From patchwork Wed May 8 09:52:39 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steve Capper X-Patchwork-Id: 2538171 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork2.kernel.org Received: from casper.infradead.org (casper.infradead.org [85.118.1.10]) by patchwork2.kernel.org (Postfix) with ESMTP id AFDB2DF2E5 for ; Wed, 8 May 2013 09:57:15 +0000 (UTC) Received: from merlin.infradead.org ([2001:4978:20e::2]) by casper.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ua15j-00027M-Pq; Wed, 08 May 2013 09:55:23 +0000 Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ua155-0005Ea-NQ; Wed, 08 May 2013 09:54:39 +0000 Received: from mail-wi0-x22d.google.com ([2a00:1450:400c:c05::22d]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Ua148-00052L-7C for linux-arm-kernel@lists.infradead.org; Wed, 08 May 2013 09:53:47 +0000 Received: by mail-wi0-f173.google.com with SMTP id ey16so4807656wid.6 for ; Wed, 08 May 2013 02:53:18 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20120113; h=x-received:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references:x-gm-message-state; bh=v59uMJnWa4oWypz0nteTgQVY4w5QUj5AUxmMn3L95lU=; b=VLsniVPkrzhg+3iS/AdsSIL1tryOol/A9Q+xSghUUE+ZsQgayiBHSk7S/4rm3mobs1 3H0vwj/UWAjmheFCuuCNm+ElIO7inblOi02TYdBRmU80+hbxMl6XJVTfBH+t/tBu0Efs 4o/5RT7HFep2/SYuxKD/AzQHPOGQy7cQTn2At5IEuDdsh2l/FZjJ7ljhHRzuFMMFNL4M /nZGpNeVZuPX8/Xp+KJrDv+oe45Zo6yaNdsOX6QGTQuwv2ONLkyxAEDvhVHB+nrAeqDD 1keY04BIwC5B9aB+zMTzoZ+Vq7qw53CIEbCRKXFNugmlzfUzA54vk2lgrPAR2zDksoy5 Nq6w== X-Received: by 10.194.133.198 with SMTP id pe6mr9359305wjb.9.1368006798244; Wed, 08 May 2013 02:53:18 -0700 (PDT) Received: from localhost.localdomain (marmot.wormnet.eu. [188.246.204.87]) by mx.google.com with ESMTPSA id m14sm8068040wij.9.2013.05.08.02.53.17 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 08 May 2013 02:53:17 -0700 (PDT) From: Steve Capper To: linux-mm@kvack.org, x86@kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: [RFC PATCH v2 07/11] ARM64: mm: Make PAGE_NONE pages read only and no-execute. Date: Wed, 8 May 2013 10:52:39 +0100 Message-Id: <1368006763-30774-8-git-send-email-steve.capper@linaro.org> X-Mailer: git-send-email 1.7.2.5 In-Reply-To: <1368006763-30774-1-git-send-email-steve.capper@linaro.org> References: <1368006763-30774-1-git-send-email-steve.capper@linaro.org> X-Gm-Message-State: ALoCoQnux/42VLkI8wWqiGkTKXwL/67ggwXkNNqtOSNLIWMkjGH9ETyvhSk13KKeQJsZcRawrKOs X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20130508_055340_617407_AA7E1F7A X-CRM114-Status: GOOD ( 11.29 ) X-Spam-Score: -1.9 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.9 points) pts rule name description ---- ---------------------- -------------------------------------------------- -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] Cc: Steve Capper , patches@linaro.org, Catalin Marinas , Will Deacon , Michal Hocko , Ken Chen , Mel Gorman X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org If we consider the following code sequence: my_pte = pte_modify(entry, myprot); x = pte_write(my_pte); y = pte_exec(my_pte); If myprot comes from a PROT_NONE page, then x and y will both be true which is undesireable behaviour. This patch sets the no-execute and read-only bits for PAGE_NONE such that the code above will return false for both x and y. Signed-off-by: Steve Capper --- arch/arm64/include/asm/pgtable.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index e333a24..b1a1b59 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -66,7 +66,7 @@ extern pgprot_t pgprot_default; #define _MOD_PROT(p, b) __pgprot_modify(p, 0, b) -#define PAGE_NONE __pgprot_modify(pgprot_default, PTE_TYPE_MASK, PTE_PROT_NONE) +#define PAGE_NONE __pgprot_modify(pgprot_default, PTE_TYPE_MASK, PTE_PROT_NONE | PTE_RDONLY | PTE_UXN) #define PAGE_SHARED _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_UXN) #define PAGE_SHARED_EXEC _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN) #define PAGE_COPY _MOD_PROT(pgprot_default, PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_RDONLY) @@ -76,7 +76,7 @@ extern pgprot_t pgprot_default; #define PAGE_KERNEL _MOD_PROT(pgprot_default, PTE_PXN | PTE_UXN | PTE_DIRTY) #define PAGE_KERNEL_EXEC _MOD_PROT(pgprot_default, PTE_UXN | PTE_DIRTY) -#define __PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE) +#define __PAGE_NONE __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE | PTE_RDONLY | PTE_UXN) #define __PAGE_SHARED __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN) #define __PAGE_SHARED_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN) #define __PAGE_COPY __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_RDONLY)