From 95a0a18880d22990bd4dcdbe3b6e3cabeaf9a31e Mon Sep 17 00:00:00 2001
From: maxv <maxv@NetBSD.org>
Date: Sun, 19 Jul 2020 07:35:08 +0000
Subject: [PATCH] Revert most of ad's movs/stos change. Instead do a lot
 simpler: declare svs_quad_copy() used by SVS only, with no need for
 instrumentation, because SVS is disabled when sanitizers are on.

---
 sys/arch/amd64/amd64/cpufunc.S    | 11 +++++++----
 sys/arch/amd64/include/frameasm.h | 24 +-----------------------
 sys/arch/i386/i386/cpufunc.S      | 20 ++------------------
 sys/arch/x86/include/pmap.h       |  4 ++--
 sys/arch/x86/x86/svs.c            |  6 +++---
 5 files changed, 15 insertions(+), 50 deletions(-)

diff --git a/sys/arch/amd64/amd64/cpufunc.S b/sys/arch/amd64/amd64/cpufunc.S
index 7b137339b8a0..8dcc9b8212a2 100644
--- a/sys/arch/amd64/amd64/cpufunc.S
+++ b/sys/arch/amd64/amd64/cpufunc.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: cpufunc.S,v 1.63 2020/06/24 18:09:37 maxv Exp $	*/
+/*	$NetBSD: cpufunc.S,v 1.64 2020/07/19 07:35:08 maxv Exp $	*/
 
 /*
  * Copyright (c) 1998, 2007, 2008, 2020 The NetBSD Foundation, Inc.
@@ -446,10 +446,13 @@ ENTRY(outl)
 	ret
 END(outl)
 
-ENTRY(x86_movs)
+/*
+ * Used by SVS only, to make an atomic but fast copy. Doesn't have
+ * sanitizer instrumentation, but sanitizers disable SVS, so no problem.
+ */
+ENTRY(svs_quad_copy)
 	movq	%rdx,%rcx
-	KMSAN_REP_STOS(8)
 	rep
 	movsq
 	ret
-END(x86_movs)
+END(svs_quad_copy)
diff --git a/sys/arch/amd64/include/frameasm.h b/sys/arch/amd64/include/frameasm.h
index d4f85d8579ce..1e3b363a89c3 100644
--- a/sys/arch/amd64/include/frameasm.h
+++ b/sys/arch/amd64/include/frameasm.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: frameasm.h,v 1.51 2020/06/21 16:53:37 bouyer Exp $	*/
+/*	$NetBSD: frameasm.h,v 1.52 2020/07/19 07:35:08 maxv Exp $	*/
 
 #ifndef _AMD64_MACHINE_FRAMEASM_H
 #define _AMD64_MACHINE_FRAMEASM_H
@@ -276,33 +276,11 @@
 	popq	%rdx			; \
 	popq	%rcx			; \
 	popq	%rax
-#define KMSAN_REP_STOS(scale)	\
-	pushq	%rax			; \
-	pushq	%rcx			; \
-	pushq	%rdx			; \
-	pushq	%rsi			; \
-	pushq	%rdi			; \
-	pushq	%r8			; \
-	pushq	%r9			; \
-	pushq	%r10			; \
-	pushq	%r11			; \
-	leaq	(,%rcx,scale),%rsi	; \
-	callq	_C_LABEL(__msan_instrument_asm_store); \
-	popq	%r11			; \
-	popq	%r10			; \
-	popq	%r9			; \
-	popq	%r8			; \
-	popq	%rdi			; \
-	popq	%rsi			; \
-	popq	%rdx			; \
-	popq	%rcx			; \
-	popq	%rax
 #else
 #define KMSAN_ENTER		/* nothing */
 #define KMSAN_LEAVE		/* nothing */
 #define KMSAN_INIT_ARG(sz)	/* nothing */
 #define KMSAN_INIT_RET(sz)	/* nothing */
-#define	KMSAN_REP_STOS(scale)	/* nothing */
 #endif
 
 #ifdef KCOV
diff --git a/sys/arch/i386/i386/cpufunc.S b/sys/arch/i386/i386/cpufunc.S
index 4043d5f65ab9..931f0962aa27 100644
--- a/sys/arch/i386/i386/cpufunc.S
+++ b/sys/arch/i386/i386/cpufunc.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: cpufunc.S,v 1.48 2020/06/24 18:09:37 maxv Exp $	*/
+/*	$NetBSD: cpufunc.S,v 1.49 2020/07/19 07:35:08 maxv Exp $	*/
 
 /*-
  * Copyright (c) 1998, 2007, 2020 The NetBSD Foundation, Inc.
@@ -38,7 +38,7 @@
 #include <sys/errno.h>
 
 #include <machine/asm.h>
-__KERNEL_RCSID(0, "$NetBSD: cpufunc.S,v 1.48 2020/06/24 18:09:37 maxv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cpufunc.S,v 1.49 2020/07/19 07:35:08 maxv Exp $");
 
 #include "opt_xen.h"
 
@@ -353,19 +353,3 @@ ENTRY(outl)
 	outl	%eax, %dx
 	ret
 END(outl)
-
-ENTRY(x86_movs)
-	pushl	%ebp
-	movl	%esp,%ebp
-	pushl	%edi
-	pushl	%esi
-	movl	8(%ebp),%edi
-	movl	12(%ebp),%esi
-	movl	16(%ebp),%ecx
-	rep
-	movsl
-	popl	%esi
-	popl	%edi
-	leave
-	ret
-END(x86_movs)
diff --git a/sys/arch/x86/include/pmap.h b/sys/arch/x86/include/pmap.h
index 34c149a955e3..b210a7d910b7 100644
--- a/sys/arch/x86/include/pmap.h
+++ b/sys/arch/x86/include/pmap.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: pmap.h,v 1.124 2020/07/14 00:45:53 yamaguchi Exp $	*/
+/*	$NetBSD: pmap.h,v 1.125 2020/07/19 07:35:08 maxv Exp $	*/
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -612,7 +612,7 @@ extern vaddr_t pmap_direct_end;
 
 #endif /* __HAVE_DIRECT_MAP */
 
-void	x86_movs(void *, void *, long);
+void	svs_quad_copy(void *, void *, long);
 
 #endif /* _KERNEL */
 
diff --git a/sys/arch/x86/x86/svs.c b/sys/arch/x86/x86/svs.c
index 0cc350a5e06c..01aa8f7f1eb9 100644
--- a/sys/arch/x86/x86/svs.c
+++ b/sys/arch/x86/x86/svs.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: svs.c,v 1.38 2020/07/14 00:45:53 yamaguchi Exp $	*/
+/*	$NetBSD: svs.c,v 1.39 2020/07/19 07:35:08 maxv Exp $	*/
 
 /*
  * Copyright (c) 2018-2020 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: svs.c,v 1.38 2020/07/14 00:45:53 yamaguchi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: svs.c,v 1.39 2020/07/19 07:35:08 maxv Exp $");
 
 #include "opt_svs.h"
 #include "opt_user_ldt.h"
@@ -704,7 +704,7 @@ svs_pdir_switch(struct pmap *pmap)
 
 	/* Copy user slots. */
 	mutex_enter(&ci->ci_svs_mtx);
-	x86_movs(ci->ci_svs_updir, pmap->pm_pdir, PDIR_SLOT_USERLIM);
+	svs_quad_copy(ci->ci_svs_updir, pmap->pm_pdir, PDIR_SLOT_USERLIM);
 	mutex_exit(&ci->ci_svs_mtx);
 
 	if (svs_pcid) {