linux-kernel - [PATCH v1 4/5] powerpc: Remove cpu-as-y completely

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Message-Id: <9e43ad8b173c2fdb540e2555a8ba3e375419f3cf.1671475543.git.christophe.leroy@csgroup.eu>
Date:   Mon, 19 Dec 2022 19:45:59 +0100
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Michael Ellerman <mpe@...erman.id.au>,
        Nicholas Piggin <npiggin@...il.com>, jbglaw@...-owl.de
Cc:     Christophe Leroy <christophe.leroy@...roup.eu>,
        linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH v1 4/5] powerpc: Remove cpu-as-y completely

cpu-as-y is there to force assembler building options.
But there is no need for that. Gcc is passed the necessary
options and it automatically pass the appropriate option to
GAS.

GCC is given -maltivec when relevant, so no need
for -Wa,-maltivec in addition

And -Wa,-many is wrong as it will hide innapropriate
instructions. Better to detect them and handle them on a
case by case basis.
-Wa,-many was added by commit 960e30029863 ("powerpc/Makefile:
Fix PPC_BOOK3S_64 ASFLAGS") in order to fix an issue with
clang and the passed -Wa,-mpower4 option. But we have now
removed it expecting the compiler to automatically pass the
proper options and instructions based on -mcpu=power4

Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/powerpc/Makefile | 12 ------------
 1 file changed, 12 deletions(-)

diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 0f9f291895cb..7e67f939a243 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -201,18 +201,6 @@ KBUILD_CFLAGS += -fno-asynchronous-unwind-tables
 # often slow when they are implemented at all
 KBUILD_CFLAGS		+= $(call cc-option,-mno-string)
 
-cpu-as-$(CONFIG_ALTIVEC)	+= $(call as-option,-Wa$(comma)-maltivec)
-
-# When using '-many -mpower4' gas will first try and find a matching power4
-# mnemonic and failing that it will allow any valid mnemonic that GAS knows
-# about. GCC will pass -many to GAS when assembling, clang does not.
-# LLVM IAS doesn't understand either flag: https://github.com/ClangBuiltLinux/linux/issues/675
-# but LLVM IAS only supports ISA >= 2.06 for Book3S 64 anyway...
-cpu-as-$(CONFIG_PPC_BOOK3S_64)	+= $(call as-option,-Wa$(comma)-many)
-
-KBUILD_AFLAGS += $(cpu-as-y)
-KBUILD_CFLAGS += $(cpu-as-y)
-
 KBUILD_AFLAGS += $(aflags-y)
 KBUILD_CFLAGS += $(cflags-y)
 
-- 
2.38.1