blob: 76b547b832320b0570ff8e0aa4a6ad1171db5348 (
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 */
//
// Code shared between 32 and 64 bit
#include <asm/spec-ctrl.h>
void __switch_to_xtra(struct task_struct *prev_p, struct task_struct *next_p);
/*
* This needs to be inline to optimize for the common case where no extra
* work needs to be done.
*/
static inline void switch_to_extra(struct task_struct *prev,
struct task_struct *next)
{
unsigned long next_tif = read_task_thread_flags(next);
unsigned long prev_tif = read_task_thread_flags(prev);
if (IS_ENABLED(CONFIG_SMP)) {
/*
* Avoid __switch_to_xtra() invocation when conditional
* STIBP is disabled and the only different bit is
* TIF_SPEC_IB. For CONFIG_SMP=n TIF_SPEC_IB is not
* in the TIF_WORK_CTXSW masks.
*/
if (!static_branch_likely(&switch_to_cond_stibp)) {
prev_tif &= ~_TIF_SPEC_IB;
next_tif &= ~_TIF_SPEC_IB;
}
}
/*
* __switch_to_xtra() handles debug registers, i/o bitmaps,
* speculation mitigations etc.
*/
if (unlikely(next_tif & _TIF_WORK_CTXSW_NEXT ||
prev_tif & _TIF_WORK_CTXSW_PREV))
__switch_to_xtra(prev, next);
}
|
