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6d7e8eda | 1 | /* Copyright (C) 2020-2023 Free Software Foundation, Inc. |
d27f0e5d RE |
2 | |
3 | This file is part of the GNU C Library. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library 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 GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library. If not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <sysdep.h> | |
20 | ||
21 | #ifdef USE_MTAG | |
22 | ||
23fd760a SN |
23 | /* Assumptions: |
24 | * | |
25 | * ARMv8-a, AArch64, MTE, LP64 ABI. | |
26 | * | |
27 | * Interface contract: | |
28 | * Address is 16 byte aligned and size is multiple of 16. | |
29 | * Returns the passed pointer. | |
30 | * The memory region may remain untagged if tagging is not enabled. | |
31 | */ | |
d27f0e5d RE |
32 | .arch armv8.5-a |
33 | .arch_extension memtag | |
34 | ||
23fd760a SN |
35 | #define dstin x0 |
36 | #define count x1 | |
37 | #define dst x2 | |
38 | #define dstend x3 | |
39 | #define tmp x4 | |
40 | #define zva_val x4 | |
41 | ||
42 | ENTRY (__libc_mtag_tag_region) | |
43 | PTR_ARG (0) | |
44 | SIZE_ARG (1) | |
45 | ||
46 | add dstend, dstin, count | |
d27f0e5d | 47 | |
23fd760a SN |
48 | cmp count, 96 |
49 | b.hi L(set_long) | |
d27f0e5d | 50 | |
23fd760a | 51 | tbnz count, 6, L(set96) |
d27f0e5d | 52 | |
23fd760a SN |
53 | /* Set 0, 16, 32, or 48 bytes. */ |
54 | lsr tmp, count, 5 | |
55 | add tmp, dstin, tmp, lsl 4 | |
56 | cbz count, L(end) | |
57 | stg dstin, [dstin] | |
58 | stg dstin, [tmp] | |
59 | stg dstin, [dstend, -16] | |
60 | L(end): | |
61 | ret | |
62 | ||
63 | .p2align 4 | |
64 | /* Set 64..96 bytes. Write 64 bytes from the start and | |
65 | 32 bytes from the end. */ | |
66 | L(set96): | |
67 | st2g dstin, [dstin] | |
68 | st2g dstin, [dstin, 32] | |
69 | st2g dstin, [dstend, -32] | |
70 | ret | |
d27f0e5d | 71 | |
23fd760a SN |
72 | .p2align 4 |
73 | /* Size is > 96 bytes. */ | |
74 | L(set_long): | |
75 | cmp count, 160 | |
76 | b.lo L(no_zva) | |
77 | ||
78 | #ifndef SKIP_ZVA_CHECK | |
79 | mrs zva_val, dczid_el0 | |
80 | and zva_val, zva_val, 31 | |
81 | cmp zva_val, 4 /* ZVA size is 64 bytes. */ | |
82 | b.ne L(no_zva) | |
d27f0e5d | 83 | #endif |
23fd760a SN |
84 | st2g dstin, [dstin] |
85 | st2g dstin, [dstin, 32] | |
86 | bic dst, dstin, 63 | |
87 | sub count, dstend, dst /* Count is now 64 too large. */ | |
88 | sub count, count, 128 /* Adjust count and bias for loop. */ | |
89 | ||
90 | .p2align 4 | |
91 | L(zva_loop): | |
92 | add dst, dst, 64 | |
93 | dc gva, dst | |
94 | subs count, count, 64 | |
95 | b.hi L(zva_loop) | |
96 | st2g dstin, [dstend, -64] | |
97 | st2g dstin, [dstend, -32] | |
d27f0e5d | 98 | ret |
23fd760a SN |
99 | |
100 | L(no_zva): | |
101 | sub dst, dstin, 32 /* Dst is biased by -32. */ | |
102 | sub count, count, 64 /* Adjust count for loop. */ | |
103 | L(no_zva_loop): | |
104 | st2g dstin, [dst, 32] | |
105 | st2g dstin, [dst, 64]! | |
106 | subs count, count, 64 | |
107 | b.hi L(no_zva_loop) | |
108 | st2g dstin, [dstend, -64] | |
109 | st2g dstin, [dstend, -32] | |
110 | ret | |
111 | ||
d27f0e5d RE |
112 | END (__libc_mtag_tag_region) |
113 | #endif /* USE_MTAG */ |