From patchwork Thu Dec 31 19:07:35 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Michael S. Tsirkin" X-Patchwork-Id: 7936961 X-Patchwork-Delegate: geert@linux-m68k.org Return-Path: X-Original-To: patchwork-linux-sh@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id D1F719F387 for ; Thu, 31 Dec 2015 19:07:52 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id EB74F20481 for ; Thu, 31 Dec 2015 19:07:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F119720489 for ; Thu, 31 Dec 2015 19:07:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754291AbbLaTHr (ORCPT ); Thu, 31 Dec 2015 14:07:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47005 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754265AbbLaTHm (ORCPT ); Thu, 31 Dec 2015 14:07:42 -0500 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (Postfix) with ESMTPS id 597FC1EB24; Thu, 31 Dec 2015 19:07:42 +0000 (UTC) Received: from redhat.com (vpn1-7-165.ams2.redhat.com [10.36.7.165]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with SMTP id tBVJ7ZHA029812; Thu, 31 Dec 2015 14:07:36 -0500 Date: Thu, 31 Dec 2015 21:07:35 +0200 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , Arnd Bergmann , linux-arch@vger.kernel.org, Andrew Cooper , virtualization@lists.linux-foundation.org, Stefano Stabellini , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , David Miller , linux-ia64@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-metag@vger.kernel.org, linux-mips@linux-mips.org, x86@kernel.org, user-mode-linux-devel@lists.sourceforge.net, adi-buildroot-devel@lists.sourceforge.net, linux-sh@vger.kernel.org, linux-xtensa@linux-xtensa.org, xen-devel@lists.xenproject.org Subject: [PATCH v2 14/32] asm-generic: add __smp_xxx wrappers Message-ID: <1451572003-2440-15-git-send-email-mst@redhat.com> References: <1451572003-2440-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1451572003-2440-1-git-send-email-mst@redhat.com> X-Mutt-Fcc: =sent X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Spam-Status: No, score=-6.9 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On !SMP, most architectures define their barriers as compiler barriers. On SMP, most need an actual barrier. Make it possible to remove the code duplication for !SMP by defining low-level __smp_xxx barriers which do not depend on the value of SMP, then use them from asm-generic conditionally. Besides reducing code duplication, these low level APIs will also be useful for virtualization, where a barrier is sometimes needed even if !SMP since we might be talking to another kernel on the same SMP system. Both virtio and Xen drivers will benefit. The smp_xxx variants should use __smp_XXX ones or barrier() depending on SMP, identically for all architectures. We keep ifndef guards around them for now - once/if all architectures are converted to use the generic code, we'll be able to remove these. Suggested-by: Peter Zijlstra Signed-off-by: Michael S. Tsirkin Acked-by: Arnd Bergmann --- include/asm-generic/barrier.h | 91 ++++++++++++++++++++++++++++++++++++++----- 1 file changed, 82 insertions(+), 9 deletions(-) diff --git a/include/asm-generic/barrier.h b/include/asm-generic/barrier.h index 987b2e0..8752964 100644 --- a/include/asm-generic/barrier.h +++ b/include/asm-generic/barrier.h @@ -54,22 +54,38 @@ #define read_barrier_depends() do { } while (0) #endif +#ifndef __smp_mb +#define __smp_mb() mb() +#endif + +#ifndef __smp_rmb +#define __smp_rmb() rmb() +#endif + +#ifndef __smp_wmb +#define __smp_wmb() wmb() +#endif + +#ifndef __smp_read_barrier_depends +#define __smp_read_barrier_depends() read_barrier_depends() +#endif + #ifdef CONFIG_SMP #ifndef smp_mb -#define smp_mb() mb() +#define smp_mb() __smp_mb() #endif #ifndef smp_rmb -#define smp_rmb() rmb() +#define smp_rmb() __smp_rmb() #endif #ifndef smp_wmb -#define smp_wmb() wmb() +#define smp_wmb() __smp_wmb() #endif #ifndef smp_read_barrier_depends -#define smp_read_barrier_depends() read_barrier_depends() +#define smp_read_barrier_depends() __smp_read_barrier_depends() #endif #else /* !CONFIG_SMP */ @@ -92,23 +108,78 @@ #endif /* CONFIG_SMP */ +#ifndef __smp_store_mb +#define __smp_store_mb(var, value) do { WRITE_ONCE(var, value); __smp_mb(); } while (0) +#endif + +#ifndef __smp_mb__before_atomic +#define __smp_mb__before_atomic() __smp_mb() +#endif + +#ifndef __smp_mb__after_atomic +#define __smp_mb__after_atomic() __smp_mb() +#endif + +#ifndef __smp_store_release +#define __smp_store_release(p, v) \ +do { \ + compiletime_assert_atomic_type(*p); \ + __smp_mb(); \ + WRITE_ONCE(*p, v); \ +} while (0) +#endif + +#ifndef __smp_load_acquire +#define __smp_load_acquire(p) \ +({ \ + typeof(*p) ___p1 = READ_ONCE(*p); \ + compiletime_assert_atomic_type(*p); \ + __smp_mb(); \ + ___p1; \ +}) +#endif + +#ifdef CONFIG_SMP + +#ifndef smp_store_mb +#define smp_store_mb(var, value) __smp_store_mb(var, value) +#endif + +#ifndef smp_mb__before_atomic +#define smp_mb__before_atomic() __smp_mb__before_atomic() +#endif + +#ifndef smp_mb__after_atomic +#define smp_mb__after_atomic() __smp_mb__after_atomic() +#endif + +#ifndef smp_store_release +#define smp_store_release(p, v) __smp_store_release(p, v) +#endif + +#ifndef smp_load_acquire +#define smp_load_acquire(p) __smp_load_acquire(p) +#endif + +#else /* !CONFIG_SMP */ + #ifndef smp_store_mb -#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); smp_mb(); } while (0) +#define smp_store_mb(var, value) do { WRITE_ONCE(var, value); barrier(); } while (0) #endif #ifndef smp_mb__before_atomic -#define smp_mb__before_atomic() smp_mb() +#define smp_mb__before_atomic() barrier() #endif #ifndef smp_mb__after_atomic -#define smp_mb__after_atomic() smp_mb() +#define smp_mb__after_atomic() barrier() #endif #ifndef smp_store_release #define smp_store_release(p, v) \ do { \ compiletime_assert_atomic_type(*p); \ - smp_mb(); \ + barrier(); \ WRITE_ONCE(*p, v); \ } while (0) #endif @@ -118,10 +189,12 @@ do { \ ({ \ typeof(*p) ___p1 = READ_ONCE(*p); \ compiletime_assert_atomic_type(*p); \ - smp_mb(); \ + barrier(); \ ___p1; \ }) #endif +#endif + #endif /* !__ASSEMBLY__ */ #endif /* __ASM_GENERIC_BARRIER_H */