Hi Daniel > -----Original Message----- > From: arm.ebbr-discuss-boun...@arm.com <arm.ebbr-discuss- > boun...@arm.com> On Behalf Of Daniel Thompson > Sent: Tuesday, October 16, 2018 9:43 PM > To: Grant Likely <grant.lik...@arm.com> > Cc: boot-architecture@lists.linaro.org; nd <n...@arm.com>; arm.ebbr-discuss > <arm.ebbr-disc...@arm.com> > Subject: Re: [Arm.ebbr-discuss] [PATCH v2] Refactor ResetSystem() > requirements > > On Thu, Oct 11, 2018 at 03:05:33PM +0000, Grant Likely wrote: > > ResetSystem() was over-specified in the document. UEFI already > > documents the behaviour of ResetSystem() sufficiently. Add notes on > > expected behaviour when platform specific or standard interface > > methods are available. > > > > Resolves: #29 > > Signed-off-by: Grant Likely <grant.lik...@arm.com> > > --- > > source/chapter2-uefi.rst | 27 ++++++++++----------------- > > 1 file changed, 10 insertions(+), 17 deletions(-) > > > > diff --git a/source/chapter2-uefi.rst b/source/chapter2-uefi.rst index > > 0cbddff..8a3ff1a 100644 > > --- a/source/chapter2-uefi.rst > > +++ b/source/chapter2-uefi.rst > > @@ -175,23 +175,16 @@ and the OS must use a device driver to control the > RTC. > > UEFI Reset and Shutdown > > ----------------------- > > > > -The UEFI Runtime service ResetSystem() must implement the following > > commands, -for purposes of power management and system control. > > - > > -- EfiResetCold() > > -- EfiResetShutdown() > > - * EfiResetShutdown must not reboot the system. > > - > > -If firmware updates are supported through the Runtime Service of > > -UpdateCapsule(), then ResetSystem() might need to support the > > following > > -command: > > - > > -- EfiWarmReset() > > - > > -.. note:: On platforms implementing the Power State Coordination Interface > > - specification [PSCI]_, it is still required that EBBR compliant > > - Operating Systems calls to reset the system will go via Runtime Services > > - and not directly to PSCI. > > +ResetSystem() is required to be implemented in boot services, but it > > +is optional for runtime services. > > +During runtime services, the operating system should first attempt to > > +use ResetSystem() to reset the system. > > This doesn't fit together quite as it should alongside the > RuntimeServicesSupported variable. Read naively it appears to recommend that > an OS call ResetSystem() even in cases where it knows that it doesn't work.
IMO, this variable is applicable for all services, not for just reset, right ? I am not sure, if this is bit mask in this variable to specify each runtime service availability, fyi, I am not able to find such variable in Table 10. Global Variables (spec 2.7) Please help, where this is defined > It's a bit tricky to word since there are three cases rather than two > (implemented, not-implemented and os-didn't-check) > > Maybe: > : ... unless the operating system has already discovered > : from the "RuntimeServicesSupported" variable that ResetSystem() > : is not implemented. > > > > > +If ResetSystem() returns EFI_UNSUPPORTED, then the OS may fall back > > +to an architecture or platform specific mechanism. > > + > > +On AArch64 platforms implementing [PSCI]_, if ResetSystem() is not > > +implemented then the Operating System should fall back to making a > > +PSCI call to reset or shutdown the system. > > > > Runtime Variable Access > > ----------------------- > > -- > > 2.13.0 > > > > > > _______________________________________________ > > Arm.ebbr-discuss mailing list > > arm.ebbr-disc...@arm.com > _______________________________________________ > Arm.ebbr-discuss mailing list > arm.ebbr-disc...@arm.com _______________________________________________ boot-architecture mailing list boot-architecture@lists.linaro.org https://lists.linaro.org/mailman/listinfo/boot-architecture
