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linux-next/arch/x86/include/asm/sync_core.h
Mathieu Desnoyers ac1ab12a3e lockin/x86: Implement sync_core_before_usermode()
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.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrea Parri <parri.andrea@gmail.com>
Cc: Andrew Hunter <ahh@google.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Avi Kivity <avi@scylladb.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Dave Watson <davejwatson@fb.com>
Cc: David Sehr <sehr@google.com>
Cc: Greg Hackmann <ghackmann@google.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maged Michael <maged.michael@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-api@vger.kernel.org
Cc: linux-arch@vger.kernel.org
Link: http://lkml.kernel.org/r/20180129202020.8515-8-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2018-02-05 21:34:57 +01:00

29 lines
744 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;
/*
* Return from interrupt and NMI is done through iret, which is core
* serializing.
*/
if (in_irq() || in_nmi())
return;
sync_core();
}
#endif /* _ASM_X86_SYNC_CORE_H */