[RFC5 PATCH v6 00/21] ILP32 for ARM64

Zhangjian (Bamvor)
2016-03-31T07:35:52Z

On 2016/3/29 21:27, Arnd Bergmann wrote:
> On Tuesday 29 March 2016 21:21:49 Zhangjian wrote:
>>>>>
>>>>> Then we could remove the __USE_FILE_OFFSET64 in stat.h and fcnt.h in
>>>>> aarch64. And truncate and ftruncate is same as truncate64 and
>>>>> ftruncate64.
>>>>
>>>> I don't know what the glibc developers prefer, but I think the
>>>> result needs to be something like that: either __OFF_T_TYPE is
>>>> defined as you write above as a 64-bit type, or the user-visible
>>>> off_t typedef unconditionally uses __OFF64_T_TYPE rather than
>>>> __OFF_T_TYPE.
>>>>
>>>
>>> I'm not the glibc developer as well, but I think it's OK.
>> IIUC, it is usually what glibc does.
>> If we want to define off_t to 64bit in ilp32, the follow syscall may
>> need to define as non-compat too:
>> sys_fadvise64
>> sys_sendfile
>> sys_sendfile64
>> sys_lseek
>> sys_splice
>> sys_sync_file_range2
>> sys_truncate
>> sys_ftruncate
>
> I'm not following here. Do you mean in the kernel or in glibc?
kernel.
>
> In the kernel, the list of syscalls is fine, because we already only
> provide syscalls passing loff_t as I said, and that is 64-bit.
Sorry I am lost here. I understand that the syscall passing loff_t
should wrap to 64bit syscall. But if we define off_t as 64bit,
then all the offset relative syscall should wrap to 64bit syscall.
>
> In glibc, I think we need to define fewer entry points, not more.
> Instead of having both lseek and lseek64, only one of them should
> be provided, and that should always take a 64-bit offset, calling
> into the kernel with the _llseek syscall entry.
Agree. We should avoid the duplicated definition.

Regards

Bamvor

>
> Arnd
>