Re: cross compiling 8xx glibc on x86

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 <redacted>
To: <redacted>
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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