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 3xpsrp2yZhzDrdP for ; Sat, 9 Sep 2017 08:47:06 +1000 (AEST) Received: by mail-qt0-x242.google.com with SMTP id q8so2360196qtb.1 for ; Fri, 08 Sep 2017 15:47:06 -0700 (PDT) Sender: Ram Pai From: Ram Pai To: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org Cc: benh@kernel.crashing.org, paulus@samba.org, khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com, bsingharora@gmail.com, hbabu@us.ibm.com, mhocko@kernel.org, bauerman@linux.vnet.ibm.com, ebiederm@xmission.com, linuxram@us.ibm.com Subject: [PATCH 13/25] powerpc: implementation for arch_override_mprotect_pkey() Date: Fri, 8 Sep 2017 15:45:01 -0700 Message-Id: <1504910713-7094-22-git-send-email-linuxram@us.ibm.com> In-Reply-To: <1504910713-7094-1-git-send-email-linuxram@us.ibm.com> References: <1504910713-7094-1-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: , arch independent code calls arch_override_mprotect_pkey() to return a pkey that best matches the requested protection. This patch provides the implementation. Signed-off-by: Ram Pai --- arch/powerpc/include/asm/mmu_context.h | 5 +++ arch/powerpc/include/asm/pkeys.h | 17 ++++++++++- arch/powerpc/mm/pkeys.c | 47 ++++++++++++++++++++++++++++++++ 3 files changed, 67 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index c705a5d..8e5a87e 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -145,6 +145,11 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, #ifndef CONFIG_PPC64_MEMORY_PROTECTION_KEYS #define pkey_initialize() #define pkey_mm_init(mm) + +static inline int vma_pkey(struct vm_area_struct *vma) +{ + return 0; +} #endif /* CONFIG_PPC64_MEMORY_PROTECTION_KEYS */ #endif /* __KERNEL__ */ diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h index f13e913..d2fffef 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -41,6 +41,16 @@ static inline u64 pkey_to_vmflag_bits(u16 pkey) ((pkey & 0x10UL) ? VM_PKEY_BIT4 : 0x0UL)); } +#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \ + VM_PKEY_BIT3 | VM_PKEY_BIT4) + +static inline int vma_pkey(struct vm_area_struct *vma) +{ + if (!pkey_inited) + return 0; + return (vma->vm_flags & ARCH_VM_PKEY_FLAGS) >> VM_PKEY_SHIFT; +} + #define arch_max_pkey() pkeys_total #define AMR_RD_BIT 0x1UL #define AMR_WR_BIT 0x2UL @@ -142,11 +152,14 @@ static inline int execute_only_pkey(struct mm_struct *mm) return __execute_only_pkey(mm); } - +extern int __arch_override_mprotect_pkey(struct vm_area_struct *vma, + int prot, int pkey); static inline int arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey) { - return 0; + if (!pkey_inited) + return 0; + return __arch_override_mprotect_pkey(vma, prot, pkey); } extern int __arch_set_user_pkey_access(struct task_struct *tsk, int pkey, diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index 8a24983..fb1a76a 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -245,3 +245,50 @@ int __execute_only_pkey(struct mm_struct *mm) mm->context.execute_only_pkey = execute_only_pkey; return execute_only_pkey; } + +static inline bool vma_is_pkey_exec_only(struct vm_area_struct *vma) +{ + /* Do this check first since the vm_flags should be hot */ + if ((vma->vm_flags & (VM_READ | VM_WRITE | VM_EXEC)) != VM_EXEC) + return false; + + return (vma_pkey(vma) == vma->vm_mm->context.execute_only_pkey); +} + +/* + * This should only be called for *plain* mprotect calls. + */ +int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, + int pkey) +{ + /* + * Is this an mprotect_pkey() call? If so, never + * override the value that came from the user. + */ + if (pkey != -1) + return pkey; + + /* + * If the currently associated pkey is execute-only, + * but the requested protection requires read or write, + * move it back to the default pkey. + */ + if (vma_is_pkey_exec_only(vma) && + (prot & (PROT_READ|PROT_WRITE))) + return 0; + + /* + * the requested protection is execute-only. Hence + * lets use a execute-only pkey. + */ + if (prot == PROT_EXEC) { + pkey = execute_only_pkey(vma->vm_mm); + if (pkey > 0) + return pkey; + } + + /* + * nothing to override. + */ + return vma_pkey(vma); +} -- 1.7.1