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x86, efi: Make "noefi" really disable EFI runtime serivces

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commit 1de63d60cd ("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 e0094244e4 ("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>
Cc: <stable@vger.kernel.org>
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>
This commit is contained in:
Matt Fleming 2013-02-20 20:36:12 +00:00 committed by H. Peter Anvin
parent 27cf929845
commit fb834c7acc
1 changed files with 3 additions and 2 deletions
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5
arch/x86/platform/efi/efi.c
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@ -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);
}