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
47extern int etext;
48__BEGIN_DECLS
49// From osmfk/kern/thread.h but considered to be private
50extern vm_offset_t min_valid_stack_address(void);
51extern vm_offset_t max_valid_stack_address(void);
52
53// From osfmk/kern/printf.c
54extern boolean_t doprnt_hide_pointers;
55
56// From osfmk/kmod.c
57extern void kmod_dump_log(vm_offset_t *addr, unsigned int cnt, boolean_t doUnslide);
58
59extern addr64_t kvtophys(vm_offset_t va);
60#if __arm__
61extern int copyinframe(vm_address_t fp, char *frame);
62#elif defined(__arm64__)
63extern int copyinframe(vm_address_t fp, char *frame, boolean_t is64bit);
64#endif
65
66__END_DECLS
67
68extern lck_grp_t *IOLockGroup;
69
70static lck_mtx_t *sOSReportLock = lck_mtx_alloc_init(IOLockGroup, LCK_ATTR_NULL);
71
72/* Use kernel_debug() to log a backtrace */
73void
74trace_backtrace(uint32_t debugid, uint32_t debugid2, uintptr_t size, uintptr_t data) {
75 void *bt[16];
76 const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
77 unsigned i;
78 int found = 0;
79
80 OSBacktrace(bt, cnt);
81
82 /* find first non-kernel frame */
83 for (i = 3; i < cnt && bt[i]; i++) {
84 if (bt[i] > (void*)&etext) {
85 found = 1;
86 break;
87 }
88 }
89 /*
90 * if there are non-kernel frames, only log these
91 * otherwise, log everything but the first two
92 */
93 if (!found) i=2;
94
95#define safe_bt(a) (uintptr_t)(a<cnt ? bt[a] : 0)
96 kernel_debug(debugid, data, size, safe_bt(i), safe_bt(i+1), 0);
97 kernel_debug(debugid2, safe_bt(i+2), safe_bt(i+3), safe_bt(i+4), safe_bt(i+5), 0);
98}
99
100/* Report a message with a 4 entry backtrace - very slow */
101void
102OSReportWithBacktrace(const char *str, ...)
103{
104 char buf[128];
105 void *bt[9] = {};
106 const unsigned cnt = sizeof(bt) / sizeof(bt[0]);
107 va_list listp;
108
109 // Ignore the our and our callers stackframes, skipping frames 0 & 1
110 (void) OSBacktrace(bt, cnt);
111
112 va_start(listp, str);
113 vsnprintf(buf, sizeof(buf), str, listp);
114 va_end(listp);
115
116 lck_mtx_lock(sOSReportLock);
117 {
118 boolean_t old_doprnt_hide_pointers = doprnt_hide_pointers;
119 doprnt_hide_pointers = FALSE;
120 printf("%s\nBacktrace 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx 0x%lx\n", buf,
121 (unsigned long) VM_KERNEL_UNSLIDE(bt[2]), (unsigned long) VM_KERNEL_UNSLIDE(bt[3]),
122 (unsigned long) VM_KERNEL_UNSLIDE(bt[4]), (unsigned long) VM_KERNEL_UNSLIDE(bt[5]),
123 (unsigned long) VM_KERNEL_UNSLIDE(bt[6]), (unsigned long) VM_KERNEL_UNSLIDE(bt[7]),
124 (unsigned long) VM_KERNEL_UNSLIDE(bt[8]));
125 kmod_dump_log((vm_offset_t *) &bt[2], cnt - 2, TRUE);
126 doprnt_hide_pointers = old_doprnt_hide_pointers;
127 }
128 lck_mtx_unlock(sOSReportLock);
129}
130
131static vm_offset_t minstackaddr = min_valid_stack_address();
132static vm_offset_t maxstackaddr = max_valid_stack_address();
133
134
135#if __x86_64__
136#define x86_64_RETURN_OFFSET 8
137static unsigned int
138x86_64_validate_raddr(vm_offset_t raddr)
139{
140 return ((raddr > VM_MIN_KERNEL_AND_KEXT_ADDRESS) &&
141 (raddr < VM_MAX_KERNEL_ADDRESS));
142}
143static unsigned int
144x86_64_validate_stackptr(vm_offset_t stackptr)
145{
146 /* Existence and alignment check
147 */
148 if (!stackptr || (stackptr & 0x7) || !x86_64_validate_raddr(stackptr))
149 return 0;
150
151 /* Is a virtual->physical translation present?
152 */
153 if (!kvtophys(stackptr))
154 return 0;
155
156 /* Check if the return address lies on the same page;
157 * If not, verify that a translation exists.
158 */
159 if (((PAGE_SIZE - (stackptr & PAGE_MASK)) < x86_64_RETURN_OFFSET) &&
160 !kvtophys(stackptr + x86_64_RETURN_OFFSET))
161 return 0;
162 return 1;
163}
164#endif
165
166void
167OSPrintBacktrace(void)
168{
169 void * btbuf[20];
170 int tmp = OSBacktrace(btbuf, 20);
171 int i;
172 for(i=0;i<tmp;i++)
173 {
174 kprintf("bt[%.2d] = %p\n", i, btbuf[i]);
175 }
176}
177
178unsigned OSBacktrace(void **bt, unsigned maxAddrs)
179{
180 unsigned frame;
181 if (!current_thread()) return 0;
182
183#if __x86_64__
184#define SANE_x86_64_FRAME_SIZE (kernel_stack_size >> 1)
185 vm_offset_t stackptr, stackptr_prev, raddr;
186 unsigned frame_index = 0;
187/* Obtain current frame pointer */
188
189 __asm__ volatile("movq %%rbp, %0" : "=m" (stackptr));
190
191 if (!x86_64_validate_stackptr(stackptr))
192 goto pad;
193
194 raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
195
196 if (!x86_64_validate_raddr(raddr))
197 goto pad;
198
199 bt[frame_index++] = (void *) raddr;
200
201 for ( ; frame_index < maxAddrs; frame_index++) {
202 stackptr_prev = stackptr;
203 stackptr = *((vm_offset_t *) stackptr_prev);
204
205 if (!x86_64_validate_stackptr(stackptr))
206 break;
207 /* Stack grows downwards */
208 if (stackptr < stackptr_prev)
209 break;
210
211 if ((stackptr - stackptr_prev) > SANE_x86_64_FRAME_SIZE)
212 break;
213
214 raddr = *((vm_offset_t *) (stackptr + x86_64_RETURN_OFFSET));
215
216 if (!x86_64_validate_raddr(raddr))
217 break;
218
219 bt[frame_index] = (void *) raddr;
220 }
221pad:
222 frame = frame_index;
223
224 for ( ; frame_index < maxAddrs; frame_index++)
225 bt[frame_index] = (void *) 0;
226#elif __arm__ || __arm64__
227 uint32_t i = 0;
228 uintptr_t frameb[2];
229 uintptr_t fp = 0;
230
231 // get the current frame pointer for this thread
232#if defined(__arm__)
233#define OSBacktraceFrameAlignOK(x) (((x) & 0x3) == 0)
234 __asm__ volatile("mov %0,r7" : "=r" (fp));
235#elif defined(__arm64__)
236#define OSBacktraceFrameAlignOK(x) (((x) & 0xf) == 0)
237 __asm__ volatile("mov %0, fp" : "=r" (fp));
238#else
239#error Unknown architecture.
240#endif
241
242 // now crawl up the stack recording the link value of each frame
243 do {
244 // check bounds
245 if ((fp == 0) || (!OSBacktraceFrameAlignOK(fp)) || (fp > VM_MAX_KERNEL_ADDRESS) || (fp < VM_MIN_KERNEL_AND_KEXT_ADDRESS)) {
246 break;
247 }
248 // safely read frame
249#ifdef __arm64__
250 if (copyinframe(fp, (char*)frameb, TRUE) != 0) {
251#else
252 if (copyinframe(fp, (char*)frameb) != 0) {
253#endif
254 break;
255 }
256
257 // No need to use copyin as this is always a kernel address, see check above
258 bt[i] = (void*)frameb[1]; // link register
259 fp = frameb[0];
260 } while (++i < maxAddrs);
261 frame= i;
262#else
263#error arch
264#endif
265 return frame;
266}
267