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    Subject[PATCH 30/31] x86, pkeys: create an x86 arch_calc_vm_prot_bits() for VMA flags
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    From: Dave Hansen <dave.hansen@linux.intel.com>

    calc_vm_prot_bits() takes PROT_{READ,WRITE,EXECUTE} bits and
    turns them in to the vma->vm_flags/VM_* bits. We need to do a
    similar thing for protection keys.

    We take a protection key (4 bits) and encode it in to the 4
    VM_PKEY_* bits.

    Note: this code is not new. It was simply a part of the
    mprotect_pkey() patch in the past. I broke it out for use
    in the execute-only support.

    Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
    ---

    b/arch/x86/include/uapi/asm/mman.h | 6 ++++++
    1 file changed, 6 insertions(+)

    diff -puN arch/x86/include/uapi/asm/mman.h~pkeys-78-arch_calc_vm_prot_bits arch/x86/include/uapi/asm/mman.h
    --- a/arch/x86/include/uapi/asm/mman.h~pkeys-78-arch_calc_vm_prot_bits 2016-01-06 15:50:16.387641877 -0800
    +++ b/arch/x86/include/uapi/asm/mman.h 2016-01-06 15:50:16.390642013 -0800
    @@ -20,6 +20,12 @@
    ((vm_flags) & VM_PKEY_BIT1 ? _PAGE_PKEY_BIT1 : 0) | \
    ((vm_flags) & VM_PKEY_BIT2 ? _PAGE_PKEY_BIT2 : 0) | \
    ((vm_flags) & VM_PKEY_BIT3 ? _PAGE_PKEY_BIT3 : 0))
    +
    +#define arch_calc_vm_prot_bits(prot, key) ( \
    + ((key) & 0x1 ? VM_PKEY_BIT0 : 0) | \
    + ((key) & 0x2 ? VM_PKEY_BIT1 : 0) | \
    + ((key) & 0x4 ? VM_PKEY_BIT2 : 0) | \
    + ((key) & 0x8 ? VM_PKEY_BIT3 : 0))
    #endif

    #include <asm-generic/mman.h>
    _

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