• Ard Biesheuvel's avatar
    efivar/ssdt: Don't iterate over EFI vars if no SSDT override was specified · c05f8f92
    Ard Biesheuvel authored
    The kernel command line option efivar_ssdt= allows the name to be
    specified of an EFI variable containing an ACPI SSDT table that should
    be loaded into memory by the OS, and treated as if it was provided by
    the firmware.
    
    Currently, that code will always iterate over the EFI variables and
    compare each name with the provided name, even if the command line
    option wasn't set to begin with.
    
    So bail early when no variable name was provided. This works around a
    boot regression on the 2012 Mac Pro, as reported by Scott.
    Tested-by: default avatarScott Talbert <swt@techie.net>
    Signed-off-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
    Cc: <stable@vger.kernel.org> # v4.9+
    Cc: Ben Dooks <ben.dooks@codethink.co.uk>
    Cc: Dave Young <dyoung@redhat.com>
    Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
    Cc: Jerry Snitselaar <jsnitsel@redhat.com>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Lukas Wunner <lukas@wunner.de>
    Cc: Lyude Paul <lyude@redhat.com>
    Cc: Matthew Garrett <mjg59@google.com>
    Cc: Octavian Purdila <octavian.purdila@intel.com>
    Cc: Peter Jones <pjones@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: linux-efi@vger.kernel.org
    Cc: linux-integrity@vger.kernel.org
    Fixes: 475fb4e8 ("efi / ACPI: load SSTDs from EFI variables")
    Link: https://lkml.kernel.org/r/20191002165904.8819-3-ard.biesheuvel@linaro.orgSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    c05f8f92
efi.c 26.5 KB