commit: fb834c7acc5e140cf4f9e86da93a66de8c0514da
From: Matt Fleming <matt.fleming@xxxxxxxxx>
Date: Wed, 20 Feb 2013 20:36:12 +0000
Subject: x86, efi: Make "noefi" really disable EFI runtime serivces
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@xxxxxxxxx>
Cc: Satoru Takeuchi <takeuchi_satoru@xxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Matt Fleming <matt.fleming@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1361392572-25657-1-git-send-email-matt@xxxxxxxxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/platform/efi/efi.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
index 928bf83..e2cd38f 100644
--- a/arch/x86/platform/efi/efi.c
+++ b/arch/x86/platform/efi/efi.c
@@ -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);
}
--
1.7.10.4
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