From patchwork Wed Jun 27 14:13:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Kani, Toshi" X-Patchwork-Id: 10491769 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6600F60230 for ; Wed, 27 Jun 2018 14:16:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 54D692933B for ; Wed, 27 Jun 2018 14:16:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4894A29340; Wed, 27 Jun 2018 14:16:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id CF6A12933B for ; Wed, 27 Jun 2018 14:16:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=tG1Tn9mZFqz1tWfyDhGwYfC6v91lQrCoESNVbhk9PCA=; b=tzSWaCah/zVjbTrdMg6Cze2GSH UT/dzKRb3g6qLFJiSdPJM2OWw2enem7ZUJqkq7uM70hkeqPR+igwDbxQRjgj/rN1USr+jZvmhUXJD SSSm0ie6+BbngklPV5Z8hLng9O+XfBwGRXt0wzqvYO7f3b8HAP6TS0MY7Jgy5cpDbZDXgm9ewbcEV 3TUq/sQAjslJKWHWK1YrdJ442Ttl074nOtRJ5iBcLU4TNHnuJggZsb8q8eiMibnKG6xPUWYPTh3PV Yn7iqgkSHopdwPvJQP+ADV3icihtCsvgQsShpl+fAuRPxhSAYR1Qw+icLUsUedQkbhgof92xholUo wjE4T1eQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1fYBFL-000196-4w; Wed, 27 Jun 2018 14:16:35 +0000 Received: from g9t5009.houston.hpe.com ([15.241.48.73]) by bombadil.infradead.org with esmtps (Exim 4.90_1 #2 (Red Hat Linux)) id 1fYBEo-0000Nw-Mn for linux-arm-kernel@lists.infradead.org; Wed, 27 Jun 2018 14:16:05 +0000 Received: from g4t3433.houston.hpecorp.net (g4t3433.houston.hpecorp.net [16.208.49.245]) by g9t5009.houston.hpe.com (Postfix) with ESMTP id E799F51; Wed, 27 Jun 2018 14:15:48 +0000 (UTC) Received: from misato.americas.hpqcorp.net (unknown [10.34.81.122]) by g4t3433.houston.hpecorp.net (Postfix) with ESMTP id 295AC47; Wed, 27 Jun 2018 14:15:48 +0000 (UTC) From: Toshi Kani To: mhocko@suse.com, akpm@linux-foundation.org, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com Subject: [PATCH v4 1/3] x86/mm: disable ioremap free page handling on x86-PAE Date: Wed, 27 Jun 2018 08:13:46 -0600 Message-Id: <20180627141348.21777-2-toshi.kani@hpe.com> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180627141348.21777-1-toshi.kani@hpe.com> References: <20180627141348.21777-1-toshi.kani@hpe.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20180627_071602_986049_9AF4B314 X-CRM114-Status: UNSURE ( 8.40 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Toshi Kani , Joerg Roedel , x86@kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, linux-mm@kvack.org, cpandya@codeaurora.org, linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP ioremap() supports pmd mappings on x86-PAE. However, kernel's pmd tables are not shared among processes on x86-PAE. Therefore, any update to sync'd pmd entries need re-syncing. Freeing a pte page also leads to a vmalloc fault and hits the BUG_ON in vmalloc_sync_one(). Disable free page handling on x86-PAE. pud_free_pmd_page() and pmd_free_pte_page() simply return 0 if a given pud/pmd entry is present. This assures that ioremap() does not update sync'd pmd entries at the cost of falling back to pte mappings. Fixes: 28ee90fe6048 ("x86/mm: implement free pmd/pte page interfaces") Reported-by: Joerg Roedel Signed-off-by: Toshi Kani Cc: Andrew Morton Cc: Michal Hocko Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Joerg Roedel Cc: --- arch/x86/mm/pgtable.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 47b5951e592b..1aeb7a5dbce5 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -719,6 +719,7 @@ int pmd_clear_huge(pmd_t *pmd) return 0; } +#ifdef CONFIG_X86_64 /** * pud_free_pmd_page - Clear pud entry and free pmd page. * @pud: Pointer to a PUD. @@ -766,4 +767,22 @@ int pmd_free_pte_page(pmd_t *pmd) return 1; } + +#else /* !CONFIG_X86_64 */ + +int pud_free_pmd_page(pud_t *pud) +{ + return pud_none(*pud); +} + +/* + * Disable free page handling on x86-PAE. This assures that ioremap() + * does not update sync'd pmd entries. See vmalloc_sync_one(). + */ +int pmd_free_pte_page(pmd_t *pmd) +{ + return pmd_none(*pmd); +} + +#endif /* CONFIG_X86_64 */ #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */