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

["H. Peter Anvin" <hpa@zytor.com>]

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.

	-hpa