x86, asm: Fix a compilation issue with clang
Clang does not support the "shortcut" we're taking here for gcc (see below).
The patch uses the macro _ASM_DX to do the job.
From arch/x86/include/asm/uaccess.h:
/*
* Careful: we have to cast the result to the type of the pointer
* for sign reasons.
*
* The use of %edx as the register specifier is a bit of a
* simplification, as gcc only cares about it as the starting point
* and not size: for a 64-bit value it will use %ecx:%edx on 32 bits
* (%ecx being the next register in gcc's x86 register sequence), and
* %rdx on 64 bits.
*/
[ hpa: I consider this a compatibility bug in clang as this reflects a
bit of a misunderstanding about how register strings are used by
gcc, but the workaround is straightforward and there is no
particular reason to not do it. ]
Signed-off-by: Jan-Simon Möller <dl9pf@gmx.de>
Link: http://lkml.kernel.org/r/1377803585-5913-3-git-send-email-dl9pf@gmx.de
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/arch/x86/include/asm/uaccess.h b/arch/x86/include/asm/uaccess.h
index 5ee2687..f715fee 100644
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -162,7 +162,7 @@
#define get_user(x, ptr) \
({ \
int __ret_gu; \
- register __inttype(*(ptr)) __val_gu asm("%edx"); \
+ register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX); \
__chk_user_ptr(ptr); \
might_fault(); \
asm volatile("call __get_user_%P3" \