From mboxrd@z Thu Jan 1 00:00:00 1970 From: Satoru Takeuchi Subject: Re: [PATCH] x86, efi: Make "noefi" really disable EFI runtime serivces Date: Thu, 21 Feb 2013 08:46:10 +0900 Message-ID: <51256042.5030704@jp.fujitsu.com> References: <1361392572-25657-1-git-send-email-matt@console-pimps.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-2022-JP" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1361392572-25657-1-git-send-email-matt-HNK1S37rvNbeXh+fF434Mdi2O/JbrIOy@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Matt Fleming Cc: "H. Peter Anvin" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Matt Fleming , stable-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-efi@vger.kernel.org Hi Matt, (2013/02/21 5:36), Matt Fleming wrote: > From: Matt Fleming > > 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. Sorry, my patch was imperfect. This patch looks good to me. Reviewed-by: Satoru Takeuchi Thanks, Satoru > > Reported-by: Walt Nelson Jr > Cc: Satoru Takeuchi > Cc: H. Peter Anvin > Cc: > Signed-off-by: Matt Fleming > --- > 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); > } >