From patchwork Thu Dec 6 18:21:31 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 153056 Delivered-To: patch@linaro.org Received: by 2002:a2e:299d:0:0:0:0:0 with SMTP id p29-v6csp10859959ljp; Thu, 6 Dec 2018 10:21:27 -0800 (PST) X-Google-Smtp-Source: AFSGD/WlkQ6DoO9j2nd+8W6N57GIOGWa+8a2hwRZUsr0R2oW6TpMJaFzSdbR68yy9DdEzg1O0diD X-Received: by 2002:aa7:8608:: with SMTP id p8mr29994067pfn.125.1544120486995; Thu, 06 Dec 2018 10:21:26 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1544120486; cv=none; d=google.com; s=arc-20160816; b=FVsn6wgqzZoLVPmb61+f+mlf9bLMBsPz+CukpNBebUjY4XhjIg6dDrCizGYishk+qr HJH5TnteBhWLDrKUvwSTrmkLfSuvgvxd9FdbpH37ZEa+598srvPJT3O2iM02VFfrGCl8 dVl5xZvLP5clXz7T35fNeiXmDxTILKov3FbXuEFrqxKbihLDnXu7T1ETDSjkGbPzy4D6 Kuqq5YXnRi0Qs8om1NEZV4Bspp9Y8mQsY+AyGEr6M1tGJxslAaBTXNpBg2/S3NNLaIXz lQnWfVXOKsVeAu7UCX2+vqwhbd8kIAJRKho0aK78/PJo8FWUNz8bAaguZjZmZn+NG/Jr TIvA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:references:in-reply-to:message-id:date :subject:cc:to:from; bh=Ka6oXZu8DJRXSCZkb2TermywvttDv1cohIKM9nr4o2s=; b=jfl+KmYBayd2xmwIbAkmQT5/83bnlyUodAuhF071HvpzX/L5HkpVg0OUZI5/w8B8tl h3UQbr3738SaFPzM73dbLySuKbrlH4Z/D2QQ5hpQyg7B40uhBmsAEN58Qa3xc/odxhcV QJG1c28B6i1lWizC11swFXkVoxeCCLk8KJu4pHxR+bxVoDGYDSrJ6EmvYaP5/Em9V/5c 0X+dLDeqJYaHlVlpBzBesbcdXm6BEfZZxcHH964MsWLKYzrws59GI3Zw/cDOCO2zvz2G +3t6Cp05GIQA0W9PxEoJ/2QIGammTjdHXP3odKS8SpRiViPyO7jFoHQZoqy29pgB93Yi CTMA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id t13si756655pgm.175.2018.12.06.10.21.26; Thu, 06 Dec 2018 10:21:26 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726143AbeLFSVU (ORCPT + 31 others); Thu, 6 Dec 2018 13:21:20 -0500 Received: from foss.arm.com ([217.140.101.70]:57826 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725901AbeLFSVQ (ORCPT ); Thu, 6 Dec 2018 13:21:16 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8D060EBD; Thu, 6 Dec 2018 10:21:15 -0800 (PST) Received: from edgewater-inn.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.72.51.249]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 5A4E33F71D; Thu, 6 Dec 2018 10:21:15 -0800 (PST) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 755961AE0BA8; Thu, 6 Dec 2018 18:21:36 +0000 (GMT) From: Will Deacon To: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, cpandya@codeaurora.org, toshi.kani@hpe.com, tglx@linutronix.de, mhocko@suse.com, sean.j.christopherson@intel.com, Will Deacon Subject: [RESEND PATCH v4 1/5] ioremap: Rework pXd_free_pYd_page() API Date: Thu, 6 Dec 2018 18:21:31 +0000 Message-Id: <1544120495-17438-2-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1544120495-17438-1-git-send-email-will.deacon@arm.com> References: <1544120495-17438-1-git-send-email-will.deacon@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The recently merged API for ensuring break-before-make on page-table entries when installing huge mappings in the vmalloc/ioremap region is fairly counter-intuitive, resulting in the arch freeing functions (e.g. pmd_free_pte_page()) being called even on entries that aren't present. This resulted in a minor bug in the arm64 implementation, giving rise to spurious VM_WARN messages. This patch moves the pXd_present() checks out into the core code, refactoring the callsites at the same time so that we avoid the complex conjunctions when determining whether or not we can put down a huge mapping. Cc: Chintan Pandya Cc: Toshi Kani Cc: Thomas Gleixner Cc: Michal Hocko Cc: Andrew Morton Suggested-by: Linus Torvalds Reviewed-by: Toshi Kani Signed-off-by: Will Deacon --- lib/ioremap.c | 56 ++++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 42 insertions(+), 14 deletions(-) -- 2.1.4 diff --git a/lib/ioremap.c b/lib/ioremap.c index 517f5853ffed..6c72764af19c 100644 --- a/lib/ioremap.c +++ b/lib/ioremap.c @@ -76,6 +76,25 @@ static int ioremap_pte_range(pmd_t *pmd, unsigned long addr, return 0; } +static int ioremap_try_huge_pmd(pmd_t *pmd, unsigned long addr, + unsigned long end, phys_addr_t phys_addr, + pgprot_t prot) +{ + if (!ioremap_pmd_enabled()) + return 0; + + if ((end - addr) != PMD_SIZE) + return 0; + + if (!IS_ALIGNED(phys_addr, PMD_SIZE)) + return 0; + + if (pmd_present(*pmd) && !pmd_free_pte_page(pmd, addr)) + return 0; + + return pmd_set_huge(pmd, phys_addr, prot); +} + static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, unsigned long end, phys_addr_t phys_addr, pgprot_t prot) { @@ -89,13 +108,8 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, do { next = pmd_addr_end(addr, end); - if (ioremap_pmd_enabled() && - ((next - addr) == PMD_SIZE) && - IS_ALIGNED(phys_addr + addr, PMD_SIZE) && - pmd_free_pte_page(pmd, addr)) { - if (pmd_set_huge(pmd, phys_addr + addr, prot)) - continue; - } + if (ioremap_try_huge_pmd(pmd, addr, next, phys_addr + addr, prot)) + continue; if (ioremap_pte_range(pmd, addr, next, phys_addr + addr, prot)) return -ENOMEM; @@ -103,6 +117,25 @@ static inline int ioremap_pmd_range(pud_t *pud, unsigned long addr, return 0; } +static int ioremap_try_huge_pud(pud_t *pud, unsigned long addr, + unsigned long end, phys_addr_t phys_addr, + pgprot_t prot) +{ + if (!ioremap_pud_enabled()) + return 0; + + if ((end - addr) != PUD_SIZE) + return 0; + + if (!IS_ALIGNED(phys_addr, PUD_SIZE)) + return 0; + + if (pud_present(*pud) && !pud_free_pmd_page(pud, addr)) + return 0; + + return pud_set_huge(pud, phys_addr, prot); +} + static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr, unsigned long end, phys_addr_t phys_addr, pgprot_t prot) { @@ -116,13 +149,8 @@ static inline int ioremap_pud_range(p4d_t *p4d, unsigned long addr, do { next = pud_addr_end(addr, end); - if (ioremap_pud_enabled() && - ((next - addr) == PUD_SIZE) && - IS_ALIGNED(phys_addr + addr, PUD_SIZE) && - pud_free_pmd_page(pud, addr)) { - if (pud_set_huge(pud, phys_addr + addr, prot)) - continue; - } + if (ioremap_try_huge_pud(pud, addr, next, phys_addr + addr, prot)) + continue; if (ioremap_pmd_range(pud, addr, next, phys_addr + addr, prot)) return -ENOMEM;