From d94b827e89dc3f92cd871d10f4992a6bd3c861e5 Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Fri, 27 Nov 2020 10:14:10 +0530 Subject: powerpc/book3s64/kuap: Use Key 3 for kernel mapping with hash translation This patch updates kernel hash page table entries to use storage key 3 for its mapping. This implies all kernel access will now use key 3 to control READ/WRITE. The patch also prevents the allocation of key 3 from userspace and UAMOR value is updated such that userspace cannot modify key 3. Signed-off-by: Aneesh Kumar K.V Reviewed-by: Sandipan Das Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20201127044424.40686-9-aneesh.kumar@linux.ibm.com --- arch/powerpc/include/asm/book3s/64/hash-pkey.h | 25 +++++++++++++++++++------ arch/powerpc/include/asm/book3s/64/hash.h | 2 +- arch/powerpc/include/asm/book3s/64/mmu-hash.h | 1 + arch/powerpc/include/asm/mmu_context.h | 2 +- arch/powerpc/mm/book3s64/hash_4k.c | 2 +- arch/powerpc/mm/book3s64/hash_64k.c | 4 ++-- arch/powerpc/mm/book3s64/hash_hugepage.c | 2 +- arch/powerpc/mm/book3s64/hash_hugetlbpage.c | 2 +- arch/powerpc/mm/book3s64/hash_pgtable.c | 2 +- arch/powerpc/mm/book3s64/hash_utils.c | 10 ++++++---- arch/powerpc/mm/book3s64/pkeys.c | 12 ++++++++++++ 11 files changed, 46 insertions(+), 18 deletions(-) (limited to 'arch/powerpc') diff --git a/arch/powerpc/include/asm/book3s/64/hash-pkey.h b/arch/powerpc/include/asm/book3s/64/hash-pkey.h index 795010897e5d..f1e60d579f6c 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-pkey.h +++ b/arch/powerpc/include/asm/book3s/64/hash-pkey.h @@ -2,6 +2,9 @@ #ifndef _ASM_POWERPC_BOOK3S_64_HASH_PKEY_H #define _ASM_POWERPC_BOOK3S_64_HASH_PKEY_H +/* We use key 3 for KERNEL */ +#define HASH_DEFAULT_KERNEL_KEY (HPTE_R_KEY_BIT0 | HPTE_R_KEY_BIT1) + static inline u64 hash__vmflag_to_pte_pkey_bits(u64 vm_flags) { return (((vm_flags & VM_PKEY_BIT0) ? H_PTE_PKEY_BIT0 : 0x0UL) | @@ -11,13 +14,23 @@ static inline u64 hash__vmflag_to_pte_pkey_bits(u64 vm_flags) ((vm_flags & VM_PKEY_BIT4) ? H_PTE_PKEY_BIT4 : 0x0UL)); } -static inline u64 pte_to_hpte_pkey_bits(u64 pteflags) +static inline u64 pte_to_hpte_pkey_bits(u64 pteflags, unsigned long flags) { - return (((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL) | - ((pteflags & H_PTE_PKEY_BIT3) ? HPTE_R_KEY_BIT3 : 0x0UL) | - ((pteflags & H_PTE_PKEY_BIT2) ? HPTE_R_KEY_BIT2 : 0x0UL) | - ((pteflags & H_PTE_PKEY_BIT1) ? HPTE_R_KEY_BIT1 : 0x0UL) | - ((pteflags & H_PTE_PKEY_BIT0) ? HPTE_R_KEY_BIT0 : 0x0UL)); + unsigned long pte_pkey; + + pte_pkey = (((pteflags & H_PTE_PKEY_BIT4) ? HPTE_R_KEY_BIT4 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT3) ? HPTE_R_KEY_BIT3 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT2) ? HPTE_R_KEY_BIT2 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT1) ? HPTE_R_KEY_BIT1 : 0x0UL) | + ((pteflags & H_PTE_PKEY_BIT0) ? HPTE_R_KEY_BIT0 : 0x0UL)); + + if (mmu_has_feature(MMU_FTR_BOOK3S_KUAP) || + mmu_has_feature(MMU_FTR_BOOK3S_KUEP)) { + if ((pte_pkey == 0) && (flags & HPTE_USE_KERNEL_KEY)) + return HASH_DEFAULT_KERNEL_KEY; + } + + return pte_pkey; } static inline u16 hash__pte_to_pkey_bits(u64 pteflags) diff --git a/arch/powerpc/include/asm/book3s/64/hash.h b/arch/powerpc/include/asm/book3s/64/hash.h index 73ad038ed10b..d959b0195ad9 100644 --- a/arch/powerpc/include/asm/book3s/64/hash.h +++ b/arch/powerpc/include/asm/book3s/64/hash.h @@ -145,7 +145,7 @@ extern void hash__mark_initmem_nx(void); extern void hpte_need_flush(struct mm_struct *mm, unsigned long addr, pte_t *ptep, unsigned long pte, int huge); -extern unsigned long htab_convert_pte_flags(unsigned long pteflags); +unsigned long htab_convert_pte_flags(unsigned long pteflags, unsigned long flags); /* Atomic PTE updates */ static inline unsigned long hash__pte_update(struct mm_struct *mm, unsigned long addr, diff --git a/arch/powerpc/include/asm/book3s/64/mmu-hash.h b/arch/powerpc/include/asm/book3s/64/mmu-hash.h index 683a9c7d1b03..9192cb05a6ab 100644 --- a/arch/powerpc/include/asm/book3s/64/mmu-hash.h +++ b/arch/powerpc/include/asm/book3s/64/mmu-hash.h @@ -452,6 +452,7 @@ static inline unsigned long hpt_hash(unsigned long vpn, #define HPTE_LOCAL_UPDATE 0x1 #define HPTE_NOHPTE_UPDATE 0x2 +#define HPTE_USE_KERNEL_KEY 0x4 extern int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, pte_t *ptep, unsigned long trap, diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h index e5a5e3cb7724..033d2f39ed28 100644 --- a/arch/powerpc/include/asm/mmu_context.h +++ b/arch/powerpc/include/asm/mmu_context.h @@ -286,7 +286,7 @@ static inline bool arch_vma_access_permitted(struct vm_area_struct *vma, #define thread_pkey_regs_init(thread) #define arch_dup_pkeys(oldmm, mm) -static inline u64 pte_to_hpte_pkey_bits(u64 pteflags) +static inline u64 pte_to_hpte_pkey_bits(u64 pteflags, unsigned long flags) { return 0x0UL; } diff --git a/arch/powerpc/mm/book3s64/hash_4k.c b/arch/powerpc/mm/book3s64/hash_4k.c index 22e787123cdf..7de1a8a0c62a 100644 --- a/arch/powerpc/mm/book3s64/hash_4k.c +++ b/arch/powerpc/mm/book3s64/hash_4k.c @@ -54,7 +54,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, * PP bits. _PAGE_USER is already PP bit 0x2, so we only * need to add in 0x1 if it's a read-only user page */ - rflags = htab_convert_pte_flags(new_pte); + rflags = htab_convert_pte_flags(new_pte, flags); rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE); if (cpu_has_feature(CPU_FTR_NOEXECUTE) && diff --git a/arch/powerpc/mm/book3s64/hash_64k.c b/arch/powerpc/mm/book3s64/hash_64k.c index 7084ce2951e6..998c6817ed47 100644 --- a/arch/powerpc/mm/book3s64/hash_64k.c +++ b/arch/powerpc/mm/book3s64/hash_64k.c @@ -72,7 +72,7 @@ int __hash_page_4K(unsigned long ea, unsigned long access, unsigned long vsid, * Handle the subpage protection bits */ subpg_pte = new_pte & ~subpg_prot; - rflags = htab_convert_pte_flags(subpg_pte); + rflags = htab_convert_pte_flags(subpg_pte, flags); if (cpu_has_feature(CPU_FTR_NOEXECUTE) && !cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) { @@ -260,7 +260,7 @@ int __hash_page_64K(unsigned long ea, unsigned long access, new_pte |= _PAGE_DIRTY; } while (!pte_xchg(ptep, __pte(old_pte), __pte(new_pte))); - rflags = htab_convert_pte_flags(new_pte); + rflags = htab_convert_pte_flags(new_pte, flags); rpte = __real_pte(__pte(old_pte), ptep, PTRS_PER_PTE); if (cpu_has_feature(CPU_FTR_NOEXECUTE) && diff --git a/arch/powerpc/mm/book3s64/hash_hugepage.c b/arch/powerpc/mm/book3s64/hash_hugepage.c index 440823797de7..c0fabe6c5a12 100644 --- a/arch/powerpc/mm/book3s64/hash_hugepage.c +++ b/arch/powerpc/mm/book3s64/hash_hugepage.c @@ -57,7 +57,7 @@ int __hash_page_thp(unsigned long ea, unsigned long access, unsigned long vsid, if (!(old_pmd & (H_PAGE_THP_HUGE | _PAGE_DEVMAP))) return 0; - rflags = htab_convert_pte_flags(new_pmd); + rflags = htab_convert_pte_flags(new_pmd, flags); #if 0 if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE)) { diff --git a/arch/powerpc/mm/book3s64/hash_hugetlbpage.c b/arch/powerpc/mm/book3s64/hash_hugetlbpage.c index 964467b3a776..b5e9fff8c217 100644 --- a/arch/powerpc/mm/book3s64/hash_hugetlbpage.c +++ b/arch/powerpc/mm/book3s64/hash_hugetlbpage.c @@ -70,7 +70,7 @@ int __hash_page_huge(unsigned long ea, unsigned long access, unsigned long vsid, if (old_pte & (H_PAGE_THP_HUGE | _PAGE_DEVMAP)) return 0; - rflags = htab_convert_pte_flags(new_pte); + rflags = htab_convert_pte_flags(new_pte, flags); if (unlikely(mmu_psize == MMU_PAGE_16G)) offset = PTRS_PER_PUD; else diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c index fd9c7f91b092..567e0c6b3978 100644 --- a/arch/powerpc/mm/book3s64/hash_pgtable.c +++ b/arch/powerpc/mm/book3s64/hash_pgtable.c @@ -443,7 +443,7 @@ void hash__mark_initmem_nx(void) start = (unsigned long)__init_begin; end = (unsigned long)__init_end; - pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL)); + pp = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL), HPTE_USE_KERNEL_KEY); WARN_ON(!hash__change_memory_range(start, end, pp)); } diff --git a/arch/powerpc/mm/book3s64/hash_utils.c b/arch/powerpc/mm/book3s64/hash_utils.c index d2dcb7757c68..e0fe1a43e7b8 100644 --- a/arch/powerpc/mm/book3s64/hash_utils.c +++ b/arch/powerpc/mm/book3s64/hash_utils.c @@ -186,7 +186,7 @@ static struct mmu_psize_def mmu_psize_defaults_gp[] = { * - We make sure R is always set and never lost * - C is _PAGE_DIRTY, and *should* always be set for a writeable mapping */ -unsigned long htab_convert_pte_flags(unsigned long pteflags) +unsigned long htab_convert_pte_flags(unsigned long pteflags, unsigned long flags) { unsigned long rflags = 0; @@ -240,7 +240,7 @@ unsigned long htab_convert_pte_flags(unsigned long pteflags) */ rflags |= HPTE_R_M; - rflags |= pte_to_hpte_pkey_bits(pteflags); + rflags |= pte_to_hpte_pkey_bits(pteflags, flags); return rflags; } @@ -255,7 +255,7 @@ int htab_bolt_mapping(unsigned long vstart, unsigned long vend, shift = mmu_psize_defs[psize].shift; step = 1 << shift; - prot = htab_convert_pte_flags(prot); + prot = htab_convert_pte_flags(prot, HPTE_USE_KERNEL_KEY); DBG("htab_bolt_mapping(%lx..%lx -> %lx (%lx,%d,%d)\n", vstart, vend, pstart, prot, psize, ssize); @@ -1316,12 +1316,14 @@ int hash_page_mm(struct mm_struct *mm, unsigned long ea, vsid = get_kernel_vsid(ea, mmu_kernel_ssize); psize = mmu_vmalloc_psize; ssize = mmu_kernel_ssize; + flags |= HPTE_USE_KERNEL_KEY; break; case IO_REGION_ID: vsid = get_kernel_vsid(ea, mmu_kernel_ssize); psize = mmu_io_psize; ssize = mmu_kernel_ssize; + flags |= HPTE_USE_KERNEL_KEY; break; default: /* @@ -1900,7 +1902,7 @@ static void kernel_map_linear_page(unsigned long vaddr, unsigned long lmi) unsigned long hash; unsigned long vsid = get_kernel_vsid(vaddr, mmu_kernel_ssize); unsigned long vpn = hpt_vpn(vaddr, vsid, mmu_kernel_ssize); - unsigned long mode = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL)); + unsigned long mode = htab_convert_pte_flags(pgprot_val(PAGE_KERNEL), HPTE_USE_KERNEL_KEY); long ret; hash = hpt_hash(vpn, PAGE_SHIFT, mmu_kernel_ssize); diff --git a/arch/powerpc/mm/book3s64/pkeys.c b/arch/powerpc/mm/book3s64/pkeys.c index c5c61aa18a04..e434c0a2ee5d 100644 --- a/arch/powerpc/mm/book3s64/pkeys.c +++ b/arch/powerpc/mm/book3s64/pkeys.c @@ -205,6 +205,18 @@ void __init pkey_early_init_devtree(void) reserved_allocation_mask |= (0x1 << 1); default_uamor &= ~(0x3ul << pkeyshift(1)); + /* handle key which is used by kernel for KAUP */ + reserved_allocation_mask |= (0x1 << 3); + /* + * Mark access for KUAP key in default amr so that + * we continue to operate with that AMR in + * copy_to/from_user(). + */ + default_amr &= ~(0x3ul << pkeyshift(3)); + default_iamr &= ~(0x1ul << pkeyshift(3)); + default_uamor &= ~(0x3ul << pkeyshift(3)); + + /* * Prevent the usage of OS reserved keys. Update UAMOR * for those keys. Also mark the rest of the bits in the -- cgit v1.2.3