Re: [PATCH] ARM: Use udiv/sdiv for __aeabi_{u}idiv library functions

[Russell King - ARM Linux <linux@arm.linux.org.uk>]

On Fri, Nov 08, 2013 at 12:50:04PM +0100, Jean-Christophe PLAGNIOL-VILLARD wrote:
> On 19:34 Thu 07 Nov     , Rob Herring wrote:
> > On Thu, Nov 7, 2013 at 1:20 PM, Stephen Boyd <sboyd@codeaurora.org> wrote:
> > > If we're running on a v7 ARM CPU, detect if the CPU supports the
> > > sdiv/udiv instructions and replace the signed and unsigned
> > > division library functions with an sdiv/udiv instruction.
> > 
> > [snip]
> > 
> > > diff --git a/arch/arm/lib/Makefile b/arch/arm/lib/Makefile
> > > index bd454b0..6ed6496 100644
> > > --- a/arch/arm/lib/Makefile
> > > +++ b/arch/arm/lib/Makefile
> > > @@ -15,6 +15,9 @@ lib-y         := backtrace.o changebit.o csumipv6.o csumpartial.o   \
> > >                    io-readsb.o io-writesb.o io-readsl.o io-writesl.o  \
> > >                    call_with_stack.o
> > >
> > > +lib-$(CONFIG_CPU_V7) += div-v7.o
> > > +CFLAGS_div-v7.o := -march=armv7-a
> > 
> > Won't this fail to build if the compiler doesn't have armv7-a support.
> > Perhaps we don't care about compilers that old.
> 
> use the propoer compiler to compile a armv7 kernel

It's probably about time to get rid of the conditionals for this in
the main arch/arm/Makefile actually - some of those date back some
10 or so years.  That's something for the v3.14 merge window.