From patchwork Wed Jan 31 15:59:29 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexandre Ghiti X-Patchwork-Id: 1893568 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.a=rsa-sha256 header.s=20230601 header.b=k08GF3Vc; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ozlabs.org (client-ip=112.213.38.117; helo=lists.ozlabs.org; envelope-from=linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org; receiver=patchwork.ozlabs.org) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4TQ6KW0lhLz23g7 for ; Thu, 1 Feb 2024 03:03:58 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.a=rsa-sha256 header.s=20230601 header.b=k08GF3Vc; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4TQ6KV25wCz3vsP for ; Thu, 1 Feb 2024 03:03:58 +1100 (AEDT) X-Original-To: linuxppc-dev@lists.ozlabs.org Delivered-To: linuxppc-dev@lists.ozlabs.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=rivosinc-com.20230601.gappssmtp.com header.i=@rivosinc-com.20230601.gappssmtp.com header.a=rsa-sha256 header.s=20230601 header.b=k08GF3Vc; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=rivosinc.com (client-ip=2a00:1450:4864:20::434; helo=mail-wr1-x434.google.com; envelope-from=alexghiti@rivosinc.com; receiver=lists.ozlabs.org) Received: from mail-wr1-x434.google.com (mail-wr1-x434.google.com [IPv6:2a00:1450:4864:20::434]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4TQ6KB2c2hz3vpn for ; Thu, 1 Feb 2024 03:03:42 +1100 (AEDT) Received: by mail-wr1-x434.google.com with SMTP id ffacd0b85a97d-33b01484cd7so752846f8f.0 for ; Wed, 31 Jan 2024 08:03:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=rivosinc-com.20230601.gappssmtp.com; s=20230601; t=1706717018; x=1707321818; darn=lists.ozlabs.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2G7N9HKTptzFvdsSy7a/wMEV20988NdsE2TTuou7VW4=; b=k08GF3VcWruFNQ4pJFoMh/Zwho+psHscKJPWjOzPw01l4Vr5npwG2LE+eY34/kYZO5 DT6i370M7Qm7KS0nddU/b2tbdESFHlZbwbjktgiFm4S5A0yoQDwoww9a8QL70tTFnCO1 IiLpsZ+iTL7eaOgufgc5DaSLG7DSK9s7hS6j33NSz6d8hzXWPl8X7VsTO2E48mL4T1Kn Grxfthqvhdf0i4Qil/uRbmlUytehlLluTOSccv95AmzFhlhxuYV1blSelZG3dQOJEuen kQzirkKOOwJ+SHJuNcz2LZuPiBhS7fTWbluALSVZquWaAOfNlw9+o7Ih6P2Zga+khg3b R3lw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1706717018; x=1707321818; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=2G7N9HKTptzFvdsSy7a/wMEV20988NdsE2TTuou7VW4=; b=bus5LCb58sBMUnq22MwSgwo0Xp8T3UqnHyTRm1aZJMRF8zQEhkLhwrq9Rha+zpHOCC R/gvyyhYEj8EfC0qm6Q1a5CKb2YUzmny96sQzgIp2K5SJQtwHjvYS9oPpKBHhtg67wAy a7oxeGlZdBWTQuOrFgMQu10GSKaGlzrU7TZENbojgqqyMeSMQ72+SYgYcLL0wMoFsvI8 qHl1Jt6Vn6kpcqBZQopxwJQM0gJbn9IBV0H/LdwGyAyLa+PN+RW4MWG32Dg3XgN8NzXX ivl07MoAH23hRBQsB59Q9DctfH446WxtAWiPJjQ3Kk487ZZWthAcMVhfxk381PEH9wd/ E9nw== X-Gm-Message-State: AOJu0YxeVDiqr63q3jsqPDiCpXarLrtPEbWTQup30OjJsyD/fEwltz0T OEzh8wP0WDDkAMkBqrLRST2bsP2fGbLQ8scleouUAKWzc8zkGZ5uofDkPWcKJZ8= X-Google-Smtp-Source: AGHT+IFv4RsKrg6kAntnJ/YCtPGAW1U1YNeeMXiuO/lnsK9Rn1OpwCBxYmcNw94F8PYwyQot8cihag== X-Received: by 2002:a5d:4448:0:b0:33a:e6cf:f564 with SMTP id x8-20020a5d4448000000b0033ae6cff564mr1365333wrr.28.1706717018193; Wed, 31 Jan 2024 08:03:38 -0800 (PST) X-Forwarded-Encrypted: i=0; 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 Received: from alex-rivos.ba.rivosinc.com (amontpellier-656-1-456-62.w92-145.abo.wanadoo.fr. [92.145.124.62]) by smtp.gmail.com with ESMTPSA id bu16-20020a056000079000b0033b0797cc14sm1358024wrb.51.2024.01.31.08.03.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 31 Jan 2024 08:03:37 -0800 (PST) From: Alexandre Ghiti To: Catalin Marinas , Will Deacon , Thomas Bogendoerfer , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Paul Walmsley , Palmer Dabbelt , Albert Ou , Andrew Morton , Ved Shanbhogue , Matt Evans , Dylan Jhong , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-riscv@lists.infradead.org, linux-mm@kvack.org Subject: [PATCH RFC/RFT v2 4/4] riscv: Stop emitting preventive sfence.vma for new userspace mappings with Svvptc Date: Wed, 31 Jan 2024 16:59:29 +0100 Message-Id: <20240131155929.169961-5-alexghiti@rivosinc.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20240131155929.169961-1-alexghiti@rivosinc.com> References: <20240131155929.169961-1-alexghiti@rivosinc.com> MIME-Version: 1.0 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Alexandre Ghiti Errors-To: linuxppc-dev-bounces+incoming=patchwork.ozlabs.org@lists.ozlabs.org Sender: "Linuxppc-dev" The preventive sfence.vma were emitted because new mappings must be made visible to the page table walker but Svvptc guarantees that xRET act as a fence, so no need to sfence.vma for the uarchs that implement this extension. This allows to drastically reduce the number of sfence.vma emitted: * Ubuntu boot to login: Before: ~630k sfence.vma After: ~200k sfence.vma * ltp - mmapstress01 Before: ~45k After: ~6.3k * lmbench - lat_pagefault Before: ~665k After: 832 (!) * lmbench - lat_mmap Before: ~546k After: 718 (!) Signed-off-by: Alexandre Ghiti --- arch/riscv/include/asm/pgtable.h | 16 +++++++++++++++- arch/riscv/mm/pgtable.c | 13 +++++++++++++ 2 files changed, 28 insertions(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h index 0c94260b5d0c..50986e4c4601 100644 --- a/arch/riscv/include/asm/pgtable.h +++ b/arch/riscv/include/asm/pgtable.h @@ -473,6 +473,9 @@ static inline void update_mmu_cache_range(struct vm_fault *vmf, struct vm_area_struct *vma, unsigned long address, pte_t *ptep, unsigned int nr) { + asm_volatile_goto(ALTERNATIVE("nop", "j %l[svvptc]", 0, RISCV_ISA_EXT_SVVPTC, 1) + : : : : svvptc); + /* * The kernel assumes that TLBs don't cache invalid entries, but * in RISC-V, SFENCE.VMA specifies an ordering constraint, not a @@ -482,12 +485,23 @@ static inline void update_mmu_cache_range(struct vm_fault *vmf, */ while (nr--) local_flush_tlb_page(address + nr * PAGE_SIZE); + +svvptc: + /* + * Svvptc guarantees that xRET act as a fence, so when the uarch does + * not cache invalid entries, we don't have to do anything. + */ + ; } #define update_mmu_cache(vma, addr, ptep) \ update_mmu_cache_range(NULL, vma, addr, ptep, 1) #define __HAVE_ARCH_UPDATE_MMU_TLB -#define update_mmu_tlb update_mmu_cache +static inline void update_mmu_tlb(struct vm_area_struct *vma, + unsigned long address, pte_t *ptep) +{ + flush_tlb_range(vma, address, address + PAGE_SIZE); +} static inline void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long address, pmd_t *pmdp) diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c index ef887efcb679..99ed389e4c8a 100644 --- a/arch/riscv/mm/pgtable.c +++ b/arch/riscv/mm/pgtable.c @@ -9,6 +9,9 @@ int ptep_set_access_flags(struct vm_area_struct *vma, unsigned long address, pte_t *ptep, pte_t entry, int dirty) { + asm_volatile_goto(ALTERNATIVE("nop", "j %l[svvptc]", 0, RISCV_ISA_EXT_SVVPTC, 1) + : : : : svvptc); + if (!pte_same(ptep_get(ptep), entry)) __set_pte_at(ptep, entry); /* @@ -16,6 +19,16 @@ int ptep_set_access_flags(struct vm_area_struct *vma, * the case that the PTE changed and the spurious fault case. */ return true; + +svvptc: + if (!pte_same(ptep_get(ptep), entry)) { + __set_pte_at(ptep, entry); + /* Here only not svadu is impacted */ + flush_tlb_page(vma, address); + return true; + } + + return false; } int ptep_test_and_clear_young(struct vm_area_struct *vma,