Re: [PATCH] [BZ #19363] Use INTERNAL_SYSCALL_TIMES for Linux times

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Wed, Dec 16, 2015 at 5:49 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Tue, Dec 15, 2015 at 5:52 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>> On Mon, Dec 14, 2015 at 9:25 PM, Dmitry V. Levin <ldv@altlinux.org> wrote:
>>> On Mon, Dec 14, 2015 at 07:27:33PM -0800, H.J. Lu wrote:
>>>> 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, there is 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
>>>
>>> Looks like there is another truncation remaining here that comes
>>> from INTERNAL_SYSCALL_ERROR_P.
>>>
>>
>> You are right.  Here is the updated patch with all INTERNAL_SYSCALL*
>> macros replaced by INTERNAL_SYSCALL_TIMES* macros.
>>
>> There is no code change on i686 nor x86-64.  OK for master?
>
> Here is the updated patch using REGISTERS_CLOBBERED_BY_SYSCALL.
> OK for master?
>
>

Any comments?  If people don't want to change
sysdeps/unix/sysv/linux/times.c, I can make a
copy and update it for x32.

Thanks.

H.J.