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    Subject[ 23/77] x86, efi: Make "noefi" really disable EFI runtime serivces
    Date
    3.8-stable review patch.  If anyone has any objections, please let me know.

    ------------------

    From: Matt Fleming <matt.fleming@intel.com>

    commit fb834c7acc5e140cf4f9e86da93a66de8c0514da upstream.

    commit 1de63d60cd5b ("efi: Clear EFI_RUNTIME_SERVICES rather than
    EFI_BOOT by "noefi" boot parameter") attempted to make "noefi" true to
    its documentation and disable EFI runtime services to prevent the
    bricking bug described in commit e0094244e41c ("samsung-laptop:
    Disable on EFI hardware"). However, it's not possible to clear
    EFI_RUNTIME_SERVICES from an early param function because
    EFI_RUNTIME_SERVICES is set in efi_init() *after* parse_early_param().

    This resulted in "noefi" effectively becoming a no-op and no longer
    providing users with a way to disable EFI, which is bad for those
    users that have buggy machines.

    Reported-by: Walt Nelson Jr <walt0924@gmail.com>
    Cc: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
    Signed-off-by: Matt Fleming <matt.fleming@intel.com>
    Link: http://lkml.kernel.org/r/1361392572-25657-1-git-send-email-matt@console-pimps.org
    Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

    ---
    arch/x86/platform/efi/efi.c | 5 +++--
    1 file changed, 3 insertions(+), 2 deletions(-)

    --- a/arch/x86/platform/efi/efi.c
    +++ b/arch/x86/platform/efi/efi.c
    @@ -85,9 +85,10 @@ int efi_enabled(int facility)
    }
    EXPORT_SYMBOL(efi_enabled);

    +static bool disable_runtime = false;
    static int __init setup_noefi(char *arg)
    {
    - clear_bit(EFI_RUNTIME_SERVICES, &x86_efi_facility);
    + disable_runtime = true;
    return 0;
    }
    early_param("noefi", setup_noefi);
    @@ -734,7 +735,7 @@ void __init efi_init(void)
    if (!efi_is_native())
    pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n");
    else {
    - if (efi_runtime_init())
    + if (disable_runtime || efi_runtime_init())
    return;
    set_bit(EFI_RUNTIME_SERVICES, &x86_efi_facility);
    }



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