linux-kernel - [PATCH] x86: disable CONFIG_GENERIC_HWEIGHT and remove __HAVE_ARCH_SW

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Message-Id: <1557665521-17570-1-git-send-email-yamada.masahiro@socionext.com>
Date:   Sun, 12 May 2019 21:52:01 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     x86@...nel.org, Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>,
        "H . Peter Anvin" <hpa@...or.com>
Cc:     Masahiro Yamada <yamada.masahiro@...ionext.com>,
        linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...hat.com>,
        Uros Bizjak <ubizjak@...il.com>
Subject: [PATCH] x86: disable CONFIG_GENERIC_HWEIGHT and remove __HAVE_ARCH_SW_HWEIGHT

arch/x86/include/asm/arch_hweight.h uses __sw_hweight{32,64} as
alternatives, and they are implemented in arch/x86/lib/hweight.S

x86 does not rely on the generic C implementation lib/hweight.c
at all, so CONFIG_GENERIC_HWEIGHT should be disabled.

__HAVE_ARCH_SW_HWEIGHT is not necessary either.

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

 arch/x86/Kconfig                    | 3 ---
 arch/x86/include/asm/arch_hweight.h | 2 --
 lib/hweight.c                       | 4 ----
 3 files changed, 9 deletions(-)

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index 4725211..3692514 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -260,9 +260,6 @@ config GENERIC_BUG
 config GENERIC_BUG_RELATIVE_POINTERS
 	bool
 
-config GENERIC_HWEIGHT
-	def_bool y
-
 config ARCH_MAY_HAVE_PC_FDC
 	def_bool y
 	depends on ISA_DMA_API
diff --git a/arch/x86/include/asm/arch_hweight.h b/arch/x86/include/asm/arch_hweight.h
index fc06935..ba88edd 100644
--- a/arch/x86/include/asm/arch_hweight.h
+++ b/arch/x86/include/asm/arch_hweight.h
@@ -12,8 +12,6 @@
 #define REG_OUT "a"
 #endif
 
-#define __HAVE_ARCH_SW_HWEIGHT
-
 static __always_inline unsigned int __arch_hweight32(unsigned int w)
 {
 	unsigned int res;
diff --git a/lib/hweight.c b/lib/hweight.c
index 7660d88..c94586b 100644
--- a/lib/hweight.c
+++ b/lib/hweight.c
@@ -10,7 +10,6 @@
  * The Hamming Weight of a number is the total number of bits set in it.
  */
 
-#ifndef __HAVE_ARCH_SW_HWEIGHT
 unsigned int __sw_hweight32(unsigned int w)
 {
 #ifdef CONFIG_ARCH_HAS_FAST_MULTIPLIER
@@ -27,7 +26,6 @@ unsigned int __sw_hweight32(unsigned int w)
 #endif
 }
 EXPORT_SYMBOL(__sw_hweight32);
-#endif
 
 unsigned int __sw_hweight16(unsigned int w)
 {
@@ -46,7 +44,6 @@ unsigned int __sw_hweight8(unsigned int w)
 }
 EXPORT_SYMBOL(__sw_hweight8);
 
-#ifndef __HAVE_ARCH_SW_HWEIGHT
 unsigned long __sw_hweight64(__u64 w)
 {
 #if BITS_PER_LONG == 32
@@ -69,4 +66,3 @@ unsigned long __sw_hweight64(__u64 w)
 #endif
 }
 EXPORT_SYMBOL(__sw_hweight64);
-#endif
-- 
2.7.4