From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751918AbcDUMzd (ORCPT ); Thu, 21 Apr 2016 08:55:33 -0400 Received: from foss.arm.com ([217.140.101.70]:54975 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591AbcDUMzc (ORCPT ); Thu, 21 Apr 2016 08:55:32 -0400 Date: Thu, 21 Apr 2016 13:55:07 +0100 From: Mark Rutland To: Leif Lindholm Cc: linux-efi@vger.kernel.org, ard.biesheuvel@linaro.org, catalin.marinas@arm.com, hpa@zytor.com, linux@arm.linux.org.uk, matt@codeblueprint.co.uk, mingo@redhat.com, tglx@linutronix.de, will.deacon@arm.com, linux-kernel@vger.kernel.org Subject: Re: [PATCHv2 1/5] efi/runtime-wrappers: add {__,}efi_call_virt templates Message-ID: <20160421125507.GM6879@leverpostej> References: <1461238529-12810-1-git-send-email-mark.rutland@arm.com> <1461238529-12810-2-git-send-email-mark.rutland@arm.com> <20160421114256.GP2904@bivouac.eciton.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160421114256.GP2904@bivouac.eciton.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 21, 2016 at 12:42:56PM +0100, Leif Lindholm wrote: > On Thu, Apr 21, 2016 at 12:35:25PM +0100, Mark Rutland wrote: > > Currently each architecture must implement two macros, efi_call_virt and > > __efi_call_virt, which only differ by the presence or absence of a > > return type. Otherwise, the logic surrounding the call is identical. > > > > As each architecture must define the entire body of each, we can't place > > any generic manipulation (e.g. irq flag validation) in the middle. > > > > This patch adds template implementations of these macros. With these, > > arch code can implement three template macros, avoiding reptition for > > the void/non-void return cases: > > > > * arch_efi_call_virt_setup > > > > Sets up the environment for the call (e.g. switching page tables, > > allowing kernel-mode use of floating point, if required). > > > > * arch_efi_call_virt > > > > Performs the call. The last expression in the macro must be the call > > itself, allowing the logic to be shared by the void and non-void > > cases. > > > > * arch_efi_call_virt_teardown > > > > Restores the usual kernel environment once the call has returned. > > > > While the savings from repition are minimal, we additionally gain the > > ability to add common code around the call with the call enviroment set > > up. This can be used to detect common firmware issues (e.g. bad irq mask > > management). > > > > Signed-off-by: Mark Rutland > > Cc: Matt Fleming > > Cc: linux-efi@vger.kernel.org > > Cc: linux-kernel@vger.kernel.org > > --- > > drivers/firmware/efi/runtime-wrappers.c | 21 +++++++++++++++++++++ > > 1 file changed, 21 insertions(+) > > > > diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c > > index de69530..1b9fa54 100644 > > --- a/drivers/firmware/efi/runtime-wrappers.c > > +++ b/drivers/firmware/efi/runtime-wrappers.c > > @@ -20,6 +20,27 @@ > > #include > > #include > > > > + > > +#ifndef efi_call_virt > > So ... not a strong complaint, but I would prefer if these weren't > ifdefd. I presume this is because ia64? Yup, and to allow the gradual migration of arm/arm64/x86 without a new CONFIG_WANT_GENERIC_EFI_CALL_VIRT or something to that effect. > Could that be given a dummy pass-through version instead? I'm not exactly sure what you mean by that. Could you elaborate? > If not, could a comment be added that this is to retain compatibility > with ia64 (so that if that architecture was to mysteriously disappear > from the tree, someone might remember to deconditionalise it)? Sure. I can also add a note to the commit message regarding the temporary need while arm/arm64/x86 are moved over. Thanks, Mark. > > +#define efi_call_virt(f, args...) \ > > +({ \ > > + efi_status_t __s; \ > > + arch_efi_call_virt_setup(); \ > > + __s = arch_efi_call_virt(f, args); \ > > + arch_efi_call_virt_teardown(); \ > > + __s; \ > > +}) > > +#endif > > + > > +#ifndef __efi_call_virt > > +#define __efi_call_virt(f, args...) \ > > +({ \ > > + arch_efi_call_virt_setup(); \ > > + arch_efi_call_virt(f, args); \ > > + arch_efi_call_virt_teardown(); \ > > +}) > > +#endif > > + > > /* > > * According to section 7.1 of the UEFI spec, Runtime Services are not fully > > * reentrant, and there are particular combinations of calls that need to be > > -- > > 1.9.1 > > >