x86, efi: Make "noefi" really disable EFI runtime serivces
authorMatt Fleming <matt.fleming@intel.com>
Wed, 20 Feb 2013 20:36:12 +0000 (20:36 +0000)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Sun, 3 Mar 2013 22:06:38 +0000 (06:06 +0800)
commit92916fb21cc71f7877c06ab998728f118e2d72cb
treeba67a2201157ed35728c749dad9c42ab8dd067ca
parente6842472eb7f8091c27eb43ad934097ce04d3fbb
x86, efi: Make "noefi" really disable EFI runtime serivces

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