ATTR_PXN
[PROT_READ] = ATTR_PXN|ATTR_UXN|ATTR_AF|ATTR_AP(3),
[PROT_WRITE] = ATTR_PXN|ATTR_UXN|ATTR_AF|ATTR_AP(1),
[PROT_WRITE|PROT_READ] = ATTR_PXN|ATTR_UXN|ATTR_AF|ATTR_AP(1),
[PROT_EXEC] = ATTR_PXN|ATTR_AF|ATTR_AP(2),
[PROT_EXEC|PROT_READ] = ATTR_PXN|ATTR_AF|ATTR_AP(3),
[PROT_EXEC|PROT_WRITE] = ATTR_PXN|ATTR_AF|ATTR_AP(1),
[PROT_EXEC|PROT_WRITE|PROT_READ] = ATTR_PXN|ATTR_AF|ATTR_AP(1),
[PROT_READ] = ATTR_PXN|ATTR_UXN|ATTR_AF|ATTR_AP(2),
[PROT_WRITE] = ATTR_PXN|ATTR_UXN|ATTR_AF|ATTR_AP(0),
[PROT_WRITE|PROT_READ] = ATTR_PXN|ATTR_UXN|ATTR_AF|ATTR_AP(0),
access_bits = ATTR_PXN | ATTR_AF;