From patchwork Mon Nov 26 17:07:43 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Will Deacon X-Patchwork-Id: 152053 Delivered-To: patch@linaro.org Received: by 2002:a2e:299d:0:0:0:0:0 with SMTP id p29-v6csp91933ljp; Mon, 26 Nov 2018 09:08:12 -0800 (PST) X-Google-Smtp-Source: AFSGD/W1tzxVgmq9gOyzV2WZsRx5qmjBfr4I43TeRgRdkToTzRXTdW0086X/Eqn9DtJCOVwD9/Yu X-Received: by 2002:a63:a611:: with SMTP id t17mr25443278pge.338.1543252092210; Mon, 26 Nov 2018 09:08:12 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1543252092; cv=none; d=google.com; s=arc-20160816; b=oWS2XJ8D2sk+1JDLS0gl0LJh9Fy9CDytixhDMaBba0YK/rMOQo6fMWUKXAigpch1WQ 7hiOo4klIg21ABgM62uYpHFFra0RiKeQ4waRDu1k51n+V2ztlykNPVSNErS857hI6c1R AEhflUKZQbmaOpTFnWhy+WDu+MeKa7J2PlJOqYb7gqeVkaxYD4vdqCCT96exRXWRDVb1 GyO87XzBTeX/2jh6VKKvCDzaWKh+D8SH4Febv1FWvaGwu28p7xWC1xXevpunVAUK6WYe BncrdwYtTB7Z7xbHp/RkX+rMTmLT4QUQNCV2zvcTJWm8LfpD5DwMtAfjYGZXoHvsezht meHw== 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=UEJ1VZrABCaEM9vKBSRHpurpjuackGwO9OMzpw4DNElqsolI9VQlVE0orsgFbTJ5eH JIH8suiPzFMN/Aio20wl9cAWunA+TDNpuf9lOVq9mn6dZmNeSCE7MnyRciJ+yRLoFjx0 pVnYIAl3SjHl4kcm8i1Xx6F0c0YyyW5qrhqcceSs3uNU3rlHO22Iqbl+zzVZXh2Fc0yp C0Z8cED4AxKrQ4YL/wy4tDtfGyYslePFidBpUs9gu0mz8F8dva8FjokaNE6I7SLadVmV elYPiShNgaS8swqqsJoGkLpNcJ7twSZPhtkwYEix3UAkzvqOvpynmihd3MegshDW+Evm XJ0A== 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 y25si809125pgl.226.2018.11.26.09.08.00; Mon, 26 Nov 2018 09:08:12 -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 S1726895AbeK0EC2 (ORCPT + 32 others); Mon, 26 Nov 2018 23:02:28 -0500 Received: from foss.arm.com ([217.140.101.70]:42918 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726253AbeK0ECO (ORCPT ); Mon, 26 Nov 2018 23:02:14 -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 CA76115AD; Mon, 26 Nov 2018 09:07:30 -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 9A9353F71D; Mon, 26 Nov 2018 09:07:30 -0800 (PST) Received: by edgewater-inn.cambridge.arm.com (Postfix, from userid 1000) id 178121AE0776; Mon, 26 Nov 2018 17:07:48 +0000 (GMT) From: Will Deacon To: linux-kernel@vger.kernel.org, linux-mm@kvack.org Cc: cpandya@codeaurora.org, toshi.kani@hpe.com, tglx@linutronix.de, mhocko@suse.com, akpm@linux-foundation.org, sean.j.christopherson@intel.com, Will Deacon Subject: [PATCH v4 1/5] ioremap: Rework pXd_free_pYd_page() API Date: Mon, 26 Nov 2018 17:07:43 +0000 Message-Id: <1543252067-30831-2-git-send-email-will.deacon@arm.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1543252067-30831-1-git-send-email-will.deacon@arm.com> References: <1543252067-30831-1-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;