[Bug time/19363] x32: times() return value wrongly truncates/sign extends from 32bit

["cvs-commit at gcc dot gnu.org" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=19363

--- Comment #4 from cvs-commit at gcc dot gnu.org <cvs-commit at gcc dot gnu.org> ---
This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".

The branch, hjl/pr19363 has been created
        at  dd66060507f86934da9eb610b384c251ebd1168f (commit)

- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=dd66060507f86934da9eb610b384c251ebd1168f

commit dd66060507f86934da9eb610b384c251ebd1168f
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Mon Dec 14 19:09:13 2015 -0800

    Use INTERNAL_SYSCALL_TIMES for Linux times

    The Linux times function, which returns clock_t, is implemented with
    INTERNAL_SYSCALL.  Since INTERNAL_SYSCALL returns 32-bit integer and
    and clock_t is 64-bit on x32, this is a mismatch on x32.  times is the
    only such function since there is lseek.S for x32.  This patch replaces
    INTERNAL_SYSCALL in Linux times.c with INTERNAL_SYSCALL_TIMES which is
    default to INTERNAL_SYSCALL and provides x32 times.c with proper
    INTERNAL_SYSCALL_TIMES.

    There is no code change on times for i686 nor x86-64.  For x32, before
    this patch, there are

    0000000 <__times>:
       0:       b8 64 00 00 40          mov    $0x40000064,%eax
       5:       0f 05                   syscall
       7:       48 63 d0                movslq %eax,%rdx
                                    ^^^^^^^^^^ Incorrect signed extension
       a:       48 83 fa f2             cmp    $0xfffffffffffffff2,%rdx
       e:       75 07                   jne    17 <__times+0x17>
      10:       3d 00 f0 ff ff          cmp    $0xfffff000,%eax
      15:       77 11                   ja     28 <__times+0x28>
      17:       48 83 fa ff             cmp    $0xffffffffffffffff,%rdx
      1b:       b8 00 00 00 00          mov    $0x0,%eax
      20:       48 0f 45 c2             cmovne %rdx,%rax
      24:       c3                      retq

    After this patch, there are

    00000000 <__times>:
       0:       b8 64 00 00 40          mov    $0x40000064,%eax
       5:       0f 05                   syscall
       7:       48 83 f8 f2             cmp    $0xfffffffffffffff2,%rax
       b:       75 07                   jne    14 <__times+0x14>
       d:       3d 00 f0 ff ff          cmp    $0xfffff000,%eax
      12:       77 14                   ja     28 <__times+0x28>
      14:       48 83 f8 ff             cmp    $0xffffffffffffffff,%rax
      18:       ba 00 00 00 00          mov    $0x0,%edx
      1d:       48 0f 44 c2             cmove  %rdx,%rax
      21:       c3                      retq

    The incorrect signed extension is gone.

        [BZ #19363]
        * sysdeps/unix/sysv/linux/times.c (INTERNAL_SYSCALL_TIMES): New.
        (__times): Replace INTERNAL_SYSCALL with INTERNAL_SYSCALL_TIMES.
        * sysdeps/unix/sysv/linux/x86_64/x32/times.c: New file.

-----------------------------------------------------------------------

-- 
You are receiving this mail because:
You are on the CC list for the bug.