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de7b5723 | 1 | /* ARMv8-M Security Extensions routines. |
99dee823 | 2 | Copyright (C) 2015-2021 Free Software Foundation, Inc. |
de7b5723 AV |
3 | Contributed by ARM Ltd. |
4 | ||
5 | This file is free software; you can redistribute it and/or modify it | |
6 | under the terms of the GNU General Public License as published by the | |
7 | Free Software Foundation; either version 3, or (at your option) any | |
8 | later version. | |
9 | ||
10 | This file is distributed in the hope that it will be useful, but | |
11 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | General Public License for more details. | |
14 | ||
15 | Under Section 7 of GPL version 3, you are granted additional | |
16 | permissions described in the GCC Runtime Library Exception, version | |
17 | 3.1, as published by the Free Software Foundation. | |
18 | ||
19 | You should have received a copy of the GNU General Public License and | |
20 | a copy of the GCC Runtime Library Exception along with this program; | |
21 | see the files COPYING3 and COPYING.RUNTIME respectively. If not, see | |
22 | <http://www.gnu.org/licenses/>. */ | |
23 | ||
24 | ||
25 | #if __ARM_FEATURE_CMSE & 1 | |
26 | ||
27 | #include <arm_cmse.h> | |
28 | ||
29 | /* ARM intrinsic function to perform a permission check on a given | |
30 | address range. See ACLE changes for ARMv8-M. */ | |
31 | ||
32 | void * | |
f0efd925 | 33 | __attribute__ ((warn_unused_result)) |
de7b5723 AV |
34 | cmse_check_address_range (void *p, size_t size, int flags) |
35 | { | |
36 | cmse_address_info_t permb, perme; | |
37 | char *pb = (char *) p, *pe; | |
38 | ||
39 | /* Check if the range wraps around. */ | |
fcf4f831 | 40 | if (__UINTPTR_MAX__ - (__UINTPTR_TYPE__) p < size) |
de7b5723 AV |
41 | return NULL; |
42 | ||
43 | /* Check if an unknown flag is present. */ | |
44 | int known = CMSE_MPU_UNPRIV | CMSE_MPU_READWRITE | CMSE_MPU_READ; | |
45 | int known_secure_level = CMSE_MPU_UNPRIV; | |
46 | #if __ARM_FEATURE_CMSE & 2 | |
47 | known |= CMSE_AU_NONSECURE | CMSE_MPU_NONSECURE; | |
48 | known_secure_level |= CMSE_MPU_NONSECURE; | |
49 | #endif | |
50 | if (flags & (~known)) | |
51 | return NULL; | |
52 | ||
53 | /* Execute the right variant of the TT instructions. */ | |
54 | pe = pb + size - 1; | |
fcf4f831 JL |
55 | const int singleCheck |
56 | = (((__UINTPTR_TYPE__) pb ^ (__UINTPTR_TYPE__) pe) < 32); | |
de7b5723 AV |
57 | switch (flags & known_secure_level) |
58 | { | |
59 | case 0: | |
60 | permb = cmse_TT (pb); | |
61 | perme = singleCheck ? permb : cmse_TT (pe); | |
62 | break; | |
63 | case CMSE_MPU_UNPRIV: | |
64 | permb = cmse_TTT (pb); | |
65 | perme = singleCheck ? permb : cmse_TTT (pe); | |
66 | break; | |
67 | #if __ARM_FEATURE_CMSE & 2 | |
68 | case CMSE_MPU_NONSECURE: | |
69 | permb = cmse_TTA (pb); | |
70 | perme = singleCheck ? permb : cmse_TTA (pe); | |
71 | break; | |
72 | case CMSE_MPU_UNPRIV | CMSE_MPU_NONSECURE: | |
73 | permb = cmse_TTAT (pb); | |
74 | perme = singleCheck ? permb : cmse_TTAT (pe); | |
75 | break; | |
76 | #endif | |
77 | default: | |
78 | /* Invalid flag, eg. CMSE_MPU_NONSECURE specified but | |
79 | __ARM_FEATURE_CMSE & 2 == 0. */ | |
80 | return NULL; | |
81 | } | |
82 | ||
83 | /* Check that the range does not cross MPU, SAU, or IDAU boundaries. */ | |
84 | if (permb.value != perme.value) | |
85 | return NULL; | |
86 | ||
87 | /* Check the permissions on the range. */ | |
88 | switch (flags & (~known_secure_level)) | |
89 | { | |
90 | #if __ARM_FEATURE_CMSE & 2 | |
91 | case CMSE_MPU_READ | CMSE_MPU_READWRITE | CMSE_AU_NONSECURE: | |
92 | case CMSE_MPU_READWRITE | CMSE_AU_NONSECURE: | |
93 | return permb.flags.nonsecure_readwrite_ok ? p : NULL; | |
94 | case CMSE_MPU_READ | CMSE_AU_NONSECURE: | |
95 | return permb.flags.nonsecure_read_ok ? p : NULL; | |
96 | case CMSE_AU_NONSECURE: | |
97 | return permb.flags.secure ? NULL : p; | |
98 | #endif | |
99 | case CMSE_MPU_READ | CMSE_MPU_READWRITE: | |
100 | case CMSE_MPU_READWRITE: | |
101 | return permb.flags.readwrite_ok ? p : NULL; | |
102 | case CMSE_MPU_READ: | |
103 | return permb.flags.read_ok ? p : NULL; | |
104 | default: | |
105 | return NULL; | |
106 | } | |
107 | } | |
108 | ||
109 | ||
110 | #endif /* __ARM_FEATURE_CMSE & 1. */ |