Messages in this thread Patch in this message | | | Date | Thu, 14 Feb 2013 09:12:52 +0900 | From | Satoru Takeuchi <> | Subject | [PATCH] efi: Clear EFI_RUNTIME_SERVICES rather than EFI_BOOT by "noefi" boot parameter |
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From: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
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 ... ===============================================================================
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Cc: Matt Fleming <matt.fleming@intel.com> Cc: David Airlie <airlied@linux.ie> Cc: Corentin Chary <corentincj@iksaif.net> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Dave Jiang <dave.jiang@intel.com> Cc: Olof Johansson <olof@lixom.net> Cc: Peter Jones <pjones@redhat.com> Cc: Colin Ian King <colin.king@canonical.com> Cc: Steve Langasek <steve.langasek@canonical.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Konrad Rzeszutek Wilk <konrad@kernel.org> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: H. Peter Anvin <hpa@linux.intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: stable@vger.kernel.org --- arch/x86/platform/efi/efi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 77cf009..928bf83 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -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
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