if (count > 1024)       // Sanity check
 185                 return FALSE;
 186
 187         for (uint32_t i = 0; i < count; ++i, r = (EfiMemoryRange *)(void *)((uint8_t *)r + size)) {
 188                 if (r->PhysicalStart + r->NumberOfPages * PAGE_SIZE > *pphys)
 189                         continue;
 190
 191                 if (!closest || r->PhysicalStart > closest->PhysicalStart)
 192                         closest = r;
 193         }
 194
 195         if (!closest)
 196                 return FALSE;
 197
 198         range->type             = closest->Type;
 199         range->phys_start       = closest->PhysicalStart;
 200         range->len                      = closest->NumberOfPages * PAGE_SIZE;
 201
 202         return TRUE;
 203 }