From c22616ec0be9dc55863761ea55ac8969dfef866d Mon Sep 17 00:00:00 2001
From: John Baldwin <jhb@FreeBSD.org>
Date: Fri, 8 Aug 2008 19:41:20 +0000
Subject: [PATCH] - Initialize the vm86 structure to a known-good state. 
 Specifically, always   set the %eflags used during a BIOS call via BTX to
 0x202.  Previously   the flags field was uninitialized garbage, and thus it
 was "random" if   interrupts were enabled or not during BIOS calls. - Use
 constants from <machine/psl.h> for fields in %eflags.

MFC after:	3 days
---
 sys/boot/i386/boot2/boot2.c     | 6 ++++--
 sys/boot/i386/gptboot/gptboot.c | 6 ++++--
 sys/boot/i386/loader/main.c     | 5 +++++
 sys/boot/pc98/loader/main.c     | 5 +++++
 4 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/sys/boot/i386/boot2/boot2.c b/sys/boot/i386/boot2/boot2.c
index 753f0b1e328a..58f217515df3 100644
--- a/sys/boot/i386/boot2/boot2.c
+++ b/sys/boot/i386/boot2/boot2.c
@@ -24,6 +24,7 @@ __FBSDID("$FreeBSD$");
 
 #include <machine/bootinfo.h>
 #include <machine/elf.h>
+#include <machine/psl.h>
 
 #include <stdarg.h>
 
@@ -83,8 +84,8 @@ __FBSDID("$FreeBSD$");
 #define NDEV		3
 #define MEM_BASE	0x12
 #define MEM_EXT 	0x15
-#define V86_CY(x)	((x) & 1)
-#define V86_ZR(x)	((x) & 0x40)
+#define V86_CY(x)	((x) & PSL_C)
+#define V86_ZR(x)	((x) & PSL_Z)
 
 #define DRV_HARD	0x80
 #define DRV_MASK	0x7f
@@ -237,6 +238,7 @@ main(void)
 
     dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - __base);
     v86.ctl = V86_FLAGS;
+    v86.efl = PSL_RESERVED_DEFAULT | PSL_I;
     dsk.drive = *(uint8_t *)PTOV(ARGS);
     dsk.type = dsk.drive & DRV_HARD ? TYPE_AD : TYPE_FD;
     dsk.unit = dsk.drive & DRV_MASK;
diff --git a/sys/boot/i386/gptboot/gptboot.c b/sys/boot/i386/gptboot/gptboot.c
index e9a183e0b1a7..405b92e62866 100644
--- a/sys/boot/i386/gptboot/gptboot.c
+++ b/sys/boot/i386/gptboot/gptboot.c
@@ -23,6 +23,7 @@ __FBSDID("$FreeBSD$");
 
 #include <machine/bootinfo.h>
 #include <machine/elf.h>
+#include <machine/psl.h>
 
 #include <stdarg.h>
 
@@ -81,8 +82,8 @@ __FBSDID("$FreeBSD$");
 #define NDEV		3
 #define MEM_BASE	0x12
 #define MEM_EXT 	0x15
-#define V86_CY(x)	((x) & 1)
-#define V86_ZR(x)	((x) & 0x40)
+#define V86_CY(x)	((x) & PSL_C)
+#define V86_ZR(x)	((x) & PSL_Z)
 
 #define DRV_HARD	0x80
 #define DRV_MASK	0x7f
@@ -235,6 +236,7 @@ main(void)
 
     dmadat = (void *)(roundup2(__base + (int32_t)&_end, 0x10000) - __base);
     v86.ctl = V86_FLAGS;
+    v86.efl = PSL_RESERVED_DEFAULT | PSL_I;
     dsk.drive = *(uint8_t *)PTOV(ARGS);
     dsk.type = dsk.drive & DRV_HARD ? TYPE_AD : TYPE_FD;
     dsk.unit = dsk.drive & DRV_MASK;
diff --git a/sys/boot/i386/loader/main.c b/sys/boot/i386/loader/main.c
index 2083456bbbae..5b23670d12d0 100644
--- a/sys/boot/i386/loader/main.c
+++ b/sys/boot/i386/loader/main.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <stand.h>
 #include <string.h>
 #include <machine/bootinfo.h>
+#include <machine/psl.h>
 #include <sys/reboot.h>
 
 #include "bootstrap.h"
@@ -86,6 +87,10 @@ main(void)
     initial_bootdev = kargs->bootdev;
     initial_bootinfo = kargs->bootinfo ? (struct bootinfo *)PTOV(kargs->bootinfo) : NULL;
 
+    /* Initialize the v86 register set to a known-good state. */
+    bzero(&v86, sizeof(v86));
+    v86.efl = PSL_RESERVED_DEFAULT | PSL_I;
+
     /* 
      * Initialise the heap as early as possible.  Once this is done, malloc() is usable.
      */
diff --git a/sys/boot/pc98/loader/main.c b/sys/boot/pc98/loader/main.c
index eee463807b24..83e9bdfa0588 100644
--- a/sys/boot/pc98/loader/main.c
+++ b/sys/boot/pc98/loader/main.c
@@ -35,6 +35,7 @@ __FBSDID("$FreeBSD$");
 #include <stand.h>
 #include <string.h>
 #include <machine/bootinfo.h>
+#include <machine/psl.h>
 #include <sys/reboot.h>
 
 #include "bootstrap.h"
@@ -86,6 +87,10 @@ main(void)
     initial_bootdev = kargs->bootdev;
     initial_bootinfo = kargs->bootinfo ? (struct bootinfo *)PTOV(kargs->bootinfo) : NULL;
 
+    /* Initialize the v86 register set to a known-good state. */
+    bzero(&v86, sizeof(v86));
+    v86.efl = PSL_RESERVED_DEFAULT | PSL_I;
+
     /* 
      * Initialise the heap as early as possible.  Once this is done, malloc() is usable.
      */