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    Subject[PATCH V7 24/26] um/mm: Enable ARCH_HAS_VM_GET_PAGE_PROT
    Date
    This enables ARCH_HAS_VM_GET_PAGE_PROT on the platform and exports standard
    vm_get_page_prot() implementation via DECLARE_VM_GET_PAGE_PROT, which looks
    up a private and static protection_map[] array. Subsequently all __SXXX and
    __PXXX macros can be dropped which are no longer needed.

    Cc: Jeff Dike <jdike@addtoit.com>
    Cc: linux-um@lists.infradead.org
    Cc: linux-kernel@vger.kernel.org
    Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
    ---
    arch/um/Kconfig | 1 +
    arch/um/include/asm/pgtable.h | 17 -----------------
    arch/um/kernel/mem.c | 20 ++++++++++++++++++++
    arch/x86/um/mem_32.c | 2 +-
    4 files changed, 22 insertions(+), 18 deletions(-)

    diff --git a/arch/um/Kconfig b/arch/um/Kconfig
    index 4ec22e156a2e..7fb43654e5b5 100644
    --- a/arch/um/Kconfig
    +++ b/arch/um/Kconfig
    @@ -10,6 +10,7 @@ config UML
    select ARCH_HAS_KCOV
    select ARCH_HAS_STRNCPY_FROM_USER
    select ARCH_HAS_STRNLEN_USER
    + select ARCH_HAS_VM_GET_PAGE_PROT
    select ARCH_NO_PREEMPT
    select HAVE_ARCH_AUDITSYSCALL
    select HAVE_ARCH_SECCOMP_FILTER
    diff --git a/arch/um/include/asm/pgtable.h b/arch/um/include/asm/pgtable.h
    index 167e236d9bb8..66bc3f99d9be 100644
    --- a/arch/um/include/asm/pgtable.h
    +++ b/arch/um/include/asm/pgtable.h
    @@ -68,23 +68,6 @@ extern unsigned long end_iomem;
    * Also, write permissions imply read permissions. This is the closest we can
    * get..
    */
    -#define __P000 PAGE_NONE
    -#define __P001 PAGE_READONLY
    -#define __P010 PAGE_COPY
    -#define __P011 PAGE_COPY
    -#define __P100 PAGE_READONLY
    -#define __P101 PAGE_READONLY
    -#define __P110 PAGE_COPY
    -#define __P111 PAGE_COPY
    -
    -#define __S000 PAGE_NONE
    -#define __S001 PAGE_READONLY
    -#define __S010 PAGE_SHARED
    -#define __S011 PAGE_SHARED
    -#define __S100 PAGE_READONLY
    -#define __S101 PAGE_READONLY
    -#define __S110 PAGE_SHARED
    -#define __S111 PAGE_SHARED

    /*
    * ZERO_PAGE is a global shared page that is always zero: used
    diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
    index 15295c3237a0..5b259f0a1f94 100644
    --- a/arch/um/kernel/mem.c
    +++ b/arch/um/kernel/mem.c
    @@ -197,3 +197,23 @@ void *uml_kmalloc(int size, int flags)
    {
    return kmalloc(size, flags);
    }
    +
    +static const pgprot_t protection_map[16] = {
    + [VM_NONE] = PAGE_NONE,
    + [VM_READ] = PAGE_READONLY,
    + [VM_WRITE] = PAGE_COPY,
    + [VM_WRITE | VM_READ] = PAGE_COPY,
    + [VM_EXEC] = PAGE_READONLY,
    + [VM_EXEC | VM_READ] = PAGE_READONLY,
    + [VM_EXEC | VM_WRITE] = PAGE_COPY,
    + [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
    + [VM_SHARED] = PAGE_NONE,
    + [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,
    + [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
    + [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
    + [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
    +};
    +DECLARE_VM_GET_PAGE_PROT
    diff --git a/arch/x86/um/mem_32.c b/arch/x86/um/mem_32.c
    index 19c5dbd46770..cafd01f730da 100644
    --- a/arch/x86/um/mem_32.c
    +++ b/arch/x86/um/mem_32.c
    @@ -17,7 +17,7 @@ static int __init gate_vma_init(void)
    gate_vma.vm_start = FIXADDR_USER_START;
    gate_vma.vm_end = FIXADDR_USER_END;
    gate_vma.vm_flags = VM_READ | VM_MAYREAD | VM_EXEC | VM_MAYEXEC;
    - gate_vma.vm_page_prot = __P101;
    + gate_vma.vm_page_prot = PAGE_READONLY;

    return 0;
    }
    --
    2.25.1
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