Re: [PATCH v6 1/6] arm/arm64: add smccc

From	Will Deacon <will.deacon@arm.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v6 1/6] arm/arm64: add smccc
Date	2015-11-02 15:50 +0100
Message-ID	<qqoAN-6vo-13@gated-at.bofh.it> (permalink)
References	<qoQKR-6cM-9@gated-at.bofh.it> <qoQKS-6cM-33@gated-at.bofh.it> <qqlWi-4QZ-31@gated-at.bofh.it> <qqnOq-5Zc-3@gated-at.bofh.it> <qqnY6-6hS-13@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Mon, Nov 02, 2015 at 02:03:13PM +0000, Mark Rutland wrote:
> > > > +/**
> > > > + * struct smccc_res - Result from SMC/HVC call
> > > > + * @a0-a3 result values from registers 0 to 3
> > > > + */
> > > > +struct smccc_res {
> > > > +	unsigned long a0;
> > > > +	unsigned long a1;
> > > > +	unsigned long a2;
> > > > +	unsigned long a3;
> > > > +};
> > > 
> > > Are there any endianness considerations for this structure?
> > 
> > No, I can't find anything in the ARM SMC Calling Convention document
> > indicating that.
> 
> The calling conventions have no bearing on the structure, which is our
> invention.
> 
> We stash register values (which don't have endianness) returned by the
> firmeware into the structure in the sequences above (which appear
> endian-clean to me).

Ah yes, the structure is populated by the kernel not the firmware, so
there's nothing to worry about. Thanks for the explanation.

Will
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Re: [PATCH v6 1/6] arm/arm64: add smccc Will Deacon <will.deacon@arm.com> - 2015-11-02 13:00 +0100
  Re: [PATCH v6 1/6] arm/arm64: add smccc Jens Wiklander <jens.wiklander@linaro.org> - 2015-11-02 15:00 +0100
    Re: [PATCH v6 1/6] arm/arm64: add smccc Mark Rutland <mark.rutland@arm.com> - 2015-11-02 15:10 +0100
      Re: [PATCH v6 1/6] arm/arm64: add smccc Will Deacon <will.deacon@arm.com> - 2015-11-02 15:50 +0100

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