From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933515AbcECBsk (ORCPT ); Mon, 2 May 2016 21:48:40 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:59652 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932779AbcECAQa (ORCPT ); Mon, 2 May 2016 20:16:30 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Catalin Marinas , Ganapatrao Kulkarni , Ganapatrao Kulkarni Subject: [PATCH 4.4 026/163] arm64: Update PTE_RDONLY in set_pte_at() for PROT_NONE permission Date: Mon, 2 May 2016 17:10:54 -0700 Message-Id: <20160503000509.399456900@linuxfoundation.org> X-Mailer: git-send-email 2.8.2 In-Reply-To: <20160503000508.556845508@linuxfoundation.org> References: <20160503000508.556845508@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Catalin Marinas commit fdc69e7df3cb24f18a93192641786e5b7ecd1dfe upstream. The set_pte_at() function must update the hardware PTE_RDONLY bit depending on the state of the PTE_WRITE and PTE_DIRTY bits of the given entry value. However, it currently only performs this for pte_valid() entries, ignoring PTE_PROT_NONE. The side-effect is that PROT_NONE mappings would not have the PTE_RDONLY bit set. Without CONFIG_ARM64_HW_AFDBM, this is not an issue since such PROT_NONE pages are not accessible anyway. With commit 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits"), the ptep_set_wrprotect() function was re-written to cope with automatic hardware updates of the dirty state. As an optimisation, only PTE_RDONLY is checked to assess the "dirty" status. Since set_pte_at() does not set this bit for PROT_NONE mappings, such pages may be considered "dirty" as a result of ptep_set_wrprotect(). This patch updates the pte_valid() check to pte_present() in set_pte_at(). It also adds PTE_PROT_NONE to the swap entry bits comment. Fixes: 2f4b829c625e ("arm64: Add support for hardware updates of the access and dirty pte bits") Signed-off-by: Catalin Marinas Reported-by: Ganapatrao Kulkarni Tested-by: Ganapatrao Kulkarni Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/pgtable.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -263,7 +263,7 @@ extern void __sync_icache_dcache(pte_t p static inline void set_pte_at(struct mm_struct *mm, unsigned long addr, pte_t *ptep, pte_t pte) { - if (pte_valid(pte)) { + if (pte_present(pte)) { if (pte_sw_dirty(pte) && pte_write(pte)) pte_val(pte) &= ~PTE_RDONLY; else @@ -640,6 +640,7 @@ extern pgd_t idmap_pg_dir[PTRS_PER_PGD]; * bits 0-1: present (must be zero) * bits 2-7: swap type * bits 8-57: swap offset + * bit 58: PTE_PROT_NONE (must be zero) */ #define __SWP_TYPE_SHIFT 2 #define __SWP_TYPE_BITS 6