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=-15.8 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 EC095C433E0 for ; Mon, 25 Jan 2021 16:38:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A40A4225AB for ; Mon, 25 Jan 2021 16:38:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730861AbhAYQie (ORCPT ); Mon, 25 Jan 2021 11:38:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730812AbhAYQgz (ORCPT ); Mon, 25 Jan 2021 11:36:55 -0500 Received: from mail-pj1-x1031.google.com (mail-pj1-x1031.google.com [IPv6:2607:f8b0:4864:20::1031]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C8039C06174A for ; Mon, 25 Jan 2021 08:36:14 -0800 (PST) Received: by mail-pj1-x1031.google.com with SMTP id e9so1680858pjj.0 for ; Mon, 25 Jan 2021 08:36:14 -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=WxIHznqwAGESe2xc5cpCSnujQzQI1SoVg8yAGG62ByY=; b=hj5zUO9EOYdqo9s5O/GMHCMj3BisbPvYUkcwSQyPR4AiJF7/Y04KNsFnQ89dQ3LvNU vqQh9iJjBYuMr1mUZ8JoXc2mLIk0/C1HrQgIBt9KFskDzMu60iVIHc2LmHmc7N3xVHEe MaJ9Dv5aTshT2t1q03/HH/U1n4Oq+wKzpcxPrOvZLdx0vVfVAKnrJ/AIoYUZuDMUEGrp 4PQWwpSeFCPWV1Nuc7OmG71IZ4bbcxYi5bZtsQsG9BTrvi6OXmCzWRTHAuCSleEqRyZD I96nTfF97c3ZQcJkuOtMIIcF+liw85+UgkocuVHVa0lAeiNL4sZuxymevlevQ+FYEDrO j+PA== 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=WxIHznqwAGESe2xc5cpCSnujQzQI1SoVg8yAGG62ByY=; b=Tj1BzTCCj6kRuU93f0PyExvUG0tR2Tefqu+0j8tPDaiWZ9SfuwQXLPXxd6qKfLZPlO ztUTW+owF7JJpUOc8R9OGEBb8xy4UN6L2MLk1p12RfcvbR49QttEDR8okDS9D3Xa5+bV kk7PSvH8Mmf1DP8XIYKREgV2JXC2KgwLx7PEeHcLI7p8yMu06HwKqJA6t5RQVX1XR1n0 Ia6Ql2ZpihzVT1TL5S3M8cCv3+g6zcbRLfAEimlrySNER77inQjG0iTgT23nPwPmTvGj tPPvEOh2CgOO+fKcb2LDZErOqX4GVNh6yPozC5EXLTZWhPF/E6U8YX+rnxxZWF+lffME vzlw== X-Gm-Message-State: AOAM532dTz4vjYI2zBNR0BrCk+ALOK7W7SngBWgKu/eH4khan/y38Nm7 HW5ylBk3Wts1N1Mds2MlcRClPAojyU32Cg== X-Google-Smtp-Source: ABdhPJxq4D/dblNlcs9Dr9mo/IDgF1x3tUjJRoNjHlM1Odxl8EBvPhUEDS3/0kQM3bjIgLRiIWH9qQ== X-Received: by 2002:a17:90a:5208:: with SMTP id v8mr1041060pjh.224.1611592574186; Mon, 25 Jan 2021 08:36:14 -0800 (PST) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id z15sm17163658pfr.89.2021.01.25.08.36.12 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Jan 2021 08:36:13 -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 V2 6/6] x86_32: use cpu_current_thread_sp0 instead of cpu_tss_rw.x86_tss.sp1 Date: Tue, 26 Jan 2021 01:34:34 +0800 Message-Id: <20210125173444.22696-7-jiangshanlai@gmail.com> X-Mailer: git-send-email 2.19.1.6.gb485710b In-Reply-To: <20210125173444.22696-1-jiangshanlai@gmail.com> References: <20210125173444.22696-1-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 sp1 is not used by hardware and is used as thread.sp0. We should just use new percpu variable. And remove unneeded TSS_sp1. Signed-off-by: Lai Jiangshan --- arch/x86/entry/entry_32.S | 6 +++--- arch/x86/include/asm/processor.h | 2 ++ arch/x86/include/asm/switch_to.h | 2 +- arch/x86/kernel/asm-offsets.c | 1 - arch/x86/kernel/cpu/common.c | 9 ++++++++- arch/x86/kernel/process.c | 2 -- 6 files changed, 14 insertions(+), 8 deletions(-) diff --git a/arch/x86/entry/entry_32.S b/arch/x86/entry/entry_32.S index 3cb42efb3c04..22cd3d8fd23e 100644 --- a/arch/x86/entry/entry_32.S +++ b/arch/x86/entry/entry_32.S @@ -472,7 +472,7 @@ movl %esp, %esi /* Load top of task-stack into %edi */ - movl PER_CPU_VAR(cpu_tss_rw + TSS_sp1), %edi + movl PER_CPU_VAR(cpu_current_thread_sp0), %edi /* Special case - entry from kernel mode via entry stack */ #ifdef CONFIG_VM86 @@ -658,7 +658,7 @@ movl PER_CPU_VAR(cpu_tss_rw + TSS_sp0), %edi /* Bytes on the task-stack to ecx */ - movl PER_CPU_VAR(cpu_tss_rw + TSS_sp1), %ecx + movl PER_CPU_VAR(cpu_current_thread_sp0), %ecx subl %esi, %ecx /* Allocate stack-frame on entry-stack */ @@ -916,7 +916,7 @@ SYM_FUNC_START(entry_SYSENTER_32) /* Switch to task stack */ movl %esp, %eax - movl PER_CPU_VAR(cpu_tss_rw + TSS_sp1), %esp + movl PER_CPU_VAR(cpu_current_thread_sp0), %esp .Lsysenter_past_esp: pushl $__USER_DS /* pt_regs->ss */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 886d32da1318..4265884c33e7 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -774,6 +774,8 @@ static inline void spin_lock_prefetch(const void *x) #define KSTK_ESP(task) (task_pt_regs(task)->sp) +DECLARE_PER_CPU(unsigned long, cpu_current_thread_sp0); + #else #define INIT_THREAD { } diff --git a/arch/x86/include/asm/switch_to.h b/arch/x86/include/asm/switch_to.h index b5f0d2ff47e4..e27eb7974797 100644 --- a/arch/x86/include/asm/switch_to.h +++ b/arch/x86/include/asm/switch_to.h @@ -69,7 +69,7 @@ static inline void update_task_stack(struct task_struct *task) if (static_cpu_has(X86_FEATURE_XENPV)) load_sp0(task->thread.sp0); else - this_cpu_write(cpu_tss_rw.x86_tss.sp1, task->thread.sp0); + this_cpu_write(cpu_current_thread_sp0, task->thread.sp0); #else /* Xen PV enters the kernel on the thread stack. */ if (static_cpu_has(X86_FEATURE_XENPV)) diff --git a/arch/x86/kernel/asm-offsets.c b/arch/x86/kernel/asm-offsets.c index 60b9f42ce3c1..3b63b6062792 100644 --- a/arch/x86/kernel/asm-offsets.c +++ b/arch/x86/kernel/asm-offsets.c @@ -98,6 +98,5 @@ static void __used common(void) /* Offset for fields in tss_struct */ OFFSET(TSS_sp0, tss_struct, x86_tss.sp0); - OFFSET(TSS_sp1, tss_struct, x86_tss.sp1); OFFSET(TSS_sp2, tss_struct, x86_tss.sp2); } diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index f3d7fd7e9684..b2c37d369137 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1789,12 +1789,19 @@ EXPORT_PER_CPU_SYMBOL(__preempt_count); /* * On x86_32, vm86 modifies tss.sp0, so sp0 isn't a reliable way to find * the top of the kernel stack. Use an extra percpu variable to track the - * top of the kernel stack directly. + * top of the kernel stack directly and an percpu variable to track the + * thread.sp0 for using in entry code. cpu_current_top_of_stack and + * cpu_current_thread_sp0 are different value because of the non-zero + * stack-padding on 32bit. See more comment at TOP_OF_KERNEL_STACK_PADDING + * and vm86. */ DEFINE_PER_CPU(unsigned long, cpu_current_top_of_stack) = (unsigned long)&init_thread_union + THREAD_SIZE; EXPORT_PER_CPU_SYMBOL(cpu_current_top_of_stack); +DEFINE_PER_CPU(unsigned long, cpu_current_thread_sp0) = TOP_OF_INIT_STACK; +EXPORT_PER_CPU_SYMBOL(cpu_current_thread_sp0); + #ifdef CONFIG_STACKPROTECTOR DEFINE_PER_CPU_ALIGNED(struct stack_canary, stack_canary); #endif diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 296de77da4b2..e6d4b5399a81 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -64,8 +64,6 @@ __visible DEFINE_PER_CPU_PAGE_ALIGNED(struct tss_struct, cpu_tss_rw) = { .sp0 = (1UL << (BITS_PER_LONG-1)) + 1, #ifdef CONFIG_X86_32 - .sp1 = TOP_OF_INIT_STACK, - .ss0 = __KERNEL_DS, .ss1 = __KERNEL_CS, #endif -- 2.19.1.6.gb485710b