• Mark Rutland's avatar
    arm: arch_timer: add arch_counter_set_user_access · b2deabe3
    Mark Rutland authored
    Several bits in CNTKCTL reset to 0, including PL0VTEN. For architectures
    using the generic timer which wish to have a fast gettimeofday vDSO
    implementation, these bits must be set to 1 by the kernel. For
    architectures without a vDSO, it's best to leave the bits set to 0 for
    now to ensure that if and when support is added, it's implemented sanely
    architecture wide.
    
    As the bootloader might set PL0VTEN to a value that doesn't correspond
    to that which the kernel prefers, we must explicitly set it to the
    architecture port's preferred value.
    
    This patch adds arch_counter_set_user_access, which sets the PL0 access
    permissions to that required by the architecture. For arch/arm, this
    currently means disabling all userspace access.
    Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
    Acked-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    b2deabe3
arch_timer.c 9.82 KB