From patchwork Wed Sep 1 02:46:20 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tong Tiangen X-Patchwork-Id: 12468155 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=-17.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable 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 28B5EC4320E for ; Wed, 1 Sep 2021 02:38:41 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id E3E116101A for ; Wed, 1 Sep 2021 02:38:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E3E116101A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=huawei.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org 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:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version: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=UmqMEj6rQ8YKk788E6qXc5EofrkoZ4fX/j3DDFQ0K2Q=; b=M2PqpmLh7osD7N XD/EzWDsGZYc4HoReeeCmZij3+zxGQS5wxsH7J2duuCmtvvVstfI3ErpZd6Ogg6I3AuFN8aw4ZPfw ekWyNH2qq3YnDzVqgPCykBdvCc3ela7ixdIssk+dXR+mwFDwr8nQqS2P/nX/Esw0zZmHn26livNOV jksf6GTh9F60f5Z1xSwMacd75ePIU/4W1/FnJJovYZcYVuh4kUDesnrKqyBxYgJh1uM6yO0rSh5MP qAjvjJg9/zUpLqCk1EI+oHuLL04t3ZVIGz1bpvyZ9mazsAqxqiSZvlevU0yMMihIJ45JMLUCIhxRf JW9qLyt1OeL22/XstUdw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mLG8j-003bVY-Az; Wed, 01 Sep 2021 02:38:13 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mLG8e-003bUB-2v for linux-riscv@lists.infradead.org; Wed, 01 Sep 2021 02:38:12 +0000 Received: from dggemv704-chm.china.huawei.com (unknown [172.30.72.54]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Gzp9t2S4jzYw2l; Wed, 1 Sep 2021 10:37:22 +0800 (CST) Received: from dggpemm000001.china.huawei.com (7.185.36.245) by dggemv704-chm.china.huawei.com (10.3.19.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 1 Sep 2021 10:38:04 +0800 Received: from localhost.localdomain (10.175.112.125) by dggpemm000001.china.huawei.com (7.185.36.245) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Wed, 1 Sep 2021 10:38:03 +0800 From: Tong Tiangen To: Paul Walmsley , Palmer Dabbelt , Palmer Dabbelt , Albert Ou , CC: , Subject: [PATCH -next v3 2/3] riscv/vdso: Move vdso data page up front Date: Wed, 1 Sep 2021 02:46:20 +0000 Message-ID: <20210901024621.2528797-3-tongtiangen@huawei.com> X-Mailer: git-send-email 2.18.0.huawei.25 In-Reply-To: <20210901024621.2528797-1-tongtiangen@huawei.com> References: <20210901024621.2528797-1-tongtiangen@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.112.125] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To dggpemm000001.china.huawei.com (7.185.36.245) X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210831_193808_511227_19BD34CE X-CRM114-Status: GOOD ( 17.38 ) 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: , Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org As commit 601255ae3c98 ("arm64: vdso: move data page before code pages"), the same issue exists on riscv, testcase is shown below, make sure that vdso.so is bigger than page size, struct timespec tp; clock_gettime(5, &tp); printf("tv_sec: %ld, tv_nsec: %ld\n", tp.tv_sec, tp.tv_nsec); without this patch, test result : tv_sec: 0, tv_nsec: 0 with this patch, test result : tv_sec: 1629271537, tv_nsec: 748000000 Move the vdso data page in front of the VDSO area to fix the issue. Fixes: ad5d1122b82fb ("riscv: use vDSO common flow to reduce the latency of the time-related functions") Signed-off-by: Tong Tiangen --- arch/riscv/include/asm/vdso.h | 2 ++ arch/riscv/kernel/vdso.c | 44 ++++++++++++++++++------------- arch/riscv/kernel/vdso/vdso.lds.S | 3 ++- 3 files changed, 30 insertions(+), 19 deletions(-) diff --git a/arch/riscv/include/asm/vdso.h b/arch/riscv/include/asm/vdso.h index 8a49f8ecfb52..34210b22ba91 100644 --- a/arch/riscv/include/asm/vdso.h +++ b/arch/riscv/include/asm/vdso.h @@ -14,6 +14,8 @@ */ #ifdef CONFIG_MMU +#define __VVAR_PAGES 1 + #ifndef __ASSEMBLY__ #include diff --git a/arch/riscv/kernel/vdso.c b/arch/riscv/kernel/vdso.c index 72e93d218335..e7bd92d8749b 100644 --- a/arch/riscv/kernel/vdso.c +++ b/arch/riscv/kernel/vdso.c @@ -23,6 +23,13 @@ struct vdso_data { extern char vdso_start[], vdso_end[]; +enum vvar_pages { + VVAR_DATA_PAGE_OFFSET, + VVAR_NR_PAGES, +}; + +#define VVAR_SIZE (VVAR_NR_PAGES << PAGE_SHIFT) + static unsigned int vdso_pages __ro_after_init; static struct page **vdso_pagelist __ro_after_init; @@ -41,7 +48,7 @@ static int __init vdso_init(void) vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT; vdso_pagelist = - kcalloc(vdso_pages + 1, sizeof(struct page *), GFP_KERNEL); + kcalloc(vdso_pages + VVAR_NR_PAGES, sizeof(struct page *), GFP_KERNEL); if (unlikely(vdso_pagelist == NULL)) { pr_err("vdso: pagelist allocation failed\n"); return -ENOMEM; @@ -66,7 +73,9 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, unsigned long vdso_base, vdso_len; int ret; - vdso_len = (vdso_pages + 1) << PAGE_SHIFT; + BUILD_BUG_ON(VVAR_NR_PAGES != __VVAR_PAGES); + + vdso_len = (vdso_pages + VVAR_NR_PAGES) << PAGE_SHIFT; mmap_write_lock(mm); vdso_base = get_unmapped_area(NULL, 0, vdso_len, 0, 0); @@ -75,29 +84,28 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, goto end; } - /* - * Put vDSO base into mm struct. We need to do this before calling - * install_special_mapping or the perf counter mmap tracking code - * will fail to recognise it as a vDSO (since arch_vma_name fails). - */ - mm->context.vdso = (void *)vdso_base; + mm->context.vdso = NULL; + ret = install_special_mapping(mm, vdso_base, VVAR_SIZE, + (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]); + if (unlikely(ret)) + goto end; ret = - install_special_mapping(mm, vdso_base, vdso_pages << PAGE_SHIFT, + install_special_mapping(mm, vdso_base + VVAR_SIZE, + vdso_pages << PAGE_SHIFT, (VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC), vdso_pagelist); - if (unlikely(ret)) { - mm->context.vdso = NULL; + if (unlikely(ret)) goto end; - } - vdso_base += (vdso_pages << PAGE_SHIFT); - ret = install_special_mapping(mm, vdso_base, PAGE_SIZE, - (VM_READ | VM_MAYREAD), &vdso_pagelist[vdso_pages]); + /* + * Put vDSO base into mm struct. We need to do this before calling + * install_special_mapping or the perf counter mmap tracking code + * will fail to recognise it as a vDSO (since arch_vma_name fails). + */ + mm->context.vdso = (void *)vdso_base + VVAR_SIZE; - if (unlikely(ret)) - mm->context.vdso = NULL; end: mmap_write_unlock(mm); return ret; @@ -108,7 +116,7 @@ const char *arch_vma_name(struct vm_area_struct *vma) if (vma->vm_mm && (vma->vm_start == (long)vma->vm_mm->context.vdso)) return "[vdso]"; if (vma->vm_mm && (vma->vm_start == - (long)vma->vm_mm->context.vdso + PAGE_SIZE)) + (long)vma->vm_mm->context.vdso - VVAR_SIZE)) return "[vdso_data]"; return NULL; } diff --git a/arch/riscv/kernel/vdso/vdso.lds.S b/arch/riscv/kernel/vdso/vdso.lds.S index e6f558bca71b..e9111f700af0 100644 --- a/arch/riscv/kernel/vdso/vdso.lds.S +++ b/arch/riscv/kernel/vdso/vdso.lds.S @@ -3,12 +3,13 @@ * Copyright (C) 2012 Regents of the University of California */ #include +#include OUTPUT_ARCH(riscv) SECTIONS { - PROVIDE(_vdso_data = . + PAGE_SIZE); + PROVIDE(_vdso_data = . - __VVAR_PAGES * PAGE_SIZE); . = SIZEOF_HEADERS; .hash : { *(.hash) } :text