From 1fa155830ba6bb658db68ed6de037df9b033ed7f Mon Sep 17 00:00:00 2001
From: Venkatesh Srinivas <me@endeavour.zapto.org>
Date: Fri, 9 Dec 2011 22:32:10 -0800
Subject: [PATCH] kernel -- Remove i686_pagezero.

i686_pagezero spent read bandwidth to search for the first non-zero word
in a page and zeroed from there. This was silly; the contents of the page
didn't matter and reading it was a waste of time. bzero() is used directly.
---
 sys/platform/pc32/i386/bzero.s     | 50 ------------------------------
 sys/platform/pc32/i386/pmap.c      | 16 ++--------
 sys/platform/pc32/include/md_var.h |  1 -
 3 files changed, 2 insertions(+), 65 deletions(-)

diff --git a/sys/platform/pc32/i386/bzero.s b/sys/platform/pc32/i386/bzero.s
index 9f06fe648c..48de8afda5 100644
--- a/sys/platform/pc32/i386/bzero.s
+++ b/sys/platform/pc32/i386/bzero.s
@@ -87,53 +87,3 @@ ENTRY(bzero)
 	popl	%edi
 	ret
 
-ENTRY(i686_pagezero)
-	pushl	%edi
-	pushl	%ebx
-
-	movl	12(%esp), %edi
-	movl	$1024, %ecx
-	cld
-
-	ALIGN_TEXT
-1:
-	xorl	%eax, %eax
-	repe
-	scasl	
-	jnz	2f
-
-	popl	%ebx
-	popl	%edi
-	ret
-
-	ALIGN_TEXT
-
-2:
-	incl	%ecx
-	subl	$4, %edi
-
-	movl	%ecx, %edx
-	cmpl	$16, %ecx
-
-	jge	3f
-
-	movl	%edi, %ebx
-	andl	$0x3f, %ebx
-	shrl	%ebx
-	shrl	%ebx
-	movl	$16, %ecx
-	subl	%ebx, %ecx
-
-3:
-	subl	%ecx, %edx
-	rep
-	stosl
-
-	movl	%edx, %ecx
-	testl	%edx, %edx
-	jnz	1b
-
-	popl	%ebx
-	popl	%edi
-	ret
-
diff --git a/sys/platform/pc32/i386/pmap.c b/sys/platform/pc32/i386/pmap.c
index 841b068128..24c3c21099 100644
--- a/sys/platform/pc32/i386/pmap.c
+++ b/sys/platform/pc32/i386/pmap.c
@@ -2691,13 +2691,7 @@ pmap_zero_page(vm_paddr_t phys)
 	*(int *)gd->gd_CMAP3 =
 		    PG_V | PG_RW | (phys & PG_FRAME) | PG_A | PG_M;
 	cpu_invlpg(gd->gd_CADDR3);
-
-#if defined(I686_CPU)
-	if (cpu_class == CPUCLASS_686)
-		i686_pagezero(gd->gd_CADDR3);
-	else
-#endif
-		bzero(gd->gd_CADDR3, PAGE_SIZE);
+	bzero(gd->gd_CADDR3, PAGE_SIZE);
 	*(int *) gd->gd_CMAP3 = 0;
 	crit_exit();
 }
@@ -2747,13 +2741,7 @@ pmap_zero_page_area(vm_paddr_t phys, int off, int size)
 		panic("pmap_zero_page: CMAP3 busy");
 	*(int *) gd->gd_CMAP3 = PG_V | PG_RW | (phys & PG_FRAME) | PG_A | PG_M;
 	cpu_invlpg(gd->gd_CADDR3);
-
-#if defined(I686_CPU)
-	if (cpu_class == CPUCLASS_686 && off == 0 && size == PAGE_SIZE)
-		i686_pagezero(gd->gd_CADDR3);
-	else
-#endif
-		bzero((char *)gd->gd_CADDR3 + off, size);
+	bzero((char *)gd->gd_CADDR3 + off, size);
 	*(int *) gd->gd_CMAP3 = 0;
 	crit_exit();
 }
diff --git a/sys/platform/pc32/include/md_var.h b/sys/platform/pc32/include/md_var.h
index ab6fc2faee..1f6addae86 100644
--- a/sys/platform/pc32/include/md_var.h
+++ b/sys/platform/pc32/include/md_var.h
@@ -123,7 +123,6 @@ void	asm_xmm_memcpy(void);
 void	asm_generic_bcopy(void);
 void	asm_mmx_bcopy(void);
 void	asm_xmm_bcopy(void);
-void	i686_pagezero (void *addr);
 void	init_AMD_Elan_sc520(void);
 void	setidt (int idx, alias_for_inthand_t *func, int typ, int dpl,
 		    int selec);
-- 
2.41.0