1 /*
2 * Copyright (c) 2022, Google, Inc. All rights reserved
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files
6 * (the "Software"), to deal in the Software without restriction,
7 * including without limitation the rights to use, copy, modify, merge,
8 * publish, distribute, sublicense, and/or sell copies of the Software,
9 * and to permit persons to whom the Software is furnished to do so,
10 * subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23
24 #include <arch/mmu.h>
25 #include <err.h>
26 #include <uapi/mm.h>
27
28 #include "util.h"
29
is_accessible(uint32_t obj_flags,uint32_t req_flags)30 bool is_accessible(uint32_t obj_flags, uint32_t req_flags) {
31 req_flags &= MMAP_FLAG_PROT_MASK;
32 return (req_flags && ((obj_flags & req_flags) == req_flags));
33 }
34
is_prot_valid(uint32_t mmap_prot)35 bool is_prot_valid(uint32_t mmap_prot) {
36 if (!(mmap_prot & MMAP_FLAG_PROT_MASK)) {
37 /* unknown flags set */
38 return false;
39 }
40
41 if (mmap_prot & MMAP_FLAG_PROT_EXEC) {
42 /* exec flags is not supported */
43 return false;
44 }
45
46 if (mmap_prot & MMAP_FLAG_PROT_WRITE) {
47 if (!(mmap_prot & MMAP_FLAG_PROT_READ)) {
48 /* write only memory is not supported */
49 return false;
50 }
51 }
52
53 return true;
54 }
55
xlat_flags(uint32_t access_prot,uint32_t mmap_prot,uint * arch_mmu_flags)56 status_t xlat_flags(uint32_t access_prot,
57 uint32_t mmap_prot,
58 uint* arch_mmu_flags) {
59 if (!is_prot_valid(mmap_prot)) {
60 return ERR_INVALID_ARGS;
61 }
62
63 if (!is_accessible(access_prot, mmap_prot)) {
64 return ERR_ACCESS_DENIED;
65 }
66
67 *arch_mmu_flags |= ARCH_MMU_FLAG_PERM_USER | ARCH_MMU_FLAG_PERM_NO_EXECUTE;
68
69 if (!(mmap_prot & MMAP_FLAG_PROT_WRITE)) {
70 *arch_mmu_flags |= ARCH_MMU_FLAG_PERM_RO;
71 }
72
73 if (mmap_prot & MMAP_FLAG_PROT_MTE) {
74 *arch_mmu_flags |= ARCH_MMU_FLAG_TAGGED;
75 }
76
77 return NO_ERROR;
78 }
79