linux-kernel - [PATCH AUTOSEL 4.19 012/237] powerpc/boot: Disable vector instructions

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Date:   Sat, 16 Nov 2019 10:37:27 -0500
From:   Sasha Levin <sashal@...nel.org>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
Cc:     Joel Stanley <joel@....id.au>,
        Michael Ellerman <mpe@...erman.id.au>,
        Sasha Levin <sashal@...nel.org>, linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH AUTOSEL 4.19 012/237] powerpc/boot: Disable vector instructions

From: Joel Stanley <joel@....id.au>

[ Upstream commit e8e132e6885962582784b6fa16a80d07ea739c0f ]

This will avoid auto-vectorisation when building with higher
optimisation levels.

We don't know if the machine can support VSX and even if it's present
it's probably not going to be enabled at this point in boot.

These flag were both added prior to GCC 4.6 which is the minimum
compiler version supported by upstream, thanks to Segher for the
details.

Signed-off-by: Joel Stanley <joel@....id.au>
Signed-off-by: Michael Ellerman <mpe@...erman.id.au>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/powerpc/boot/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 25e3184f11f78..7d5ddf53750ce 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -32,8 +32,8 @@ else
 endif
 
 BOOTCFLAGS    := -Wall -Wundef -Wstrict-prototypes -Wno-trigraphs \
-		 -fno-strict-aliasing -Os -msoft-float -pipe \
-		 -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \
+		 -fno-strict-aliasing -Os -msoft-float -mno-altivec -mno-vsx \
+		 -pipe -fomit-frame-pointer -fno-builtin -fPIC -nostdinc \
 		 -D$(compress-y)
 
 ifdef CONFIG_PPC64_BOOT_WRAPPER
-- 
2.20.1