Commit-ID: e61938a921a46347d7725badc40ec436ebfff977 Gitweb: https://git.kernel.org/tip/e61938a921a46347d7725badc40ec436ebfff977 Author: Mathieu Desnoyers <[email protected]> AuthorDate: Mon, 29 Jan 2018 15:20:15 -0500 Committer: Ingo Molnar <[email protected]> CommitDate: Mon, 5 Feb 2018 21:34:50 +0100
locking: Introduce sync_core_before_usermode() Introduce an architecture function that ensures the current CPU issues a core serializing instruction before returning to usermode. This is needed for the membarrier "sync_core" command. Architectures defining the sync_core_before_usermode() static inline need to select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE. Signed-off-by: Mathieu Desnoyers <[email protected]> Acked-by: Thomas Gleixner <[email protected]> Acked-by: Peter Zijlstra (Intel) <[email protected]> Cc: Andrea Parri <[email protected]> Cc: Andrew Hunter <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Avi Kivity <[email protected]> Cc: Benjamin Herrenschmidt <[email protected]> Cc: Boqun Feng <[email protected]> Cc: Dave Watson <[email protected]> Cc: David Sehr <[email protected]> Cc: Greg Hackmann <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Maged Michael <[email protected]> Cc: Michael Ellerman <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Paul Mackerras <[email protected]> Cc: Russell King <[email protected]> Cc: Will Deacon <[email protected]> Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- include/linux/sync_core.h | 21 +++++++++++++++++++++ init/Kconfig | 3 +++ 2 files changed, 24 insertions(+) diff --git a/include/linux/sync_core.h b/include/linux/sync_core.h new file mode 100644 index 0000000..013da4b --- /dev/null +++ b/include/linux/sync_core.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_SYNC_CORE_H +#define _LINUX_SYNC_CORE_H + +#ifdef CONFIG_ARCH_HAS_SYNC_CORE_BEFORE_USERMODE +#include <asm/sync_core.h> +#else +/* + * This is a dummy sync_core_before_usermode() implementation that can be used + * on all architectures which return to user-space through core serializing + * instructions. + * If your architecture returns to user-space through non-core-serializing + * instructions, you need to write your own functions. + */ +static inline void sync_core_before_usermode(void) +{ +} +#endif + +#endif /* _LINUX_SYNC_CORE_H */ + diff --git a/init/Kconfig b/init/Kconfig index 837adcf..535421f 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1918,3 +1918,6 @@ config ASN1 functions to call on what tags. source "kernel/Kconfig.locks" + +config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE + bool
