• Mark Rutland's avatar
    arm64: simplify ptrauth initialization · 62a679cb
    Mark Rutland authored
    Currently __cpu_setup conditionally initializes the address
    authentication keys and enables them in SCTLR_EL1, doing so differently
    for the primary CPU and secondary CPUs, and skipping this work for CPUs
    returning from an idle state. For the latter case, cpu_do_resume
    restores the keys and SCTLR_EL1 value after the MMU has been enabled.
    
    This flow is rather difficult to follow, so instead let's move the
    primary and secondary CPU initialization into their respective boot
    paths. By following the example of cpu_do_resume and doing so once the
    MMU is enabled, we can always initialize the keys from the values in
    thread_struct, and avoid the machinery necessary to pass the keys in
    secondary_data or open-coding initialization for the boot CPU.
    
    This means we perform an additional RMW of SCTLR_EL1, but we already do
    this in the cpu_do_resume path, and for other features in cpufeature.c,
    so this isn't a major concern in a bringup path. Note that even while
    the enable bits are clear, the key registers are accessible.
    
    As this now renders the argument to __cpu_setup redundant, let's also
    remove that entirely. Future extensions can follow a similar approach to
    initialize values that differ for primary/secondary CPUs.
    Signed-off-by: default avatarMark Rutland <mark.rutland@arm.com>
    Tested-by: default avatarAmit Daniel Kachhap <amit.kachhap@arm.com>
    Reviewed-by: default avatarAmit Daniel Kachhap <amit.kachhap@arm.com>
    Cc: Amit Daniel Kachhap <amit.kachhap@arm.com>
    Cc: Catalin Marinas <catalin.marinas@arm.com>
    Cc: James Morse <james.morse@arm.com>
    Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
    Cc: Will Deacon <will@kernel.org>
    Link: https://lore.kernel.org/r/20200423101606.37601-3-mark.rutland@arm.comSigned-off-by: default avatarWill Deacon <will@kernel.org>
    62a679cb
asm_pointer_auth.h 2.8 KB