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 DFDD0C433E6 for ; Wed, 27 Jan 2021 15:40:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 919B3207D8 for ; Wed, 27 Jan 2021 15:40:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236061AbhA0PkY (ORCPT ); Wed, 27 Jan 2021 10:40:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58554 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236245AbhA0Pe4 (ORCPT ); Wed, 27 Jan 2021 10:34:56 -0500 Received: from mail-pg1-x52e.google.com (mail-pg1-x52e.google.com [IPv6:2607:f8b0:4864:20::52e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABA97C061786 for ; Wed, 27 Jan 2021 07:34:15 -0800 (PST) Received: by mail-pg1-x52e.google.com with SMTP id i7so1809004pgc.8 for ; Wed, 27 Jan 2021 07:34:15 -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=RW+ddIYgRpxVAudma0S26NHqjC8I6ofivy+rOJrw1Q8=; b=EHWrP9QsvCwkvbps77tSaxpjJ9H/c0Zz7EZ9HE2lnFPgzJLxgVwpnK9y/8x/2y/XAg 0nX3CZm7Rki2IIYoF26e01YkqmQT5oL0stGZxeMbDc6SaPzfLZqD0blXYt3Eyv+GbN6j wO9fSEbHEO0mSVT6GnTADEoGYIhXRrJvu2FN6XQIIXfusIBGwVOXIVymvuAuSnm1oJkI M6+Ysbe+duSlyCQ0+es+kGPia8gX+s7QEPl23gb1qQINUyZ3RI72xJ7QOGTl4LDTgxmH +fWB3kvyJiBomPSJaHuaOnjvLD9bTZJH7vFWrHFAmWekcUKKgzhzu+wern6H4CqIHTQG lE0w== 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=RW+ddIYgRpxVAudma0S26NHqjC8I6ofivy+rOJrw1Q8=; b=WxWA2WerpH6XkYDyyieCVciBVfpqaVwEYGhA90O4vScTYjuPqu/0UZWC9BTv566t+Q 0OZo/y1R3bRt+u7kEYfBZy+SdoiQopIaPJJdCeqNzF+QZ+jcv2/K+bA2GzQf/CAykLtj kx+JNt60x6xx2cGwJXPOTkJn6mlw6LLE5LlHiFwn0LBaTPejiJSn1R/t5wtlM/TuiIee gMB3zs+fNmDS3mg9k5S9WjYTNfGit/51oNSXMQ4IoAt5qa0pEtpLVILUAKIW4xwmyPgc 98ekuek61/gjMTNTb2zdNFouGGlRRD3aBpfCzc7NmCoJOPHLemTvmm4b4rxhFPYLXzzW CzHg== X-Gm-Message-State: AOAM532zIyPQqACAHqp2aj0eHtXXpPsd/3IGjW31sLOVnLsyWX+GsO4w jplJepyZzxq/YlPd8b3DD+FXud4tn2Plqw== X-Google-Smtp-Source: ABdhPJwnvS+C1yPBauKsIL47Gm4afzay1A+L/yIS458o1HDZHhY5VKUnuanmwmvlurr2u11GQLQ9Jw== X-Received: by 2002:a62:1794:0:b029:1be:c822:52c3 with SMTP id 142-20020a6217940000b02901bec82252c3mr11101428pfx.66.1611761654835; Wed, 27 Jan 2021 07:34:14 -0800 (PST) Received: from localhost ([47.251.4.198]) by smtp.gmail.com with ESMTPSA id c19sm2727621pfc.122.2021.01.27.07.34.11 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 27 Jan 2021 07:34:13 -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 V3 6/6] x86_32: use cpu_current_thread_sp0 instead of cpu_tss_rw.x86_tss.sp1 Date: Thu, 28 Jan 2021 00:32:22 +0800 Message-Id: <20210127163231.12709-7-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 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 d5b5b43fd0c0..55dcf5c35141 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