Re: [RFC5 PATCH v6 00/21] ILP32 for ARM64

From: Zhangjian (Bamvor)
Date: Thu Mar 31 2016 - 03:37:45 EST

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

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

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:

I'm not following here. Do you mean in the kernel or in glibc?

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.