linux-kernel - [PATCH] x86/boot: drop memset from copy.S

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Date:   Mon, 7 Jan 2019 15:40:56 +0800
From:   Cao jin <caoj.fnst@...fujitsu.com>
To:     <x86@...nel.org>, <linux-kernel@...r.kernel.org>
CC:     <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
        <hpa@...or.com>
Subject: [PATCH] x86/boot: drop memset from copy.S

According to objdump output of setup, function memset is not used in
setup code. Currently, all usage of memset in setup come from macro
definition of string.h.

Signed-off-by: Cao jin <caoj.fnst@...fujitsu.com>
---
Compiled and booted under x86_64; compiled under i386.

Questions: now there is 2 definition of memcpy, one lies in copy.S,
another lies in string.h which is mapped to gcc builtin function. Do we
still need 2 definition? Could we move the content of copy.S to
boot/string.c?

At first glance, the usage of string.{c.h} of setup is kind of confusing,
they are also used in compressed/ and purgatory/

 arch/x86/boot/copy.S | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/arch/x86/boot/copy.S b/arch/x86/boot/copy.S
index 15d9f74b0008..5157d08b0ff2 100644
--- a/arch/x86/boot/copy.S
+++ b/arch/x86/boot/copy.S
@@ -33,21 +33,6 @@ GLOBAL(memcpy)
 	retl
 ENDPROC(memcpy)
 
-GLOBAL(memset)
-	pushw	%di
-	movw	%ax, %di
-	movzbl	%dl, %eax
-	imull	$0x01010101,%eax
-	pushw	%cx
-	shrw	$2, %cx
-	rep; stosl
-	popw	%cx
-	andw	$3, %cx
-	rep; stosb
-	popw	%di
-	retl
-ENDPROC(memset)
-
 GLOBAL(copy_from_fs)
 	pushw	%ds
 	pushw	%fs
-- 
2.17.0