Commit-ID: e61938a921a46347d7725badc40ec436ebfff977 Gitweb: https://git.kernel.org/tip/e61938a921a46347d7725badc40ec436ebfff977 Author: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> AuthorDate: Mon, 29 Jan 2018 15:20:15 -0500 Committer: Ingo Molnar <mingo@xxxxxxxxxx> 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 <mathieu.desnoyers@xxxxxxxxxxxx> Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Andrea Parri <parri.andrea@xxxxxxxxx> Cc: Andrew Hunter <ahh@xxxxxxxxxx> Cc: Andy Lutomirski <luto@xxxxxxxxxx> Cc: Arnd Bergmann <arnd@xxxxxxxx> Cc: Avi Kivity <avi@xxxxxxxxxxxx> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> Cc: Boqun Feng <boqun.feng@xxxxxxxxx> Cc: Dave Watson <davejwatson@xxxxxx> Cc: David Sehr <sehr@xxxxxxxxxx> Cc: Greg Hackmann <ghackmann@xxxxxxxxxx> Cc: H. Peter Anvin <hpa@xxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Maged Michael <maged.michael@xxxxxxxxx> Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx> Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx> Cc: Paul Mackerras <paulus@xxxxxxxxx> Cc: Russell King <linux@xxxxxxxxxxxxxxx> Cc: Will Deacon <will.deacon@xxxxxxx> Cc: linux-api@xxxxxxxxxxxxxxx Cc: linux-arch@xxxxxxxxxxxxxxx Link: http://lkml.kernel.org/r/20180129202020.8515-7-mathieu.desnoyers@xxxxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html