From mboxrd@z Thu Jan 1 00:00:00 1970 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7D93C433EF for ; Wed, 10 Nov 2021 11:59:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C318061152 for ; Wed, 10 Nov 2021 11:59:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231698AbhKJMCE (ORCPT ); Wed, 10 Nov 2021 07:02:04 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35574 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231722AbhKJMCC (ORCPT ); Wed, 10 Nov 2021 07:02:02 -0500 Received: from mail-pj1-x1029.google.com (mail-pj1-x1029.google.com [IPv6:2607:f8b0:4864:20::1029]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 51461C061764 for ; Wed, 10 Nov 2021 03:59:15 -0800 (PST) Received: by mail-pj1-x1029.google.com with SMTP id nh10-20020a17090b364a00b001a69adad5ebso1476718pjb.2 for ; Wed, 10 Nov 2021 03:59:15 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=or3jAOB1bNItBPsbmfV4gAOL85INAEE09CRqDlIF7AM=; b=PnF8ewyTt5bfzqsAjvKGw2OfbwgaHPbWz44Ool++CUamxcyVin55wUt2Z2i+RS1E6i EDqCb7j6q8ZqrvQjFU4vMiXSCaeo0/QyeGGBkhv4nvcUHjLnKnV28Xfp+v2vNKUK36QK XVtbo65TchM71hb6D8pSOe1Sw7cMwZvr7Vss7GgU7Es4/7BAEtoV5SUCmUcFshalTNMU 25IBnkKgbca48NPWFqDO5BQY4qVG21rQ0WOfRFrBKU/i4IoktD4TYvt7d54VLWp3/0uL HsviFvKpV9vvqGM9UWPiLj40cIG1QsPOwt4XbrXAlLEIVGRNQEZtEP9SnZ6UqQM3KQoB cb8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=or3jAOB1bNItBPsbmfV4gAOL85INAEE09CRqDlIF7AM=; b=lpGYUukdR0SaM/5VR3AyKEl7oaBte7EyTM8bdGtFEiQAmYnKnaVSisi0lPx1iYDSAY fjV4MJ2riPX9w79txB06yeFyA+2w+h/Xp9oz+pA4T+FATNOX+ZCIX4HbsOfE8qz4L25w huRvPriDXJwH3oVdA1o2KehQUdUPv51VA8ccTOAbSPADak71x78qYqWbiP2HJYsDxjww Jddfypcl6ecZn+pX6B2qRu40Ckji/ekSvrML6k9wlv56tjwzwNAKTrneHDxsFYWL13tj c/hawNLyNuMMX7l9P8NVOobDoM4TwD30IE4VZjgkBuqmfYZFRnKRvmNvLEqkwaoczyBu Yv2w== X-Gm-Message-State: AOAM531nG/NVMzBIp79cn3XPwA6AZCS7Hp7gSh2fmr/LxrLzEpsfHIBm 7+uGMARjF1DsjhhE0vVswT5FQCoVVEI= X-Google-Smtp-Source: ABdhPJxeZSL956OO7lAwYvEN1osoWjfoYDtIDdMSQ6ZFzv2TPYRemlIVy5hnMyK39aLNrfe9xuFoTw== X-Received: by 2002:a17:90b:3b45:: with SMTP id ot5mr15869785pjb.235.1636545554773; Wed, 10 Nov 2021 03:59:14 -0800 (PST) Received: from localhost ([198.11.178.15]) by smtp.gmail.com with ESMTPSA id y4sm24160636pfi.178.2021.11.10.03.59.13 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 10 Nov 2021 03:59:14 -0800 (PST) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Lai Jiangshan , Josh Poimboeuf , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" Subject: [PATCH V5 17/50] x86/entry: Add C user_entry_swapgs_and_fence() Date: Wed, 10 Nov 2021 19:57:03 +0800 Message-Id: <20211110115736.3776-18-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20211110115736.3776-1-jiangshanlai@gmail.com> References: <20211110115736.3776-1-jiangshanlai@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Lai Jiangshan The C user_entry_swapgs_and_fence() implements the ASM code: swapgs FENCE_SWAPGS_USER_ENTRY It will be used in the user entry swapgs code path, doing the swapgs and lfence to prevent a speculative swapgs when coming from kernel space. Cc: Josh Poimboeuf Suggested-by: Peter Zijlstra Signed-off-by: Lai Jiangshan --- arch/x86/entry/entry64.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/arch/x86/entry/entry64.c b/arch/x86/entry/entry64.c index bdc9540f25d3..3db503ea0703 100644 --- a/arch/x86/entry/entry64.c +++ b/arch/x86/entry/entry64.c @@ -49,6 +49,9 @@ static __always_inline void switch_to_kernel_cr3(void) {} * fence_swapgs_kernel_entry is used in the kernel entry code path without * CR3 write or with conditinal CR3 write only, to prevent the swapgs from * getting speculatively skipped when coming from user space. + * + * user_entry_swapgs_and_fence is a wrapper of swapgs and fence for user entry + * code path. */ static __always_inline void fence_swapgs_user_entry(void) { @@ -59,3 +62,9 @@ static __always_inline void fence_swapgs_kernel_entry(void) { alternative("", "lfence", X86_FEATURE_FENCE_SWAPGS_KERNEL); } + +static __always_inline void user_entry_swapgs_and_fence(void) +{ + native_swapgs(); + fence_swapgs_user_entry(); +} -- 2.19.1.6.gb485710b