Re: [PATCH] ARM: zImage: Skip relinking if nothing changes

[Troy Kisky]

On 8/18/2011 12:31 PM, Russell King - ARM Linux wrote:
> On Thu, Aug 18, 2011 at 02:03:43PM -0400, Arnaud Lacombe wrote:
> > Hi,
> >
> > On Wed, Aug 17, 2011 at 11:44 PM, Nicolas Pitre<nico@xxxxxxxxxxx>  wrote:
> > > On Fri, 12 Aug 2011, Arnaud Lacombe wrote:
> > > > On Fri, Aug 12, 2011 at 4:48 PM, Arnaud Lacombe<lacombar@xxxxxxxxx>  wrote:
> > > > > On Fri, Aug 12, 2011 at 3:00 PM, Stephen Boyd<sboyd@xxxxxxxxxxxxxx>  wrote:
> > > > > > diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
> > > > > > index 0c74a6f..937fd26 100644
> > > > > > --- a/arch/arm/boot/compressed/Makefile
> > > > > > +++ b/arch/arm/boot/compressed/Makefile
> > > > > > @@ -91,7 +91,7 @@ suffix_$(CONFIG_KERNEL_LZMA) = lzma
> > > > > >
> > > > > >   targets       := vmlinux vmlinux.lds \
> > > > > >                  piggy.$(suffix_y) piggy.$(suffix_y).o \
> > > > > > -                font.o font.c head.o misc.o $(OBJS)
> > > > > > +                font.o font.c head.o misc.o lib1funcs.o lib1funcs.S $(OBJS)
> > > > > >
> > > > > >   # Make sure files are removed during clean
> > > > > >   extra-y       += piggy.gzip piggy.lzo piggy.lzma lib1funcs.S
> > > > > > @@ -121,9 +121,7 @@ LDFLAGS_vmlinux += -X
> > > > > >   LDFLAGS_vmlinux += -T
> > > > > >
> > > > > >   # For __aeabi_uidivmod
> > > > > > -lib1funcs = $(obj)/lib1funcs.o
> > > > > > -
> > > > > > -$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S FORCE
> > > > > > +$(obj)/lib1funcs.S: $(srctree)/arch/$(SRCARCH)/lib/lib1funcs.S
> > > > > >         $(call cmd,shipped)
> > > > > You should be able to avoid the extra copy altogether by doing something ala:
> > > > >
> > > > > $(obj)/lib1funcs.o: $(srctree)/arch/arm/lib/lib1funcs.S
> > > > >         $(call cmd,as_o_S)
> > > > >
> > > > > note that I also remove the $(SRCARCH), as there is no other
> > > > > `arch/*/lib/lib1funcs.S' than `arch/arm/lib/lib1funcs.S'
> > > > I withdraw this proposal and will hack around this to find a proper
> > > > solution from within kbuild, and eventually come back on these uses
> > > > :-)
> > > Any progress on this?
> > >
> > > I have a patch doing multiple similar $(call cmd,shipped) at the moment
> > > and this is far from looking nice.
> > What is your use-case ? Is it re-use of code in a different
> > subdirectory (use-case presented in this thread), or aliasing of the
> > same source under different object name in the same directory (as used
> > in the alpha tree) ?
> It is to be able to reuse the same file source file in both the main
> kernel and the decompressor, sometimes rebuilding it with differing
> options from the main kernel build.
>
> As the two environments are entirely separate, it is not always
> appropriate to clone the previously built object file.
>
> Hence, we copy the source file and re-build it.
>
> The alternative is that we could keep two copies of the same source
> in two different locations, but that's just plain idiotic just to
> satisfy some silly kbuild restriction.
Can the second file just contain a "#include " of the 1st?

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