Re: X32 project status update

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

On Sat, May 21, 2011 at 4:48 PM, H.J. Lu <hjl.tools@gmail.com> wrote:
> On Sat, May 21, 2011 at 1:01 PM, Anvin, H Peter <h.peter.anvin@intel.com> wrote:
>> I'll look at it but possibly not until the weekend.
>
> I checked it into hjl/x32/syscall branch at
>
> http://git.kernel.org/?p=linux/kernel/git/hjl/linux-2.6.38.y.git;a=summary
>

We need to investigate if we need to have different x32 syscalls for

        .quad sys32_fanotify_mark
        .quad compat_sys_open_by_handle_at
        .quad compat_sys_clock_adjtime
        .quad compat_sys_sendmmsg       /* 345 */

My guess is yes for the last 3 and unsure for fanotify_mark.

H.J.
> ---
>> -----Original Message-----
>> From:?H.J. Lu [hjl.tools@gmail.com]
>> Sent:?Saturday, May 21, 2011 12:39 PM Pacific Standard Time
>> To:?Anvin, H Peter
>> Cc:?x32-abi@googlegroups.com; Arnd Bergmann; GCC Development; GNU C Library;
>> LKML
>> Subject:?Re: X32 project status update
>>
>> On Sat, May 21, 2011 at 11:55 AM, H. Peter Anvin
>> <h.peter.anvin@intel.com> wrote:
>>> On 05/21/2011 09:27 AM, H.J. Lu wrote:
>>>> On Sat, May 21, 2011 at 8:34 AM, H.J. Lu <hjl.tools@gmail.com> wrote:
>>>>> On Sat, May 21, 2011 at 8:27 AM, Arnd Bergmann <arnd@arndb.de> wrote:
>>>>>> On Saturday 21 May 2011 17:01:33 H.J. Lu wrote:
>>>>>>> This is the x32 project status update:
>>>>>>>
>>>>>>> https://sites.google.com/site/x32abi/
>>>>>>>
>>>>>>
>>>>>> I've had another look at the kernel patch. It basically
>>>>>> looks all good, but the system call table appears to
>>>>>> diverge from the x86_64 list for no (documented) reason,
>>>>>> in the calls above 302. Is that intentional?
>>>>>>
>>>>>> I can see why you might want to keep the numbers identical,
>>>>>> but if they are already different, why not use the generic
>>>>>> system call table from asm-generic/unistd.h for the new
>>>>>> ABI?
>>>>>
>>>>> We can sort it out when we start merging x32 kernel changes.
>>>>>
>>>>
>>>> Peter, is that possible to use the single syscall table for
>>>> both x86-64 and x32 system calls? Out of 300+ system
>>>> calls, only 84 are different for x86-64 and x32. ?That
>>>> is additional 8*84 == 672 bytes in syscall table.
>>>>
>>>
>>> Sort of... remember we talked about merging system calls at the tail
>>> end? ?The problem with that is that some system calls (like read()!)
>>> actually are different system calls in very subtle situations, due to
>>> abuse in some subsystems of the is_compat() construct. ?I think that may
>>> mean we have to have an unambiguous flag after all...
>>>
>>> Now, perhaps we can use a high bit for that and mask it before dispatch,
>>> then we don't need the additional table. ?A bit of a hack, but it should
>>> work.
>>
>> How about this patch?
>>
>> ?? Merge x32 system calls with x86-64 system calls
>>
>> ??? Implemented with
>>
>> ??? 1. Mark all x86-64 specific system calls with __NR_64_.
>> ??? 2. Mark all x32 specific system calls with __NR_x32_.
>> ??? 3. Include unistd_64_compat.h, instead of unistd_x32.h for kernel
>> ??? build, which provides __NR_ versions of x86-64 specific system calls.
>> ??? 4. Append x32 specific system calls after the current x86-64 system
>> ??? calls.
>> ??? 5. Generate unistd_x32.h from unistd_64.h, replacing __NR_x32_ with
>> ??? _NR_.
>> ??? 6. Install user-space unistd_64.h, replacing __NR_64_ with _NR_.
>>
>> --
>> H.J.
>>
>
>
>
> --
> H.J.
>



-- 
H.J.