• Andrew Murray's avatar
    arm64: HWCAP: add support for AT_HWCAP2 · aaba098f
    Andrew Murray authored
    As we will exhaust the first 32 bits of AT_HWCAP let's start
    exposing AT_HWCAP2 to userspace to give us up to 64 caps.
    
    Whilst it's possible to use the remaining 32 bits of AT_HWCAP, we
    prefer to expand into AT_HWCAP2 in order to provide a consistent
    view to userspace between ILP32 and LP64. However internal to the
    kernel we prefer to continue to use the full space of elf_hwcap.
    
    To reduce complexity and allow for future expansion, we now
    represent hwcaps in the kernel as ordinals and use a
    KERNEL_HWCAP_ prefix. This allows us to support automatic feature
    based module loading for all our hwcaps.
    
    We introduce cpu_set_feature to set hwcaps which complements the
    existing cpu_have_feature helper. These helpers allow us to clean
    up existing direct uses of elf_hwcap and reduce any future effort
    required to move beyond 64 caps.
    
    For convenience we also introduce cpu_{have,set}_named_feature which
    makes use of the cpu_feature macro to allow providing a hwcap name
    without a {KERNEL_}HWCAP_ prefix.
    Signed-off-by: default avatarAndrew Murray <andrew.murray@arm.com>
    [will: use const_ilog2() and tweak documentation]
    Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
    aaba098f
nhpoly1305-neon-glue.c 2.07 KB