From 59511cfd08f32d0e9d363ffa0fdaaa75afdc52b1 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Wed, 10 Mar 2021 11:49:42 +0100 Subject: arm64: mm: use XN table mapping attributes for user/kernel mappings As the kernel and user space page tables are strictly mutually exclusive when it comes to executable permissions, we can set the UXN table attribute on all table entries that are created while creating kernel mappings in the swapper page tables, and the PXN table attribute on all table entries that are created while creating user space mappings in user space page tables. While at it, get rid of a redundant comment. Reviewed-by: Anshuman Khandual Signed-off-by: Ard Biesheuvel Link: https://lore.kernel.org/r/20210310104942.174584-4-ardb@kernel.org Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/pgalloc.h | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) (limited to 'arch') diff --git a/arch/arm64/include/asm/pgalloc.h b/arch/arm64/include/asm/pgalloc.h index 27cc643d0509..31fbab3d6f99 100644 --- a/arch/arm64/include/asm/pgalloc.h +++ b/arch/arm64/include/asm/pgalloc.h @@ -27,7 +27,10 @@ static inline void __pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot) static inline void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmdp) { - __pud_populate(pudp, __pa(pmdp), PUD_TYPE_TABLE); + pudval_t pudval = PUD_TYPE_TABLE; + + pudval |= (mm == &init_mm) ? PUD_TABLE_UXN : PUD_TABLE_PXN; + __pud_populate(pudp, __pa(pmdp), pudval); } #else static inline void __pud_populate(pud_t *pudp, phys_addr_t pmdp, pudval_t prot) @@ -45,7 +48,10 @@ static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot) static inline void p4d_populate(struct mm_struct *mm, p4d_t *p4dp, pud_t *pudp) { - __p4d_populate(p4dp, __pa(pudp), P4D_TYPE_TABLE); + p4dval_t p4dval = P4D_TYPE_TABLE; + + p4dval |= (mm == &init_mm) ? P4D_TABLE_UXN : P4D_TABLE_PXN; + __p4d_populate(p4dp, __pa(pudp), p4dval); } #else static inline void __p4d_populate(p4d_t *p4dp, phys_addr_t pudp, p4dval_t prot) @@ -70,16 +76,15 @@ static inline void __pmd_populate(pmd_t *pmdp, phys_addr_t ptep, static inline void pmd_populate_kernel(struct mm_struct *mm, pmd_t *pmdp, pte_t *ptep) { - /* - * The pmd must be loaded with the physical address of the PTE table - */ - __pmd_populate(pmdp, __pa(ptep), PMD_TYPE_TABLE); + VM_BUG_ON(mm != &init_mm); + __pmd_populate(pmdp, __pa(ptep), PMD_TYPE_TABLE | PMD_TABLE_UXN); } static inline void pmd_populate(struct mm_struct *mm, pmd_t *pmdp, pgtable_t ptep) { - __pmd_populate(pmdp, page_to_phys(ptep), PMD_TYPE_TABLE); + VM_BUG_ON(mm == &init_mm); + __pmd_populate(pmdp, page_to_phys(ptep), PMD_TYPE_TABLE | PMD_TABLE_PXN); } #define pmd_pgtable(pmd) pmd_page(pmd) -- cgit