[tip:x86/asm] x86: Use POPCNT mnemonics in arch_hweight.h

From: tip-bot for Uros Bizjak
Date: Mon Nov 05 2018 - 04:55:23 EST


Commit-ID: 566b62a3676caed1f8c626e26066ff3ae3a38918
Gitweb: https://git.kernel.org/tip/566b62a3676caed1f8c626e26066ff3ae3a38918
Author: Uros Bizjak <ubizjak@xxxxxxxxx>
AuthorDate: Sun, 14 Oct 2018 22:23:54 +0200
Committer: Borislav Petkov <bp@xxxxxxx>
CommitDate: Mon, 5 Nov 2018 10:42:32 +0100

x86: Use POPCNT mnemonics in arch_hweight.h

Recently, the minimum required version of binutils was changed to
2.20, which supports POPCNT instruction mnemonics.

Replace the byte-wise specification of POPCNT with those proper
mnemonics.

[ bp: massage commit message and remove line breaks. ]

Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Signed-off-by: Borislav Petkov <bp@xxxxxxx>
CC: "H. Peter Anvin" <hpa@xxxxxxxxx>
CC: Ingo Molnar <mingo@xxxxxxxxxx>
CC: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/20181014202354.21281-1-ubizjak@xxxxxxxxx
---
arch/x86/include/asm/arch_hweight.h | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/arch_hweight.h b/arch/x86/include/asm/arch_hweight.h
index 34a10b2d5b73..fc0693569f7a 100644
--- a/arch/x86/include/asm/arch_hweight.h
+++ b/arch/x86/include/asm/arch_hweight.h
@@ -5,15 +5,9 @@
#include <asm/cpufeatures.h>

#ifdef CONFIG_64BIT
-/* popcnt %edi, %eax */
-#define POPCNT32 ".byte 0xf3,0x0f,0xb8,0xc7"
-/* popcnt %rdi, %rax */
-#define POPCNT64 ".byte 0xf3,0x48,0x0f,0xb8,0xc7"
#define REG_IN "D"
#define REG_OUT "a"
#else
-/* popcnt %eax, %eax */
-#define POPCNT32 ".byte 0xf3,0x0f,0xb8,0xc0"
#define REG_IN "a"
#define REG_OUT "a"
#endif
@@ -24,7 +18,7 @@ static __always_inline unsigned int __arch_hweight32(unsigned int w)
{
unsigned int res;

- asm (ALTERNATIVE("call __sw_hweight32", POPCNT32, X86_FEATURE_POPCNT)
+ asm (ALTERNATIVE("call __sw_hweight32", "popcntl %1, %0", X86_FEATURE_POPCNT)
: "="REG_OUT (res)
: REG_IN (w));

@@ -52,7 +46,7 @@ static __always_inline unsigned long __arch_hweight64(__u64 w)
{
unsigned long res;

- asm (ALTERNATIVE("call __sw_hweight64", POPCNT64, X86_FEATURE_POPCNT)
+ asm (ALTERNATIVE("call __sw_hweight64", "popcntq %1, %0", X86_FEATURE_POPCNT)
: "="REG_OUT (res)
: REG_IN (w));