[Bug build/31867] New: "CPU ISA level is lower than required" on SSE2-free CPUs

[Bug build/31867] New: "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

            Bug ID: 31867
           Summary: "CPU ISA level is lower than required" on SSE2-free
                    CPUs
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: build
          Assignee: unassigned at sourceware dot org
          Reporter: sam at gentoo dot org
                CC: carlos at redhat dot com
  Target Milestone: ---

Initially reported downstream in Gentoo at https://bugs.gentoo.org/933764.

We found that our release media ("stage3" builds - tarballs of a rootfs)
couldn't be chrooted into on x86 (32-bit) systems without SSE2.

e.g. using
https://distfiles.gentoo.org/releases/x86/autobuilds/current-stage3-i686-openrc/stage3-i686-openrc-20240603T164904Z.tar.xz:
```
$ chroot /mnt/gentoo
/usr/lib/libc.so.6: CPU ISA level is lower than required
```

Upon further investigation, it looks like this got exposed by
46c999741340ea559784c20a45077955b50aca43 for PR31676, which also got backported
for 2.39.

I _think_ what's happening here is that libc_cv_have_x86_isa_level gets set to
'baseline' for both 32-bit and 64-bit (even with -march=i686 on a pure,
non-multilib i686-* setup) and then the ISA marker gets added.

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://bugs.gentoo.org/sho
                   |                            |w_bug.cgi?id=933764

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hjl.tools at gmail dot com

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

--- Comment #1 from Sam James <sam at gentoo dot org> ---
In sysdeps/x86/isa-level.h, we correctly do:
```
#if defined __SSE__ && defined __SSE2__
/* NB: ISAs, excluding MMX, in x86-64 ISA level baseline are used.  */
# define __X86_ISA_V1 1
#else
# define __X86_ISA_V1 0
#endif
```

But when we run the configure test, we do...
```
cat > conftest.c <<EOF
#include <sysdeps/x86/isa-level.h>
#if MINIMUM_X86_ISA_LEVEL >= 4
libc_cv_have_x86_isa_level=4
#elif MINIMUM_X86_ISA_LEVEL == 3
libc_cv_have_x86_isa_level=3
#elif MINIMUM_X86_ISA_LEVEL == 2
libc_cv_have_x86_isa_level=2
#else
libc_cv_have_x86_isa_level=baseline
#endif
EOF
```

On a CPU without SSE2, we will get 'baseline', and then...

```
if test $libc_cv_have_x86_isa_level = baseline; then
AC_DEFINE_UNQUOTED(MINIMUM_X86_ISA_LEVEL, 1)
else
AC_DEFINE_UNQUOTED(MINIMUM_X86_ISA_LEVEL, $libc_cv_have_x86_isa_level)
fi
```

We set MINIMUM_X86_ISA_LEVEL to 1, not 0, which seems wrong.

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

--- Comment #2 from Sam James <sam at gentoo dot org> ---
I still see the v3 marker appearing unexpectedly, so investigating more.

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

--- Comment #3 from Sam James <sam at gentoo dot org> ---
(In reply to Sam James from comment #2)
> I still see the v3 marker appearing unexpectedly, so investigating more.

(Is there a way to get bfd to print why it's adding a marker? e.g. inherited
from X obj)

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |skpgkp2 at gmail dot com

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |awilfox at adelielinux dot org

--- Comment #4 from Sam James <sam at gentoo dot org> ---
(In reply to Sam James from comment #2)
> I still see the v3 marker appearing unexpectedly, so investigating more.

I think ignore the v3 thing. This appears to be a separate issue.

(In reply to Sam James from comment #3)
> (In reply to Sam James from comment #2)
> > I still see the v3 marker appearing unexpectedly, so investigating more.
> 
> (Is there a way to get bfd to print why it's adding a marker? e.g. inherited
> from X obj)

I'll file a bfd bug for discussion.

--

Patch posted by awilfox:
https://inbox.sourceware.org/libc-alpha/20240609133933.62366-1-AWilcox@Wilcox-Tech.com/T/#u

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://sourceware.org/bugz
                   |                            |illa/show_bug.cgi?id=31868

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

H.J. Lu <hjl.tools at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at sourceware dot org   |hjl.tools at gmail dot com
             Status|NEW                         |WAITING

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> ---
Created attachment 15573
  --> https://sourceware.org/bugzilla/attachment.cgi?id=15573&action=edit
A patch

Please try this.

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[hjl.tools at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

--- Comment #6 from H.J. Lu <hjl.tools at gmail dot com> ---
(In reply to Sam James from comment #4)
> 
> Patch posted by awilfox:
> https://inbox.sourceware.org/libc-alpha/20240609133933.62366-1-
> AWilcox@Wilcox-Tech.com/T/#u

This is wrong since the minimum ISA level for x86-64 is 1, not 0.

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

--- Comment #7 from Sam James <sam at gentoo dot org> ---
(In reply to H.J. Lu from comment #5)
> Created attachment 15573 [details]
> A patch
> 
> Please try this.

This works. Thanks!

Tested-by: Ian Jordan <immoloism@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

--- Comment #8 from Sourceware Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by H.J. Lu <hjl@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=09bc68b0ac26331a0109f0578c9368e09176da18

commit 09bc68b0ac26331a0109f0578c9368e09176da18
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Jun 10 13:02:06 2024 -0700

    x86: Properly set MINIMUM_X86_ISA_LEVEL for i386 [BZ #31867]

    On i386, set the default minimum ISA level to 0, not 1 (baseline which
    includes SSE2).  There are no changes in config.h nor in config.make on
    x86-64.  This fixes BZ #31867.

    Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
    Tested-by: Ian Jordan <immoloism@gmail.com>
    Reviewed-by: Sam James <sam@gentoo.org>
    Reviewed-by: Florian Weimer <fweimer@redhat.com>

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|---                         |FIXED

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://sourceware.org/bugz
                   |                            |illa/show_bug.cgi?id=31883

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|unspecified                 |2.40

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |2.40

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[sam at gentoo dot org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

Sam James <sam at gentoo dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
            Version|2.40                        |2.39

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[Bug build/31867] "CPU ISA level is lower than required" on SSE2-free CPUs

[cvs-commit at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=31867

--- Comment #9 from Sourceware Commits <cvs-commit at gcc dot gnu.org> ---
The release/2.39/master branch has been updated by Sam James
<sjames@sourceware.org>:

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=b7f5b0a7114e29577daf64e68970673b61e5fcba

commit b7f5b0a7114e29577daf64e68970673b61e5fcba
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Jun 10 13:02:06 2024 -0700

    x86: Properly set MINIMUM_X86_ISA_LEVEL for i386 [BZ #31867]

    On i386, set the default minimum ISA level to 0, not 1 (baseline which
    includes SSE2).  There are no changes in config.h nor in config.make on
    x86-64.  This fixes BZ #31867.

    Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
    Tested-by: Ian Jordan <immoloism@gmail.com>
    Reviewed-by: Sam James <sam@gentoo.org>
    Reviewed-by: Florian Weimer <fweimer@redhat.com>
    (cherry picked from commit 09bc68b0ac26331a0109f0578c9368e09176da18)

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