Re: [PATCH] x86: ipc: fix x32 version of shmid64_ds and msqid64_ds

H.J. Lu
2018-04-22T12:38:45Z

On Fri, Apr 20, 2018 at 7:38 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> On Fri, Apr 20, 2018 at 3:53 PM, Jeffrey Walton <noloader@gmail.com> wrote:
>>> +#if !defined(__x86_64__) || !defined(__ilp32__)
>>> #include <asm-generic/msgbuf.h>
>>> +#else
>>
>> I understand there's some progress having Clang compile the kernel.
>> Clang treats __ILP32__ and friends differently than GCC. I believe
>> ILP32 shows up just about everywhere there are 32-bit ints, longs and
>> pointers. You might find it on Aarch64 or you might find it on MIPS64
>> when using Clang.
>>
>> I think that means this may be a little suspicious:
>>
>> > +#if !defined(__x86_64__) || !defined(__ilp32__)
>>
>> I kind of felt LLVM was wandering away from the x32 ABI, but the LLVM
>> devs insisted they were within their purview. Also see
>> https://lists.llvm.org/pipermail/cfe-dev/2015-December/046300.html.
>>
>> Sorry about the top-post. I just wanted to pick out that one piece.
>
> It seems I made a typo and it needs to be __ILP32__ rather than
> __ilp32__ (corrected that locally, will resend once we have resolved
> this).
>
> Aside from that, the #if check seems to be correct to me: this
> is an x86-specific header, so it won't ever be seen on other
> architectures. On x86-32, __x86_64__ isn't set, so we don't care
> about whether __ilp32__ is set or not, and on x86-64 (lp64),
> __ilp32__ is never set, so we still get the asm-generic header.
>

Glibc has correct header files for system calls. I have a very old
program to check if Linux kernel header files are correct for user
space:

https://github.com/hjl-tools/linux-header

It needs update to check uapi.

--
H.J.
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