For UEFI, we need to install the memory mappings used for Runtime Services in a dedicated set of page tables. Add create_pgd_mapping(), which allows us to allocate and install those page table entries early. This also adds a 'map_xn' option, that creates regions with the PXN and UXN bits set.
Signed-off-by: Ard Biesheuvel <[email protected]> --- arch/arm64/include/asm/mmu.h | 3 +++ arch/arm64/mm/mmu.c | 28 ++++++++++++++++++++-------- 2 files changed, 23 insertions(+), 8 deletions(-) diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index c2f006c48bdb..bcf166043a8b 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -33,5 +33,8 @@ extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt); extern void init_mem_pgprot(void); /* create an identity mapping for memory (or io if map_io is true) */ extern void create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io); +extern void create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, + unsigned long virt, phys_addr_t size, + int map_io, int map_xn); #endif diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 7eaa6a8c8467..f7d17a5a1f56 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -157,7 +157,7 @@ static void __init alloc_init_pte(pmd_t *pmd, unsigned long addr, static void __init alloc_init_pmd(struct mm_struct *mm, pud_t *pud, unsigned long addr, unsigned long end, - phys_addr_t phys, int map_io) + phys_addr_t phys, int map_io, int map_xn) { pmd_t *pmd; unsigned long next; @@ -167,6 +167,9 @@ static void __init alloc_init_pmd(struct mm_struct *mm, pud_t *pud, if (map_io) { prot_sect = PROT_SECT_DEVICE_nGnRE; prot_pte = __pgprot(PROT_DEVICE_nGnRE); + } else if (map_xn) { + prot_sect = PROT_SECT_NORMAL; + prot_pte = PAGE_KERNEL; } else { prot_sect = PROT_SECT_NORMAL_EXEC; prot_pte = PAGE_KERNEL_EXEC; @@ -203,7 +206,7 @@ static void __init alloc_init_pmd(struct mm_struct *mm, pud_t *pud, static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, unsigned long addr, unsigned long end, - unsigned long phys, int map_io) + unsigned long phys, int map_io, int map_xn) { pud_t *pud; unsigned long next; @@ -221,7 +224,7 @@ static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, /* * For 4K granule only, attempt to put down a 1GB block */ - if (!map_io && (PAGE_SHIFT == 12) && + if (!map_io && !map_xn && (PAGE_SHIFT == 12) && ((addr | next | phys) & ~PUD_MASK) == 0) { pud_t old_pud = *pud; set_pud(pud, __pud(phys | PROT_SECT_NORMAL_EXEC)); @@ -239,7 +242,8 @@ static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, flush_tlb_all(); } } else { - alloc_init_pmd(mm, pud, addr, next, phys, map_io); + alloc_init_pmd(mm, pud, addr, next, phys, map_io, + map_xn); } phys += next - addr; } while (pud++, addr = next, addr != end); @@ -251,7 +255,7 @@ static void __init alloc_init_pud(struct mm_struct *mm, pgd_t *pgd, */ static void __init __create_mapping(struct mm_struct *mm, pgd_t *pgd, phys_addr_t phys, unsigned long virt, - phys_addr_t size, int map_io) + phys_addr_t size, int map_io, int map_xn) { unsigned long addr, length, end, next; @@ -261,7 +265,7 @@ static void __init __create_mapping(struct mm_struct *mm, pgd_t *pgd, end = addr + length; do { next = pgd_addr_end(addr, end); - alloc_init_pud(mm, pgd, addr, next, phys, map_io); + alloc_init_pud(mm, pgd, addr, next, phys, map_io, map_xn); phys += next - addr; } while (pgd++, addr = next, addr != end); } @@ -275,7 +279,7 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt, return; } __create_mapping(&init_mm, pgd_offset_k(virt & PAGE_MASK), phys, virt, - size, 0); + size, 0, 0); } void __init create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io) @@ -285,7 +289,15 @@ void __init create_id_mapping(phys_addr_t addr, phys_addr_t size, int map_io) return; } __create_mapping(&init_mm, &idmap_pg_dir[pgd_index(addr)], - addr, addr, size, map_io); + addr, addr, size, map_io, 0); +} + +void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys, + unsigned long virt, phys_addr_t size, + int map_io, int map_xn) +{ + __create_mapping(mm, pgd_offset(mm, virt), phys, virt, size, map_io, + map_xn); } static void __init map_mem(void) -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-efi" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
