From patchwork Sun Apr 24 09:02:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mayuresh Chitale X-Patchwork-Id: 12824821 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 0511EC433F5 for ; Sun, 24 Apr 2022 09:03:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:List-Subscribe:List-Help: List-Post:List-Archive:List-Unsubscribe:List-Id:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=2sRwOVWfabqZfqotHQk+HIu28TW5weXTh15MZktKnXg=; b=qRJwboPhr12wUp SGhSrxVPt3hjiZYwObgnqvi44+nX6JOqQNYAnuNaroChdQ5b3eifTcrzk7O8YIwE5Io8Yr6o65StV 0Opj8K1g10+MR79APstHk6GumHOGNZsVlS16kiLaWWdTnFrnDaypa6rfENjdfO6DVLpYorNWDtftt JXRAuS7T1ZC4fRvmWarLrcDKWbwPbfJULHiwQ5PcH0IsogGXu5WWRtHYjcKuLZf2lTmXsSj+LR+DK ILsdIaLILb4unpB8lWDm2rgg0wj7VTuoFTZqeNl9oOL55SY5sLxNRuY63ywNsshuU7O0tUX+5uctE vXRQ0QO2tPeMg5OF7ZHw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1niY94-006Dxh-9L; Sun, 24 Apr 2022 09:03:06 +0000 Received: from mail-pl1-x62b.google.com ([2607:f8b0:4864:20::62b]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1niY8x-006Dub-NI for linux-riscv@lists.infradead.org; Sun, 24 Apr 2022 09:03:03 +0000 Received: by mail-pl1-x62b.google.com with SMTP id c23so20556352plo.0 for ; Sun, 24 Apr 2022 02:02:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ventanamicro.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=d9BUQmhk3lChVnY6CUm3s/EVuwl6eb9JDwfzH9Ov/0E=; b=DyAB6oK0mdVTaAEzFlw+qD5q2XqxT9bDfv1m+gIm73P+OeG5OhoZxu6LJPzed/0PtR 7b2kfaV204DLp6zYmIAJHvlauTdJ/SPN+nXuOQSyWWy9hahWCkEjg1AR0+qi84eOSqUX 5Ho3NP3dCwVCZIz6gM8MHE1uGE3uODSrrXT8SbDv87d9+Xv9bJKewvl5kqwW2Vkmdaa/ 7vNF2+Ko0s7rxewFtejceUay7i0XY60fzGkM9VCzK1CmRR6LG5SMen6s4ESAZaQpLFA0 NR5WLTdh/5tstInbGFXTDkcob0qYoNq3Q5fMN2V4usGJG6OZyrUWDJQgQgs8tHAr1Lx1 hoxw== 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; bh=d9BUQmhk3lChVnY6CUm3s/EVuwl6eb9JDwfzH9Ov/0E=; b=QfUzldJq873zCUHO4BM3oG3ocg8WI31XTzQOton9UvDV3uIbMrFX8eshn8w4QfRi6c kUoKTSNASAYHeqScWWmrfZxC1mOYv5Cx/E/06OlAtoyTJ+573/dPd6OFsWkyG72iwi4u qOmncboeHAM7EJKJ7frplW5tD/TAO4xja6DtLLNATD0MSoqhWbo+yzAl7YJL3EZtf8yH qOLAgYTrHr9yarkmVI3kNTth8UZVdJNMUCW8HlQJfS92gFJtc2C1yi2D+ivTj+J2Tu24 1AUaX1TfoyZFWckvoL/SdeeG2uaWYvYJHOPRqKLwXjTUfJ6WAINbuis25KrskWB7GzO2 ZmEw== X-Gm-Message-State: AOAM530Xq7OSdPIZpEWSIb04HRclTwhIM6IFPD99Fair+HhsH+ksencS YTf3/exWZDBQ7+qGw24IvrM4wA== X-Google-Smtp-Source: ABdhPJz8PtnjylMruGoNqjwFOZqUI9x2f9O63wNF/V9pXXMIGYwlnwj1e0JWcTjO6uOqZl4kaDDUIw== X-Received: by 2002:a17:90b:1d8f:b0:1d2:e15a:de8 with SMTP id pf15-20020a17090b1d8f00b001d2e15a0de8mr14631450pjb.139.1650790976872; Sun, 24 Apr 2022 02:02:56 -0700 (PDT) Received: from ThinkPad-T490.dc1.ventanamicro.com ([122.169.86.15]) by smtp.googlemail.com with ESMTPSA id n7-20020a17090a73c700b001d9682ad948sm628090pjk.0.2022.04.24.02.02.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 24 Apr 2022 02:02:56 -0700 (PDT) From: Mayuresh Chitale To: Palmer Dabbelt , Paul Walmsley , Albert Ou Cc: Mayuresh Chitale , Atish Patra , Anup Patel , linux-riscv@lists.infradead.org Subject: [RFC PATCH v2 2/2] riscv: mm: use svinval instructions instead of sfence.vma Date: Sun, 24 Apr 2022 14:32:16 +0530 Message-Id: <20220424090216.21887-3-mchitale@ventanamicro.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20220424090216.21887-1-mchitale@ventanamicro.com> References: <20220424090216.21887-1-mchitale@ventanamicro.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220424_020259_834007_1E8B2CE4 X-CRM114-Status: GOOD ( 17.66 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org When svinval is supported the local_flush_tlb_page* functions would prefer to use the following sequence to optimize the tlb flushes instead of a simple sfence.vma: sfence.w.inval svinval.vma . . svinval.vma sfence.inval.ir The maximum number of consecutive svinval.vma instructions that can be executed in local_flush_tlb_page* functions is limited to PTRS_PER_PTE. This is required to avoid soft lockups and the approach is similar to that used in arm64. Signed-off-by: Mayuresh Chitale --- arch/riscv/include/asm/tlbflush.h | 12 ++++ arch/riscv/kernel/setup.c | 1 + arch/riscv/mm/tlbflush.c | 116 ++++++++++++++++++++++++++++-- 3 files changed, 123 insertions(+), 6 deletions(-) diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h index 801019381dea..b535467c99f0 100644 --- a/arch/riscv/include/asm/tlbflush.h +++ b/arch/riscv/include/asm/tlbflush.h @@ -22,6 +22,18 @@ static inline void local_flush_tlb_page(unsigned long addr) { ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory")); } + +void riscv_tlbflush_init(void); +void __riscv_sfence_w_inval(void); +void __riscv_sfence_inval_ir(void); +void __riscv_sinval_vma(unsigned long addr); +void __riscv_sinval_vma_asid(unsigned long addr, unsigned long asid); + +/* Check if we can use sinval for tlb flush */ +DECLARE_STATIC_KEY_FALSE(riscv_flush_tlb_svinval); +#define riscv_use_flush_tlb_svinval() \ + static_branch_unlikely(&riscv_flush_tlb_svinval) + #else /* CONFIG_MMU */ #define local_flush_tlb_all() do { } while (0) #define local_flush_tlb_page(addr) do { } while (0) diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c index 834eb652a7b9..13de04259de9 100644 --- a/arch/riscv/kernel/setup.c +++ b/arch/riscv/kernel/setup.c @@ -295,6 +295,7 @@ void __init setup_arch(char **cmdline_p) #endif riscv_fill_hwcap(); + riscv_tlbflush_init(); } static int __init topology_init(void) diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c index 27a7db8eb2c4..800953f9121e 100644 --- a/arch/riscv/mm/tlbflush.c +++ b/arch/riscv/mm/tlbflush.c @@ -1,11 +1,14 @@ // SPDX-License-Identifier: GPL-2.0 +#define pr_fmt(fmt) "riscv: " fmt #include #include #include #include #include +static unsigned long tlb_flush_all_threshold __read_mostly = PTRS_PER_PTE; + static inline void local_flush_tlb_all_asid(unsigned long asid) { __asm__ __volatile__ ("sfence.vma x0, %0" @@ -23,22 +26,110 @@ static inline void local_flush_tlb_page_asid(unsigned long addr, : "memory"); } +static inline void riscv_sfence_inval_ir(void) +{ + /* + * SFENCE.INVAL.IR + * 0001100 00001 00000 000 00000 1110011 + */ + asm volatile (".word 0x18100073" ::: "memory"); +} + +static inline void riscv_sfence_w_inval(void) +{ + /* + * SFENCE.W.INVAL + * 0001100 00000 00000 000 00000 1110011 + */ + asm volatile (".word 0x18000073" ::: "memory"); +} + +static inline void riscv_sinval_vma_asid(unsigned long vma, unsigned long asid) +{ + /* + * rs1 = a0 (VMA) + * rs2 = a1 (asid) + * SINVAL.VMA a0, a1 + * 0001011 01011 01010 000 00000 1110011 + */ + asm volatile ("srli a0, %0, 2\n" + "add a1, %1, zero\n" + ".word 0x16B50073\n" + :: "r" (vma), "r" (asid) + : "a0", "a1", "memory"); +} + +static inline void riscv_sinval_vma(unsigned long vma) +{ + /* + * rs1 = a0 (VMA) + * rs2 = 0 + * SINVAL.VMA a0 + * 0001011 00000 01010 000 00000 1110011 + */ + asm volatile ("srli a0, %0, 2\n" + ".word 0x16050073\n" + :: "r" (vma) : "a0", "memory"); +} + static inline void local_flush_tlb_range(unsigned long start, unsigned long size, unsigned long stride) { - if (size <= stride) - local_flush_tlb_page(start); - else + if ((size / stride) <= tlb_flush_all_threshold) { + if (riscv_use_flush_tlb_svinval()) { + riscv_sfence_w_inval(); + while (size) { + riscv_sinval_vma(start); + start += stride; + if (size > stride) + size -= stride; + else + size = 0; + } + riscv_sfence_inval_ir(); + } else { + while (size) { + local_flush_tlb_page(start); + start += stride; + if (size > stride) + size -= stride; + else + size = 0; + } + } + } else { local_flush_tlb_all(); + } } static inline void local_flush_tlb_range_asid(unsigned long start, unsigned long size, unsigned long stride, unsigned long asid) { - if (size <= stride) - local_flush_tlb_page_asid(start, asid); - else + if ((size / stride) <= tlb_flush_all_threshold) { + if (riscv_use_flush_tlb_svinval()) { + riscv_sfence_w_inval(); + while (size) { + riscv_sinval_vma_asid(start, asid); + start += stride; + if (size > stride) + size -= stride; + else + size = 0; + } + riscv_sfence_inval_ir(); + } else { + while (size) { + local_flush_tlb_page_asid(start, asid); + start += stride; + if (size > stride) + size -= stride; + else + size = 0; + } + } + } else { local_flush_tlb_all_asid(asid); + } } static void __ipi_flush_tlb_all(void *info) @@ -149,3 +240,16 @@ void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start, __flush_tlb_range(vma->vm_mm, start, end - start, PMD_SIZE); } #endif + +DEFINE_STATIC_KEY_FALSE(riscv_flush_tlb_svinval); +EXPORT_SYMBOL_GPL(riscv_flush_tlb_svinval); + +void riscv_tlbflush_init(void) +{ + if (riscv_isa_extension_available(NULL, SVINVAL)) { + pr_info("Svinval extension supported\n"); + static_branch_enable(&riscv_flush_tlb_svinval); + } else { + static_branch_disable(&riscv_flush_tlb_svinval); + } +}