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=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 00FBAC04EB8 for ; Thu, 6 Dec 2018 18:21:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C658D208E7 for ; Thu, 6 Dec 2018 18:21:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C658D208E7 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726143AbeLFSVU (ORCPT ); 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(-) 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; -- 2.1.4