Re: powerpc 860 and glibc sysdeps/powerpc/power3/memset.S: CPU15 "dcbX" errata
From: Nye Liu <hidden>
Date: 2008-10-22 21:36:41
On Mon, Oct 20, 2008 at 11:52:32PM -0700, nyet wrote:
quoted hunk
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
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