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
  59 panic_hooks_init(void)
  60 {
  61         hw_lock_init(&panic_hooks_lock);
  62         queue_init(&panic_hooks);
  63 }
  64
  65 void
  66 panic_hook(panic_hook_t *hook_, panic_hook_fn_t hook_fn)
  67 {
  68         struct panic_hook *hook = (struct panic_hook *)hook_;
  69
  70         hook->magic1    = PANIC_HOOK_MAGIC1;
  71         hook->magic2    = PANIC_HOOK_MAGIC2;
  72         hook->hook_fn   = hook_fn;
  73         hook->thread    = current_thread();
  74
  75         hw_lock_lock(&panic_hooks_lock, LCK_GRP_NULL);
  76         queue_enter(&panic_hooks, hook, struct panic_hook *, chain);
  77         hw_lock_unlock(&panic_hooks_lock);
  78 }
  79
  80 void
  81 panic_unhook(panic_hook_t *hook_)
  82 {
  83         struct panic_hook *hook = (struct panic_hook *)hook_;
  84
  85         hw_lock_lock(&panic_hooks_lock, LCK_GRP_NULL);
  86         queue_remove(&panic_hooks, hook, struct panic_hook *, chain);
  87         hw_lock_unlock(&panic_hooks_lock);
  88 }
  89
  90 void
  91 panic_check_hook(void)
  92 {
  93         struct panic_hook *hook;
  94         thread_t thread = current_thread();
  95         uint32_t count = 0;
  96
  97         queue_iterate(&panic_hooks, hook, struct panic_hook *, chain) {
  98                 if (++count > 1024
  99                 || !kvtophys((vm_offset_t)hook)
 100                 || !kvtophys((vm_offset_t)hook + sizeof(*hook) - 1)
 101                 || hook->magic1 != PANIC_HOOK_MAGIC1
 102                 || hook->magic2 != PANIC_HOOK_MAGIC2
 103                 || !kvtophys((vm_offset_t)hook->hook_fn)) {
 104                         return;
 105                 }
 106
 107                 if (hook->thread == thread) {
 108                         hook->hook_fn((panic_hook_t *)hook);
 109                         return;
 110                 }
 111         }
 112 }
 113
 114 /*
 115  * addr should be page aligned and len should be multiple of page
 116  * size.  This will currently only work if each page can be compressed
 117  * to no more than 4095 bytes.
 118  *
 119  * Remember the debug buffer isn't very big so don't try and dump too
 120  * much.
 121  */
 122 void
 123 panic_dump_mem(const void *addr, int len)
 124 {
 125         void *scratch = panic_dump_buf + 4096;
 126
 127         for (; len > 0; addr = (const uint8_t *)addr + PAGE_SIZE, len -= PAGE_SIZE) {
 128                 if (!kvtophys((vm_offset_t)addr)) {
 129                         continue;
 130                 }
 131
 132                 // 4095 is multiple of 3 -- see below
 133                 int n = WKdm_compress_new((const WK_word *)addr, (WK_word *)(void *)panic_dump_buf,
 134                     scratch, 4095);
 135
 136                 if (n == -1) {
 137                         return; // Give up
 138                 }
 139                 kdb_log("%p: ", addr);
 140
 141                 // Dump out base64
 142                 static char base64_table[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
 143                     "abcdefghijklmnopqrstuvwxyz0123456789+/";
 144
 145                 // Pad to multiple of 3
 146                 switch (n % 3) {
 147                 case 1:
 148                         panic_dump_buf[n++] = 0;
 149                 case 2:
 150                         panic_dump_buf[n++] = 0;
 151                 }
 152
 153                 uint8_t *p = panic_dump_buf;
 154                 while (n) {
 155                         uint8_t c;
 156
 157                         c = p[0] >> 2;
 158                         consdebug_log(base64_table[c]);
 159
 160                         c = (p[0] << 4 | p[1] >> 4) & 0x3f;
 161                         consdebug_log(base64_table[c]);
 162
 163                         c = (p[1] << 2 | p[2] >> 6) & 0x3f;
 164                         consdebug_log(base64_table[c]);
 165
 166                         c = p[2] & 0x3f;
 167                         consdebug_log(base64_table[c]);
 168
 169                         p += 3;
 170                         n -= 3;
 171                 }
 172
 173                 consdebug_log('\n');
 174         }
 175 }
 176
 177 boolean_t
 178 panic_phys_range_before(const void *addr, uint64_t *pphys,
 179     panic_phys_range_t *range)
 180 {
 181         *pphys = kvtophys((vm_offset_t)addr);
 182
 183         const boot_args *args = PE_state.bootArgs;
 184
 185         if (!kvtophys((vm_offset_t)args)) {
 186                 return FALSE;
 187         }
 188
 189         const EfiMemoryRange *r = PHYSMAP_PTOV((uintptr_t)args->MemoryMap), *closest = NULL;
 190         const uint32_t size = args->MemoryMapDescriptorSize;
 191         const uint32_t count = args->MemoryMapSize / size;
 192
 193         if (count > 1024) {     // Sanity check
 194                 return FALSE;
 195         }
 196
 197         for (uint32_t i = 0; i < count; ++i, r = (const EfiMemoryRange *)(const void *)((const uint8_t *)r + size)) {
 198                 if (r->PhysicalStart + r->NumberOfPages * PAGE_SIZE > *pphys) {
 199                         continue;
 200                 }
 201
 202                 if (!closest || r->PhysicalStart > closest->PhysicalStart) {
 203                         closest = r;
 204                 }
 205         }
 206
 207         if (!closest) {
 208                 return FALSE;
 209         }
 210
 211         range->type             = closest->Type;
 212         range->phys_start       = closest->PhysicalStart;
 213         range->len                      = closest->NumberOfPages * PAGE_SIZE;
 214
 215         return TRUE;
 216 }