protection_map[] maps the lower four bits from vm_flags into platform page protection mask. Default initialization (and possible re-initialization in the platform) does not make it clear that these indices are just derived from various vm_flags protections (VM_SHARED, VM_READ, VM_WRITE, VM_EXEC). This defines macros for protection_map[] indices which concatenate various vm_flag attributes, making it clear and explicit. Cc: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Cc: linux-mips@xxxxxxxxxxxxxxx Cc: sparclinux@xxxxxxxxxxxxxxx Cc: linux-mm@xxxxxxxxx Cc: linux-kernel@xxxxxxxxxxxxxxx Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx> --- This applies on v5.15-rc3 after the following patch. https://lore.kernel.org/all/20210924060821.1138281-1-guoren@xxxxxxxxxx/ arch/mips/mm/cache.c | 34 +++++++++++++++++----------------- arch/sparc/mm/init_64.c | 32 ++++++++++++++++---------------- include/linux/mm.h | 31 +++++++++++++++++++++++++++++++ mm/debug_vm_pgtable.c | 8 ++++---- mm/mmap.c | 18 ++++++++++++++++-- 5 files changed, 84 insertions(+), 39 deletions(-) diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c index 830ab91e574f..d0197cc1fb5a 100644 --- a/arch/mips/mm/cache.c +++ b/arch/mips/mm/cache.c @@ -161,24 +161,24 @@ EXPORT_SYMBOL(_page_cachable_default); static inline void setup_protection_map(void) { - protection_map[0] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[1] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[2] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[3] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[4] = PM(_PAGE_PRESENT); - protection_map[5] = PM(_PAGE_PRESENT); - protection_map[6] = PM(_PAGE_PRESENT); - protection_map[7] = PM(_PAGE_PRESENT); - - protection_map[8] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); - protection_map[9] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); - protection_map[10] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | + protection_map[PROTMAP_IDX_XXXX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[PROTMAP_IDX_XRXX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[PROTMAP_IDX_XXWX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[PROTMAP_IDX_XRWX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[PROTMAP_IDX_XXXE] = PM(_PAGE_PRESENT); + protection_map[PROTMAP_IDX_XRXE] = PM(_PAGE_PRESENT); + protection_map[PROTMAP_IDX_XXWE] = PM(_PAGE_PRESENT); + protection_map[PROTMAP_IDX_XRWE] = PM(_PAGE_PRESENT); + + protection_map[PROTMAP_IDX_SXXX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_NO_READ); + protection_map[PROTMAP_IDX_SRXX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC); + protection_map[PROTMAP_IDX_SXWX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE | _PAGE_NO_READ); - protection_map[11] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); - protection_map[12] = PM(_PAGE_PRESENT); - protection_map[13] = PM(_PAGE_PRESENT); - protection_map[14] = PM(_PAGE_PRESENT | _PAGE_WRITE); - protection_map[15] = PM(_PAGE_PRESENT | _PAGE_WRITE); + protection_map[PROTMAP_IDX_SRWX] = PM(_PAGE_PRESENT | _PAGE_NO_EXEC | _PAGE_WRITE); + protection_map[PROTMAP_IDX_SXXE] = PM(_PAGE_PRESENT); + protection_map[PROTMAP_IDX_SRXE] = PM(_PAGE_PRESENT); + protection_map[PROTMAP_IDX_SXWE] = PM(_PAGE_PRESENT | _PAGE_WRITE); + protection_map[PROTMAP_IDX_SRWE] = PM(_PAGE_PRESENT | _PAGE_WRITE); } #undef PM diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c index 1b23639e2fcd..1a7fe97c8167 100644 --- a/arch/sparc/mm/init_64.c +++ b/arch/sparc/mm/init_64.c @@ -2642,22 +2642,22 @@ static void prot_init_common(unsigned long page_none, PAGE_COPY = __pgprot(page_copy); PAGE_SHARED = __pgprot(page_shared); - protection_map[0x0] = __pgprot(page_none); - protection_map[0x1] = __pgprot(page_readonly & ~page_exec_bit); - protection_map[0x2] = __pgprot(page_copy & ~page_exec_bit); - protection_map[0x3] = __pgprot(page_copy & ~page_exec_bit); - protection_map[0x4] = __pgprot(page_readonly); - protection_map[0x5] = __pgprot(page_readonly); - protection_map[0x6] = __pgprot(page_copy); - protection_map[0x7] = __pgprot(page_copy); - protection_map[0x8] = __pgprot(page_none); - protection_map[0x9] = __pgprot(page_readonly & ~page_exec_bit); - protection_map[0xa] = __pgprot(page_shared & ~page_exec_bit); - protection_map[0xb] = __pgprot(page_shared & ~page_exec_bit); - protection_map[0xc] = __pgprot(page_readonly); - protection_map[0xd] = __pgprot(page_readonly); - protection_map[0xe] = __pgprot(page_shared); - protection_map[0xf] = __pgprot(page_shared); + protection_map[PROTMAP_IDX_XXXX] = __pgprot(page_none); + protection_map[PROTMAP_IDX_XRXX] = __pgprot(page_readonly & ~page_exec_bit); + protection_map[PROTMAP_IDX_XXWX] = __pgprot(page_copy & ~page_exec_bit); + protection_map[PROTMAP_IDX_XRWX] = __pgprot(page_copy & ~page_exec_bit); + protection_map[PROTMAP_IDX_XXXE] = __pgprot(page_readonly); + protection_map[PROTMAP_IDX_XRXE] = __pgprot(page_readonly); + protection_map[PROTMAP_IDX_XXWE] = __pgprot(page_copy); + protection_map[PROTMAP_IDX_XRWE] = __pgprot(page_copy); + protection_map[PROTMAP_IDX_SXXX] = __pgprot(page_none); + protection_map[PROTMAP_IDX_SRXX] = __pgprot(page_readonly & ~page_exec_bit); + protection_map[PROTMAP_IDX_SXWX] = __pgprot(page_shared & ~page_exec_bit); + protection_map[PROTMAP_IDX_SRWX] = __pgprot(page_shared & ~page_exec_bit); + protection_map[PROTMAP_IDX_SXXE] = __pgprot(page_readonly); + protection_map[PROTMAP_IDX_SRXE] = __pgprot(page_readonly); + protection_map[PROTMAP_IDX_SXWE] = __pgprot(page_shared); + protection_map[PROTMAP_IDX_SRWE] = __pgprot(page_shared); } static void __init sun4u_pgprot_init(void) diff --git a/include/linux/mm.h b/include/linux/mm.h index 73a52aba448f..4f99a49749a5 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -431,9 +431,40 @@ extern unsigned int kobjsize(const void *objp); /* * mapping from the currently active vm_flags protection bits (the * low four bits) to a page protection mask.. + * + * VM_EXEC ---------------------| + * | + * VM_WRITE ---------------| | + * | | + * VM_READ -----------| | | + * | | | + * VM_SHARED ----| | | | + * | | | | + * v v v v + * PROTMAP_IDX_(S|X)(R|X)(W|X)(E|X) + * + * X - The protection flag is absent + * */ extern pgprot_t protection_map[16]; +#define PROTMAP_IDX_XXXX (VM_NONE) +#define PROTMAP_IDX_XRXX (VM_READ) +#define PROTMAP_IDX_XXWX (VM_WRITE) +#define PROTMAP_IDX_XRWX (VM_READ | VM_WRITE) +#define PROTMAP_IDX_XXXE (VM_EXEC) +#define PROTMAP_IDX_XRXE (VM_READ | VM_EXEC) +#define PROTMAP_IDX_XXWE (VM_WRITE | VM_EXEC) +#define PROTMAP_IDX_XRWE (VM_READ | VM_WRITE | VM_EXEC) +#define PROTMAP_IDX_SXXX (VM_SHARED | VM_NONE) +#define PROTMAP_IDX_SRXX (VM_SHARED | VM_READ) +#define PROTMAP_IDX_SXWX (VM_SHARED | VM_WRITE) +#define PROTMAP_IDX_SRWX (VM_SHARED | VM_READ | VM_WRITE) +#define PROTMAP_IDX_SXXE (VM_SHARED | VM_EXEC) +#define PROTMAP_IDX_SRXE (VM_SHARED | VM_READ | VM_EXEC) +#define PROTMAP_IDX_SXWE (VM_SHARED | VM_WRITE | VM_EXEC) +#define PROTMAP_IDX_SRWE (VM_SHARED | VM_READ | VM_WRITE | VM_EXEC) + /** * enum fault_flag - Fault flag definitions. * @FAULT_FLAG_WRITE: Fault was a write fault. diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index 228e3954b90c..2e01d0d395bb 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -1104,14 +1104,14 @@ static int __init init_args(struct pgtable_debug_args *args) /* * Initialize the debugging data. * - * protection_map[0] (or even protection_map[8]) will help create - * page table entries with PROT_NONE permission as required for - * pxx_protnone_tests(). + * protection_map[PROTMAP_IDX_XXXX] (or even protection_map[PROTMAP_IDX_SXXX]) + * will help create page table entries with PROT_NONE permission as required + * for pxx_protnone_tests(). */ memset(args, 0, sizeof(*args)); args->vaddr = get_random_vaddr(); args->page_prot = vm_get_page_prot(VMFLAGS); - args->page_prot_none = protection_map[0]; + args->page_prot_none = protection_map[PROTMAP_IDX_XXXX]; args->is_contiguous_page = false; args->pud_pfn = ULONG_MAX; args->pmd_pfn = ULONG_MAX; diff --git a/mm/mmap.c b/mm/mmap.c index 88dcc5c25225..d38bd4e305f9 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -101,8 +101,22 @@ static void unmap_region(struct mm_struct *mm, * x: (yes) yes */ pgprot_t protection_map[16] __ro_after_init = { - __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111, - __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111 + [PROTMAP_IDX_XXXX] = __P000, + [PROTMAP_IDX_XRXX] = __P001, + [PROTMAP_IDX_XXWX] = __P010, + [PROTMAP_IDX_XRWX] = __P011, + [PROTMAP_IDX_XXXE] = __P100, + [PROTMAP_IDX_XRXE] = __P101, + [PROTMAP_IDX_XXWE] = __P110, + [PROTMAP_IDX_XRWE] = __P111, + [PROTMAP_IDX_SXXX] = __S000, + [PROTMAP_IDX_SRXX] = __S001, + [PROTMAP_IDX_SXWX] = __S010, + [PROTMAP_IDX_SRWX] = __S011, + [PROTMAP_IDX_SXXE] = __S100, + [PROTMAP_IDX_SRXE] = __S101, + [PROTMAP_IDX_SXWE] = __S110, + [PROTMAP_IDX_SRWE] = __S111 }; #ifndef CONFIG_ARCH_HAS_FILTER_PGPROT -- 2.20.1
