Hi Mark > -----Original Message----- > From: Mark Brown [mailto:broo...@kernel.org] > Sent: Thursday, July 12, 2018 8:20 PM > To: Udit Kumar <udit.ku...@nxp.com> > Cc: Ard Biesheuvel <ard.biesheu...@linaro.org>; Architecture Mailman List > <boot-architecture@lists.linaro.org>; nd <n...@arm.com>; arm.ebbr-discuss > <arm.ebbr-disc...@arm.com> > Subject: Re: [Arm.ebbr-discuss] [RFC] uefi: Account for SetVariable() not > working > at runtime > > On Thu, Jul 12, 2018 at 02:19:49PM +0000, Udit Kumar wrote: > > > > > Do any existing implementations change variables from non-volatile > > > > to volatile? > > > > The UEFI spec is explicit about which variables are volatile and which > > > are not. > > > Simply relaxing non-volatile to volatile in the general case doesn't > > > seem like a useful approach to me. > > > I believe at boot-time, UEFI specs will be followed for volatile and > > non-volatile > variables. > > Having this in statement EBBR, will help those platform, which cannot expose > non-volatile variables at runtime. > > If nothing currently does it the chances that anything will actually cope well > seem minimal. Like Daniel said it seems more likely to break things - if the > variables are defined as being non-volatile then the OS is unlikely to be > checking > at runtime if that's the case or not unless it's explicitly written to work > with > EBBR. If an error is generated because a non-volatile variable can't be set > then > that should at least fall into whatever error handling code is there to cover > normal rutime failures which has some chance of doing something sensible.
Right, There will be some breaks or say diversion from UEFI specs. If we need to follow UEFI specs 'Table 10. Global Variables' on such platform where we cannot write to NV storage at runtime, then in either case 1/ passing OS as no-efi-runtime or 2/ Returning errors/not saving to NV storage is violation of UEFI spec. Which divergence is acceptable ? Regards Udit _______________________________________________ boot-architecture mailing list boot-architecture@lists.linaro.org https://lists.linaro.org/mailman/listinfo/boot-architecture
