Re: [PATCH] arm64: add <asm/asm-prototypes.h>

[Will Deacon <will.deacon@arm.com>]

On Wed, Dec 12, 2018 at 01:29:52PM +0000, Mark Rutland wrote:
> On Wed, Dec 12, 2018 at 01:15:15PM +0000, Robin Murphy wrote:
> > On 12/12/2018 12:22, Mark Rutland wrote:
> > > While we can export symbols from assembly files, CONFIG_MODVERIONS requires C
> > > declarations of anyhting that's exported.
> > > 
> > > Let's account for this as other architectures do by placing these declarations
> > > in <asm/asm-prototypes.h>, which kbuild will automatically use to generate
> > > modversion information for assembly files.
> > > 
> > > Since we already define most prototypes in existing headers, we simply need to
> > > include those headers in <asm/asm-prototypes.h>, and don't need to duplicate
> > > these.
> > > 
> > > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> > > Cc: Will Deacon <will.deacon@arm.com>
> > > ---
> > >   arch/arm64/include/asm/asm-prototypes.h | 25 +++++++++++++++++++++++++
> > >   1 file changed, 25 insertions(+)
> > >   create mode 100644 arch/arm64/include/asm/asm-prototypes.h
> > > 
> > > Hi Will,
> > > 
> > > I believe this covers all assembly exports for an arm64 allmodconfig. My laptop
> > > is rather slow at building all of that, so I can't confirm just yet, but I
> > > thought it was better to send this out in the mean time (or in case you can
> > > verify that locally).
> > > 
> > > Mark.
> > > 
> > > diff --git a/arch/arm64/include/asm/asm-prototypes.h b/arch/arm64/include/asm/asm-prototypes.h
> > > new file mode 100644
> > > index 000000000000..597434ea857d
> > > --- /dev/null
> > > +++ b/arch/arm64/include/asm/asm-prototypes.h
> > > @@ -0,0 +1,25 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 */
> > > +#ifndef __ASM_PROTOTYPES_H
> > > +#define __ASM_PROTOTYPES_H
> > > +/*
> > > + * CONFIG_MODEVERIONS requires a C declaration to generate the appropriate CRC
> > > + * for each symbol. Since commit:
> > > + *
> > > + *   4efca4ed05cbdfd1 ("kbuild: modversions for EXPORT_SYMBOL() for asm")
> > > + *
> > > + * ... kbuild will automatically pick these up from <asm/asm-prototypes.h> and
> > > + * feed this to genksyms when building assembly files.
> > > + */
> > > +#include <linux/arm-smccc.h>
> > > +
> > > +#include <asm/ftrace.h>
> > > +#include <asm/string.h>
> > 
> > This is virtually identical to what I came up with in parallel, except I had
> > <asm/page.h> here instead - I guess this still manages to pick up clear_page
> > and copy_page transitively (and mine got lucky for memcmp and friends), but
> > I guess it would be safer to explicitly add that as well.
> 
> Whoops, yes.
> 
> Will, are you happy to fold that in?

Sure, no problem.

Will

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