Introduce PAGE_NONE_X macro which provides exec-only rights. For the time being, this is a copy of PAGE_READONLY_X on all subarches except on book3s/64 where PAGE_EXECONLY becomes PAGE_NONE_X.
On book3s/64, as PAGE_EXECONLY is only valid for Radix add VM_READ flag in vm_get_page_prot() for non-Radix. And update access_error() so that a non exec fault on a VM_EXEC only mapping is always invalid, even when the underlying layer don't always generate a fault for that. Signed-off-by: Christophe Leroy <christophe.le...@csgroup.eu> Cc: Russell Currey <rus...@russell.cc> Cc: Kees Cook <keesc...@chromium.org> --- arch/powerpc/include/asm/book3s/32/pgtable.h | 1 + arch/powerpc/include/asm/book3s/64/pgtable.h | 4 ++-- arch/powerpc/include/asm/nohash/32/pte-40x.h | 1 + arch/powerpc/include/asm/nohash/32/pte-44x.h | 1 + arch/powerpc/include/asm/nohash/32/pte-85xx.h | 1 + arch/powerpc/include/asm/nohash/32/pte-8xx.h | 1 + arch/powerpc/include/asm/nohash/pte-e500.h | 1 + arch/powerpc/mm/book3s64/pgtable.c | 10 ++++------ arch/powerpc/mm/fault.c | 9 +++++---- arch/powerpc/mm/pgtable.c | 4 ++-- 10 files changed, 19 insertions(+), 14 deletions(-) diff --git a/arch/powerpc/include/asm/book3s/32/pgtable.h b/arch/powerpc/include/asm/book3s/32/pgtable.h index d49c2a9d4ffe..96a38ce29a76 100644 --- a/arch/powerpc/include/asm/book3s/32/pgtable.h +++ b/arch/powerpc/include/asm/book3s/32/pgtable.h @@ -105,6 +105,7 @@ static inline bool pte_user(pte_t pte) * Write permissions imply read permissions for now. */ #define PAGE_NONE __pgprot(_PAGE_BASE) +#define PAGE_NONE_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h index 4acc9690f599..4ae909e95d46 100644 --- a/arch/powerpc/include/asm/book3s/64/pgtable.h +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h @@ -144,14 +144,14 @@ * possible on platforms that define _PAGE_EXEC */ #define PAGE_NONE __pgprot(_PAGE_BASE | _PAGE_PRIVILEGED) +/* Radix only, Hash uses PAGE_READONLY_X + execute-only pkey instead */ +#define PAGE_NONE_X __pgprot(_PAGE_BASE | _PAGE_EXEC) #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_RW) #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_RW | _PAGE_EXEC) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_READ) #define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC) #define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_READ) #define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_READ | _PAGE_EXEC) -/* Radix only, Hash uses PAGE_READONLY_X + execute-only pkey instead */ -#define PAGE_EXECONLY __pgprot(_PAGE_BASE | _PAGE_EXEC) /* Permission masks used for kernel mappings */ #define PAGE_KERNEL __pgprot(_PAGE_BASE | _PAGE_KERNEL_RW) diff --git a/arch/powerpc/include/asm/nohash/32/pte-40x.h b/arch/powerpc/include/asm/nohash/32/pte-40x.h index 6fe46e754556..b5ad980cca64 100644 --- a/arch/powerpc/include/asm/nohash/32/pte-40x.h +++ b/arch/powerpc/include/asm/nohash/32/pte-40x.h @@ -77,6 +77,7 @@ /* Permission masks used to generate the __P and __S table */ #define PAGE_NONE __pgprot(_PAGE_BASE) +#define PAGE_NONE_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) diff --git a/arch/powerpc/include/asm/nohash/32/pte-44x.h b/arch/powerpc/include/asm/nohash/32/pte-44x.h index b7ed13cee137..afea625b6ad2 100644 --- a/arch/powerpc/include/asm/nohash/32/pte-44x.h +++ b/arch/powerpc/include/asm/nohash/32/pte-44x.h @@ -107,6 +107,7 @@ /* Permission masks used to generate the __P and __S table */ #define PAGE_NONE __pgprot(_PAGE_BASE) +#define PAGE_NONE_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) diff --git a/arch/powerpc/include/asm/nohash/32/pte-85xx.h b/arch/powerpc/include/asm/nohash/32/pte-85xx.h index 16451df5ddb0..7cfe4913f3aa 100644 --- a/arch/powerpc/include/asm/nohash/32/pte-85xx.h +++ b/arch/powerpc/include/asm/nohash/32/pte-85xx.h @@ -63,6 +63,7 @@ /* Permission masks used to generate the __P and __S table */ #define PAGE_NONE __pgprot(_PAGE_BASE) +#define PAGE_NONE_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_EXEC) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) diff --git a/arch/powerpc/include/asm/nohash/32/pte-8xx.h b/arch/powerpc/include/asm/nohash/32/pte-8xx.h index 1a89ebdc3acc..b234a93b05f1 100644 --- a/arch/powerpc/include/asm/nohash/32/pte-8xx.h +++ b/arch/powerpc/include/asm/nohash/32/pte-8xx.h @@ -79,6 +79,7 @@ /* Permission masks used to generate the __P and __S table */ #define PAGE_NONE __pgprot(_PAGE_BASE | _PAGE_NA) +#define PAGE_NONE_X __pgprot(_PAGE_BASE | _PAGE_RO | _PAGE_EXEC) #define PAGE_SHARED __pgprot(_PAGE_BASE) #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_EXEC) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_RO) diff --git a/arch/powerpc/include/asm/nohash/pte-e500.h b/arch/powerpc/include/asm/nohash/pte-e500.h index d8924cbd61e4..1cd9c19b81a0 100644 --- a/arch/powerpc/include/asm/nohash/pte-e500.h +++ b/arch/powerpc/include/asm/nohash/pte-e500.h @@ -91,6 +91,7 @@ /* Permission masks used to generate the __P and __S table */ #define PAGE_NONE __pgprot(_PAGE_BASE) +#define PAGE_NONE_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_BAP_UX) #define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) #define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_BAP_UX) #define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) diff --git a/arch/powerpc/mm/book3s64/pgtable.c b/arch/powerpc/mm/book3s64/pgtable.c index 2f2872986b09..d1d7e314c0d8 100644 --- a/arch/powerpc/mm/book3s64/pgtable.c +++ b/arch/powerpc/mm/book3s64/pgtable.c @@ -557,12 +557,10 @@ pgprot_t vm_get_page_prot(unsigned long vm_flags) unsigned long prot; /* Radix supports execute-only, but protection_map maps X -> RX */ - if (radix_enabled() && ((vm_flags & VM_ACCESS_FLAGS) == VM_EXEC)) { - prot = pgprot_val(PAGE_EXECONLY); - } else { - prot = pgprot_val(protection_map[vm_flags & - (VM_ACCESS_FLAGS | VM_SHARED)]); - } + if (!radix_enabled() && ((vm_flags & VM_ACCESS_FLAGS) == VM_EXEC)) + vm_flags |= VM_READ; + + prot = pgprot_val(protection_map[vm_flags & (VM_ACCESS_FLAGS | VM_SHARED)]); if (vm_flags & VM_SAO) prot |= _PAGE_SAO; diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c index 5bfdf6ecfa96..50e1bfffe552 100644 --- a/arch/powerpc/mm/fault.c +++ b/arch/powerpc/mm/fault.c @@ -266,14 +266,15 @@ static bool access_error(bool is_write, bool is_exec, struct vm_area_struct *vma } /* - * VM_READ, VM_WRITE and VM_EXEC all imply read permissions, as - * defined in protection_map[]. Read faults can only be caused by - * a PROT_NONE mapping, or with a PROT_EXEC-only mapping on Radix. + * VM_READ, VM_WRITE and VM_EXEC may imply read permissions, as + * defined in protection_map[]. In that case Read faults can only be + * caused by a PROT_NONE mapping. However a non exec access on a + * VM_EXEC only mapping is invalid anyway, so report it as such. */ if (unlikely(!vma_is_accessible(vma))) return true; - if (unlikely(radix_enabled() && ((vma->vm_flags & VM_ACCESS_FLAGS) == VM_EXEC))) + if ((vma->vm_flags & VM_ACCESS_FLAGS) == VM_EXEC) return true; /* diff --git a/arch/powerpc/mm/pgtable.c b/arch/powerpc/mm/pgtable.c index cb2dcdb18f8e..1a27489e235b 100644 --- a/arch/powerpc/mm/pgtable.c +++ b/arch/powerpc/mm/pgtable.c @@ -479,7 +479,7 @@ const pgprot_t protection_map[16] = { [VM_READ] = PAGE_READONLY, [VM_WRITE] = PAGE_COPY, [VM_WRITE | VM_READ] = PAGE_COPY, - [VM_EXEC] = PAGE_READONLY_X, + [VM_EXEC] = PAGE_NONE_X, [VM_EXEC | VM_READ] = PAGE_READONLY_X, [VM_EXEC | VM_WRITE] = PAGE_COPY_X, [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY_X, @@ -487,7 +487,7 @@ const pgprot_t protection_map[16] = { [VM_SHARED | VM_READ] = PAGE_READONLY, [VM_SHARED | VM_WRITE] = PAGE_SHARED, [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED, - [VM_SHARED | VM_EXEC] = PAGE_READONLY_X, + [VM_SHARED | VM_EXEC] = PAGE_NONE_X, [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY_X, [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED_X, [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED_X -- 2.41.0