linux-kernel - [PATCH 1/2] um: remove -fno-unit-at-a-time workaround for pre-4.0 GCC

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Date:   Mon, 12 Nov 2018 11:35:19 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>, x86@...nel.org
Cc:     Richard Weinberger <richard@...ma-star.at>,
        linuxppc-dev@...ts.ozlabs.org,
        Michael Ellerman <mpe@...erman.id.au>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        "H. Peter Anvin" <hpa@...or.com>, Borislav Petkov <bp@...en8.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] um: remove -fno-unit-at-a-time workaround for pre-4.0 GCC

Commit cafa0010cd51 ("Raise the minimum required gcc version to 4.6")
bumped the minimum GCC version to 4.6 for all architectures.

'$(call cc-option,-fno-unit-at-a-time)' is now dead code since
'$(cc-version) -lt 0400' is always false.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
---

 arch/x86/Makefile.um | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/arch/x86/Makefile.um b/arch/x86/Makefile.um
index 91085a0..577976b 100644
--- a/arch/x86/Makefile.um
+++ b/arch/x86/Makefile.um
@@ -26,12 +26,8 @@ cflags-y += $(call cc-option,-mpreferred-stack-boundary=2)
 # an unresolved reference.
 cflags-y += -ffreestanding
 
-# Disable unit-at-a-time mode on pre-gcc-4.0 compilers, it makes gcc use
-# a lot more stack due to the lack of sharing of stacklots.  Also, gcc
-# 4.3.0 needs -funit-at-a-time for extern inline functions.
-KBUILD_CFLAGS += $(shell if [ $(cc-version) -lt 0400 ] ; then \
-			echo $(call cc-option,-fno-unit-at-a-time); \
-			else echo $(call cc-option,-funit-at-a-time); fi ;)
+# gcc 4.3.0 needs -funit-at-a-time for extern inline functions.
+KBUILD_CFLAGS += $(call cc-option,-funit-at-a-time)
 
 KBUILD_CFLAGS += $(cflags-y)
 
-- 
2.7.4