Philippe Gerum wrote:
Jim Cromie wrote:
Gilles Chanteperdrix wrote:
Tobias Marschall wrote:
> Hello,
> > On Thursday 13 April 2006 21:00, you wrote:
> > I saw a similar error when using --enable-x86-sep and not
having NPTL
> > enabled in glibc.
> > Try configuring without --enable-x86-sep (used in the
README.INSTALL
> > Pentium x86 example, the default is disabled).
> that did the trick, thank you for the hint! I did check that the
cpu supported > the sep instruction, but I wasn't aware that NPTL
is required in this case.
> > Mentioning this in README.INSTALL would be helpful. I wonder
if that mistake > could be caught by configure.
It could be caught by configure, at least if not cross-compiling, by
running getconf GNU_LIBPTHREAD_VERSION.
ie:
[EMAIL PROTECTED] xenomai]$ getconf GNU_LIBPTHREAD_VERSION
NPTL 2.3.6
doesnt /proc/cpuinfo, flags entry, indicate whether the cpu supports
SEP ?
It should, yes.
flags : fpu vme de pse tsc msr mce cx8 apic mtrr pge mca
cmov pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe est tm2
Strange indeed, if that's a recent genuine Intel CPU.
Well, Im not *stoned*, but it clearly looks like I am..
heres the whole thing:
[EMAIL PROTECTED] linux-2.6.16]$ cat /proc/cpuinfo
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 13
model name : Intel(R) Pentium(R) M processor 1.70GHz
stepping : 6
cpu MHz : 600.000
cache size : 2048 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 2
wp : yes
flags : fpu vme de pse tsc msr mce cx8 apic mtrr pge mca cmov
pat clflush dts acpi mmx fxsr sse sse2 ss tm pbe est tm2
bogomips : 1198.01
very strange. Ive seen someone elses P-4 cpuinfo, flag is there,
spelled 'sep'
what x86 processors support --enable-x86-sep ? Pentium-4 ? Xeon ?
Athlon ?
my Pentium-M apparently doesnt.
AFAIK, Intel supports sysenter/sysexit since the PII, and AMD
introduced them with the K7. The genuine Pentium M does support them,
no doubt.
Perhaps I need to email LKML.
What would you expect if I built with --enable-sep (for my laptop) ?
success / illegal-instruction exception / undefined-wierd behavior ?
WRT inferring more stuff from the build/host machine, I have some
concerns;
I build on my 686 laptop for a smaller/different 586 target. This is
not 'cross-compilation',
and could be compromised by too many automatic optimizations.
So, ideally, Id like the potentially troublesome optimizations to be
identified and gated by a prompt.
Maybe we need a script thats run on the target box, that collects
the needed configuration factors; presumably including:
CPUFLAGS=`grep flags /proc/cpuinfo`
NPTL_AVAIL=`getconf GNU_LIBPTHREAD_VERSION`
The problem is that we might not always have the target at hand when
building the user-space support (e.g. LiveCD, deployment distro
stuff). Therefore it could only be some optional helper, but not part
of the regular build process.
Ack.
I was thinking in terms of a script run on target, which produces an .rc
file,
which defines the factor=value pairs needed.
that file, if supplied to prepare-kernel as --target-info=<foo>
would supply the customizations.
Yes, somewhat cumbersome..
Perhaps Ive just been lucky, 'cross-compiling' for 586 on 686.
Ill try hacking prepare-kernel and re-building.
Somewhat related: prepare-kernel asks me for target architecture, I
started by entering i586 explicitly,
but after a while, just took the i686 default. Ive not noticed
anything different/wrong,
but would appreciate confirmation/explanation.
Which information did you look at to determine that it was using the
686 profile?
The script output told me. In response to my post, Gilles sent me the
snippet
from scripts/prepare-kernel where all x86) select i386.
Im not sure what youre asking, so I'll answer something (hopefully) close:
config/config.guess is providing the basis for the answer
if test x$linux_arch = x; then
build_arch=`$xenomai_root/config/config.guess`
default_linux_arch=`echo $build_arch|cut -f1 -d-`
fi
which 'returns' this:
test x"${LIBC}" != x && echo "${UNAME_MACHINE}-pc-linux-${LIBC}"
&& exit 0
ie
sh -vx config/config.guess
...
+ eval LIBC=gnu
LIBC=gnu
++ LIBC=gnu
+ test xgnu '!=' x
+ echo i686-pc-linux-gnu
i686-pc-linux-gnu
thanks
jimc
PS. attached is an attempt to improve README.INSTALL along these and
other lines.
will redo per your comments
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