* Re: powerpc 860 and glibc sysdeps/powerpc/power3/memset.S: CPU15 "dcbX" errata
[not found] <48FD7C30.1010505@mrv.com>
@ 2008-10-22 21:24 ` Nye Liu
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From: Nye Liu @ 2008-10-22 21:24 UTC (permalink / raw)
To: crossgcc; +Cc: Nye Liu (nyet.org), linuxppc-embedded
On Mon, Oct 20, 2008 at 11:52:32PM -0700, nyet wrote:
> I am working on a powerpc 860 toolchain, but I am having problems
> convincing glibc to not emit code that uses the dcbz instruction (CPU15
> dcbX bug). The source of the problem is sysdeps/powerpc/power3/memset.S
>
> in crosstool, we had something like this:
>
> Index: crosstool.sh
> ===================================================================
> --- crosstool.sh (.../vendor/crosstool/current) (revision 6652)
> +++ crosstool.sh (.../trunk/tools/crosstool) (revision 6652)
> @@ -529,6 +529,11 @@
> export libc_cv_forced_unwind libc_cv_c_cleanup
> fi
>
> + case ${TARGET} in
> + # remove inline asm powerpc memset, which is broken for 8xx
> + powerpc-8* ) rm -f ${GLIBC_DIR}/sysdeps/powerpc/powerpc32/memset.S ;;
> + esac
> +
> BUILD_CC=gcc CFLAGS="$TARGET_CFLAGS $EXTRA_TARGET_CFLAGS" CC="${TARGET}-gcc $GLIBC_EXTRA_CC_ARGS" \
> AR=${TARGET}-ar RANLIB=${TARGET}-ranlib \
> ${GLIBC_DIR}/configure --prefix=/usr \
>
> but i dont know what the proper place is to put the equivalent in crosstool-ng
>
> see also my crosstool patch here
>
> http://sourceware.org/ml/crossgcc/2006-12/msg00057.html
>
> and a discussion of the CPU15 errata here
>
> http://mlblog.osdir.com/linux.ports.ppc.embedded/2005-04/index.shtml
>
> It is worth noting that according to freescale, dcbi, dcibst, dcbf, and
> icbi are similarly affected, whch means
> sysdeps/powerpc/powerpc32/dl-machine.c might also cause problems, since
> it uses dcbst and icbi.
>
> the glibc maintainers seem aware of the problem, but don't seem to think
> anybody uses glibc with the 860 series. wolfgang denk is also apparently
> doing his own workarounds for the toolchains he builds for eldk.
>
This is what i ended up with. I have no idea if there is a better way;
I'd rather fix this up in a glibc patch but the way sysdeps works is
beyond my knowledge.
Index: scripts/build/libc/glibc.sh
===================================================================
--- scripts/build/libc/glibc.sh (revision 1113)
+++ scripts/build/libc/glibc.sh (working copy)
@@ -386,6 +386,15 @@
echo libc_cv_c_cleanup=yes
fi >config.cache
+ case ${CT_TARGET} in
+ # Remove inline asm powerpc memset, which is broken for FreeScale 8xx
+ # (CPU15 errata)
+ # http://sourceware.org/ml/crossgcc/2006-12/msg00057.html
+ # http://mlblog.osdir.com/linux.ports.ppc.embedded/2005-04/index.shtml
+ # http://ozlabs.org/pipermail/linuxppc-embedded/2005-January/016351.html
+ powerpc-8* ) rm -f ${CT_SRC_DIR}/${CT_LIBC_FILE}/sysdeps/powerpc/powerpc32/memset.S ;;
+ esac
+
# Configure with --prefix the way we want it on the target...
# There are a whole lot of settings here. You'll probably want
# to read up on what they all mean, and customize a bit, possibly by setting GLIBC_EXTRA_CONFIG
--
Nye Liu
nliu@mrv.com
(818) 772-6235x248
(818) 772-0576 fax
"Who would be stupid enough to quote a fictitious character?"
-- Don Quixote
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