[RFC PATCH 05/13] arm64: gpr-num: Add wxN aliases for wN registers

[Mark Rutland]

Some A64 instructions require a W register name for specific register
arguments, and will not accept an X register name. For example:

	STRH <Wt>, [<Xn|SP>, (<Wm>|<Xm>){, <extend> {<amount>}}]

This is painful when writing macros for inline assembly, especially
where a single register is used as both an X register and a W register.

We solve this for plain assembly by adding a wxN alias for each xN
register in commit:

  4c4dcd3541f83d21 ("arm64: assembler: introduce wxN aliases for wN registers")

Add the same facility for inline assembly, with a new
__DEFINE_ASM_GPR_ALIASES macro.

As with the other macros in gpr-num.h, different escaping is necessary
for inline vs non-inline assembly, so we can't share a single definition
that we stringify().

Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Ada Couprie Diaz <ada.coupriediaz@xxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Jinjie Ruan <ruanjinjie@xxxxxxxxxx>
Cc: Marc Zyngier <maz@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Vladimir Murzin <vladimir.murzin@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yang Shi <yang@xxxxxxxxxxxxxxxxxxxxxx>
---
 arch/arm64/include/asm/gpr-num.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/arch/arm64/include/asm/gpr-num.h b/arch/arm64/include/asm/gpr-num.h
index a114e4f8209b0..240cd25d55c5a 100644
--- a/arch/arm64/include/asm/gpr-num.h
+++ b/arch/arm64/include/asm/gpr-num.h
@@ -21,6 +21,11 @@
 "	.equ	.L__gpr_num_xzr, 31\n"				\
 "	.equ	.L__gpr_num_wzr, 31\n"
 
+#define __DEFINE_ASM_GPR_ALIASES									\
+"	.irp	n,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30\n"	\
+"	wx\\n	.req	w\\n\n"										\
+"	.endr\n"
+
 #endif /* __ASSEMBLER__ */
 
 #endif /* __ASM_GPR_NUM_H */
-- 
2.30.2