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 X-Spam-Level: X-Spam-Status: No, score=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EEC6DC433E0 for ; Wed, 27 Jan 2021 15:55:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BA5A3207D0 for ; Wed, 27 Jan 2021 15:55:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236701AbhA0Pz3 (ORCPT ); Wed, 27 Jan 2021 10:55:29 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236071AbhA0Pdn (ORCPT ); Wed, 27 Jan 2021 10:33:43 -0500 Received: from mail-pf1-x42b.google.com (mail-pf1-x42b.google.com [IPv6:2607:f8b0:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F218C061574 for ; Wed, 27 Jan 2021 07:33:03 -0800 (PST) Received: by mail-pf1-x42b.google.com with SMTP id w18so1403132pfu.9 for ; Wed, 27 Jan 2021 07:33:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=BlAqhwi52CDU/L4m2USiDoxymFbBrES3zkm124j7yww=; b=FjqepHQ/sgq1FCRIabGe68voPUd4OwvwrmBvr1u8hzsckboo+31Hz0fPErZanzdsKT dCXHkyOa8gLmLaU5m24RCMjNmdwKP97wESsWPKjuZ5RU8cNWtNGvwzgAF50aqgcmBn0N aUxZSpGgyBJ51lRc8gJDiBlZEwajESfmX6HLZP5VuI5VNw7K+FaN24+bdv039n8JbcSm +Ck/0u1Keejy0JUGiK0uYgqS6lpoenqoxDPbdNaNLHVdFPzqGj6coFlO/oIS2ElqhuKa iwCm0c/oBRAM7D3o9vm5V2d5rkmI9kuxE7dyZFZmW2nrn+NPSjzH9JMp44MSprz636U0 V9fg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=BlAqhwi52CDU/L4m2USiDoxymFbBrES3zkm124j7yww=; b=rBk3FrH8sxnYnG3Onv0tjPN7D2D9C8tr/PhnxBrfiE3ukZbMPAS0w7hf3xmJsr+EZK xzFYcQWmpjs+tAOnbrgwRRib6HiTsOqF27IgqChxAUANvfmUxgxen7hnQCir/C5LkD8X n0S8AHXHsLuWusM91+aVsSahcwXrpNy8GzK5d1WYiwgOSHLemkOjnZ6Tte7wiQuFYH8v GBC+P8C2x43aTPJnkKLr5iwWwADsv3RsfDPJnQwPABWgpsRXr5ZCMfGa2rOSJIvJRdS8 2HdvYFZr30uQu7E0EWPzsf0cPabyqY34dvPwWN5OB5gtEmrkgASDE7mIqbeIJOR4CPq6 /fFA== X-Gm-Message-State: AOAM531qz+aM4DKnZFcxOXQKA813F1pAfdw04nsxPVG2CtGNPn0Iwr8h 9StyNE3+lYsyopnghhvyfFzUPF+PdMPgK/nO X-Google-Smtp-Source: ABdhPJy5RAw+undZ46u8lqsssixKJUW8pdLYYhCOeJTv1Q+6fSmP7FRip1zcwg4lfm/LHXwXDBr2Zw== X-Received: by 2002:a62:36c3:0:b029:1b9:e110:e126 with SMTP id d186-20020a6236c30000b02901b9e110e126mr11110102pfa.64.1611761582420; Wed, 27 Jan 2021 07:33:02 -0800 (PST) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id u26sm2825374pfm.61.2021.01.27.07.33.01 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Jan 2021 07:33:01 -0800 (PST) From: Lai Jiangshan To: linux-kernel@vger.kernel.org Cc: Lai Jiangshan , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Dave Hansen , Peter Zijlstra , Al Viro , Vincenzo Frascino , Joerg Roedel , Ricardo Neri , Reinette Chatre , Andrew Morton , Gabriel Krisman Bertazi , Kees Cook , Frederic Weisbecker , Jens Axboe , Arvind Sankar , Brian Gerst , Ard Biesheuvel , Andi Kleen , Mike Rapoport , Mike Hommey , Mark Gross , Fenghua Yu , Tony Luck , Anthony Steinhauser , Jay Lang , "Chang S. Bae" Subject: [PATCH V3 2/6] x86_32: use percpu instead of offset-calculation to get thread.sp0 when SWITCH_TO_KERNEL_STACK Date: Thu, 28 Jan 2021 00:32:18 +0800 Message-Id: <20210127163231.12709-3-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20210127163231.12709-1-jiangshanlai@gmail.com> References: <20210127163231.12709-1-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 TSS_entry2task_stack is used to refer to tss.sp1 which is stored the value of thread.sp0. At the code where TSS_entry2task_stack is used in SWITCH_TO_KERNEL_STACK, the CR3 is already kernel CR3 and kernel segments is loaded. So we can directly use the percpu to get tss.sp1(thread.sp0) instead of the complex offset-calculation. Signed-off-by: Lai Jiangshan --- arch/x86/entry/entry_32.S | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index df8c017e6161..3b4d1a63d1f0 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -465,16 +465,11 @@ cmpl $SIZEOF_entry_stack, %ecx jae .Lend_\@ - /* Load stack pointer into %esi and %edi */ + /* Load stack pointer into %esi */ movl %esp, %esi - movl %esi, %edi - - /* Move %edi to the top of the entry stack */ - andl $(MASK_entry_stack), %edi - addl $(SIZEOF_entry_stack), %edi /* Load top of task-stack into %edi */ - movl TSS_entry2task_stack(%edi), %edi + movl PER_CPU_VAR(cpu_tss_rw + TSS_sp1), %edi /* Special case - entry from kernel mode via entry stack */ #ifdef CONFIG_VM86 -- 2.19.1.6.gb485710b