1 | /* Copyright (c) (2021,2022) Apple Inc. All rights reserved. |
2 | * |
3 | * corecrypto is licensed under Apple Inc.’s Internal Use License Agreement (which |
4 | * is contained in the License.txt file distributed with corecrypto) and only to |
5 | * people who accept that license. IMPORTANT: Any license rights granted to you by |
6 | * Apple Inc. (if any) are limited to internal use within your organization only on |
7 | * devices and computers you own or control, for the sole purpose of verifying the |
8 | * security characteristics and correct functioning of the Apple Software. You may |
9 | * not, directly or indirectly, redistribute the Apple Software or any portions thereof. |
10 | * |
11 | * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ |
12 | * |
13 | * This file contains Original Code and/or Modifications of Original Code |
14 | * as defined in and that are subject to the Apple Public Source License |
15 | * Version 2.0 (the 'License'). You may not use this file except in |
16 | * compliance with the License. The rights granted to you under the License |
17 | * may not be used to create, or enable the creation or redistribution of, |
18 | * unlawful or unlicensed copies of an Apple operating system, or to |
19 | * circumvent, violate, or enable the circumvention or violation of, any |
20 | * terms of an Apple operating system software license agreement. |
21 | * |
22 | * Please obtain a copy of the License at |
23 | * http://www.opensource.apple.com/apsl/ and read it before using this file. |
24 | * |
25 | * The Original Code and all software distributed under the License are |
26 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
27 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
28 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
29 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
30 | * Please see the License for the specific language governing rights and |
31 | * limitations under the License. |
32 | * |
33 | * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ |
34 | */ |
35 | |
36 | #include "cc_internal.h" |
37 | |
38 | #if CC_DIT_MAYBE_SUPPORTED |
39 | |
40 | // Ignore "unreachable code" warnings when compiling against SDKs |
41 | // that don't support checking for DIT support at runtime. |
42 | #pragma clang diagnostic push |
43 | #pragma clang diagnostic ignored "-Wunreachable-code" |
44 | |
45 | void |
46 | cc_disable_dit(volatile bool *dit_was_enabled) |
47 | { |
48 | if (!CC_HAS_DIT()) { |
49 | return; |
50 | } |
51 | |
52 | #if CC_BUILT_FOR_TESTING |
53 | // DIT should be enabled. |
54 | cc_try_abort_if(!cc_is_dit_enabled(), "DIT not enabled" ); |
55 | #endif |
56 | |
57 | // Disable DIT, if this was the frame that enabled it. |
58 | if (*dit_was_enabled) { |
59 | // Encoding of <msr dit, #0>. |
60 | __asm__ __volatile__ (".long 0xd503405f" ); |
61 | cc_assert(!cc_is_dit_enabled()); |
62 | } |
63 | } |
64 | |
65 | #pragma clang diagnostic pop |
66 | |
67 | #endif // CC_DIT_MAYBE_SUPPORTED |
68 | |