linux-kernel - [PATCH 1/2] ARM: drop unnecessary WASM

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Message-Id: <13835555f8ef44b21d1b7ddfe1c4203d0981f77e.1551824161.git.stefan@agner.ch>
Date:   Tue,  5 Mar 2019 23:18:26 +0100
From:   Stefan Agner <stefan@...er.ch>
To:     linux@...linux.org.uk
Cc:     will.deacon@....com, ndesaulniers@...gle.com,
        natechancellor@...il.com, arnd@...db.de, ard.biesheuvel@...aro.org,
        nicolas.pitre@...aro.org, thierry.reding@...il.com,
        julien.thierry@....com, mark.rutland@....com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Stefan Agner <stefan@...er.ch>
Subject: [PATCH 1/2] ARM: drop unnecessary WASM

The W macro for generating wide instructions when targeting Thumb-2
is not required for the preload data instructions (pld, pldw) since
they are only available as wide instructions. The GNU assembler seems
to work with or without the .w appended when compiling an Thumb-2
kernel. However, Clang's integrated assembler does not consider the
.w variants as valid instructions:

  ./arch/arm/include/asm/processor.h:133:5: error: invalid instruction
                          "pldw.w\t%a0 \n"
                           ^
  <inline asm>:2:1: note: instantiated into assembly here
  pldw.w  [r0]
  ^
  1 error generated.

Drop the macro to make sure non-wide variants of pld and pldw are
emitted in all cases.

Signed-off-by: Stefan Agner <stefan@...er.ch>
---
 arch/arm/include/asm/processor.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 120f4c9bbfde..042d77cf686d 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -131,8 +131,8 @@ static inline void prefetchw(const void *ptr)
 	__asm__ __volatile__(
 		".arch_extension	mp\n"
 		__ALT_SMP_ASM(
-			WASM(pldw)		"\t%a0",
-			WASM(pld)		"\t%a0"
+			"pldw\t%a0",
+			"pld\t%a0"
 		)
 		:: "p" (ptr));
 }
-- 
2.20.1