Re: [GIT PULL] x86/vdso changes for v3.16

From: Sam Ravnborg
Date: Sun Jun 08 2014 - 13:19:16 EST


On Fri, Jun 06, 2014 at 02:07:11PM -0700, H. Peter Anvin wrote:
> On 06/06/2014 02:00 PM, Andrew Morton wrote:
> > On Wed, 4 Jun 2014 15:35:42 -0700 "H. Peter Anvin" <hpa@xxxxxxxxxxxxxxx> wrote:
> >
> >> Vdso cleanups and improvements largely from Andy Lutomirski.
> >
> > arch/x86/vdso/vdso2c.h: In function 'go64':
> > arch/x86/vdso/vdso2c.h:21: warning: implicit declaration of function 'le64toh'
> > arch/x86/vdso/vdso2c.h:21: warning: implicit declaration of function 'le32toh'
> > arch/x86/vdso/vdso2c.h:21: warning: implicit declaration of function 'le16toh'
> > arch/x86/vdso/vdso2c.h:119: warning: implicit declaration of function 'htole16'
> >
> > My Fedora Core 6 (lol gotcha) test box doesn't have these.
> >
> > http://www.unix.com/man-page/linux/3/le64toh/ has some details. I
> > don't appear to have letoh64 and friends either.
> >
>
> OK... so now we have a tools baseline problem. It isn't that we
> couldn't open-code these functions, but of course we'd also like to not
> *have* to do so... but also we don't want to have the kernel build rely
> on autoconf ;)
>
> So we have a few options, here:
>
> 1. We could use the unaligned macros defined in
> tools/include/tools/*_byteshift.h.
>
> 2. Open-code it.
>
> 3. Define a baseline which includes these kinds of functions.
>
> I guess I would be leaning toward #1, but would also wonder if that also
> means we should add -I$(srctree)/tools/include to the global settings
> ... we are *already* adding it to HOSTCFLAGS_sortextable.o.

I would say that tools/include/tools/* should be considered the baseline
for programs running on the host.
So therefore unconditionally adding -I$(srctree)/tools/include should then
be OK.

Sam
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