asm-prototypes: Clear any CPP defines before declaring the functions
authorMichal Marek <mmarek@suse.com>
Tue, 3 Jan 2017 12:49:42 +0000 (13:49 +0100)
committerMichal Marek <mmarek@suse.com>
Thu, 5 Jan 2017 11:57:42 +0000 (12:57 +0100)
commitc7858bf16c0b2cc62f475f31e6df28c3a68da1d6
tree53cd1f9f5d0be28c7564f2fd00d8b065fc63dce4
parent7ce7d89f48834cefece7804d38fc5d85382edf77
asm-prototypes: Clear any CPP defines before declaring the functions

The asm-prototypes.h file is used to provide dummy function declarations
for genksyms, when processing asm files with EXPORT_SYMBOL. Make sure
that any architecture defines get out of our way. x86 currently has an
issue with memcpy on 64bit with CONFIG_KMEMCHECK=y and with
memset/__memset on 32bit:

$ cat init/test.c
#include <asm/asm-prototypes.h>
$ make -s init/test.o
In file included from ./arch/x86/include/asm/string.h:4:0,
 from ./include/linux/string.h:18,
 from ./include/linux/bitmap.h:8,
 from ./include/linux/cpumask.h:11,
 from ./arch/x86/include/asm/cpumask.h:4,
 from ./arch/x86/include/asm/msr.h:10,
 from ./arch/x86/include/asm/processor.h:20,
 from ./arch/x86/include/asm/cpufeature.h:4,
 from ./arch/x86/include/asm/thread_info.h:52,
 from ./include/linux/thread_info.h:25,
 from ./arch/x86/include/asm/preempt.h:6,
 from ./include/linux/preempt.h:59,
 from ./include/linux/spinlock.h:50,
 from ./include/linux/seqlock.h:35,
 from ./include/linux/time.h:5,
 from ./include/uapi/linux/timex.h:56,
 from ./include/linux/timex.h:56,
 from ./include/linux/sched.h:19,
 from ./include/linux/uaccess.h:4,
 from ./arch/x86/include/asm/asm-prototypes.h:2,
 from init/test.c:1:
./arch/x86/include/asm/string_64.h:52:47: error: expected declaration specifiers or ‘...’ before ‘(’ token
 #define memcpy(dst, src, len) __inline_memcpy((dst), (src), (len))
 ./include/asm-generic/asm-prototypes.h:6:14: note: in expansion of macro ‘memcpy’
  extern void *memcpy(void *, const void *, __kernel_size_t);

       ^
...

During real build, this manifests itself by genksyms segfaulting.

Fixes: 334bb7738764 ("x86/kbuild: enable modversions for symbols exported from asm")
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Michal Marek <mmarek@suse.com>
include/asm-generic/asm-prototypes.h