From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt0-x241.google.com (mail-qt0-x241.google.com [IPv6:2607:f8b0:400d:c0d::241]) (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 3xLKf254RszDrDX for ; Mon, 31 Jul 2017 10:12:42 +1000 (AEST) Received: by mail-qt0-x241.google.com with SMTP id i19so16859348qte.1 for ; Sun, 30 Jul 2017 17:12:42 -0700 (PDT) Sender: Ram Pai From: Ram Pai To: linuxppc-dev@lists.ozlabs.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, hbabu@us.ibm.com, linuxram@us.ibm.com, bauerman@linux.vnet.ibm.com, mhocko@kernel.org Subject: [RFC v7 02/25] powerpc: track allocation status of all pkeys Date: Sun, 30 Jul 2017 17:12:03 -0700 Message-Id: <1501459946-11619-3-git-send-email-linuxram@us.ibm.com> In-Reply-To: <1501459946-11619-1-git-send-email-linuxram@us.ibm.com> References: <1501459946-11619-1-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: , Total 32 keys are available on power7 and above. However pkey 0,1 are reserved. So effectively we have 30 pkeys. On 4K kernels, we do not have 5 bits in the PTE to represent all the keys; we only have 3bits.Two of those keys are reserved; pkey 0 and pkey 1. So effectively we have 6 pkeys. This patch keeps track of reserved keys, allocated keys and keys that are currently free. Also it adds skeletal functions and macros, that the architecture-independent code expects to be available. Signed-off-by: Ram Pai --- arch/powerpc/include/asm/book3s/64/mmu.h | 9 +++ arch/powerpc/include/asm/mmu_context.h | 1 + arch/powerpc/include/asm/pkeys.h | 98 ++++++++++++++++++++++++++++- arch/powerpc/mm/mmu_context_book3s64.c | 2 + arch/powerpc/mm/pkeys.c | 2 + 5 files changed, 108 insertions(+), 4 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/64/mmu.h b/arch/powerpc/include/asm/book3s/64/mmu.h index 77529a3..104ad72 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu.h +++ b/arch/powerpc/include/asm/book3s/64/mmu.h @@ -108,6 +108,15 @@ struct patb_entry { #ifdef CONFIG_SPAPR_TCE_IOMMU struct list_head iommu_group_mem_list; #endif + +#ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS + /* + * Each bit represents one protection key. + * bit set -> key allocated + * bit unset -> key available for allocation + */ + u32 pkey_allocation_map; +#endif } mm_context_t; /* diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index 4b93547..4705dab 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -184,6 +184,7 @@ 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) #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 4ccb8f5..def385f 100644 --- a/arch/powerpc/include/asm/pkeys.h +++ b/arch/powerpc/include/asm/pkeys.h @@ -2,6 +2,8 @@ #define _ASM_PPC64_PKEYS_H extern bool pkey_inited; +extern int pkeys_total; /* total pkeys as per device tree */ +extern u32 initial_allocation_mask;/* bits set for reserved keys */ /* * powerpc needs an additional vma bit to support 32 keys. @@ -20,21 +22,76 @@ #define VM_PKEY_BIT4 VM_HIGH_ARCH_4 #endif -#define ARCH_VM_PKEY_FLAGS 0 +#define arch_max_pkey() pkeys_total +#define ARCH_VM_PKEY_FLAGS (VM_PKEY_BIT0 | VM_PKEY_BIT1 | VM_PKEY_BIT2 | \ + VM_PKEY_BIT3 | VM_PKEY_BIT4) + +#define pkey_alloc_mask(pkey) (0x1 << pkey) + +#define mm_pkey_allocation_map(mm) (mm->context.pkey_allocation_map) + +#define mm_set_pkey_allocated(mm, pkey) { \ + mm_pkey_allocation_map(mm) |= pkey_alloc_mask(pkey); \ +} + +#define mm_set_pkey_free(mm, pkey) { \ + mm_pkey_allocation_map(mm) &= ~pkey_alloc_mask(pkey); \ +} + +#define mm_set_pkey_is_allocated(mm, pkey) \ + (mm_pkey_allocation_map(mm) & pkey_alloc_mask(pkey)) + +#define mm_set_pkey_is_reserved(mm, pkey) (initial_allocation_mask & \ + pkey_alloc_mask(pkey)) static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey) { - return (pkey == 0); + /* a reserved key is never considered as 'explicitly allocated' */ + return ((pkey < arch_max_pkey()) && + !mm_set_pkey_is_reserved(mm, pkey) && + mm_set_pkey_is_allocated(mm, pkey)); } +/* + * Returns a positive, 5-bit key on success, or -1 on failure. + */ static inline int mm_pkey_alloc(struct mm_struct *mm) { - return -1; + /* + * Note: this is the one and only place we make sure + * that the pkey is valid as far as the hardware is + * concerned. The rest of the kernel trusts that + * only good, valid pkeys come out of here. + */ + u32 all_pkeys_mask = (u32)(~(0x0)); + int ret; + + if (!pkey_inited) + return -1; + /* + * Are we out of pkeys? We must handle this specially + * because ffz() behavior is undefined if there are no + * zeros. + */ + if (mm_pkey_allocation_map(mm) == all_pkeys_mask) + return -1; + + ret = ffz((u32)mm_pkey_allocation_map(mm)); + mm_set_pkey_allocated(mm, ret); + return ret; } static inline int mm_pkey_free(struct mm_struct *mm, int pkey) { - return -EINVAL; + if (!pkey_inited) + return -1; + + if (!mm_pkey_is_allocated(mm, pkey)) + return -EINVAL; + + mm_set_pkey_free(mm, pkey); + + return 0; } /* @@ -58,12 +115,45 @@ static inline int arch_set_user_pkey_access(struct task_struct *tsk, int pkey, return 0; } +static inline void pkey_mm_init(struct mm_struct *mm) +{ + if (!pkey_inited) + return; + mm_pkey_allocation_map(mm) = initial_allocation_mask; +} + static inline void pkey_initialize(void) { + int os_reserved, i; + /* disable the pkey system till everything * is in place. A patch further down the * line will enable it. */ pkey_inited = false; + + /* Lets assume 32 keys */ + pkeys_total = 32; + +#ifdef CONFIG_PPC_4K_PAGES + /* + * the OS can manage only 8 pkeys + * due to its inability to represent + * them in the linux 4K-PTE. + */ + os_reserved = pkeys_total-8; +#else + os_reserved = 0; +#endif + /* + * Bits are in LE format. + * NOTE: 1, 0 are reserved. + * key 0 is the default key, which allows read/write/execute. + * key 1 is recommended not to be used. + * PowerISA(3.0) page 1015, programming note. + */ + initial_allocation_mask = ~0x0; + for (i = 2; i < (pkeys_total - os_reserved); i++) + initial_allocation_mask &= ~(0x1< #include #include +#include #include #include #include @@ -120,6 +121,7 @@ static int hash__init_new_context(struct mm_struct *mm) subpage_prot_init_new_context(mm); + pkey_mm_init(mm); return index; } diff --git a/arch/powerpc/mm/pkeys.c b/arch/powerpc/mm/pkeys.c index c3acee1..37dacc5 100644 --- a/arch/powerpc/mm/pkeys.c +++ b/arch/powerpc/mm/pkeys.c @@ -16,3 +16,5 @@ #include /* PKEY_* */ bool pkey_inited; +int pkeys_total; /* total pkeys as per device tree */ +u32 initial_allocation_mask; /* bits set for reserved keys */ -- 1.7.1