• Suzuki K Poulose's avatar
    arm64: cpufeature: ctr: Fix cpu capability check for late CPUs · b85000e8
    Suzuki K Poulose authored
    [ Upstream commit 8ab66cbe ]
    
    The matches() routine for a capability must honor the "scope"
    passed to it and return the proper results.
    i.e, when passed with SCOPE_LOCAL_CPU, it should check the
    status of the capability on the current CPU. This is used by
    verify_local_cpu_capabilities() on a late secondary CPU to make
    sure that it's compliant with the established system features.
    However, ARM64_HAS_CACHE_{IDC/DIC} always checks the system wide
    registers and this could mean that a late secondary CPU could return
    "true" (since the CPU hasn't updated the system wide registers yet)
    and thus lead the system in an inconsistent state, where
    the system assumes it has IDC/DIC feature, while the new CPU
    doesn't.
    
    Fixes: commit 6ae4b6e0 ("arm64: Add support for new control bits CTR_EL0.DIC and CTR_EL0.IDC")
    Cc: Philip Elcan <pelcan@codeaurora.org>
    Cc: Shanker Donthineni <shankerd@codeaurora.org>
    Cc: Mark Rutland <mark.rutland@arm.com>
    Cc: Will Deacon <will.deacon@arm.com>
    Signed-off-by: default avatarSuzuki K Poulose <suzuki.poulose@arm.com>
    Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    b85000e8
cpufeature.c 56.3 KB