blob: 5312ae4c6f311c47cb4973ea577c0c40a92ec516 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
|
/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright 2018 Amazon.com, Inc. or its affiliates. All Rights Reserved. */
#ifndef _ASM_X86_NOSPEC_H
#define _ASM_X86_NOSPEC_H
#include <asm/alternative.h>
/* Allow to insert a read memory barrier into conditionals */
static always_inline bool barrier_nospec_true(void)
{
#ifdef CONFIG_SPECULATIVE_HARDEN_BRANCH
alternative("lfence", "", X86_FEATURE_SC_NO_BRANCH_HARDEN);
#endif
return true;
}
/* Allow to protect evaluation of conditionals with respect to speculation */
static always_inline bool evaluate_nospec(bool condition)
{
return condition ? barrier_nospec_true() : !barrier_nospec_true();
}
/* Allow to block speculative execution in generic code */
static always_inline void block_speculation(void)
{
barrier_nospec_true();
}
#endif /* _ASM_X86_NOSPEC_H */
/*
* Local variables:
* mode: C
* c-file-style: "BSD"
* c-basic-offset: 4
* indent-tabs-mode: nil
* End:
*/
|
