| From fb834c7acc5e140cf4f9e86da93a66de8c0514da Mon Sep 17 00:00:00 2001 |
| From: Matt Fleming <matt.fleming@intel.com> |
| Date: Wed, 20 Feb 2013 20:36:12 +0000 |
| Subject: x86, efi: Make "noefi" really disable EFI runtime serivces |
| |
| 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 |
| @@ -84,9 +84,10 @@ 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); |
| @@ -733,7 +734,7 @@ 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); |
| } |
