cross compiling 8xx glibc on x86

cross compiling 8xx glibc on x86

[Dr. Craig Hollabaugh]

Folks,

I've spend two days scouring the postings here and read much as I can find on cross compiling
glibc with no fpu options. I've read all kinds of things, compiled for hours, but nothing.  I've been somewhat unsuccessful,  I'm close to giving up but that's why I'm writing.

I can compile glibc-2.2.3 (no mention of no fpu on configure) but bash segment
faults (actually init respawns to fast). I can get bash running if I use the montavista compiled glibc* from their rpm. So I know that my kernel/filesystem works etc. But still I want to compile glibc for 8xx myself.

Here's my configure line

SRCFILELOC=/root/cross/
BUILDLOC=/root/cross/builds
PREFIX=/usr
ARCH=ppc
TARGET=powerpc-linux

CC=$TARGET-gcc CFLAGS="-msoft-float -D_SOFT_FLOAT -mcpu=860" \
../$GLIBVERSION/configure $TARGET --build=i586-linux \
                                  --prefix=$PREFIX/$TARGET \
                                  --enable-add-ons \
                                  -without-fp

I get this error (I'm not the first one with this error,
http://lists.linuxppc.org/linuxppc-embedded/200106/msg00178.html)

powerpc-linux-gcc -msoft-float ../sysdeps/powerpc/fclrexcpt.c -c -O2 -Wall -Winline -Wstrict-prototypes -Wwrite-strings -g -mnew-mnemonics -Wa,-mppc -mpowerpc   -fpic   -Wno-uninitialized  -I../include -I. -I/root/cross/builds/powerpc-linux-glibc/math -I.. -I../libio  -I/root/cross/builds/powerpc-linux-glibc -I../sysdeps/powerpc/elf -I../linuxthreads/sysdeps/unix/sysv/linux -I../linuxthreads/sysdeps/pthread -I../linuxthreads/sysdeps/unix/sysv -I../linuxthreads/sysdeps/unix -I../linuxthreads/sysdeps/powerpc -I../sysdeps/unix/sysv/linux/powerpc -I../sysdeps/unix/sysv/linux -I../sysdeps/gnu -I../sysdeps/unix/common -I../sysdeps/unix/mman -I../sysdeps/unix/inet -I../sysdeps/unix/sysv -I../sysdeps/unix/powerpc -I../sysdeps/unix -I../sysdeps/posix -I../sysdeps/powerpc -I../sysdeps/wordsize-32 -I../sysdeps/ieee754/flt-32 -I../sysdeps/ieee754/dbl-64 -I../sysdeps/powerpc/soft-fp -I../sysdeps/ieee754 -I../sysdeps/generic/elf -I../sysdeps/generic   -D_LIBC_REENTRANT -include ../include/l!
ibc-symbols.h  -DPIC -DSHARED   -I../soft-fp/ -D__NO_MATH_INLINES -D__LIBC_INTERNAL_MATH_INLINES -DNO_LONG_DOUBLE -D_Mlong_double_=double -o /root/cross/builds/powerpc-linux-glibc/math/fclrexcpt.os
../sysdeps/powerpc/fclrexcpt.c:20: fenv_libc.h: No such file or directory

I fooled around a bit trying to pass the Ipath to gcc for fenv_libc.h. But didn't figure that out.

I then tried compiling the montavista glibc source but get errors because I don't know which of the  10 patches to apply. I've tried using compiled libs from debian but bash seg faults ( I guess because debian glibc is compiled with fpu).

That's when I figured I should write and ask these questions.

Has anyone cross compiled glibc2.2.3 successfully for the 8xx (no fpu)?
Did you use the GNU source or did you use the MontaVista source?
If you use the MontaVista source, which patches did you apply and in what order?
What's your configure line?
Once you got glibc compiled, how did you check the fpu operation? Printing pi or what?


I'm at a loss. Any ideas? I'm stuck and would really like some suggestions.

Thanks for any help.
Craig




___________________________________________________________
Dr. Craig Hollabaugh                           craig@hollabaugh.com
304 6th Avenue, P.O. Box 1405
Ouray, CO 81427-1405                       See my "kitchen sink" resume at
970 325 0319 home                                  www.hollabaugh.com/resume.html
970 325 0509 office
215 882 1880 cell


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Re: cross compiling 8xx glibc on x86

[À̽µ¿(Seungdong Lee)]

Hi, did you consider the cache line size.
Glibc for powerpc-linux is written for 32 byte cache-line size.
As far as I know, only 8xx CPU has the cache whose line size is 16byte.
This discrepancy usually affects dynamic linking mechanism and results in illegal instruction.
You can check this point by looking into sysdeps/powerpc/dl-machine.c.
There will be PPC_DCBST macro. It should be called at every four long word.
(I didn't see 2.2.3 but 2.1.2 version had a problem like that.)
If it is called at every eight long word, it should be modified.
You can also check this point indirectly. Link bash statically and try to run it.
If it is OK, then it is dynamic linking problem. It might be cache-line size problem.

Good luck.

-- Seungdong Lee


----- Original Message -----
From: Dr. Craig Hollabaugh <craig@hollabaugh.com>
To: <linuxppc-embedded@lists.linuxppc.org>
Sent: Thursday, August 16, 2001 11:35 AM
Subject: cross compiling 8xx glibc on x86


>
> Folks,
>
> I've spend two days scouring the postings here and read much as I can find on cross compiling
> glibc with no fpu options. I've read all kinds of things, compiled for hours, but nothing.  I've been somewhat unsuccessful,  I'm close to giving up but that's why I'm writing.
>
> I can compile glibc-2.2.3 (no mention of no fpu on configure) but bash segment
> faults (actually init respawns to fast). I can get bash running if I use the montavista compiled glibc* from their rpm. So I know that my kernel/filesystem works etc. But still I want to compile glibc for 8xx myself.
>
> Here's my configure line
>
> SRCFILELOC=/root/cross/
> BUILDLOC=/root/cross/builds
> PREFIX=/usr
> ARCH=ppc
> TARGET=powerpc-linux
>
> CC=$TARGET-gcc CFLAGS="-msoft-float -D_SOFT_FLOAT -mcpu=860" \
> ../$GLIBVERSION/configure $TARGET --build=i586-linux \
>                                   --prefix=$PREFIX/$TARGET \
>                                   --enable-add-ons \
>                                   -without-fp
>
> I get this error (I'm not the first one with this error,
> http://lists.linuxppc.org/linuxppc-embedded/200106/msg00178.html)
>
> powerpc-linux-gcc -msoft-float ../sysdeps/powerpc/fclrexcpt.c -c -O2 -Wall -Winline -Wstrict-prototypes -Wwrite-strings -g -mnew-mnemonics -Wa,-mppc -mpowerpc   -fpic   -Wno-uninitialized  -I../include -I. -I/root/cross/builds/powerpc-linux-glibc/math -I.. -I../libio  -I/root/cross/builds/powerpc-linux-glibc -I../sysdeps/powerpc/elf -I../linuxthreads/sysdeps/unix/sysv/linux -I../linuxthreads/sysdeps/pthread -I../linuxthreads/sysdeps/unix/sysv -I../linuxthreads/sysdeps/unix -I../linuxthreads/sysdeps/powerpc -I../sysdeps/unix/sysv/linux/powerpc -I../sysdeps/unix/sysv/linux -I../sysdeps/gnu -I../sysdeps/unix/common -I../sysdeps/unix/mman -I../sysdeps/unix/inet -I../sysdeps/unix/sysv -I../sysdeps/unix/powerpc -I../sysdeps/unix -I../sysdeps/posix -I../sysdeps/powerpc -I../sysdeps/wordsize-32 -I../sysdeps/ieee754/flt-32 -I../sysdeps/ieee754/dbl-64 -I../sysdeps/powerpc/soft-fp -I../sysdeps/ieee754 -I../sysdeps/generic/elf -I../sysdeps/generic   -D_LIBC_REENTRANT -include ../include!
/l!
> ibc-symbols.h  -DPIC -DSHARED   -I../soft-fp/ -D__NO_MATH_INLINES -D__LIBC_INTERNAL_MATH_INLINES -DNO_LONG_DOUBLE -D_Mlong_double_=double -o /root/cross/builds/powerpc-linux-glibc/math/fclrexcpt.os
> ../sysdeps/powerpc/fclrexcpt.c:20: fenv_libc.h: No such file or directory
>
> I fooled around a bit trying to pass the Ipath to gcc for fenv_libc.h. But didn't figure that out.
>
> I then tried compiling the montavista glibc source but get errors because I don't know which of the  10 patches to apply. I've tried using compiled libs from debian but bash seg faults ( I guess because debian glibc is compiled with fpu).
>
> That's when I figured I should write and ask these questions.
>
> Has anyone cross compiled glibc2.2.3 successfully for the 8xx (no fpu)?
> Did you use the GNU source or did you use the MontaVista source?
> If you use the MontaVista source, which patches did you apply and in what order?
> What's your configure line?
> Once you got glibc compiled, how did you check the fpu operation? Printing pi or what?
>
>
> I'm at a loss. Any ideas? I'm stuck and would really like some suggestions.
>
> Thanks for any help.
> Craig
>
>
>
>
> ___________________________________________________________
> Dr. Craig Hollabaugh                           craig@hollabaugh.com
> 304 6th Avenue, P.O. Box 1405
> Ouray, CO 81427-1405                       See my "kitchen sink" resume at
> 970 325 0319 home                                  www.hollabaugh.com/resume.html
> 970 325 0509 office
> 215 882 1880 cell
>
>
>

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Re: cross compiling 8xx glibc on x86

[Mark Hatle]

À̽µ¿(Seungdong Lee) wrote:
>
> Hi, did you consider the cache line size.
> Glibc for powerpc-linux is written for 32 byte cache-line size.
> As far as I know, only 8xx CPU has the cache whose line size is 16byte.

Just as an FYI, the IBM PPC 403GCX and Motorola PPC 8xx series are the
onlys ones that are 4 word (16 bytes).  The 405, 6xx, 7xx, 74xx, 82xx
series are all 8 words (32 bytes) and the Power3/4 are 16 words (64
bytes).

--Mark

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Re: cross compiling 8xx glibc on x86

[Mark Hatle]

> ../sysdeps/powerpc/fclrexcpt.c:20: fenv_libc.h: No such file or directory

That error is due to glibc not being setup to run w/o floating point on
PowerPC.

> I fooled around a bit trying to pass the Ipath to gcc for fenv_libc.h. But didn't figure that out.

Look at the patch titled "hhl-powerpc-fpu.patch".  This will move the
files to where they need to be for it to work right.  It will also
remove the floating point loads/saves in the setjmp/longjmp call.

To find out the order of the patches that we apply, just look at the
%build section, they are layed out in the order in which they are
applied for our product.

> Has anyone cross compiled glibc2.2.3 successfully for the 8xx (no fpu)?

HHL 2.0 is based on glibc2.2.3pre1 (due to release schedules).  But we
do have glibc-2.2.3 release working in house, it was trivial since
2.2.3pre1 was already done.

> Did you use the GNU source or did you use the MontaVista source?

I use MontaVista's Source.. <grin>

> If you use the MontaVista source, which patches did you apply and in what order?
> What's your configure line?
> Once you got glibc compiled, how did you check the fpu operation? Printing pi or what?

The easiest way is to build bash and use the builtin (shell) printf
command and see if it prints out "nan" or the number.  If you get the
number it is working correctly.

One side note, you don't really need the no floating point patches, if
you are willing to live with the emulation overhead it works fine in the
kernel.

However, on the 8xx there is one thing that you can not "live w/o"
doing.  Specifically you must either "fix" or (easy way) delete the
sysdeps/powerpc/memset.S file.  This file is hard coded to 8 word wide
cache lines.. and the 8xx only has 4 words wide cache.

So...  if you can live w/ emulation, do that it's easier.....
but regardless you will need to delete the sysdeps/powerpc/memset.S
file.

--Mark

BTW the memset.S is being worked on in the PowerPC community to allow
for various cacheline optimizations from (4 words) 8xx, to (16 words)
Power3/4 series.

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Re: cross compiling 8xx glibc on x86

[Dr. Craig Hollabaugh]

Mark,

Thanks for the speedy reply, do you guys sleep over there?



At 10:28 PM 8/15/2001 -0500, Mark Hatle wrote:
>> ../sysdeps/powerpc/fclrexcpt.c:20: fenv_libc.h: No such file or directory
>
>That error is due to glibc not being setup to run w/o floating point on
>PowerPC.
>> I fooled around a bit trying to pass the Ipath to gcc for fenv_libc.h. But didn't figure that out.
>
>Look at the patch titled "hhl-powerpc-fpu.patch".  This will move the
>files to where they need to be for it to work right.  It will also
>remove the floating point loads/saves in the setjmp/longjmp call.

Are you saying that applying hhl-powerpc-fpu.patch to 2.2.3 then configuring with

CC=$TARGET-gcc CFLAGS="-msoft-float -D_SOFT_FLOAT -mcpu=860" \
../$GLIBVERSION/configure $TARGET --build=i586-linux \
--prefix=$PREFIX/$TARGET \
--enable-add-ons \
-without-fp

should work?

Patching 2.2.3 with hhl-powerpc-fpu.patch succeeds but configure fails with

make[2]: *** No rule to make target `../sysdeps/powerpc/fpu_control.h', needed by `/root/cross/builds/powerpc-linux-glibc/csu/init-first.d'.  Stop.

See next statement

>To find out the order of the patches that we apply, just look at the
>%build section, they are layed out in the order in which they are
>applied for our product.

Are you talking about this?
Patch3: manual-texinfo4.dpatch
Patch4: ldd.dpatch
Patch5: glibcbug.dpatch
Patch6: hurd-ldflags.dpatch
Patch7: fhs-linux-paths.dpatch
Patch8: pthread_create-manpage.dpatch
Patch9: string2-pointer-arith.dpatch
Patch10: glibc22-nss-upgrade.dpatch
Patch11: glibc22-disable-static.dpatch
Patch12: glibc22-eo_EO.dpatch
Patch13: glibc22-getaddrinfo.dpatch
Patch30: glibc-rpc-cross.patch
Patch31: hhl-powerpc-fpu.patch
Patch32: hhl-powerpc-altivec.patch
Patch33: glibc-223pre1-fe_invalid.patch
Patch34: glibc-mips-abi.patch
Patch35: glibc22-27.patch
Patch36: hhl-mips-siginfo.patch
Patch37: hhl-glibc-2.2.3-config.patch
Patch38: glibc-2.2.3-sh.patch
Patch39: 405-atomicity.patch

A lot of these patches fail when applied to 2.2.3. I'm somewhat inexperienced here but I want to learn what's going on.



The easiest way is to build bash and use the builtin (shell) printf
>command and see if it prints out "nan" or the number.  If you get the
>number it is working correctly.

Hmm, sounds simple but last night's all nighter is making me stupid. Can you
give an example of a floating point divide in bash using the printf statement?



>One side note, you don't really need the no floating point patches, if
>you are willing to live with the emulation overhead it works fine in the
>kernel.

Are you talking about setting this CONFIG_MATH_EMULATION=y?



>However, on the 8xx there is one thing that you can not "live w/o"
>doing.  Specifically you must either "fix" or (easy way) delete the
>sysdeps/powerpc/memset.S file.  This file is hard coded to 8 word wide
>cache lines.. and the 8xx only has 4 words wide cache.
>
>So...  if you can live w/ emulation, do that it's easier.....
>but regardless you will need to delete the sysdeps/powerpc/memset.S
>file.

I can live with emulation. If so, should I just go back and recompile the tools,
after I remove all the fpu flags and remove memset.S? After that, do you think
a C program with printf("%f",22.0/7.0) will work?

Thanks again!
Craig


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Re: cross compiling 8xx glibc on x86

[Mark Hatle]

"Dr. Craig Hollabaugh" wrote:
>
> Mark,
>
> Thanks for the speedy reply, do you guys sleep over there?

No.. we don't.. <grin>

> Are you saying that applying hhl-powerpc-fpu.patch to 2.2.3 then configuring with
>
> CC=$TARGET-gcc CFLAGS="-msoft-float -D_SOFT_FLOAT -mcpu=860" \
> ../$GLIBVERSION/configure $TARGET --build=i586-linux \
> --prefix=$PREFIX/$TARGET \
> --enable-add-ons \
> -without-fp
>
> should work?

yes it should.

>
> Patching 2.2.3 with hhl-powerpc-fpu.patch succeeds but configure fails with
>
> make[2]: *** No rule to make target `../sysdeps/powerpc/fpu_control.h', needed by `/root/cross/builds/powerpc-linux-glibc/csu/init-first.d'.  Stop.

I just compared our 2.2.3pre1 and 2.2.3 release hhl-powerpc-fpu.patch
and they are identical.  Obviously I am not getting that error.  The
expanded configure line we use comes out be:

./configure --host=powerpc-hardhat-linux --build=i686-pc-linux-gnu
--prefix=/usr --exec-prefix=/usr --bindir=/usr/bin --sbindir=/usr/sbin
--sysconfdir=/etc --datadir=/usr/share --includedir=/usr/include
--libdir=/usr/lib --libexecdir=/usr/libexec --localstatedir=/var
--sharedstatedir=/usr/share --mandir=/usr/share/man
--infodir=/usr/share/info --libexecdir=/usr/lib
--build=i686-pc-linux-gnu --enable-add-ons --without-cvs --without-fp

Obviously you will not need most of the things setting the various
prefixes..  but you will need the --host, --build, --enable-add-ons,
--without-fp  (ignore the second --build above.. configure evaluates the
last --build passed in..  it's an artifact of our build system...)

As for the CC, we set it to our compiler as the norm...  and we do not
set CFLAGS, but we have slightly modified gcc to default to
-msoft-float.

>
> See next statement
>
> >To find out the order of the patches that we apply, just look at the
> >%build section, they are layed out in the order in which they are
> >applied for our product.
>
> Are you talking about this?
> Patch3: manual-texinfo4.dpatch
> ...
> Patch39: 405-atomicity.patch
>
> A lot of these patches fail when applied to 2.2.3. I'm somewhat inexperienced here but I want to learn what's going on.

No.. go further down and look for "%prep".  This section of the .spec
file indicates what to do to "prep" the package for building.

As I said, the released version is 2.2.3pre1, very few changes have been
made to 2.2.3 release, so you may have to manually apply some of the
patches.

Also the patches 30-39 are the montavista specific patches.  The other
ones you probably do not need.

> The easiest way is to build bash and use the builtin (shell) printf
> >command and see if it prints out "nan" or the number.  If you get the
> >number it is working correctly.
>
> Hmm, sounds simple but last night's all nighter is making me stupid. Can you
> give an example of a floating point divide in bash using the printf statement?

Don't even need to do a floating point divide.  Just using floating
point.. i.e. "printf %f 1.01" will return "nan" (or crash) if
soft-floating point is not working..  it will return 1.010000 if
floating point is working right.

>
> >One side note, you don't really need the no floating point patches, if
> >you are willing to live with the emulation overhead it works fine in the
> >kernel.
>
> Are you talking about setting this CONFIG_MATH_EMULATION=y?

yes.

>
> >However, on the 8xx there is one thing that you can not "live w/o"
> >doing.  Specifically you must either "fix" or (easy way) delete the
> >sysdeps/powerpc/memset.S file.  This file is hard coded to 8 word wide
> >cache lines.. and the 8xx only has 4 words wide cache.
> >
> >So...  if you can live w/ emulation, do that it's easier.....
> >but regardless you will need to delete the sysdeps/powerpc/memset.S
> >file.
>
> I can live with emulation. If so, should I just go back and recompile the tools,
> after I remove all the fpu flags and remove memset.S? After that, do you think
> a C program with printf("%f",22.0/7.0) will work?

It should.  One thing to keep in mind.  -msoft-float changes the ABI, so
you can not switch back and forth while running the system.  Either
everything has to be -msoft-float, or nothing should be -msoft-float.

As you can see, building/reproducing a working toolchain with everything
configured "just right" isn't exactly the easiest thing to do.  :)  It
is fairly straight forward, but once you have done it a few thousand
times it becomes much easier.


--Mark

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Re: cross compiling 8xx glibc on x86

[Michael Habermann]

At 08:35 PM 8/15/2001 -0600, you wrote:
>I've spend two days scouring the postings here and read much as I can find
>on cross compiling
>glibc with no fpu options. I've read all kinds of things, compiled for
>hours, but nothing.  I've been somewhat unsuccessful,  I'm close to giving
>up but that's why I'm writing.

It took me two weeks until I gave up. This glibc is the trickiest part. I
wish Wolfgang would write one - oh, a subset is already in PPCBoot. :)


>I can compile glibc-2.2.3 (no mention of no fpu on configure) but bash segment
>faults (actually init respawns to fast). I can get bash running if I use
>the montavista compiled glibc* from their rpm. So I know that my
>kernel/filesystem works etc. But still I want to compile glibc for 8xx myself.

A statically linked bash should work, even with the cacheline bug.


>I get this error (I'm not the first one with this error,
>http://lists.linuxppc.org/linuxppc-embedded/200106/msg00178.html)

Yes it looks very much like the same. I asked again some time later. Here
is the reply that probably helps you:
http://lists.linuxppc.org/linuxppc-embedded/200106/msg00247.html


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Re: cross compiling 8xx glibc on x86

[Wolfgang Denk]

In message <5.1.0.14.0.20010816175113.00a4f0d0@pop.gmx.de> you wrote:
>
> >I've spend two days scouring the postings here and read much as I can find
> >on cross compiling
> >glibc with no fpu options. I've read all kinds of things, compiled for
> >hours, but nothing.  I've been somewhat unsuccessful,  I'm close to giving
> >up but that's why I'm writing.
>
> It took me two weeks until I gave up. This glibc is the trickiest part. I
> wish Wolfgang would write one - oh, a subset is already in PPCBoot. :)

Well, I did this nearly two years ago. You can find the build scripts
and patches I used on our FTP server. They still work. And  yes,  you
still  can  find  ALL  the old tarballs on the web, just use a search
engine.

> >I can compile glibc-2.2.3 (no mention of no fpu on configure) but bash segment
> >faults (actually init respawns to fast). I can get bash running if I use
> >the montavista compiled glibc* from their rpm. So I know that my
> >kernel/filesystem works etc. But still I want to compile glibc for 8xx myself.

Well, why don't you do it, then? If the MV version is fine  for  you,
and all you want to do is compile it yourself (just to burn some time
and  CPU resources, I guess), then grab the MV source RPM, unpack it,
and follow the build instructions in the RPM's "spec" file.

There is absolutely no magig involved. Anybody can do that. You don't
even have to understand what you're doing :-(

> A statically linked bash should work, even with the cacheline bug.

But only if it's linked against "clean" libs.


Ummm... I think you're just wasting your time. And ours.

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Life. Don't talk to me about life.      - Marvin the Paranoid Android

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