Re: [PATCH v15 15/23] x86/sgx: Add wrappers for ENCLS leaf functions

From: Jarkko Sakkinen
Date: Tue Nov 06 2018 - 07:03:54 EST


On Mon, Nov 05, 2018 at 10:39:46PM +0200, Andy Shevchenko wrote:
> On Mon, Nov 5, 2018 at 7:30 PM Jarkko Sakkinen
> <jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote:
> >
> > On Sat, Nov 03, 2018 at 03:17:35PM +0200, Andy Shevchenko wrote:
> > > On Sat, Nov 3, 2018 at 1:18 AM Jarkko Sakkinen
> > > <jarkko.sakkinen@xxxxxxxxxxxxxxx> wrote:
> > > >
> > > > ENCLS is an umbrella instruction for a variety of cpl0 SGX functions.
> > > > The ENCLS function that is executed is specified in EAX, with each
> > > > function potentially having more leaf-specific operands beyond EAX.
> > > > ENCLS introduces its own (positive value) error codes that (some)
> > > > leafs use to return failure information in EAX. Leafs that return
> > > > an error code also modify RFLAGS. And finally, ENCLS generates
> > > > ENCLS-specific non-fatal #GPs and #PFs, i.e. a bug-free kernel may
> > > > encounter faults on ENCLS that must be handled gracefully.
> > > >
> > > > Because of the complexity involved in encoding ENCLS and handling its
> > > > assortment of failure paths, executing any given leaf is not a simple
> > > > matter of emitting ENCLS.
> > > >
> > > > To enable adding support for ENCLS leafs with minimal fuss, add a
> > > > two-layer macro system along with an encoding scheme to allow wrappers
> > > > to return trap numbers along ENCLS-specific error codes. The bottom
> > > > layer of the macro system splits between the leafs that return an
> > > > error code and those that do not. The second layer generates the
> > > > correct input/output annotations based on the number of operands for
> > > > each leaf function.
> > >
> > > > +/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
> > >
> > > > +/**
> > >
> > > I dunno if kernel-doc script still complains about this.
> >
> > Is there a way to ask for make htmldocs to do only a subset of docs?
> > Still kind of trying to figure out what would be a good flow for
> > working with Sphinx.
>
> What I'm telling here is about Copyright notice, which in my
> understanding is not a part of kernel-doc formatting. Though I might
> be mistaken.
> I remember some USB code has that and I saw a warning.
>
> --
> With Best Regards,
> Andy Shevchenko

I'll remove it because I don't find it in other headers under arch/x86.

/Jarkko