Recently the minimum required version of binutils was changed to 2.20, which supports popcnt instruction mnemonics. The patch removes corresponding #defines that implement popcnt instructions using target-dependant .byte streams and uses unified instruction mnemonics instead.
Tested by building x86_64 and i386 version of the kernel and comparing objdump dumps of the pathced and unpatched vmlinux.o. They were the same. v2: Update commit message to emphasize removal of #defines. Signed-off-by: Uros Bizjak <ubiz...@gmail.com> --- arch/x86/include/asm/arch_hweight.h | 12 ++++-------- 1 file changed, 4 insertions(+), 8 deletions(-) diff --git a/arch/x86/include/asm/arch_hweight.h b/arch/x86/include/asm/arch_hweight.h index 34a10b2d5b73..d668e411bd32 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 +18,8 @@ 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 +47,8 @@ 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)); -- 2.17.2