Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753371AbdGEV1U (ORCPT ); Wed, 5 Jul 2017 17:27:20 -0400 Received: from mail-qt0-f195.google.com ([209.85.216.195]:35405 "EHLO mail-qt0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753064AbdGEVXf (ORCPT ); Wed, 5 Jul 2017 17:23:35 -0400 From: Ram Pai To: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org, linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, dave.hansen@intel.com, hbabu@us.ibm.com, linuxram@us.ibm.com, arnd@arndb.de, akpm@linux-foundation.org, corbet@lwn.net, mingo@redhat.com Subject: [RFC v5 25/38] powerpc: helper to validate key-access permissions of a pte Date: Wed, 5 Jul 2017 14:22:02 -0700 Message-Id: <1499289735-14220-26-git-send-email-linuxram@us.ibm.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> References: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2630 Lines: 84 helper function that checks if the read/write/execute is allowed on the pte. Signed-off-by: Ram Pai --- arch/powerpc/include/asm/book3s/64/pgtable.h | 2 + arch/powerpc/include/asm/pkeys.h | 9 +++++++ arch/powerpc/mm/pkeys.c | 31 ++++++++++++++++++++++++++ 3 files changed, 42 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index d9c87c4..aad205c 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -474,6 +474,8 @@ static inline void write_uamor(u64 value) mtspr(SPRN_UAMOR, value); } +extern bool arch_pte_access_permitted(u64 pte, bool write, bool execute); + #else /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ static inline u64 read_amr(void) diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index 6477b87..01f2bfc 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -31,6 +31,15 @@ static inline u64 pte_to_hpte_pkey_bits(u64 pteflags) ((pteflags & H_PAGE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL)); } +static inline u16 pte_to_pkey_bits(u64 pteflags) +{ + return (((pteflags & H_PAGE_PKEY_BIT0) ? 0x10 : 0x0UL) | + ((pteflags & H_PAGE_PKEY_BIT1) ? 0x8 : 0x0UL) | + ((pteflags & H_PAGE_PKEY_BIT2) ? 0x4 : 0x0UL) | + ((pteflags & H_PAGE_PKEY_BIT3) ? 0x2 : 0x0UL) | + ((pteflags & H_PAGE_PKEY_BIT4) ? 0x1 : 0x0UL)); +} + static inline int vma_pkey(struct vm_area_struct *vma) { return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT; diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index c60a045..044a17d 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -170,3 +170,34 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, */ return vma_pkey(vma); } + +static bool pkey_access_permitted(int pkey, bool write, bool execute) +{ + int pkey_shift; + u64 amr; + + if (!pkey) + return true; + + pkey_shift = pkeyshift(pkey); + if (!(read_uamor() & (0x3UL << pkey_shift))) + return true; + + if (execute && !(read_iamr() & (IAMR_EX_BIT << pkey_shift))) + return true; + + if (!write) { + amr = read_amr(); + if (!(amr & (AMR_AD_BIT << pkey_shift))) + return true; + } + + amr = read_amr(); /* delay reading amr uptil absolutely needed */ + return (write && !(amr & (AMR_WD_BIT << pkey_shift))); +} + +bool arch_pte_access_permitted(u64 pte, bool write, bool execute) +{ + return pkey_access_permitted(pte_to_pkey_bits(pte), + write, execute); +} -- 1.7.1