bringing back 'make symlinks'?

bringing back 'make symlinks'?

[Dan Kegel]

In the 2.4 kernel, 'make symlinks' created the symlinks needed
to use the kernel tree's headers for building a gcc/glibc toolchain.

In the 2.6 kernel, you can do the same thing with 'include include/asm'.
Unless you're trying to build arm or cris, or maybe others, in which case you also need
'include/asm-$(ARCH)/.arch'.

That's fine, but it means that a script (like crosstool) or a book (like LFS)
that's trying to build a gcc/glibc toolchain for both 2.4 and 2.6 ends up
with a section like

case "$KERNEL_VERSION.$KERNEL_PATCHLEVEL.x" in
2.2.x|2.4.x) make ARCH=$ARCH symlinks    include/linux/version.h
              ;;
2.6.x)       make ARCH=$ARCH include/asm include/linux/version.h
              case $ARCH in
              arm*|cris*) make ARCH=$ARCH include/asm-$ARCH/.arch
                          ;;
              esac
              ;;
*)           abort "Unsupported kernel version $KERNEL_VERSION.$KERNEL_PATCHLEVEL"
esac

which is a bit ugly.  It'd be nice if 'make symlinks' did the neccesary
stuff in 2.6, too.  Think a patch to do that would be accepted?
- Dan

-- 
My technical stuff: http://kegel.com
My politics: see http://www.misleader.org for examples of why I'm for regime change

Re: bringing back 'make symlinks'?

[Sam Ravnborg]

On Tue, May 25, 2004 at 08:45:18AM -0700, Dan Kegel wrote:
> In the 2.4 kernel, 'make symlinks' created the symlinks needed
> to use the kernel tree's headers for building a gcc/glibc toolchain.
> 
> In the 2.6 kernel, you can do the same thing with 'include include/asm'.
> Unless you're trying to build arm or cris, or maybe others, in which case 
> you also need
> 'include/asm-$(ARCH)/.arch'.
> 
> That's fine, but it means that a script (like crosstool) or a book (like 
> LFS)
> that's trying to build a gcc/glibc toolchain for both 2.4 and 2.6 ends up
> with a section like
> 
> case "$KERNEL_VERSION.$KERNEL_PATCHLEVEL.x" in
> 2.2.x|2.4.x) make ARCH=$ARCH symlinks    include/linux/version.h
>              ;;
> 2.6.x)       make ARCH=$ARCH include/asm include/linux/version.h
>              case $ARCH in
>              arm*|cris*) make ARCH=$ARCH include/asm-$ARCH/.arch
>                          ;;
>              esac
>              ;;
> *)           abort "Unsupported kernel version 
> $KERNEL_VERSION.$KERNEL_PATCHLEVEL"
> esac

In current 2.6 there exitst a target named: modules_prepare
It does a bit more than what symlinks did in 2.4 - actually prepare for
building external modules.

	Sam

Re: bringing back 'make symlinks'?

[Dan Kegel]

Sam Ravnborg wrote:
> On Tue, May 25, 2004 at 08:45:18AM -0700, Dan Kegel wrote:
> 
>>In the 2.4 kernel, 'make symlinks' created the symlinks needed
>>to use the kernel tree's headers for building a gcc/glibc toolchain.
>>
>>In the 2.6 kernel, you can do the same thing with 'include include/asm'.
>>Unless you're trying to build arm or cris, or maybe others, in which case 
>>you also need 'include/asm-$(ARCH)/.arch'.
> ...
> 
> In current 2.6 there exitst a target named: modules_prepare
> It does a bit more than what symlinks did in 2.4 - actually prepare for
> building external modules.

Right, and that's a problem, because the 'bit more' it does
requires a target compiler -- which isn't available while
bootstrapping the target compiler!

The way things are now, I can build toolchains for everything
except the sh architecture (though my toolchain bootstrap script
is ugly as noted due to the lack of 'make symlinks').
I'm not sure if the sh architecture makefile even has targets
to make all the needed symlinks in the absense of a working
target compiler; I'll look at that and maybe submit a minimal
patch when I get a chance.
- Dan

-- 
My technical stuff: http://kegel.com
My politics: see http://www.misleader.org for examples of why I'm for regime change

Re: bringing back 'make symlinks'?

[Sam Ravnborg]

On Tue, May 25, 2004 at 08:47:51PM -0700, Dan Kegel wrote:
> 
> The way things are now, I can build toolchains for everything
> except the sh architecture (though my toolchain bootstrap script
> is ugly as noted due to the lack of 'make symlinks').

Does the following meet the needs of your cross-tool scripts?

	Sam

===== Makefile 1.492 vs edited =====
--- 1.492/Makefile	2004-05-30 08:24:06 +02:00
+++ edited/Makefile	2004-05-30 12:52:36 +02:00
@@ -632,6 +632,10 @@
 # All the preparing..
 prepare-all: prepare0 prepare
 
+# symlinks provided for compatibility with 2.4 - this allows boot-strapping
+# tool chains to be simpler
+symlinks: prepare-all
+
 #	Leave this as default for preprocessing vmlinux.lds.S, which is now
 #	done in arch/$(ARCH)/kernel/Makefile
 

Re: bringing back 'make symlinks'?

[Dan Kegel]

Sam Ravnborg wrote:
>>The way things are now, I can build toolchains for everything
>>except the sh architecture (though my toolchain bootstrap script
>>is ugly as noted due to the lack of 'make symlinks').
> 
> Does the following meet the needs of your cross-tool scripts?
> 
> 	Sam
> 
> ===== Makefile 1.492 vs edited =====
> --- 1.492/Makefile	2004-05-30 08:24:06 +02:00
> +++ edited/Makefile	2004-05-30 12:52:36 +02:00
> @@ -632,6 +632,10 @@
>  # All the preparing..
>  prepare-all: prepare0 prepare
>  
> +# symlinks provided for compatibility with 2.4 - this allows boot-strapping
> +# tool chains to be simpler
> +symlinks: prepare-all
> +
>  #	Leave this as default for preprocessing vmlinux.lds.S, which is now
>  #	done in arch/$(ARCH)/kernel/Makefile

Well, let's try it:

$ make ARCH=sh prepare
   Making asm-sh/cpu -> asm-sh/ link
   Making asm-sh/mach -> asm-sh/ link
   Generating include/asm-sh/machtypes.h

So far so good (excellent, in fact, since there is no other way
at the moment to create those two links).

$ make ARCH=ppc prepare
   HOSTCC  scripts/conmakehash
   HOSTCC  scripts/kallsyms
   CC      scripts/empty.o
cc1: invalid option `multiple'
cc1: invalid option `string'
cc1: warning: unknown register name: r2
make[1]: *** [scripts/empty.o] Error 1

Whoops, bad luck.  Let's try another:

$ make ARCH=arm prepare
   SPLIT   include/linux/autoconf.h -> include/config/*
   HOSTCC  scripts/conmakehash
   HOSTCC  scripts/kallsyms
   CC      scripts/empty.o
cc1: invalid option `apcs'
cc1: invalid option `no-sched-prolog'
cc1: invalid option `little-endian'
cc1: invalid option `apcs-32'
cc1: invalid option `short-load-bytes'
make[1]: *** [scripts/empty.o] Error 1
make: *** [scripts] Error 2

Bad luck again.

Your change works for some architectures, but for those
that try to build something with the target compilers, it fails
because at this point in the bootstrap process, there *is* no
target compiler.  (That's the next step.  We have to install the
kernel headers to build the target compiler...)

By the way, the mips architecture doesn't even make symlinks anymore,
preferring instead to use -I's.   This makes emulating 'make symlinks'
a bit more challenging.

For what it's worth, here's my current workaround.  I'm up
and happy on all architectures with this, I think.  (Well,
happy but ugly and afraid of future breakage, I guess.
And maybe not so happy on mips.)

case "$KERNEL_VERSION.$KERNEL_PATCHLEVEL.x" in
2.2.x|2.4.x) make ARCH=$ARCH symlinks    include/linux/version.h
              ;;
2.6.x)       case $ARCH in
              sh*)        # sh does secret stuff in 'make prepare' that can't be triggered separately,
                          # but happily, it doesn't use target gcc, so we can use it
                          make ARCH=$ARCH prepare
                          ;;
              arm*|cris*) make ARCH=$ARCH include/asm include/linux/version.h include/asm-$ARCH/.arch
                          ;;
              mips*)      # for linux-2.6, 'make prepare' for mips doesn't
                          # actually create any symlinks.  Hope generic is ok.
                          # Note that glibc ignores all -I flags passed in CFLAGS,
                          # so you have to use -isystem.
                          make ARCH=$ARCH include/asm include/linux/version.h
                          TARGET_CFLAGS="$TARGET_CFLAGS -isystem $LINUX_DIR/include/asm-mips/mach-generic"
                          ;;
              *)          make ARCH=$ARCH include/asm include/linux/version.h
                          ;;
              esac
              ;;
*)           abort "Unsupported kernel version $KERNEL_VERSION.$KERNEL_PATCHLEVEL"
esac

- Dan

-- 
My technical stuff: http://kegel.com
My politics: see http://www.misleader.org for examples of why I'm for regime change

Re: bringing back 'make symlinks'?

[Sam Ravnborg]

On Mon, May 31, 2004 at 11:40:18AM -0700, Dan Kegel wrote:
> $ make ARCH=ppc prepare
>   HOSTCC  scripts/conmakehash
>   HOSTCC  scripts/kallsyms
>   CC      scripts/empty.o
> cc1: invalid option `multiple'
> cc1: invalid option `string'
> cc1: warning: unknown register name: r2
> make[1]: *** [scripts/empty.o] Error 1
> 
> Whoops, bad luck.  Let's try another:

OK - now I got the picture.

For 2.6 I'm not prepared to make a change that would allow what you need.
I know for 2.7 we will start to take a new approach with the kernel headers,
so I hope we do do it right there.
For 2.6 you have to live with the ugly workaround.

	Sam