[Bug libc/27623] New: powerpc: Missing registers in sc[v] clobbers list

[Bug libc/27623] New: powerpc: Missing registers in sc[v] clobbers list

[msc at linux dot ibm.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27623

            Bug ID: 27623
           Summary: powerpc: Missing registers in sc[v] clobbers list
           Product: glibc
           Version: unspecified
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: libc
          Assignee: unassigned at sourceware dot org
          Reporter: msc at linux dot ibm.com
                CC: drepper.fsp at gmail dot com
  Target Milestone: ---

The current clobbers list for syscalls using sc or scv in
sysdeps/unix/sysv/linux/powerpc/sysdep.h is not complete, as the kernel
zeroes XER register on exit and per the kernel documentation scv may also
clobber the condition register.

This is unlikely to be causing issues in the wild today, as the code has
been missing the XER clobber for years and I couldn't find any reported bugs
related to that. Also, the kernel currently restores the CR on exit, but
that could change in the future, as that is not mandated by the ABI for all
CR fields.

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[Bug libc/27623] powerpc: Missing registers in sc[v] clobbers list

[msc at linux dot ibm.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27623

--- Comment #1 from Matheus Castanho <msc at linux dot ibm.com> ---
I'm preparing a patch and will post to libc-alpha shortly.

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[Bug libc/27623] powerpc: Missing registers in sc[v] clobbers list

[tuliom at ascii dot art.br]

https://sourceware.org/bugzilla/show_bug.cgi?id=27623

Tulio Magno Quites Machado Filho <tuliom at ascii dot art.br> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |powerpc64*
            Version|unspecified                 |2.33
                 CC|                            |tuliom at ascii dot art.br
           Assignee|unassigned at sourceware dot org   |msc at linux dot ibm.com

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[Bug libc/27623] powerpc: Missing registers in sc[v] clobbers list

[msc at linux dot ibm.com]

https://sourceware.org/bugzilla/show_bug.cgi?id=27623

Matheus Castanho <msc at linux dot ibm.com> changed:

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

--- Comment #2 from Matheus Castanho <msc at linux dot ibm.com> ---
Fixed by 

commit 5d61fc2021922b4f572be218dad5b299e2939346
Author: Matheus Castanho <msc@linux.ibm.com>
Date:   Wed Mar 17 10:14:15 2021 -0300

    powerpc: Add missing registers to clobbers list for syscalls [BZ #27623]

https://sourceware.org/git/?p=glibc.git;a=commit;h=5d61fc2021922b4f572be218dad5b299e2939346

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[Bug libc/27623] powerpc: Missing registers in sc[v] clobbers list

[tuliom at ascii dot art.br]

https://sourceware.org/bugzilla/show_bug.cgi?id=27623

Tulio Magno Quites Machado Filho <tuliom at ascii dot art.br> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |2.34

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