efi: Clear EFI_RUNTIME_SERVICES rather than EFI_BOOT by "noefi" boot parameter
Subsystems (3)
PATCH 1/1 efi: Clear EFI_RUNTIME_SERVICES rather than EFI_BOOT by "noefi" boot parameter
From: Satoru Takeuchi <[email protected]>
There was a serious problem in samsung-laptop that its platform driver is designed to run under BIOS and running under EFI can cause the machine to become bricked or can cause Machine Check Exceptions.
Discussion about this problem:
https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557
https://bugzilla.kernel.org/show_bug.cgi?id=47121
The patches to fix this problem:
efi: Make 'efi_enabled' a function to query EFI facilities 83e68189745ad931c2afd45d8ee3303929233e7f
samsung-laptop: Disable on EFI hardware
e0094244e41c4d0c7ad69920681972fc45d8ce34
Unfortunately this problem comes back again if users specify "noefi" option. This parameter clears EFI_BOOT and that driver continues to run even if running under EFI. Refer to the document, this parameter should clear EFI_RUNTIME_SERVICES instead.
Documentation/kernel-parameters.txt:
===============================================================================
...
noefi [X86] Disable EFI runtime services support.
...
===============================================================================
Documentation/x86/x86_64/uefi.txt:
===============================================================================
...
- If some or all EFI runtime services don't work, you can try following kernel command line parameters to turn off some or all EFI runtime services.
noefi turn off all EFI runtime services
...
===============================================================================
--- arch/x86/platform/efi/efi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/platform/efi/efi.c +1 -1
@@ -87,7 +87,7 @@ EXPORT_SYMBOL(efi_enabled);static int __init setup_noefi (char *arg) { -clear_bit (EFI_BOOT , &x86_efi_facility); +clear_bit (EFI_RUNTIME_SERVICES , &x86_efi_facility);return 0 ; }early_param ("noefi" , setup_noefi);
-- 1.7.10.4
H. Peter Anvin
reviewerQuoted 6 lines · Satoru Takeuchi
From: Satoru Takeuchi <[email protected]>
There was a serious problem in samsung-laptop that its platform driver is designed to run under BIOS and running under EFI can cause the machine to become bricked or can cause Machine Check Exceptions.
Matt, unless you object I'll pick this one up as urgent, please take the cleanup patch in normal order.
-hpa
Quoted 10 lines · H. Peter Anvin
Quoted 6 lines · Satoru Takeuchi
From: Satoru Takeuchi <[email protected]>
There was a serious problem in samsung-laptop that its platform driver is designed to run under BIOS and running under EFI can cause the machine to become bricked or can cause Machine Check Exceptions.
Matt, unless you object I'll pick this one up as urgent, please take the cleanup patch in normal order.
No objection from me, this looks correct.
Commit-ID: 1de63d60cd5b0d33a812efa455d5933bf1564a51 Gitweb: http://git.kernel.org/tip/1de63d60cd5b0d33a812efa455d5933bf1564a51 Author: Satoru Takeuchi <[email protected]> AuthorDate: Thu, 14 Feb 2013 09:12:52 +0900 Committer: H. Peter Anvin <[email protected]> CommitDate: Wed, 13 Feb 2013 17:24:11 -0800
efi: Clear EFI_RUNTIME_SERVICES rather than EFI_BOOT by "noefi" boot parameter
There was a serious problem in samsung-laptop that its platform driver is designed to run under BIOS and running under EFI can cause the machine to become bricked or can cause Machine Check Exceptions.
Discussion about this problem:
https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557
https://bugzilla.kernel.org/show_bug.cgi?id=47121
The patches to fix this problem:
efi: Make 'efi_enabled' a function to query EFI facilities 83e68189745ad931c2afd45d8ee3303929233e7f
samsung-laptop: Disable on EFI hardware
e0094244e41c4d0c7ad69920681972fc45d8ce34
Unfortunately this problem comes back again if users specify "noefi" option. This parameter clears EFI_BOOT and that driver continues to run even if running under EFI. Refer to the document, this parameter should clear EFI_RUNTIME_SERVICES instead.
Documentation/kernel-parameters.txt:
===============================================================================
...
noefi [X86] Disable EFI runtime services support.
...
===============================================================================
Documentation/x86/x86_64/uefi.txt:
===============================================================================
...
- If some or all EFI runtime services don't work, you can try following kernel command line parameters to turn off some or all EFI runtime services.
noefi turn off all EFI runtime services
...
===============================================================================
--- arch/x86/platform/efi/efi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
arch/x86/platform/efi/efi.c +1 -1
@@ -87,7 +87,7 @@ EXPORT_SYMBOL(efi_enabled);static int __init setup_noefi (char *arg) { -clear_bit (EFI_BOOT , &x86_efi_facility); +clear_bit (EFI_RUNTIME_SERVICES , &x86_efi_facility);return 0 ; }early_param ("noefi" , setup_noefi);