From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x242.google.com (mail-qt0-x242.google.com [IPv6:2607:f8b0:400d:c0d::242]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3x2v4M3tNPzDr3F for ; Thu, 6 Jul 2017 07:23:31 +1000 (AEST) Received: by mail-qt0-x242.google.com with SMTP id c20so201585qte.0 for ; Wed, 05 Jul 2017 14:23:31 -0700 (PDT) Sender: Ram Pai 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> In-Reply-To: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> References: <1499289735-14220-1-git-send-email-linuxram@us.ibm.com> List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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