Re: [PATCH] Use __kernel_long_t/__kernel_ulong_t in <linux/resource.h>

From: H.J. Lu
Date: Thu Dec 26 2013 - 13:08:13 EST

On Thu, Dec 26, 2013 at 9:58 AM, H. Peter Anvin <hpa@xxxxxxxxx> wrote:
> On 12/26/2013 05:52 AM, H.J. Lu wrote:
>>> c) why you suddenly need these changes now and not when the x32 ABI
>>> support was submitted and hopefully heavily tested
>> Kernel headers had been wrong for -m32/-mx32 on x86-64
>> for a long long time. Linux/x86-64 normally use header
>> files from glibc, which avoids broken kernel header files.
>> Kernel uabi header files fix -m32, but not -mx32, which I am
>> working on now.
> In other words, this work is really part of making *libc make use the
> kernel uabi headers, which is a valuable work. The fact that the kernel
> headers never got fully ported to x32 is a big reason why x32 is still
> labeled experimental.
> MIPS N32 and ARM64 ILP32 are x32-like ABIs which of course need to not
> be broken. However, currently __kernel_[u]long_t is [unsigned] long for
> all ABIs other than x32, so changing [unsigned] long to
> __kernel_[u]long_t will be a null change for anything but x32. They
> perhaps *SHOULD* be different for N32 or ARM64 ILP32, but that is for
> those arch maintainers to set.
> However, I believe H.J.'s patches from this morning conditionalizing
> this on __BITS_PER_LONG are just plain wrong.

FWIW, I prefer my first alternative. I only added the second one
since I can't test for other ABIs.

I am enclosing my kernel header file checker. It compares
kernel header files against glibc header files for -m64, -m32
and -mx32.


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