[PATCH v4 11/21] arm64: gpr-num: add __GPR_NUM() helper

[Mark Rutland <mark.rutland@arm.com>]

The gpr-num infrastructure requires users to concatenate the register
name with a long prefix in order to get a symbol that evaluates to a
compile-time constant. Doing this manually is error-prone and painful to
read.

Add a new __GPR_NUM() helper which wraps the concatenation.

For the moment I've left existing open-coded concatenation as-is. In
particular, the DEFINE_MRS_S() and DEFINE_MSR_S() macros have awkward
stringification requirements and would require invasive changes that
outweigh the benefit. I have plans to rework those in the near future to
remove the need to use gpr-num values.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Muhammad Usama Anjum <usama.anjum@arm.com>
Cc: Ada Couprie Diaz <ada.coupriediaz@arm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Jinjie Ruan <ruanjinjie@huawei.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Shi <yang@os.amperecomputing.com>
---
 arch/arm64/include/asm/gpr-num.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/include/asm/gpr-num.h b/arch/arm64/include/asm/gpr-num.h
index 240cd25d55c5a..30fb8a67b19f0 100644
--- a/arch/arm64/include/asm/gpr-num.h
+++ b/arch/arm64/include/asm/gpr-num.h
@@ -11,6 +11,8 @@
 	.equ	.L__gpr_num_xzr, 31
 	.equ	.L__gpr_num_wzr, 31
 
+#define __GPR_NUM(gpr)		(.L__gpr_num_##gpr)
+
 #else /* __ASSEMBLER__ */
 
 #define __DEFINE_ASM_GPR_NUMS					\
@@ -26,6 +28,8 @@
 "	wx\\n	.req	w\\n\n"										\
 "	.endr\n"
 
+#define __GPR_NUM(gpr)		"(.L__gpr_num_" gpr ")"
+
 #endif /* __ASSEMBLER__ */
 
 #endif /* __ASM_GPR_NUM_H */
-- 
2.30.2