From patchwork Mon Dec 11 09:44:11 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrea Parri X-Patchwork-Id: 176560 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:bcd1:0:b0:403:3b70:6f57 with SMTP id r17csp6930672vqy; Mon, 11 Dec 2023 01:44:39 -0800 (PST) X-Google-Smtp-Source: AGHT+IFNxiGdwwfgdC45p8qoap/y6d7NXjrVLOlBp7+b7uTfnzYffL26/HgNK0UGV9dHeKA1z5BX X-Received: by 2002:a05:6870:d18c:b0:1fb:2bec:9fb5 with SMTP id a12-20020a056870d18c00b001fb2bec9fb5mr5461271oac.0.1702287879246; Mon, 11 Dec 2023 01:44:39 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702287879; cv=none; d=google.com; s=arc-20160816; b=RJxng27/2fe5Iin8g9D4lhgwRzWmtzH8rpjyNOR4Rqm0TuaCvWsg0EChF1t4b+HXvh 33ZS2f7OoA9FceiNvL8NtS3ZwxFd4XwyHYXfwSn8RFoPTpTmn3LZDkcU7985qXgiBbiN prEjZ1ysYPatL3Y/w0NHKmMYc37vrvHPdsnCQUGLrVDJ59BLA/CMor1Uf1nzWBZ1k5OG 8OPB7blGAeTtdNUfEGxzm+TsO0zlPEzwD6NAX6okmvPD/yqcuHiBOvUsTUwcmZcj+dsC TNE9u2v351pAeeSdYoW1qFNjOhL+/fLN2y2yYc03bf2jeGUl5y7GBhyKqn+G2Ehs95m7 bKVg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=qp+2/AFV5zmaxe9luf0MNfHGuX9N1n8phVhdPWTto6c=; fh=6I8UF0n155JlUMKXPHZEdVXaDDfdWw9idVSmXg1+KEE=; b=BYOpiYOP5NXtGEmVqYOzSsGTTLluI+jw+1vI+as9WhlaozGUloVzFwCGHuOEVT6bIt c3KH00sitz5rEA+10A+anMveM/uY04QtsSLVpJ0iqgOMS2UfKlwSnmmc3h3jXQlPANn8 w3YGBACVuvKJ/laauJZlqaLylJUrE55KtW3IiaT/xRvtHKuBglD/jFaO/Hszuv8Ridk2 EsihsTIj8yspjD4M3xJi6bNLtxzeI1A92eET3Uzu7/L+jgbS8JyjIb5yG9zidxmQaUaP VlcdOZZPWdHJ+rzfmfmBL0Wriuw+fj1TehoZCvqolEXWQqeY37zSR7Ed8P9MuNiF7c+c woZw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=PqGsMHqr; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from lipwig.vger.email (lipwig.vger.email. [23.128.96.33]) by mx.google.com with ESMTPS id s15-20020a65690f000000b005c66a7d710esi5653957pgq.456.2023.12.11.01.44.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:44:39 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) client-ip=23.128.96.33; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=PqGsMHqr; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.33 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by lipwig.vger.email (Postfix) with ESMTP id 6072C8063020; Mon, 11 Dec 2023 01:44:35 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at lipwig.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234610AbjLKJo0 (ORCPT + 99 others); Mon, 11 Dec 2023 04:44:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51036 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234589AbjLKJoZ (ORCPT ); Mon, 11 Dec 2023 04:44:25 -0500 Received: from mail-ed1-x532.google.com (mail-ed1-x532.google.com [IPv6:2a00:1450:4864:20::532]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3D022CE for ; Mon, 11 Dec 2023 01:44:31 -0800 (PST) Received: by mail-ed1-x532.google.com with SMTP id 4fb4d7f45d1cf-54dccf89cfdso5385384a12.0 for ; Mon, 11 Dec 2023 01:44:31 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702287870; x=1702892670; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=qp+2/AFV5zmaxe9luf0MNfHGuX9N1n8phVhdPWTto6c=; b=PqGsMHqrjIbOG1jeGkSr5qWqzFYVWDDMX2+ZplyFD6V1BP1jeJixc6eJG8wanxalza CXiDQ3MfUJ9EAWTNColLMQPgdvHbWNX/O1K4KIG3EqHS91lfFYxvlAQuvkw3myANLlM3 +ojd0pcWPb0Uk2WrHFdEekbv3bg4U2xQxPaxpPruXY+zEcas+OP+r+YfKQSMt0484S6g IyP9i2L6jjQEo3HC0srDA2vZQWoyQ0Z1PB6cc2BE/KxbMXQKVsoRnx3vsfhCllXlJ7vn VXkirjB5gUuq0Fu1vE88MBFD0JntwDoDy69Aiks7/ee/a9zHigXa21jqUHeIbiRhqEQZ jwUw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702287870; x=1702892670; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=qp+2/AFV5zmaxe9luf0MNfHGuX9N1n8phVhdPWTto6c=; b=rs6GZM+xuL1pxP21uT3taGqAdf7mZe5SjYFEMVLnt5iZIiU66YTE2L1Pv4D7GA5BLX IYJmvn/Ll9JbI6+ztwbZ6aC5Atqfzeuo2zO8rWvsSWI4VcqHVs8MjlBMpUgd9j3FXPaE 4UQ/P/x/P2Wx7nk0D6D8mMJz7MBNFmAmstFdHlLJZ/G+WvqrKfCasQ1zCw0zzB1jfQIB YF7tXV99IOzry6ZMrNjIdp6JIvdnk/Ge/4alIcHwYYDXA7d/ZK+GBiMYjSue8YABDRoj CI/GoJT5KVrDXXr8ur5gxBaaYRkbjYGixdiQHjYH5w0zzgenJf1KI7rsfN/T+oHFmLG/ VC1A== X-Gm-Message-State: AOJu0YwHaAK39W8733Vi94mgztxBdIrXrV/xbu92N6butfOP3KHLtec2 rWUIuZHSenGLGTWg05RGsLY= X-Received: by 2002:a50:c908:0:b0:551:12f7:84e with SMTP id o8-20020a50c908000000b0055112f7084emr996214edh.28.1702287869354; Mon, 11 Dec 2023 01:44:29 -0800 (PST) Received: from andrea.wind3.hub ([31.189.124.152]) by smtp.gmail.com with ESMTPSA id if3-20020a0564025d8300b0054afcab0af2sm3463505edb.59.2023.12.11.01.44.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:44:28 -0800 (PST) From: Andrea Parri To: mathieu.desnoyers@efficios.com, paulmck@kernel.org, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu Cc: mmaas@google.com, hboehm@google.com, striker@us.ibm.com, charlie@rivosinc.com, rehn@rivosinc.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Andrea Parri Subject: [PATCH v2 1/4] membarrier: riscv: Add full memory barrier in switch_mm() Date: Mon, 11 Dec 2023 10:44:11 +0100 Message-Id: <20231211094414.8078-2-parri.andrea@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231211094414.8078-1-parri.andrea@gmail.com> References: <20231211094414.8078-1-parri.andrea@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lipwig.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (lipwig.vger.email [0.0.0.0]); Mon, 11 Dec 2023 01:44:35 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784978215664176642 X-GMAIL-MSGID: 1784978215664176642 The membarrier system call requires a full memory barrier after storing to rq->curr, before going back to user-space. The barrier is only needed when switching between processes: the barrier is implied by mmdrop() when switching from kernel to userspace, and it's not needed when switching from userspace to kernel. Rely on the feature/mechanism ARCH_HAS_MEMBARRIER_CALLBACKS and on the primitive membarrier_arch_switch_mm(), already adopted by the PowerPC architecture, to insert the required barrier. Fixes: fab957c11efe2f ("RISC-V: Atomic and Locking Code") Signed-off-by: Andrea Parri Reported-by: Mathieu Desnoyers Reviewed-by: Mathieu Desnoyers --- MAINTAINERS | 2 +- arch/riscv/Kconfig | 1 + arch/riscv/include/asm/membarrier.h | 29 +++++++++++++++++++++++++++++ arch/riscv/mm/context.c | 2 ++ kernel/sched/core.c | 5 +++-- 5 files changed, 36 insertions(+), 3 deletions(-) create mode 100644 arch/riscv/include/asm/membarrier.h diff --git a/MAINTAINERS b/MAINTAINERS index e2c6187a3ac80..a9166d82ffced 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13807,7 +13807,7 @@ M: Mathieu Desnoyers M: "Paul E. McKenney" L: linux-kernel@vger.kernel.org S: Supported -F: arch/powerpc/include/asm/membarrier.h +F: arch/*/include/asm/membarrier.h F: include/uapi/linux/membarrier.h F: kernel/sched/membarrier.c diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 95a2a06acc6a6..f7db95097caf1 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -27,6 +27,7 @@ config RISCV select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_GIGANTIC_PAGE select ARCH_HAS_KCOV + select ARCH_HAS_MEMBARRIER_CALLBACKS select ARCH_HAS_MMIOWB select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_PMEM_API diff --git a/arch/riscv/include/asm/membarrier.h b/arch/riscv/include/asm/membarrier.h new file mode 100644 index 0000000000000..4be218fa03b14 --- /dev/null +++ b/arch/riscv/include/asm/membarrier.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +#ifndef _ASM_RISCV_MEMBARRIER_H +#define _ASM_RISCV_MEMBARRIER_H + +static inline void membarrier_arch_switch_mm(struct mm_struct *prev, + struct mm_struct *next, + struct task_struct *tsk) +{ + /* + * Only need the full barrier when switching between processes. + * Barrier when switching from kernel to userspace is not + * required here, given that it is implied by mmdrop(). Barrier + * when switching from userspace to kernel is not needed after + * store to rq->curr. + */ + if (IS_ENABLED(CONFIG_SMP) && + likely(!(atomic_read(&next->membarrier_state) & + (MEMBARRIER_STATE_PRIVATE_EXPEDITED | + MEMBARRIER_STATE_GLOBAL_EXPEDITED)) || !prev)) + return; + + /* + * The membarrier system call requires a full memory barrier + * after storing to rq->curr, before going back to user-space. + */ + smp_mb(); +} + +#endif /* _ASM_RISCV_MEMBARRIER_H */ diff --git a/arch/riscv/mm/context.c b/arch/riscv/mm/context.c index 217fd4de61342..ba8eb3944687c 100644 --- a/arch/riscv/mm/context.c +++ b/arch/riscv/mm/context.c @@ -323,6 +323,8 @@ void switch_mm(struct mm_struct *prev, struct mm_struct *next, if (unlikely(prev == next)) return; + membarrier_arch_switch_mm(prev, next, task); + /* * Mark the current MM context as inactive, and the next as * active. This is at least used by the icache flushing diff --git a/kernel/sched/core.c b/kernel/sched/core.c index a708d225c28e8..711dc753f7216 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6670,8 +6670,9 @@ static void __sched notrace __schedule(unsigned int sched_mode) * * Here are the schemes providing that barrier on the * various architectures: - * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC. - * switch_mm() rely on membarrier_arch_switch_mm() on PowerPC. + * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC, + * RISC-V. switch_mm() relies on membarrier_arch_switch_mm() + * on PowerPC and on RISC-V. * - finish_lock_switch() for weakly-ordered * architectures where spin_unlock is a full barrier, * - switch_to() for arm64 (weakly-ordered, spin_unlock From patchwork Mon Dec 11 09:44:12 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrea Parri X-Patchwork-Id: 176561 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:bcd1:0:b0:403:3b70:6f57 with SMTP id r17csp6930781vqy; Mon, 11 Dec 2023 01:44:52 -0800 (PST) X-Google-Smtp-Source: AGHT+IFsYqjAQqakGPBWubBMNUB+BgGV7H664moQdc7fp1DqxxHaC9UGjiaehek9YA8SczcahCA+ X-Received: by 2002:a05:6a00:22d6:b0:6ce:5312:c413 with SMTP id f22-20020a056a0022d600b006ce5312c413mr1698975pfj.15.1702287892085; Mon, 11 Dec 2023 01:44:52 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702287892; cv=none; d=google.com; s=arc-20160816; b=ShsI30Zb1xUW6g/UaDOzFQfP08xQNsTERNEeW3Jg5HKMNMgE0t8KsziflDoxewrlTi P1Ms17tC2ffXvMVXbqUO6pmgnQr2AnSBAUc7slL94Ddp3dva8o45c2m90oKFvA5VOILv RFmLddj9KP1hZUkDXXLId2z4pEgP4BBZGERtfXXixmCM0pwO/ToaETmjHA6Qyd84N+kn SKjYzMehw+9xvzdJaH2IhDurwQyN+PHyq+UigHdVG8fWZ+6dRl/C3jbbDavMuJAgqwbu St96a0vd1sA8EryeD1B3Ld9GP5aJbEXW+2vTK88EE0nMDhSjimJtxOreZYIoM5NNwx4B iZUQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=mfT6yTigw0JL9rPQ3RLVTHss5/tTMRXlGfMsOm5hiBA=; fh=6I8UF0n155JlUMKXPHZEdVXaDDfdWw9idVSmXg1+KEE=; b=PIiLdGA191667sI5NJNDJUx+6VI5oKUuOR2mDIRB8w5GDkgJLiFBEx9DWDfEfW7F/Z d8ox/Z6cHwSKpbB0nbqJ9/9TL79QiWtZuxC+ndpju4CUEkuiD9OpoBp9KxFsJUQWH4OE 8tV9lI+ZO49gWtXV++KuZMCtpnFgYoIbwyTeINf0nHHAVGsguXs/Wv9tZbhc20oG0wN5 kkbVGy+630zV73WJYeN8n65j5h95m2SmaYVjkJR9CBHi02RIr9Y141Czur0pLaxEJDGE +BYSpB4tEIo8pNcYYKES3cJyBGBgBsJIMALA4KdNd2FlKKOkYJl1d5tUAj9pom9Ah6fn jiNg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=LxX+NeJm; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from groat.vger.email (groat.vger.email. [23.128.96.35]) by mx.google.com with ESMTPS id b5-20020a63eb45000000b005bd85b32495si6055497pgk.685.2023.12.11.01.44.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:44:52 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) client-ip=23.128.96.35; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=LxX+NeJm; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.35 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by groat.vger.email (Postfix) with ESMTP id 6537580752AD; Mon, 11 Dec 2023 01:44:49 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at groat.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234655AbjLKJob (ORCPT + 99 others); Mon, 11 Dec 2023 04:44:31 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234619AbjLKJo1 (ORCPT ); Mon, 11 Dec 2023 04:44:27 -0500 Received: from mail-ed1-x533.google.com (mail-ed1-x533.google.com [IPv6:2a00:1450:4864:20::533]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4EBC5CE for ; Mon, 11 Dec 2023 01:44:33 -0800 (PST) Received: by mail-ed1-x533.google.com with SMTP id 4fb4d7f45d1cf-54da61eb366so5658441a12.3 for ; Mon, 11 Dec 2023 01:44:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702287872; x=1702892672; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=mfT6yTigw0JL9rPQ3RLVTHss5/tTMRXlGfMsOm5hiBA=; b=LxX+NeJmku4hhfwrCuLd7Y4EmSUJY/rWF4dkOk0wtCBLRLkUdksgBUIQT/wywyFOiW Ikm6SeMjQX2C/WuocV9tTcrHLtlvFC+zCdsqHQVofwfmntMnxLXnjPhYlOsLJn7rQQ5J MQNXYs1+GQQ6yLePwB5ukueLn4vCbBJPjKTaMmZmRXRCQLLnYQfrIB9HQKxAvUouOAJx NERDYxemmIj9ObiiDjfRn4EluEb/Xlw5nAo5oB1ZkiOxzpriI0MZYTN+U7p0rn+pEhTj ogqsXa/+W2dnuzPl1qe6sM0nLLDS9xJo0Uxiv0TWK5Kn+AvHnk0Fnxx5gfL5vworcrCo emag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702287872; x=1702892672; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=mfT6yTigw0JL9rPQ3RLVTHss5/tTMRXlGfMsOm5hiBA=; b=BH3tTKaQQnnmfJaJcqyXsh3njcIqqBBimppTZ4C0Z2T1koobDg1TrWSg+HJz8ujjsI ICQ9KcSc37boEnV21wKj6cw6xnxF0mKc4w+tpy5dJMWG0gVGFaDEbon4O7lzcKli15Z7 oai255l0CeHC+lYsBO2DcnSP4cquKIkF8gBd3TX38OJqzL/yPnuTAxFnN1JCvZ1DY9cr 4LcxCp0hTyHqBQpdOa41AqwmWhkspklAujITN+yFFqlnxpeW9iJpV2WKCQZqkZlywuLm kIKh/i0z/WF4BMFlCGHVx0yHfrnF40oXq3JTX1NOF3iVnhUqs3hXAc5gvYzcokSOKcly 6jmA== X-Gm-Message-State: AOJu0YzilyW7ffo4LQUXiO/t1Xj1UfUhkvGYe1FK/MhoQVoFqgC6U15D A5kRX4bq69GiZkhzkhageoQ= X-Received: by 2002:a50:fb8b:0:b0:54c:4837:93f7 with SMTP id e11-20020a50fb8b000000b0054c483793f7mr2864378edq.62.1702287871520; Mon, 11 Dec 2023 01:44:31 -0800 (PST) Received: from andrea.wind3.hub ([31.189.124.152]) by smtp.gmail.com with ESMTPSA id if3-20020a0564025d8300b0054afcab0af2sm3463505edb.59.2023.12.11.01.44.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:44:31 -0800 (PST) From: Andrea Parri To: mathieu.desnoyers@efficios.com, paulmck@kernel.org, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu Cc: mmaas@google.com, hboehm@google.com, striker@us.ibm.com, charlie@rivosinc.com, rehn@rivosinc.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Andrea Parri Subject: [PATCH v2 2/4] locking: Introduce prepare_sync_core_cmd() Date: Mon, 11 Dec 2023 10:44:12 +0100 Message-Id: <20231211094414.8078-3-parri.andrea@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231211094414.8078-1-parri.andrea@gmail.com> References: <20231211094414.8078-1-parri.andrea@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on groat.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (groat.vger.email [0.0.0.0]); Mon, 11 Dec 2023 01:44:49 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784978228711425353 X-GMAIL-MSGID: 1784978228711425353 Introduce an architecture function that architectures can use to set up ("prepare") SYNC_CORE commands. The function will be used by RISC-V to update its "deferred icache- flush" data structures (icache_stale_mask). Architectures defining prepare_sync_core_cmd() static inline need to select ARCH_HAS_PREPARE_SYNC_CORE_CMD. Suggested-by: Mathieu Desnoyers Signed-off-by: Andrea Parri Reviewed-by: Mathieu Desnoyers --- include/linux/sync_core.h | 16 +++++++++++++++- init/Kconfig | 3 +++ kernel/sched/membarrier.c | 1 + 3 files changed, 19 insertions(+), 1 deletion(-) diff --git a/include/linux/sync_core.h b/include/linux/sync_core.h index 013da4b8b3272..67bb9794b8758 100644 --- a/include/linux/sync_core.h +++ b/include/linux/sync_core.h @@ -17,5 +17,19 @@ static inline void sync_core_before_usermode(void) } #endif -#endif /* _LINUX_SYNC_CORE_H */ +#ifdef CONFIG_ARCH_HAS_PREPARE_SYNC_CORE_CMD +#include +#else +/* + * This is a dummy prepare_sync_core_cmd() implementation that can be used on + * all architectures which provide unconditional core serializing instructions + * in switch_mm(). + * If your architecture doesn't provide such core serializing instructions in + * switch_mm(), you may need to write your own functions. + */ +static inline void prepare_sync_core_cmd(struct mm_struct *mm) +{ +} +#endif +#endif /* _LINUX_SYNC_CORE_H */ diff --git a/init/Kconfig b/init/Kconfig index 9ffb103fc927b..87daf50838f02 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1972,6 +1972,9 @@ source "kernel/Kconfig.locks" config ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE bool +config ARCH_HAS_PREPARE_SYNC_CORE_CMD + bool + config ARCH_HAS_SYNC_CORE_BEFORE_USERMODE bool diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index 2ad881d07752c..58f801e013988 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -320,6 +320,7 @@ static int membarrier_private_expedited(int flags, int cpu_id) MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY)) return -EPERM; ipi_func = ipi_sync_core; + prepare_sync_core_cmd(mm); } else if (flags == MEMBARRIER_FLAG_RSEQ) { if (!IS_ENABLED(CONFIG_RSEQ)) return -EINVAL; From patchwork Mon Dec 11 09:44:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrea Parri X-Patchwork-Id: 176562 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:bcd1:0:b0:403:3b70:6f57 with SMTP id r17csp6930788vqy; Mon, 11 Dec 2023 01:44:54 -0800 (PST) X-Google-Smtp-Source: AGHT+IHddyxOhYE7xJ6J3ijs8wvb0PAVNWgfk2y9ic/96z3FxdN6c///OnHf3/Q4iMTbavdahvny X-Received: by 2002:a05:6a20:3a87:b0:18f:97c:8a40 with SMTP id d7-20020a056a203a8700b0018f097c8a40mr4348748pzh.107.1702287893920; Mon, 11 Dec 2023 01:44:53 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702287893; cv=none; d=google.com; s=arc-20160816; b=s56VXJziPhOHCNrwjQ2kRNZUW3lxw+cZFB6vGT6wtK5UU9QxAHwsQnOFvqSzsnDaFI QX7XvKgjW7cyT4vXs7aCy12MN5kPBydSjBHw80dQmXgoJiNlvJi2kOAulUno6fW6bJtp EvvkVaJU/de1MHrGO3LEEZELR0FbeMCOM+rcD9oPJZURTeYrYvZCex4+4zvspGBOOfAU 9TveGOzTzSijkXTa/VMN5BnQjXwS7x+9jhTVLDvMOacHnAHn1WBTsa4pr0fa9nrlIz7m 9OC6iZOMID6c0xFk/KUjkk7T+I4WRx0OAxZUQWiB817syNjtf4PMwfHUk1Q0iC9PBEYR tmLQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=EGt5t/kAxS1mkU99JyGnFu1ODAbdCKJM932jBFyIPCw=; fh=6I8UF0n155JlUMKXPHZEdVXaDDfdWw9idVSmXg1+KEE=; b=y0NJJPAHI2fPU0+/Bf8K9/N7DRBCw3edGd5dOoI93yqB35CH4j8xlzvbztbm+Bpl3v OGRwnOM4LQnGKskpkWiU7vKBSvLZC6yUC3571SRlrD6Bc4PGzid9ibFQB2XIJjBxk8sm OG9E1tNqPyZG19jd7LiTKpd7kyH0N4TmKjtyA7E8olNjeXeFCQGtjApgC/zVPPTxaUud UC0292vw4nT+flCJcqtlIP/KRtNF2zU51Q9QQThvACFmq9+4cjUftz1ERylsWBFW9a3S oacQf/0d3TMsACLEzIujeoB+dT5cW/+6VGiO3/DdMFxXCHTrT+AQV1NwISyNzXtvvdyS SuQQ== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=TFQAoIA5; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from fry.vger.email (fry.vger.email. [23.128.96.38]) by mx.google.com with ESMTPS id h2-20020a056a00170200b006c33a1bdf92si5936915pfc.307.2023.12.11.01.44.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:44:53 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) client-ip=23.128.96.38; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=TFQAoIA5; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.38 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by fry.vger.email (Postfix) with ESMTP id AB1A0807862C; Mon, 11 Dec 2023 01:44:50 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at fry.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234678AbjLKJoe (ORCPT + 99 others); Mon, 11 Dec 2023 04:44:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51158 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234622AbjLKJoa (ORCPT ); Mon, 11 Dec 2023 04:44:30 -0500 Received: from mail-ed1-x52f.google.com (mail-ed1-x52f.google.com [IPv6:2a00:1450:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 23D70F2 for ; Mon, 11 Dec 2023 01:44:36 -0800 (PST) Received: by mail-ed1-x52f.google.com with SMTP id 4fb4d7f45d1cf-54c5d041c23so5943464a12.2 for ; Mon, 11 Dec 2023 01:44:36 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702287874; x=1702892674; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=EGt5t/kAxS1mkU99JyGnFu1ODAbdCKJM932jBFyIPCw=; b=TFQAoIA5kaXlornVednRGzuDG84+cOGWfuw0MsWFVyvlGOdncSA3NAwvI1J7bV14J4 zz6ZWceQMAez2sidmPK9q6fKXkEUTiI6af85EFfTHiQgheTIasIfsP+B+SIHACPuuttm 8pHy+03bL4NLd7kqk3d2C6CxLscOkESFaJHOHdPOyoZ1dXPUqhTmdNxwCh5xcpC1BP2J sxWZj5dKqxCMMWe620DBJxWTRvKtFSngB7PL1Sj1C3cvOn0ccE3xf+pVD2Y3YWgSeNim sf5mb9OjbKeSfSnF8OLwxbsRfyI8lI0UzvdyD47C1RBc+wqz3Lm84yvDtuUuoN7Pmyhy B7RQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702287874; x=1702892674; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=EGt5t/kAxS1mkU99JyGnFu1ODAbdCKJM932jBFyIPCw=; b=QWFLYXq4BKzyxcmnyH1tAwKGkuZjgAAPS73MucBfKcSKLozheC7YNMd/e0cuD4vHyz Zxcpsf7vfq9ysNK/5c4LIs0vVCmVCPHWYqeUbz7K1r0UCr1dB2yyMM/ktweAWFPch62i nRc8vunvlRKuiAax947FKm2apIRcDzQ+dRzMYhIwmofvQn17bfcT6Tgm1YthhsqRna+g bxGeUGVOB/nsWkhbRiBXCn5swiZN5Z5zmQXjbXbP6KShlNlJ8VUZ2sZXrGuuPDm9UPar 2VohB9QhIM4RzPmR/3YNGF5g4r6fao7fHceM6wkdDKFIWbecLNJDSczsmXaLXof9kb5H g9yw== X-Gm-Message-State: AOJu0Yxz6nx6Ub7nR5MUxKeklw9Qb7AqUJY8XiqwINCeg9sUQJLmeAp0 XbKDg9PWieViHqecaCUzjHY= X-Received: by 2002:a50:cd47:0:b0:54c:9cf0:fb67 with SMTP id d7-20020a50cd47000000b0054c9cf0fb67mr1257371edj.48.1702287874167; Mon, 11 Dec 2023 01:44:34 -0800 (PST) Received: from andrea.wind3.hub ([31.189.124.152]) by smtp.gmail.com with ESMTPSA id if3-20020a0564025d8300b0054afcab0af2sm3463505edb.59.2023.12.11.01.44.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:44:33 -0800 (PST) From: Andrea Parri To: mathieu.desnoyers@efficios.com, paulmck@kernel.org, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu Cc: mmaas@google.com, hboehm@google.com, striker@us.ibm.com, charlie@rivosinc.com, rehn@rivosinc.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Andrea Parri Subject: [PATCH v2 3/4] membarrier: riscv: Provide core serializing command Date: Mon, 11 Dec 2023 10:44:13 +0100 Message-Id: <20231211094414.8078-4-parri.andrea@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231211094414.8078-1-parri.andrea@gmail.com> References: <20231211094414.8078-1-parri.andrea@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on fry.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (fry.vger.email [0.0.0.0]); Mon, 11 Dec 2023 01:44:50 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784978230588336321 X-GMAIL-MSGID: 1784978230588336321 RISC-V uses xRET instructions on return from interrupt and to go back to user-space; the xRET instruction is not core serializing. Use FENCE.I for providing core serialization as follows: - by calling sync_core_before_usermode() on return from interrupt (cf. ipi_sync_core()), - via switch_mm() and sync_core_before_usermode() (respectively, for uthread->uthread and kthread->uthread transitions) to go back to user-space. On RISC-V, the serialization in switch_mm() is activated by resetting the icache_stale_mask of the mm at prepare_sync_core_cmd(). Suggested-by: Palmer Dabbelt Signed-off-by: Andrea Parri --- .../membarrier-sync-core/arch-support.txt | 18 +++++++++++- MAINTAINERS | 1 + arch/riscv/Kconfig | 3 ++ arch/riscv/include/asm/membarrier.h | 19 ++++++++++++ arch/riscv/include/asm/sync_core.h | 29 +++++++++++++++++++ 5 files changed, 69 insertions(+), 1 deletion(-) create mode 100644 arch/riscv/include/asm/sync_core.h diff --git a/Documentation/features/sched/membarrier-sync-core/arch-support.txt b/Documentation/features/sched/membarrier-sync-core/arch-support.txt index d96b778b87ed8..a163170fc0f48 100644 --- a/Documentation/features/sched/membarrier-sync-core/arch-support.txt +++ b/Documentation/features/sched/membarrier-sync-core/arch-support.txt @@ -10,6 +10,22 @@ # Rely on implicit context synchronization as a result of exception return # when returning from IPI handler, and when returning to user-space. # +# * riscv +# +# riscv uses xRET as return from interrupt and to return to user-space. +# +# Given that xRET is not core serializing, we rely on FENCE.I for providing +# core serialization: +# +# - by calling sync_core_before_usermode() on return from interrupt (cf. +# ipi_sync_core()), +# +# - via switch_mm() and sync_core_before_usermode() (respectively, for +# uthread->uthread and kthread->uthread transitions) to go back to +# user-space. +# +# The serialization in switch_mm() is activated by prepare_sync_core_cmd(). +# # * x86 # # x86-32 uses IRET as return from interrupt, which takes care of the IPI. @@ -43,7 +59,7 @@ | openrisc: | TODO | | parisc: | TODO | | powerpc: | ok | - | riscv: | TODO | + | riscv: | ok | | s390: | ok | | sh: | TODO | | sparc: | TODO | diff --git a/MAINTAINERS b/MAINTAINERS index a9166d82ffced..f6f1fdc76cf46 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13808,6 +13808,7 @@ M: "Paul E. McKenney" L: linux-kernel@vger.kernel.org S: Supported F: arch/*/include/asm/membarrier.h +F: arch/*/include/asm/sync_core.h F: include/uapi/linux/membarrier.h F: kernel/sched/membarrier.c diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index f7db95097caf1..db7b1acd943e4 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -28,14 +28,17 @@ config RISCV select ARCH_HAS_GIGANTIC_PAGE select ARCH_HAS_KCOV select ARCH_HAS_MEMBARRIER_CALLBACKS + select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_MMIOWB select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_PMEM_API + select ARCH_HAS_PREPARE_SYNC_CORE_CMD select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_SET_DIRECT_MAP if MMU select ARCH_HAS_SET_MEMORY if MMU select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL select ARCH_HAS_STRICT_MODULE_RWX if MMU && !XIP_KERNEL + select ARCH_HAS_SYNC_CORE_BEFORE_USERMODE select ARCH_HAS_SYSCALL_WRAPPER select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAS_UBSAN_SANITIZE_ALL diff --git a/arch/riscv/include/asm/membarrier.h b/arch/riscv/include/asm/membarrier.h index 4be218fa03b14..a1071039c20ed 100644 --- a/arch/riscv/include/asm/membarrier.h +++ b/arch/riscv/include/asm/membarrier.h @@ -22,6 +22,25 @@ static inline void membarrier_arch_switch_mm(struct mm_struct *prev, /* * The membarrier system call requires a full memory barrier * after storing to rq->curr, before going back to user-space. + * + * The barrier is also needed for the SYNC_CORE command when + * switching between processes; in particular, on a transition + * from a thread belonging to another mm to a thread belonging + * to the mm for which a membarrier SYNC_CORE is done on CPU0: + * + * - [CPU0] sets all bits in the mm icache_stale_mask. + * + * - [CPU1] store to rq->curr (by the scheduler). + * + * - [CPU0] loads rq->curr within membarrier and observes + * cpu_rq(1)->curr->mm != mm, so the IPI is skipped on + * CPU1; this means membarrier relies on switch_mm() to + * issue the sync-core. + * + * - [CPU1] switch_mm() loads icache_stale_mask; if the bit + * is zero, switch_mm() may incorrectly skip the sync-core. + * + * Matches the full barrier in membarrier_private_expedited(). */ smp_mb(); } diff --git a/arch/riscv/include/asm/sync_core.h b/arch/riscv/include/asm/sync_core.h new file mode 100644 index 0000000000000..9153016da8f14 --- /dev/null +++ b/arch/riscv/include/asm/sync_core.h @@ -0,0 +1,29 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_RISCV_SYNC_CORE_H +#define _ASM_RISCV_SYNC_CORE_H + +/* + * RISC-V implements return to user-space through an xRET instruction, + * which is not core serializing. + */ +static inline void sync_core_before_usermode(void) +{ + asm volatile ("fence.i" ::: "memory"); +} + +#ifdef CONFIG_SMP +/* + * Ensure the next switch_mm() on every CPU issues a core serializing + * instruction for the given @mm. + */ +static inline void prepare_sync_core_cmd(struct mm_struct *mm) +{ + cpumask_setall(&mm->context.icache_stale_mask); +} +#else +static inline void prepare_sync_core_cmd(struct mm_struct *mm) +{ +} +#endif /* CONFIG_SMP */ + +#endif /* _ASM_RISCV_SYNC_CORE_H */ From patchwork Mon Dec 11 09:44:14 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrea Parri X-Patchwork-Id: 176563 Return-Path: Delivered-To: ouuuleilei@gmail.com Received: by 2002:a59:bcd1:0:b0:403:3b70:6f57 with SMTP id r17csp6930854vqy; Mon, 11 Dec 2023 01:45:04 -0800 (PST) X-Google-Smtp-Source: AGHT+IHbkfWeh0uJd2K48fG88ZWQ/vfifXlKpAuqx6gUZTYoyJ304jpJDMzPBo28SSffiDxexI31 X-Received: by 2002:a17:902:b7c3:b0:1d0:6ffe:a0e with SMTP id v3-20020a170902b7c300b001d06ffe0a0emr3928184plz.108.1702287903794; Mon, 11 Dec 2023 01:45:03 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1702287903; cv=none; d=google.com; s=arc-20160816; b=O1+dZ6SYiUF0MJu2GWpzoH2EilXAzidmjuZqv37Iuvy25k4qSWl9lB4W1Z+5EgIpnS WW8JNl29iWVK3TYT/HvEaaquc30Jr37q0/CZIjuWIv4KMotuGIpDuBfZgu6+HO3pNAYv ECJ+fZWr2M6FW5VfcxRK0AIZI0nDjSD07pzT2oGL8IuY+U1jo8H8CzFatGxO1jbNqouE ugn263BvKtUANmadoSPfjpaLgzD8WakyQn534nrgQk76S7wd2Fd4e9NnBlEq2smqNFQ1 cyFbgnni03frC6WH9de+6jaLJb+nJnHHN2D3/5sSed1ta9tu1LAYcoRqbF5qmC8SCW3w iuqg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=JrL6R0s9TI3vntjjPRtwaASPjZe5TnGAbwALAE/nUuU=; fh=6I8UF0n155JlUMKXPHZEdVXaDDfdWw9idVSmXg1+KEE=; b=jeGS3AGbZpHYMJR9P7WTWFQZiyig626LsoRIOaeb2K0UoGcjpTE/u47CHaL0QYx9Yn bE0NzELzCL28Z4ip1oC7JgHscjy5xap06/sCD11j1WSVMR1Ueo/cb6kU9Imv89zD576h 3m48Rrc/Jpj2BpCH+cPHaS1U7+RZbbKozNFZiMUIUMrvEjX5IAo7KBv6H5Y4kDo93uUQ 1zhO3zDnwsGmDVDOdA1Rubh9sr8tMUaoNcv0E0NMcDTsHP7qjN8BT3Msdd1PbZsVJDP0 tICPVcAhBRJ1V/XhCHQ/XtkXgy//ZQ29xv93oMe/iCHKAjR8HKJMlI8HBpWHgUiy7cVb JTEw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=jZGpXf6Y; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from howler.vger.email (howler.vger.email. [2620:137:e000::3:4]) by mx.google.com with ESMTPS id j12-20020a170903024c00b001d096757addsi5881819plh.0.2023.12.11.01.45.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:45:03 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) client-ip=2620:137:e000::3:4; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20230601 header.b=jZGpXf6Y; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:4 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=QUARANTINE dis=NONE) header.from=gmail.com Received: from out1.vger.email (depot.vger.email [IPv6:2620:137:e000::3:0]) by howler.vger.email (Postfix) with ESMTP id 694AB809B477; Mon, 11 Dec 2023 01:44:55 -0800 (PST) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.103.11 at howler.vger.email Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234622AbjLKJoq (ORCPT + 99 others); Mon, 11 Dec 2023 04:44:46 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51152 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234679AbjLKJol (ORCPT ); Mon, 11 Dec 2023 04:44:41 -0500 Received: from mail-ed1-x529.google.com (mail-ed1-x529.google.com [IPv6:2a00:1450:4864:20::529]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA1A211F for ; Mon, 11 Dec 2023 01:44:40 -0800 (PST) Received: by mail-ed1-x529.google.com with SMTP id 4fb4d7f45d1cf-54dccf89cfdso5385740a12.0 for ; Mon, 11 Dec 2023 01:44:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1702287879; x=1702892679; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=JrL6R0s9TI3vntjjPRtwaASPjZe5TnGAbwALAE/nUuU=; b=jZGpXf6Yf9lg/3vMgnX8sxCNCEbznYYAn6j5HXXw83XVo4GTHyPS5ZfBQ20/UG8jTl GqKIUfPxNNiEkAddA7XkNsnts1+h04G34o2h/ZT4hUSJs4SrVfzsWh9EkqW56ymMu96q 9aInNCR6V2TSTrsyx/nAsXyVHkTkz68GyOWy7rnvT+M9bYBDOtxS1wJ9Q5LrflXB+AH7 zZXzdg2WJ0ZJ+t3lmc9X4svURQTu3MRGk0wSHp0raJZlSZCIIHOJglKDEnK4JJJOLqVg v30r2rve2reZXi7+kUcrURYGdeewEalpEdP3zlqvT2v5lD9O3+Zvbq7f9VN69YQ+uiMw OuaQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1702287879; x=1702892679; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=JrL6R0s9TI3vntjjPRtwaASPjZe5TnGAbwALAE/nUuU=; b=RyYPcGWmzsb3FkCQfApR2g7WGcDCuLp3IM+fDRQKobKz6TW/IQIcdwW+LUu2lfnH5A rrMFArwDpV6htFIq7tspBJlipVTa1WlmUQobW/NUX8I4ZjERg9YOzPVN1apw/2n/Npht /4vEQoxxEMDbcE8WHEJPH8EFo/SDGYO4hIfXxEmF3Py34Uxb10I1GgHJG8+PwtJ2cU+V PQdHeMgwb0cotA3igN91JN0SJKzZw3Ep4ZP4RxD9trnvUTXrTngYEnp0SOUVjCjU38Om 24/XdaNIXiN5myJHvObxlwvxWnw7tDuFVwnNzEMLKNu9ZK8UN/+4J+VoE/WhHKSNh0+z Z6iQ== X-Gm-Message-State: AOJu0YwjWog0WZuVSLrwPZjuaUJ8ivdXCbHPBQ81+ZG12djUzZ0WEIWd BzJBtZwJBGzfTqItpAf0tEM= X-Received: by 2002:a50:8dc7:0:b0:54c:4837:9a8d with SMTP id s7-20020a508dc7000000b0054c48379a8dmr2213085edh.52.1702287878685; Mon, 11 Dec 2023 01:44:38 -0800 (PST) Received: from andrea.wind3.hub ([31.189.124.152]) by smtp.gmail.com with ESMTPSA id if3-20020a0564025d8300b0054afcab0af2sm3463505edb.59.2023.12.11.01.44.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 11 Dec 2023 01:44:38 -0800 (PST) From: Andrea Parri To: mathieu.desnoyers@efficios.com, paulmck@kernel.org, palmer@dabbelt.com, paul.walmsley@sifive.com, aou@eecs.berkeley.edu Cc: mmaas@google.com, hboehm@google.com, striker@us.ibm.com, charlie@rivosinc.com, rehn@rivosinc.com, linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, Andrea Parri Subject: [RFC PATCH 4/4] membarrier: Introduce Kconfig ARCH_HAS_MEMBARRIER Date: Mon, 11 Dec 2023 10:44:14 +0100 Message-Id: <20231211094414.8078-5-parri.andrea@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20231211094414.8078-1-parri.andrea@gmail.com> References: <20231211094414.8078-1-parri.andrea@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-0.6 required=5.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,T_SCC_BODY_TEXT_LINE autolearn=unavailable autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on howler.vger.email Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-Greylist: Sender passed SPF test, not delayed by milter-greylist-4.6.4 (howler.vger.email [0.0.0.0]); Mon, 11 Dec 2023 01:44:55 -0800 (PST) X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: 1784978241038528580 X-GMAIL-MSGID: 1784978241038528580 Architectures supporting the "private expedited" membarrier command must select the Kconfig to use the command. Document status and requirements for each architecture in a single file under Documentation/features. Suggested-by: Mathieu Desnoyers Signed-off-by: Andrea Parri --- The TODOs in the arch-support table below should really be interpreted as "I'm not sure/haven't checked" (the respective arch maintainers will be able to verify and amend such information). Based on the following inline comment in __schedule(): /* * The membarrier system call requires each architecture * to have a full memory barrier after updating * rq->curr, before returning to user-space. * * Here are the schemes providing that barrier on the * various architectures: * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC, * RISC-V. switch_mm() relies on membarrier_arch_switch_mm() * on PowerPC and on RISC-V. * - finish_lock_switch() for weakly-ordered * architectures where spin_unlock is a full barrier, * - switch_to() for arm64 (weakly-ordered, spin_unlock * is a RELEASE barrier), */ .../sched/membarrier/arch-support.txt | 50 +++++++++++++++++++ MAINTAINERS | 1 + arch/alpha/Kconfig | 1 + arch/arc/Kconfig | 1 + arch/arm/Kconfig | 1 + arch/arm64/Kconfig | 1 + arch/hexagon/Kconfig | 1 + arch/mips/Kconfig | 1 + arch/powerpc/Kconfig | 1 + arch/riscv/Kconfig | 1 + arch/s390/Kconfig | 1 + arch/sparc/Kconfig | 1 + arch/x86/Kconfig | 1 + init/Kconfig | 3 ++ kernel/sched/core.c | 4 +- kernel/sched/membarrier.c | 15 +++++- 16 files changed, 80 insertions(+), 4 deletions(-) create mode 100644 Documentation/features/sched/membarrier/arch-support.txt diff --git a/Documentation/features/sched/membarrier/arch-support.txt b/Documentation/features/sched/membarrier/arch-support.txt new file mode 100644 index 0000000000000..95e65195e47c2 --- /dev/null +++ b/Documentation/features/sched/membarrier/arch-support.txt @@ -0,0 +1,50 @@ +# +# Feature name: membarrier +# Kconfig: ARCH_HAS_MEMBARRIER +# description: arch supports MEMBARRIER_CMD_PRIVATE_EXPEDITED +# +# Architecture requirements +# +# The membarrier() system call requires each architecture to have a full memory +# barrier after updating rq->curr, before returning to user-space. +# +# Here are the schemes providing that barrier on the various architectures: +# +# * alpha/arc/arm/hexagon/mips +# +# We rely on the full barrier implied by spin_unlock() in finish_lock_switch(). +# +# * arm64 +# +# We rely on the full barrier implied by switch_to(). +# +# * powerpc/riscv/s390/sparc/x86 +# +# We rely on the full barrier implied by switch_mm(), if mm isn't NULL; we rely +# on the full barrier implied by mmdrop(), otherwise. +# + ----------------------- + | arch |status| + ----------------------- + | alpha: | ok | + | arc: | ok | + | arm: | ok | + | arm64: | ok | + | csky: | TODO | + | hexagon: | ok | + | loongarch: | TODO | + | m68k: | TODO | + | microblaze: | TODO | + | mips: | ok | + | nios2: | TODO | + | openrisc: | TODO | + | parisc: | TODO | + | powerpc: | ok | + | riscv: | ok | + | s390: | ok | + | sh: | TODO | + | sparc: | ok | + | um: | TODO | + | x86: | ok | + | xtensa: | TODO | + ----------------------- diff --git a/MAINTAINERS b/MAINTAINERS index f6f1fdc76cf46..c5a053605cbc4 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -13807,6 +13807,7 @@ M: Mathieu Desnoyers M: "Paul E. McKenney" L: linux-kernel@vger.kernel.org S: Supported +F: Documentation/features/sched/membarrier*/ F: arch/*/include/asm/membarrier.h F: arch/*/include/asm/sync_core.h F: include/uapi/linux/membarrier.h diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig index d6968d090d49a..f98d6cba0bd9a 100644 --- a/arch/alpha/Kconfig +++ b/arch/alpha/Kconfig @@ -24,6 +24,7 @@ config ALPHA select GENERIC_IRQ_SHOW select ARCH_WANT_IPC_PARSE_VERSION select ARCH_HAVE_NMI_SAFE_CMPXCHG + select ARCH_HAS_MEMBARRIER select AUDIT_ARCH select GENERIC_CPU_VULNERABILITIES select GENERIC_SMP_IDLE_THREAD diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 3162db540ee96..1d8a6ba98ae33 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -9,6 +9,7 @@ config ARC select ARCH_HAS_CACHE_LINE_SIZE select ARCH_HAS_DEBUG_VM_PGTABLE select ARCH_HAS_DMA_PREP_COHERENT + select ARCH_HAS_MEMBARRIER select ARCH_HAS_PTE_SPECIAL select ARCH_HAS_SETUP_DMA_OPS select ARCH_HAS_SYNC_DMA_FOR_CPU diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index f8567e95f98be..700d1d9ff2f8b 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -14,6 +14,7 @@ config ARM select ARCH_HAS_FORTIFY_SOURCE select ARCH_HAS_KEEPINITRD select ARCH_HAS_KCOV + select ARCH_HAS_MEMBARRIER select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE select ARCH_HAS_PTE_SPECIAL if ARM_LPAE diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 7b071a00425d2..d21788e6920f6 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -31,6 +31,7 @@ config ARM64 select ARCH_HAS_GIGANTIC_PAGE select ARCH_HAS_KCOV select ARCH_HAS_KEEPINITRD + select ARCH_HAS_MEMBARRIER select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig index a880ee067d2ec..c2b2713c01bbd 100644 --- a/arch/hexagon/Kconfig +++ b/arch/hexagon/Kconfig @@ -5,6 +5,7 @@ comment "Linux Kernel Configuration for Hexagon" config HEXAGON def_bool y select ARCH_32BIT_OFF_T + select ARCH_HAS_MEMBARRIER select ARCH_HAS_SYNC_DMA_FOR_DEVICE select ARCH_NO_PREEMPT select DMA_GLOBAL_POOL diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 797ae590ebdba..4b65e73e34c16 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -16,6 +16,7 @@ config MIPS select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST select ARCH_HAS_UBSAN_SANITIZE_ALL select ARCH_HAS_GCOV_PROFILE_ALL + select ARCH_HAS_MEMBARRIER select ARCH_KEEP_MEMBLOCK select ARCH_USE_BUILTIN_BSWAP select ARCH_USE_CMPXCHG_LOCKREF if 64BIT diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 6f105ee4f3cf5..c13980eac3585 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -137,6 +137,7 @@ config PPC select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_HUGEPD if HUGETLB_PAGE select ARCH_HAS_KCOV + select ARCH_HAS_MEMBARRIER select ARCH_HAS_MEMBARRIER_CALLBACKS select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_MEMREMAP_COMPAT_ALIGN if PPC_64S_HASH_MMU diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index db7b1acd943e4..fd4c6a74ebd61 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -27,6 +27,7 @@ config RISCV select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_GIGANTIC_PAGE select ARCH_HAS_KCOV + select ARCH_HAS_MEMBARRIER select ARCH_HAS_MEMBARRIER_CALLBACKS select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_MMIOWB diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig index 3bec98d20283b..2e044d424fd4a 100644 --- a/arch/s390/Kconfig +++ b/arch/s390/Kconfig @@ -72,6 +72,7 @@ config S390 select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_GIGANTIC_PAGE select ARCH_HAS_KCOV + select ARCH_HAS_MEMBARRIER select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_MEM_ENCRYPT select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig index 49849790e66dc..40eb179c2416a 100644 --- a/arch/sparc/Kconfig +++ b/arch/sparc/Kconfig @@ -30,6 +30,7 @@ config SPARC select RTC_SYSTOHC select HAVE_ARCH_JUMP_LABEL if SPARC64 select GENERIC_IRQ_SHOW + select ARCH_HAS_MEMBARRIER select ARCH_WANT_IPC_PARSE_VERSION select GENERIC_PCI_IOMAP select HAS_IOPORT diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 3762f41bb0929..83f63e00312ee 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -82,6 +82,7 @@ config X86 select ARCH_HAS_GCOV_PROFILE_ALL select ARCH_HAS_KCOV if X86_64 select ARCH_HAS_MEM_ENCRYPT + select ARCH_HAS_MEMBARRIER select ARCH_HAS_MEMBARRIER_SYNC_CORE select ARCH_HAS_NMI_SAFE_THIS_CPU_OPS select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE diff --git a/init/Kconfig b/init/Kconfig index 87daf50838f02..8114404b52b91 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1742,6 +1742,9 @@ config KALLSYMS_BASE_RELATIVE # syscall, maps, verifier +config ARCH_HAS_MEMBARRIER + bool + config ARCH_HAS_MEMBARRIER_CALLBACKS bool diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 711dc753f7216..dff1c6df337f9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6673,8 +6673,8 @@ static void __sched notrace __schedule(unsigned int sched_mode) * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC, * RISC-V. switch_mm() relies on membarrier_arch_switch_mm() * on PowerPC and on RISC-V. - * - finish_lock_switch() for weakly-ordered - * architectures where spin_unlock is a full barrier, + * - finish_lock_switch() for alpha, arc, arm, hexagon, mips + * where spin_unlock is a full barrier, * - switch_to() for arm64 (weakly-ordered, spin_unlock * is a RELEASE barrier), */ diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index 58f801e013988..248a38c9b261c 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -137,6 +137,14 @@ * Bitmask made from a "or" of all commands within enum membarrier_cmd, * except MEMBARRIER_CMD_QUERY. */ +#ifdef CONFIG_ARCH_HAS_MEMBARRIER +#define MEMBARRIER_PRIVATE_EXPEDITED_BITMASK \ + (MEMBARRIER_CMD_PRIVATE_EXPEDITED \ + | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED) +#else +#define MEMBARRIER_PRIVATE_EXPEDITED_BITMASK 0 +#endif + #ifdef CONFIG_ARCH_HAS_MEMBARRIER_SYNC_CORE #define MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK \ (MEMBARRIER_CMD_PRIVATE_EXPEDITED_SYNC_CORE \ @@ -156,8 +164,7 @@ #define MEMBARRIER_CMD_BITMASK \ (MEMBARRIER_CMD_GLOBAL | MEMBARRIER_CMD_GLOBAL_EXPEDITED \ | MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED \ - | MEMBARRIER_CMD_PRIVATE_EXPEDITED \ - | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED \ + | MEMBARRIER_PRIVATE_EXPEDITED_BITMASK \ | MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK \ | MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK \ | MEMBARRIER_CMD_GET_REGISTRATIONS) @@ -329,6 +336,8 @@ static int membarrier_private_expedited(int flags, int cpu_id) return -EPERM; ipi_func = ipi_rseq; } else { + if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER)) + return -EINVAL; WARN_ON_ONCE(flags); if (!(atomic_read(&mm->membarrier_state) & MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY)) @@ -519,6 +528,8 @@ static int membarrier_register_private_expedited(int flags) ready_state = MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ_READY; } else { + if (!IS_ENABLED(CONFIG_ARCH_HAS_MEMBARRIER)) + return -EINVAL; WARN_ON_ONCE(flags); }