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authorSatoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>2013-02-14 09:12:52 +0900
committerH. Peter Anvin <hpa@linux.intel.com>2013-02-13 17:24:11 -0800
commit1de63d60cd5b0d33a812efa455d5933bf1564a51 (patch)
tree336e5e18d14b139bfa43f51f667214e14219053f
parent323a72d83c9b2963bd1e46c8e6963e468d4658d7 (diff)
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 ... =============================================================================== Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Link: http://lkml.kernel.org/r/511C2C04.2070108@jp.fujitsu.com Cc: Matt Fleming <matt.fleming@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
-rw-r--r--arch/x86/platform/efi/efi.c2
1 files changed, 1 insertions, 1 deletions
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);