From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mathieu Desnoyers Subject: [PATCH for 4.16 06/11] Introduce sync_core_before_usermode Date: Wed, 17 Jan 2018 11:54:53 -0500 Message-ID: <20180117165458.13330-7-mathieu.desnoyers@efficios.com> References: <20180117165458.13330-1-mathieu.desnoyers@efficios.com> Return-path: In-Reply-To: <20180117165458.13330-1-mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Ingo Molnar , Peter Zijlstra , Thomas Gleixner Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andy Lutomirski , "Paul E . McKenney" , Boqun Feng , Andrew Hunter , Maged Michael , Avi Kivity , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Dave Watson , "H . Peter Anvin" , Andrea Parri , Russell King , Greg Hackmann , Will Deacon , David Sehr , Linus Torvalds , x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Mathieu Desnoyers List-Id: linux-api@vger.kernel.org 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 CC: Thomas Gleixner CC: Peter Zijlstra CC: Andy Lutomirski CC: Paul E. McKenney CC: Boqun Feng CC: Andrew Hunter CC: Maged Michael CC: Avi Kivity CC: Benjamin Herrenschmidt CC: Paul Mackerras CC: Michael Ellerman CC: Dave Watson CC: Ingo Molnar CC: "H. Peter Anvin" CC: Andrea Parri CC: Russell King CC: Greg Hackmann CC: Will Deacon CC: David Sehr CC: Linus Torvalds CC: x86-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org CC: linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org --- include/linux/processor.h | 6 ++++++ init/Kconfig | 3 +++ 2 files changed, 9 insertions(+) diff --git a/include/linux/processor.h b/include/linux/processor.h index dbc952eec869..866de5326d34 100644 --- a/include/linux/processor.h +++ b/include/linux/processor.h @@ -68,4 +68,10 @@ do { \ #endif +#ifndef CONFIG_ARCH_HAS_SYNC_CORE_BEFORE_USERMODE +static inline void sync_core_before_usermode(void) +{ +} +#endif + #endif /* _LINUX_PROCESSOR_H */ diff --git a/init/Kconfig b/init/Kconfig index 2d118b6adee2..30208da2221f 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 -- 2.11.0