linux-kernel - Re: [PATCH] x86: drop REG_OUT macro from hweight functions

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Date:   Mon, 29 Jul 2019 12:04:47 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Alexey Dobriyan <adobriyan@...il.com>
Cc:     tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, hpa@...or.com,
        x86@...nel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86: drop REG_OUT macro from hweight functions

On Mon, Jul 29, 2019 at 11:43:29AM +0200, Peter Zijlstra wrote:

> I _think_ something like the below should also work:
> 
> (fwiw _ASM_ARG 5 and 6 are broken, as are all the QLWB variants)

Fixed that, because

> ---
> diff --git a/arch/x86/include/asm/arch_hweight.h b/arch/x86/include/asm/arch_hweight.h
> index ba88edd0d58b..88704612b2f7 100644
> --- a/arch/x86/include/asm/arch_hweight.h
> +++ b/arch/x86/include/asm/arch_hweight.h
> @@ -3,22 +3,15 @@
>  #define _ASM_X86_HWEIGHT_H
>  
>  #include <asm/cpufeatures.h>
> -
> -#ifdef CONFIG_64BIT
> -#define REG_IN "D"
> -#define REG_OUT "a"
> -#else
> -#define REG_IN "a"
> -#define REG_OUT "a"
> -#endif
> +#include <asm/asm.h>
>  
>  static __always_inline unsigned int __arch_hweight32(unsigned int w)
>  {
>  	unsigned int res;
>  
>  	asm (ALTERNATIVE("call __sw_hweight32", "popcntl %1, %0", X86_FEATURE_POPCNT)
> -			 : "="REG_OUT (res)
> -			 : REG_IN (w));
> +			 : "=a" (res)
> +			 : _ASM_ARG1 (w));

That needs _ASM_ARG1L because popcntl..

---
diff --git a/arch/x86/include/asm/arch_hweight.h b/arch/x86/include/asm/arch_hweight.h
index ba88edd0d58b..3cab7f382a43 100644
--- a/arch/x86/include/asm/arch_hweight.h
+++ b/arch/x86/include/asm/arch_hweight.h
@@ -3,22 +3,15 @@
 #define _ASM_X86_HWEIGHT_H
 
 #include <asm/cpufeatures.h>
-
-#ifdef CONFIG_64BIT
-#define REG_IN "D"
-#define REG_OUT "a"
-#else
-#define REG_IN "a"
-#define REG_OUT "a"
-#endif
+#include <asm/asm.h>
 
 static __always_inline unsigned int __arch_hweight32(unsigned int w)
 {
 	unsigned int res;
 
 	asm (ALTERNATIVE("call __sw_hweight32", "popcntl %1, %0", X86_FEATURE_POPCNT)
-			 : "="REG_OUT (res)
-			 : REG_IN (w));
+			 : "=a" (res)
+			 : _ASM_ARG1L (w));
 
 	return res;
 }
@@ -45,8 +38,8 @@ static __always_inline unsigned long __arch_hweight64(__u64 w)
 	unsigned long res;
 
 	asm (ALTERNATIVE("call __sw_hweight64", "popcntq %1, %0", X86_FEATURE_POPCNT)
-			 : "="REG_OUT (res)
-			 : REG_IN (w));
+			 : "=a" (res)
+			 : _ASM_ARG1 (w));
 
 	return res;
 }
diff --git a/arch/x86/include/asm/asm.h b/arch/x86/include/asm/asm.h
index 3ff577c0b102..0bb0bbcd4551 100644
--- a/arch/x86/include/asm/asm.h
+++ b/arch/x86/include/asm/asm.h
@@ -53,17 +53,17 @@
 #define _ASM_ARG2	_ASM_DX
 #define _ASM_ARG3	_ASM_CX
 
-#define _ASM_ARG1L	eax
-#define _ASM_ARG2L	edx
-#define _ASM_ARG3L	ecx
+#define _ASM_ARG1L	_ASM_ARG1
+#define _ASM_ARG2L	_ASM_ARG2
+#define _ASM_ARG3L	_ASM_ARG3
 
-#define _ASM_ARG1W	ax
-#define _ASM_ARG2W	dx
-#define _ASM_ARG3W	cx
+#define _ASM_ARG1W	__ASM_FORM_RAW(ax)
+#define _ASM_ARG2W	__ASM_FORM_RAW(dx)
+#define _ASM_ARG3W	__ASM_FORM_RAW(cx)
 
-#define _ASM_ARG1B	al
-#define _ASM_ARG2B	dl
-#define _ASM_ARG3B	cl
+#define _ASM_ARG1B	__ASM_FORM_RAW(al)
+#define _ASM_ARG2B	__ASM_FORM_RAW(dl)
+#define _ASM_ARG3B	__ASM_FORM_RAW(cl)
 
 #else
 /* 64 bit */
@@ -72,36 +72,29 @@
 #define _ASM_ARG2	_ASM_SI
 #define _ASM_ARG3	_ASM_DX
 #define _ASM_ARG4	_ASM_CX
-#define _ASM_ARG5	r8
-#define _ASM_ARG6	r9
-
-#define _ASM_ARG1Q	rdi
-#define _ASM_ARG2Q	rsi
-#define _ASM_ARG3Q	rdx
-#define _ASM_ARG4Q	rcx
-#define _ASM_ARG5Q	r8
-#define _ASM_ARG6Q	r9
-
-#define _ASM_ARG1L	edi
-#define _ASM_ARG2L	esi
-#define _ASM_ARG3L	edx
-#define _ASM_ARG4L	ecx
-#define _ASM_ARG5L	r8d
-#define _ASM_ARG6L	r9d
-
-#define _ASM_ARG1W	di
-#define _ASM_ARG2W	si
-#define _ASM_ARG3W	dx
-#define _ASM_ARG4W	cx
-#define _ASM_ARG5W	r8w
-#define _ASM_ARG6W	r9w
-
-#define _ASM_ARG1B	dil
-#define _ASM_ARG2B	sil
-#define _ASM_ARG3B	dl
-#define _ASM_ARG4B	cl
-#define _ASM_ARG5B	r8b
-#define _ASM_ARG6B	r9b
+#define _ASM_ARG5	__ASM_REG(8)
+#define _ASM_ARG6	__ASM_REG(9)
+
+#define _ASM_ARG1L	__ASM_FORM_RAW(edi)
+#define _ASM_ARG2L	__ASM_FORM_RAW(esi)
+#define _ASM_ARG3L	__ASM_FORM_RAW(edx)
+#define _ASM_ARG4L	__ASM_FORM_RAW(ecx)
+#define _ASM_ARG5L	__ASM_FORM_RAW(r8d)
+#define _ASM_ARG6L	__ASM_FORM_RAW(r9d)
+
+#define _ASM_ARG1W	__ASM_FORM_RAW(di)
+#define _ASM_ARG2W	__ASM_FORM_RAW(si)
+#define _ASM_ARG3W	__ASM_FORM_RAW(dx)
+#define _ASM_ARG4W	__ASM_FORM_RAW(cx)
+#define _ASM_ARG5W	__ASM_FORM_RAW(r8w)
+#define _ASM_ARG6W	__ASM_FORM_RAW(r9w)
+
+#define _ASM_ARG1B	__ASM_FORM_RAW(dil)
+#define _ASM_ARG2B	__ASM_FORM_RAW(sil)
+#define _ASM_ARG3B	__ASM_FORM_RAW(dl)
+#define _ASM_ARG4B	__ASM_FORM_RAW(cl)
+#define _ASM_ARG5B	__ASM_FORM_RAW(r8b)
+#define _ASM_ARG6B	__ASM_FORM_RAW(r9b)
 
 #endif