From patchwork Sat Oct 25 17:59:57 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jungseung Lee X-Patchwork-Id: 5151581 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 5BCA5C11AC for ; Sat, 25 Oct 2014 18:03:20 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 45ACA202D1 for ; Sat, 25 Oct 2014 18:03:19 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 6654B202C8 for ; Sat, 25 Oct 2014 18:03:18 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xi5dr-0000Cb-3J; Sat, 25 Oct 2014 18:00:43 +0000 Received: from mail-pd0-x22e.google.com ([2607:f8b0:400e:c02::22e]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1Xi5dn-0000Bj-3b for linux-arm-kernel@lists.infradead.org; Sat, 25 Oct 2014 18:00:39 +0000 Received: by mail-pd0-f174.google.com with SMTP id p10so3188320pdj.19 for ; Sat, 25 Oct 2014 11:00:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=ydsTEITjUlhvvjtKA83Rkl+GFK7sn20L6l2aYu+laRg=; b=DLg1opLSpDVddz6P0CsdDGgHoXa2lcEpfgyP57DL3XVOgJxUpwBAjUerS7nhAJOnB6 LDJascvV3/x/jOCAJegJ8GJnODKf/1e1/y8IbnSNyk3VHSqme2a6ahyISVN/SdtfFulW B27BYlluW7h1oFWCDZXVGjOdZd7Wcpl0fa8iZI8UIqKveQ+p8oa5RAKV21By/NPZ6N1b TVgT1xbmzukWgyjaqm3VMrP5gkYUJxEr2zNf0FfNq+ljRL4watRWpzdqXDc/7OXnRNLN RlKKlQTCWi2pth7I9p9mM0HTEO5M4wXxTH5VssilNSHPXE0xGb8vrGkYqC4fR7Dct9mJ 4Law== X-Received: by 10.68.57.232 with SMTP id l8mr12265735pbq.113.1414260016782; Sat, 25 Oct 2014 11:00:16 -0700 (PDT) Received: from localhost.localdomain ([112.150.44.91]) by mx.google.com with ESMTPSA id kk7sm6774866pab.31.2014.10.25.11.00.13 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Sat, 25 Oct 2014 11:00:15 -0700 (PDT) From: Jungseung Lee To: Russell King , Catalin Marinas , Ard Biesheuvel , Laura Abbott , Will Deacon , linux-arm-kernel@lists.infradead.org Subject: [PATCH] arm: Support for the PXN CPU feature on ARMv7. Date: Sun, 26 Oct 2014 02:59:57 +0900 Message-Id: <1414259997-9350-1-git-send-email-js07.lee@gmail.com> X-Mailer: git-send-email 1.9.1 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20141025_110039_228473_9803FBBF X-CRM114-Status: GOOD ( 15.79 ) X-Spam-Score: -0.8 (/) Cc: Jungseung Lee X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.18-1 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 X-Spam-Status: No, score=-3.2 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_NONE, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Modern ARMv7-A/R cores can optionally implement below new hardware feature: - PXN: Privileged execute-never(PXN) is a security feature. PXN bit determines whether the processor can execute software from the region. This is effective solution against ret2usr attack. On an implementation that does not include the LPAE, PXN is optionally supported. This patch set PXN bit on user page table for preventing user code execution with privilege mode. Signed-off-by: Jungseung Lee --- arch/arm/include/asm/pgalloc.h | 12 +++++++++++- arch/arm/include/asm/pgtable-2level-hwdef.h | 2 ++ arch/arm/kernel/setup.c | 7 +++++++ 3 files changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/arm/include/asm/pgalloc.h b/arch/arm/include/asm/pgalloc.h index 78a7793..a931544 100644 --- a/arch/arm/include/asm/pgalloc.h +++ b/arch/arm/include/asm/pgalloc.h @@ -25,6 +25,10 @@ #define _PAGE_USER_TABLE (PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_USER)) #define _PAGE_KERNEL_TABLE (PMD_TYPE_TABLE | PMD_BIT4 | PMD_DOMAIN(DOMAIN_KERNEL)) +#ifdef CONFIG_CPU_V7 +extern bool cpu_has_pxn; +#endif + #ifdef CONFIG_ARM_LPAE static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr) @@ -157,7 +161,13 @@ pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep) static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep) { - __pmd_populate(pmdp, page_to_phys(ptep), _PAGE_USER_TABLE); +#ifdef CONFIG_CPU_V7 + if (cpu_has_pxn) + __pmd_populate(pmdp, page_to_phys(ptep), + _PAGE_USER_TABLE | PMD_PXNTABLE); + else +#endif + __pmd_populate(pmdp, page_to_phys(ptep), _PAGE_USER_TABLE); } #define pmd_pgtable(pmd) pmd_page(pmd) diff --git a/arch/arm/include/asm/pgtable-2level-hwdef.h b/arch/arm/include/asm/pgtable-2level-hwdef.h index 5cfba15..5e68278 100644 --- a/arch/arm/include/asm/pgtable-2level-hwdef.h +++ b/arch/arm/include/asm/pgtable-2level-hwdef.h @@ -20,12 +20,14 @@ #define PMD_TYPE_FAULT (_AT(pmdval_t, 0) << 0) #define PMD_TYPE_TABLE (_AT(pmdval_t, 1) << 0) #define PMD_TYPE_SECT (_AT(pmdval_t, 2) << 0) +#define PMD_PXNTABLE (_AT(pmdval_t, 1) << 2) /* v7 */ #define PMD_BIT4 (_AT(pmdval_t, 1) << 4) #define PMD_DOMAIN(x) (_AT(pmdval_t, (x)) << 5) #define PMD_PROTECTION (_AT(pmdval_t, 1) << 9) /* v5 */ /* * - section */ +#define PMD_SECT_PXN (_AT(pmdval_t, 1) << 0) /* v7 */ #define PMD_SECT_BUFFERABLE (_AT(pmdval_t, 1) << 2) #define PMD_SECT_CACHEABLE (_AT(pmdval_t, 1) << 3) #define PMD_SECT_XN (_AT(pmdval_t, 1) << 4) /* v6 */ diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index c031063..8556044 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -104,6 +104,9 @@ EXPORT_SYMBOL(elf_hwcap); unsigned int elf_hwcap2 __read_mostly; EXPORT_SYMBOL(elf_hwcap2); +#ifdef CONFIG_CPU_V7 +bool cpu_has_pxn; +#endif #ifdef MULTI_CPU struct processor processor __read_mostly; @@ -390,6 +393,10 @@ static void __init cpuid_init_hwcaps(void) /* LPAE implies atomic ldrd/strd instructions */ vmsa = (read_cpuid_ext(CPUID_EXT_MMFR0) & 0xf) >> 0; +#ifdef CONFIG_CPU_V7 + if (vmsa >= 4) + cpu_has_pxn = 1; +#endif if (vmsa >= 5) elf_hwcap |= HWCAP_LPAE; }