From 2fdfb5dab29b9ca308fa90f8ee19ae5df27c64d5 Mon Sep 17 00:00:00 2001
From: Philip Guenther <guenther@cvs.openbsd.org>
Date: Sun, 23 Nov 2014 00:25:06 +0000
Subject: Make sure the direction bit is cleared on entry to the kernel by
 syscall or interrupt, as specified by the ABIs.  Our current gcc doesn't
 assume this bit of the ABI, but future compilers may and some ASM can be
 simplified by assuming it.

in snaps for a bit
---
 sys/arch/amd64/amd64/cpu.c    | 4 ++--
 sys/arch/amd64/amd64/vector.S | 7 ++++++-
 sys/arch/i386/i386/locore.s   | 3 ++-
 3 files changed, 10 insertions(+), 4 deletions(-)

(limited to 'sys')

diff --git a/sys/arch/amd64/amd64/cpu.c b/sys/arch/amd64/amd64/cpu.c
index d40dbdd070f..e27de4ba448 100644
--- a/sys/arch/amd64/amd64/cpu.c
+++ b/sys/arch/amd64/amd64/cpu.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: cpu.c,v 1.69 2014/11/22 18:31:46 mlarkin Exp $	*/
+/*	$OpenBSD: cpu.c,v 1.70 2014/11/23 00:25:05 guenther Exp $	*/
 /* $NetBSD: cpu.c,v 1.1 2003/04/26 18:39:26 fvdl Exp $ */
 
 /*-
@@ -900,7 +900,7 @@ cpu_init_msrs(struct cpu_info *ci)
 	    ((uint64_t)GSEL(GUCODE32_SEL, SEL_UPL) << 48));
 	wrmsr(MSR_LSTAR, (uint64_t)Xsyscall);
 	wrmsr(MSR_CSTAR, (uint64_t)Xsyscall32);
-	wrmsr(MSR_SFMASK, PSL_NT|PSL_T|PSL_I|PSL_C);
+	wrmsr(MSR_SFMASK, PSL_NT|PSL_T|PSL_I|PSL_C|PSL_D);
 
 	wrmsr(MSR_FSBASE, 0);
 	wrmsr(MSR_GSBASE, (u_int64_t)ci);
diff --git a/sys/arch/amd64/amd64/vector.S b/sys/arch/amd64/amd64/vector.S
index 19fa93eff88..2e23826add2 100644
--- a/sys/arch/amd64/amd64/vector.S
+++ b/sys/arch/amd64/amd64/vector.S
@@ -1,4 +1,4 @@
-/*	$OpenBSD: vector.S,v 1.34 2013/11/02 14:23:38 kettenis Exp $	*/
+/*	$OpenBSD: vector.S,v 1.35 2014/11/23 00:25:05 guenther Exp $	*/
 /*	$NetBSD: vector.S,v 1.5 2004/06/28 09:13:11 fvdl Exp $	*/
 
 /*
@@ -122,6 +122,7 @@ IDTVEC(trap07)
 	pushq	$T_DNA
 	INTRENTRY
 	sti
+	cld
 	movq	CPUVAR(SELF),%rdi
 	call	_C_LABEL(fpudna)
 	INTRFASTEXIT
@@ -247,6 +248,7 @@ NENTRY(alltraps)
 	sti
 	.globl	calltrap
 calltrap:
+	cld
 #ifdef DIAGNOSTIC
 	movl	CPUVAR(ILEVEL),%ebx
 #endif /* DIAGNOSTIC */
@@ -332,6 +334,7 @@ IDTVEC(resume_lapic_ipi)
 	incl	CPUVAR(IDEPTH)
 	movl	$IPL_IPI,CPUVAR(ILEVEL)
         sti
+	cld
 	pushq	%rbx
 	call	_C_LABEL(x86_ipi_handler)
 	jmp	_C_LABEL(Xdoreti)
@@ -413,6 +416,7 @@ IDTVEC(resume_lapic_ltimer)
 	incl	CPUVAR(IDEPTH)
 	movl	$IPL_CLOCK,CPUVAR(ILEVEL)
 	sti
+	cld
 	pushq	%rbx
 	xorq	%rdi,%rdi
 	call	_C_LABEL(lapic_clockintr)
@@ -463,6 +467,7 @@ IDTVEC(intr_##name##num)						;\
 	pushq	%r13							;\
 	movl	%ebx,CPUVAR(ILEVEL)					;\
 	sti								;\
+	cld								;\
 	incl	CPUVAR(IDEPTH)						;\
 	movq	IS_HANDLERS(%r14),%rbx					;\
 6:									\
diff --git a/sys/arch/i386/i386/locore.s b/sys/arch/i386/i386/locore.s
index 16ff2377e08..4c24cb91987 100644
--- a/sys/arch/i386/i386/locore.s
+++ b/sys/arch/i386/i386/locore.s
@@ -1,4 +1,4 @@
-/*	$OpenBSD: locore.s,v 1.147 2013/06/13 02:26:53 deraadt Exp $	*/
+/*	$OpenBSD: locore.s,v 1.148 2014/11/23 00:25:05 guenther Exp $	*/
 /*	$NetBSD: locore.s,v 1.145 1996/05/03 19:41:19 christos Exp $	*/
 
 /*-
@@ -104,6 +104,7 @@
  * These are used on interrupt or trap entry or exit.
  */
 #define	INTRENTRY \
+	cld			; \
 	pushl	%eax		; \
 	pushl	%ecx		; \
 	pushl	%edx		; \
-- 
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