From patchwork Wed Dec 7 16:43:37 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Michal Clapinski X-Patchwork-Id: 631778 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7521FC47089 for ; Wed, 7 Dec 2022 16:44:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229988AbiLGQn7 (ORCPT ); Wed, 7 Dec 2022 11:43:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229989AbiLGQn5 (ORCPT ); Wed, 7 Dec 2022 11:43:57 -0500 Received: from mail-lj1-x24a.google.com (mail-lj1-x24a.google.com [IPv6:2a00:1450:4864:20::24a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 418D35E9D2 for ; Wed, 7 Dec 2022 08:43:56 -0800 (PST) Received: by mail-lj1-x24a.google.com with SMTP id r26-20020a2e80da000000b00279e2a0f0e1so4553574ljg.11 for ; Wed, 07 Dec 2022 08:43:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=R3UNgITk2mCHM+aO+s0l1dU1wLZipt6ouG5VCup5ogI=; b=Jz0dxAj0ez7bZFI3NVyATAAqCsijUj/bzAPgNXTFygZTZgQ7y23Uu5QmZcfivd00bR FmMEyREyeUPS7o3HvpZZNDrw54Yx1zKt/muSqK8Sr9e8cZTsd7f6bZQfVAaC02fU0qiA 0qw7J4effoSo8816N1fDYWHLcMSFieumfGy3ZND2thOacnib8n+YHGL1sjtx6EpfGfEr QTcIeXFfHOcBZHwtWestLk7LrC1y/fORCxalyHJDqBzrldLw6w/iMyiFCikm4kqhtT9I rOWvSSGCgPzneb18q9SmmAWALdrGRojrscCR+hddi8noVtF232wCoXfsvNc3KvOrCHDd b6og== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=R3UNgITk2mCHM+aO+s0l1dU1wLZipt6ouG5VCup5ogI=; b=054ztEUIwKTdZ9QwnPzTzvOWXq4NhCGI4QLsnUnX0EBzUbtzWTMQIJigZzaXfXmxDE 8abdhN4We69vXAnHWNdZcb/+PsU4d6CBhBvHua5GQEQfdWDrr9vQHU5ul2LbcPC6zf/+ 3Qe0cJlCs+AdJ4Vmab+1v80JolXNP954ADaZKFowl1h2qF6bcwdQlOEDYTNduwq92VJ9 cTiLS0JkpUcw9DUVasfQ93OKypCKAbKJYPfTYJQPWdLvlaZ6Znq6f7cGQI9ZWNo1B7bk E+j4XSCH//H+v78AwKsRRQ7VV938fh28s5Wbi8ZkVDmToQ1ytbHgQ9ZdmFRfPzTaN7v1 P2IA== X-Gm-Message-State: ANoB5pn5wm8v1tix2q9svgN47+TKZg4by5fdNfRxS/bHHEDhIMDSccGv SDosyVMlv0dAr3rR7S+Cf4Vd/FlowdnbkAkY X-Google-Smtp-Source: AA0mqf6hwzNXlz8mWqisoOstIk8lU431OMAtI0FDtAlpn3oNcMNpSObbMyM4FovQgMHkq/Xk99Z3UP2pVjMWxsbu X-Received: from mclapinski.waw.corp.google.com ([2a00:79e0:9b:0:3d6d:f78e:bc73:df]) (user=mclapinski job=sendgmr) by 2002:a05:651c:12ca:b0:277:a9d:9355 with SMTP id 10-20020a05651c12ca00b002770a9d9355mr21109826lje.102.1670431434519; Wed, 07 Dec 2022 08:43:54 -0800 (PST) Date: Wed, 7 Dec 2022 17:43:37 +0100 In-Reply-To: <20221207164338.1535591-1-mclapinski@google.com> Mime-Version: 1.0 References: <20221207164338.1535591-1-mclapinski@google.com> X-Mailer: git-send-email 2.39.0.rc0.267.gcb52ba06e7-goog Message-ID: <20221207164338.1535591-2-mclapinski@google.com> Subject: [PATCH 1/2] sched/membarrier: Introduce MEMBARRIER_CMD_GET_REGISTRATIONS From: Michal Clapinski To: Mathieu Desnoyers , "Paul E. McKenney" Cc: Ingo Molnar , Peter Zijlstra , Andrei Vagin , Shuah Khan , linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Michal Clapinski Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Provide a method to query previously issued registrations. Signed-off-by: Michal Clapinski --- include/uapi/linux/membarrier.h | 4 ++++ kernel/sched/membarrier.c | 39 ++++++++++++++++++++++++++++++++- 2 files changed, 42 insertions(+), 1 deletion(-) diff --git a/include/uapi/linux/membarrier.h b/include/uapi/linux/membarrier.h index 737605897f36..5f3ad6d5be6f 100644 --- a/include/uapi/linux/membarrier.h +++ b/include/uapi/linux/membarrier.h @@ -137,6 +137,9 @@ * @MEMBARRIER_CMD_SHARED: * Alias to MEMBARRIER_CMD_GLOBAL. Provided for * header backward compatibility. + * @MEMBARRIER_CMD_GET_REGISTRATIONS: + * Returns a bitmask of previously issued + * registration commands. * * Command to be passed to the membarrier system call. The commands need to * be a single bit each, except for MEMBARRIER_CMD_QUERY which is assigned to @@ -153,6 +156,7 @@ enum membarrier_cmd { MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE = (1 << 6), MEMBARRIER_CMD_PRIVATE_EXPEDITED_RSEQ = (1 << 7), MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ = (1 << 8), + MEMBARRIER_CMD_GET_REGISTRATIONS = (1 << 9), /* Alias for header backward compatibility. */ MEMBARRIER_CMD_SHARED = MEMBARRIER_CMD_GLOBAL, diff --git a/kernel/sched/membarrier.c b/kernel/sched/membarrier.c index 0c5be7ebb1dc..2ad881d07752 100644 --- a/kernel/sched/membarrier.c +++ b/kernel/sched/membarrier.c @@ -159,7 +159,8 @@ | MEMBARRIER_CMD_PRIVATE_EXPEDITED \ | MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED \ | MEMBARRIER_PRIVATE_EXPEDITED_SYNC_CORE_BITMASK \ - | MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK) + | MEMBARRIER_PRIVATE_EXPEDITED_RSEQ_BITMASK \ + | MEMBARRIER_CMD_GET_REGISTRATIONS) static void ipi_mb(void *info) { @@ -540,6 +541,40 @@ static int membarrier_register_private_expedited(int flags) return 0; } +static int membarrier_get_registrations(void) +{ + struct task_struct *p = current; + struct mm_struct *mm = p->mm; + int registrations_mask = 0, membarrier_state, i; + static const int states[] = { + MEMBARRIER_STATE_GLOBAL_EXPEDITED | + MEMBARRIER_STATE_GLOBAL_EXPEDITED_READY, + MEMBARRIER_STATE_PRIVATE_EXPEDITED | + MEMBARRIER_STATE_PRIVATE_EXPEDITED_READY, + MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE | + MEMBARRIER_STATE_PRIVATE_EXPEDITED_SYNC_CORE_READY, + MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ | + MEMBARRIER_STATE_PRIVATE_EXPEDITED_RSEQ_READY + }; + static const int registration_cmds[] = { + MEMBARRIER_CMD_REGISTER_GLOBAL_EXPEDITED, + MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED, + MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_SYNC_CORE, + MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ + }; + BUILD_BUG_ON(ARRAY_SIZE(states) != ARRAY_SIZE(registration_cmds)); + + membarrier_state = atomic_read(&mm->membarrier_state); + for (i = 0; i < ARRAY_SIZE(states); ++i) { + if (membarrier_state & states[i]) { + registrations_mask |= registration_cmds[i]; + membarrier_state &= ~states[i]; + } + } + WARN_ON_ONCE(membarrier_state != 0); + return registrations_mask; +} + /** * sys_membarrier - issue memory barriers on a set of threads * @cmd: Takes command values defined in enum membarrier_cmd. @@ -623,6 +658,8 @@ SYSCALL_DEFINE3(membarrier, int, cmd, unsigned int, flags, int, cpu_id) return membarrier_private_expedited(MEMBARRIER_FLAG_RSEQ, cpu_id); case MEMBARRIER_CMD_REGISTER_PRIVATE_EXPEDITED_RSEQ: return membarrier_register_private_expedited(MEMBARRIER_FLAG_RSEQ); + case MEMBARRIER_CMD_GET_REGISTRATIONS: + return membarrier_get_registrations(); default: return -EINVAL; }