On 5/3/17 10:35 AM, David Miller wrote:
From: Alexei Starovoitov <a...@fb.com>
Date: Wed, 3 May 2017 09:54:42 -0700
/usr/include/asm/types.h -> asm-generic/int-ll64.h
as far as I can see that should be the same on most archs.
Why doesn't it work for sparc?
You can't assume anything about the kernel headers installed,
on my debian Sparc box /usr/include/asm/types.h is below.
They do things this way to facilitate multiarch building. I think
it's pretty reasonable.
#ifndef _SPARC_TYPES_H
#define _SPARC_TYPES_H
/*
* This file is never included by application software unless
* explicitly requested (e.g., via linux/types.h) in which case the
* application is Linux specific so (user-) name space pollution is
* not a major issue. However, for interoperability, libraries still
* need to be careful to avoid a name clashes.
*/
#if defined(__sparc__)
#include <asm-generic/int-ll64.h>
#ifndef __ASSEMBLY__
typedef unsigned short umode_t;
#endif /* __ASSEMBLY__ */
#endif /* defined(__sparc__) */
if it was something like
#ifdef __sparc__
...
#else
#include_next <asm/types.h>
I would buy that debian folks indeed care about multi-arch, but
what above does is making #include <linux/types.h> to be a nop
for any cross-compiler on sparc that included it.
Which is probably quite painful to debug as we found out.
You're right that we cannot assume much about /usr/include craziness.
In that sense adding __native_arch__ macro is also wrong, since
it assumes sane /usr/include without inline asm or other things
that clang for bpf arch can consume.
In that sense the only way to be independent from arch dependent
things in /usr/include is to put all arch specific headers
into our own dir in tools/selftests/ (or may be tools/bpf/include)
and point clang to that. I think the list of .h in there will be
limited. Only things like linux/types.h and gnu/stubs.h,
so it will be manageable.
Thoughts?
