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1 | /* This test program is part of GDB, the GNU debugger. |
2 | ||
88b9d363 | 3 | Copyright 2021-2022 Free Software Foundation, Inc. |
bf0aecce LM |
4 | |
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | /* Exercise AArch64's Memory Tagging Extension with tagged pointers. */ | |
19 | ||
20 | /* This test was based on the documentation for the AArch64 Memory Tagging | |
21 | Extension from the Linux Kernel, found in the sources in | |
22 | Documentation/arm64/memory-tagging-extension.rst. */ | |
23 | ||
24 | #include <errno.h> | |
25 | #include <stdio.h> | |
26 | #include <stdlib.h> | |
27 | #include <unistd.h> | |
28 | #include <sys/auxv.h> | |
29 | #include <sys/mman.h> | |
30 | #include <sys/prctl.h> | |
31 | ||
32 | /* From arch/arm64/include/uapi/asm/hwcap.h */ | |
33 | #define HWCAP2_MTE (1 << 18) | |
34 | ||
35 | /* From arch/arm64/include/uapi/asm/mman.h */ | |
36 | #define PROT_MTE 0x20 | |
37 | ||
38 | /* From include/uapi/linux/prctl.h */ | |
39 | #define PR_SET_TAGGED_ADDR_CTRL 55 | |
40 | #define PR_GET_TAGGED_ADDR_CTRL 56 | |
41 | #define PR_TAGGED_ADDR_ENABLE (1UL << 0) | |
42 | #define PR_MTE_TCF_SHIFT 1 | |
43 | #define PR_MTE_TCF_NONE (0UL << PR_MTE_TCF_SHIFT) | |
44 | #define PR_MTE_TCF_SYNC (1UL << PR_MTE_TCF_SHIFT) | |
45 | #define PR_MTE_TCF_ASYNC (2UL << PR_MTE_TCF_SHIFT) | |
46 | #define PR_MTE_TCF_MASK (3UL << PR_MTE_TCF_SHIFT) | |
47 | #define PR_MTE_TAG_SHIFT 3 | |
48 | #define PR_MTE_TAG_MASK (0xffffUL << PR_MTE_TAG_SHIFT) | |
49 | ||
50 | void | |
51 | access_memory (unsigned char *tagged_ptr, unsigned char *untagged_ptr) | |
52 | { | |
53 | tagged_ptr[0] = 'a'; | |
54 | } | |
55 | ||
56 | int | |
57 | main (int argc, char **argv) | |
58 | { | |
59 | unsigned char *tagged_ptr; | |
60 | unsigned char *untagged_ptr; | |
61 | unsigned long page_sz = sysconf (_SC_PAGESIZE); | |
62 | unsigned long hwcap2 = getauxval(AT_HWCAP2); | |
63 | ||
64 | /* Bail out if MTE is not supported. */ | |
65 | if (!(hwcap2 & HWCAP2_MTE)) | |
66 | return 1; | |
67 | ||
68 | /* Enable the tagged address ABI, synchronous MTE tag check faults and | |
69 | allow all non-zero tags in the randomly generated set. */ | |
70 | if (prctl (PR_SET_TAGGED_ADDR_CTRL, | |
71 | PR_TAGGED_ADDR_ENABLE | PR_MTE_TCF_SYNC | |
72 | | (0xfffe << PR_MTE_TAG_SHIFT), | |
73 | 0, 0, 0)) | |
74 | { | |
75 | perror ("prctl () failed"); | |
76 | return 1; | |
77 | } | |
78 | ||
79 | /* Create a mapping that will have PROT_MTE set. */ | |
80 | tagged_ptr = mmap (0, page_sz, PROT_READ | PROT_WRITE, | |
81 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
82 | if (tagged_ptr == MAP_FAILED) | |
83 | { | |
84 | perror ("mmap () failed"); | |
85 | return 1; | |
86 | } | |
87 | ||
88 | /* Create another mapping that won't have PROT_MTE set. */ | |
89 | untagged_ptr = mmap (0, page_sz, PROT_READ | PROT_WRITE, | |
90 | MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); | |
91 | if (untagged_ptr == MAP_FAILED) | |
92 | { | |
93 | perror ("mmap () failed"); | |
94 | return 1; | |
95 | } | |
96 | ||
97 | /* Enable MTE on the above anonymous mmap. */ | |
98 | if (mprotect (tagged_ptr, page_sz, PROT_READ | PROT_WRITE | PROT_MTE)) | |
99 | { | |
100 | perror ("mprotect () failed"); | |
101 | return 1; | |
102 | } | |
103 | ||
104 | access_memory (tagged_ptr, untagged_ptr); | |
105 | ||
106 | return 0; | |
107 | } |