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Subject[PATCH 4.4 46/48] asm-prototypes: Clear any CPP defines before declaring the functions
Date
From: Michal Marek <mmarek@suse.com>

commit c7858bf16c0b2cc62f475f31e6df28c3a68da1d6 upstream.

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>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
include/asm-generic/asm-prototypes.h | 6 ++++++
1 file changed, 6 insertions(+)

--- a/include/asm-generic/asm-prototypes.h
+++ b/include/asm-generic/asm-prototypes.h
@@ -1,7 +1,13 @@
#include <linux/bitops.h>
+#undef __memset
extern void *__memset(void *, int, __kernel_size_t);
+#undef __memcpy
extern void *__memcpy(void *, const void *, __kernel_size_t);
+#undef __memmove
extern void *__memmove(void *, const void *, __kernel_size_t);
+#undef memset
extern void *memset(void *, int, __kernel_size_t);
+#undef memcpy
extern void *memcpy(void *, const void *, __kernel_size_t);
+#undef memmove
extern void *memmove(void *, const void *, __kernel_size_t);

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