30 lines
894 B
C
30 lines
894 B
C
/* SPDX-License-Identifier: GPL-2.0 */
|
|
#ifndef _ASM_X86_SYNC_CORE_H
|
|
#define _ASM_X86_SYNC_CORE_H
|
|
|
|
#include <linux/preempt.h>
|
|
#include <asm/processor.h>
|
|
#include <asm/cpufeature.h>
|
|
|
|
/*
|
|
* Ensure that a core serializing instruction is issued before returning
|
|
* to user-mode. x86 implements return to user-space through sysexit,
|
|
* sysrel, and sysretq, which are not core serializing.
|
|
*/
|
|
static inline void sync_core_before_usermode(void)
|
|
{
|
|
/* With PTI, we unconditionally serialize before running user code. */
|
|
if (static_cpu_has(X86_FEATURE_PTI))
|
|
return;
|
|
|
|
/*
|
|
* Even if we're in an interrupt, we might reschedule before returning,
|
|
* in which case we could switch to a different thread in the same mm
|
|
* and return using SYSRET or SYSEXIT. Instead of trying to keep
|
|
* track of our need to sync the core, just sync right away.
|
|
*/
|
|
sync_core();
|
|
}
|
|
|
|
#endif /* _ASM_X86_SYNC_CORE_H */
|