1 /*
2 * Copyright (C) 2020 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #if defined(ANDROID_EXPERIMENTAL_MTE)
18
19 #include <sys/ptrace.h>
20 #include <sys/uio.h>
21
22 #include <bionic/mte.h>
23 #include <bionic/mte_kernel.h>
24
25 #include "MemoryLocal.h"
26 #include "MemoryRemote.h"
27
28 namespace unwindstack {
29
ReadTag(uint64_t addr)30 long MemoryRemote::ReadTag(uint64_t addr) {
31 #if defined(__aarch64__)
32 char tag;
33 iovec iov = {&tag, 1};
34 if (ptrace(PTRACE_PEEKMTETAGS, pid_, reinterpret_cast<void*>(addr), &iov) != 0 ||
35 iov.iov_len != 1) {
36 return -1;
37 }
38 return tag;
39 #else
40 (void)addr;
41 return -1;
42 #endif
43 }
44
ReadTag(uint64_t addr)45 long MemoryLocal::ReadTag(uint64_t addr) {
46 #if defined(__aarch64__)
47 // Check that the memory is readable first. This is racy with the ldg but there's not much
48 // we can do about it.
49 char data;
50 if (!mte_supported() || !Read(addr, &data, 1)) {
51 return -1;
52 }
53
54 __asm__ __volatile__(".arch_extension mte; ldg %0, [%0]" : "+r"(addr) : : "memory");
55 return (addr >> 56) & 0xf;
56 #else
57 (void)addr;
58 return -1;
59 #endif
60 }
61
62 } // namespace unwindstack
63
64 #endif
65