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Add a couple of debug register helper functions to assist in setting

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and clearing watchpoints.

Reviewed by:	jwd@FreeBSD.org, -hackers@
This commit is contained in:
Brian S. Dean 2000-09-21 17:07:27 +00:00
parent c0cfc79790
commit 9d90941a83
9 changed files with 269 additions and 4 deletions
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6
lib/libc/amd64/sys/Makefile.inc
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@ -1,8 +1,8 @@
# from: Makefile.inc,v 1.1 1993/09/03 19:04:23 jtc Exp
# $FreeBSD$
SRCS+= i386_get_ioperm.c i386_get_ldt.c i386_set_ioperm.c i386_set_ldt.c \
i386_vm86.c
SRCS+= i386_clr_watch.c i386_get_ioperm.c i386_get_ldt.c i386_set_ioperm.c \
i386_set_ldt.c i386_set_watch.c i386_vm86.c
MDASM= Ovfork.S brk.S cerror.S exect.S fork.S pipe.S ptrace.S reboot.S \
rfork.S sbrk.S setlogin.S sigreturn.S syscall.S
@ -22,7 +22,9 @@ PSEUDOR= _exit.o
.if ${LIB} == "c"
MAN2+= i386_get_ioperm.2 i386_get_ldt.2 i386_vm86.2
MAN3+= i386_set_watch.3
MLINKS+=i386_get_ioperm.2 i386_set_ioperm.2
MLINKS+=i386_get_ldt.2 i386_set_ldt.2
MLINKS+=i386_set_watch.3 i386_clr_watch.3
.endif

6
lib/libc/i386/sys/Makefile.inc
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@ -1,8 +1,8 @@
# from: Makefile.inc,v 1.1 1993/09/03 19:04:23 jtc Exp
# $FreeBSD$
SRCS+= i386_get_ioperm.c i386_get_ldt.c i386_set_ioperm.c i386_set_ldt.c \
i386_vm86.c
SRCS+= i386_clr_watch.c i386_get_ioperm.c i386_get_ldt.c i386_set_ioperm.c \
i386_set_ldt.c i386_set_watch.c i386_vm86.c
MDASM= Ovfork.S brk.S cerror.S exect.S fork.S pipe.S ptrace.S reboot.S \
rfork.S sbrk.S setlogin.S sigreturn.S syscall.S
@ -22,7 +22,9 @@ PSEUDOR= _exit.o
.if ${LIB} == "c"
MAN2+= i386_get_ioperm.2 i386_get_ldt.2 i386_vm86.2
MAN3+= i386_set_watch.3
MLINKS+=i386_get_ioperm.2 i386_set_ioperm.2
MLINKS+=i386_get_ldt.2 i386_set_ldt.2
MLINKS+=i386_set_watch.3 i386_clr_watch.3
.endif

50
lib/libc/i386/sys/i386_clr_watch.c Normal file
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@ -0,0 +1,50 @@
/*
* Copyright 2000 Brian S. Dean <bsd@bsdhome.com>
* All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY BRIAN S. DEAN ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BRIAN S. DEAN BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/
/*
* $FreeBSD$
*/
#include <machine/reg.h>
#include <machine/sysarch.h>
int
i386_clr_watch(int watchnum, struct dbreg * d)
{
if (watchnum < 0 || watchnum >= 4)
return -1;
d->dr7 = d->dr7 & ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
DBREG_DRX(d,watchnum) = 0;
return 0;
}

103
lib/libc/i386/sys/i386_set_watch.3 Normal file
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@ -0,0 +1,103 @@
.\" Copyright (c) 2000 Brian S. Dean
.\" All rights reserved.
.\"
.\" This man-page is based on a similar man-page by Jonathan Lemon
.\" which is copyrighted under the following conditions:
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in the
.\" documentation and/or other materials provided with the distribution.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" $FreeBSD$
.\"
.Dd August 24, 2000
.Os
.Dt I386_SET_WATCH 3
.Sh NAME
.Nm i386_clr_watch ,
.Nm i386_set_watch
.Nd manage i386 debug register values
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include <machine/reg.h>
.Fd #include <machine/sysarch.h>
.Ft int
.Fn i386_clr_watch "int watchnum" "struct dbreg *d"
.Ft int
.Fn i386_set_watch "int watchnum" "unsigned int watchaddr" "int size" "int access" "struct dbreg *d"
.Sh DESCRIPTION
.Fn i386_clr_watch
will disable the indicated watch point within the specified debug
register set.
.Pp
.Fn i386_set_watch
will set up the specified debug registers as indicated by the
parameters. The
.Fa watchnum
argument specifies which watch register is used, 0, 1, 2, 3, or -1. If
.Fa watchnum
is -1, a free watch register is found and used. If there are no free
watch registers, an error code of -1 is returned.
.Fa Watchaddr
specifies the watch address,
.Fa size
specifies the size in bytes of the area to be watched (1, 2, or 4 bytes),
and
.Fa access
specifes the type of watch point:
.Pp
.Bd -literal -offset indent -compact
DBREG_DR7_EXEC An execution breakpoint.
DBREG_DR7_WRONLY Break only when the watch area is written to.
DBREG_DR7_RDWR Break when the watch area is read from or written
to.
.Ed
.Pp
Note that these functions do not actually set or clear breakpoints;
they manipulate the indicated debug register set. You must use
.Xr ptrace 2
to retrieve and install the debug register values for a process.
.Sh RETURN VALUES
.Fn i386_clr_watch
returns 0 on success, or -1 if
.Fa watchnum
is invalid (not in the range of 0-3).
.Pp
.Fn i386_set_watch
will return the
.Fa watchnum
argument, or the watchnum actually used in the case that
.Fa watchnum
is -1 on success. On error,
.Fn i386_set_watch
will return -1 indicating that the watchpoint could not be set up
because either no more watchpoints are available, or
.Fa watchnum ,
.Fa size ,
or
.Fa access
is invalid.
.Sh SEE ALSO
.Xr ptrace 2 ,
.Xr procfs 5
.Sh AUTHORS
This man page was written by
.An Brian S. Dean .

88
lib/libc/i386/sys/i386_set_watch.c Normal file
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@ -0,0 +1,88 @@
/*
* Copyright 2000 Brian S. Dean <bsd@bsdhome.com>
* All Rights Reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY BRIAN S. DEAN ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL BRIAN S. DEAN BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
* USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
*/
/*
* $FreeBSD$
*/
#include <machine/reg.h>
#include <machine/sysarch.h>
int
i386_set_watch(int watchnum, unsigned int watchaddr, int size,
int access, struct dbreg * d)
{
int i;
unsigned int mask;
if (watchnum == -1) {
for (i = 0, mask = 0x3; i < 4; i++, mask <<= 2)
if ((d->dr7 & mask) == 0)
break;
if (i < 4)
watchnum = i;
else
return -1;
}
switch (access) {
case DBREG_DR7_EXEC:
size = 1; /* size must be 1 for an execution breakpoint */
/* fall through */
case DBREG_DR7_WRONLY:
case DBREG_DR7_RDWR:
break;
default : return -1; break;
}
/*
* we can watch a 1, 2, or 4 byte sized location
*/
switch (size) {
case 1 : mask = 0x00; break;
case 2 : mask = 0x01 << 2; break;
case 4 : mask = 0x03 << 2; break;
default : return -1; break;
}
mask |= access;
/* clear the bits we are about to affect */
d->dr7 &= ~((0x3 << (watchnum*2)) | (0x0f << (watchnum*4+16)));
/* set drN register to the address, N=watchnum */
DBREG_DRX(d,watchnum) = watchaddr;
/* enable the watchpoint */
d->dr7 |= (0x2 << (watchnum*2)) | (mask << (watchnum*4+16));
return watchnum;
}

6
sys/amd64/include/reg.h
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@ -132,6 +132,12 @@ struct dbreg {
unsigned int dr7; /* debug control register */
};
#define DBREG_DR7_EXEC 0x00 /* break on execute */
#define DBREG_DR7_WRONLY 0x01 /* break on write */
#define DBREG_DR7_RDWR 0x03 /* break on read or write */
#define DBREG_DRX(d,x) ((&d->dr0)[x]) /* reference dr0 - dr7 by
register number */
#ifdef _KERNEL
/*

4
sys/amd64/include/sysarch.h
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@ -68,6 +68,7 @@ struct i386_vm86_args {
#include <sys/cdefs.h>
union descriptor;
struct dbreg;
__BEGIN_DECLS
int i386_get_ldt __P((int, union descriptor *, int));
@ -75,6 +76,9 @@ int i386_set_ldt __P((int, union descriptor *, int));
int i386_get_ioperm __P((unsigned int, unsigned int *, int *));
int i386_set_ioperm __P((unsigned int, unsigned int, int));
int i386_vm86 __P((int, void *));
int i386_set_watch __P((int watchnum, unsigned int watchaddr, int size,
int access, struct dbreg * d));
int i386_clr_watch __P((int watchnum, struct dbreg * d));
__END_DECLS
#endif

6
sys/i386/include/reg.h
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@ -132,6 +132,12 @@ struct dbreg {
unsigned int dr7; /* debug control register */
};
#define DBREG_DR7_EXEC 0x00 /* break on execute */
#define DBREG_DR7_WRONLY 0x01 /* break on write */
#define DBREG_DR7_RDWR 0x03 /* break on read or write */
#define DBREG_DRX(d,x) ((&d->dr0)[x]) /* reference dr0 - dr7 by
register number */
#ifdef _KERNEL
/*

4
sys/i386/include/sysarch.h
View File

@ -68,6 +68,7 @@ struct i386_vm86_args {
#include <sys/cdefs.h>
union descriptor;
struct dbreg;
__BEGIN_DECLS
int i386_get_ldt __P((int, union descriptor *, int));
@ -75,6 +76,9 @@ int i386_set_ldt __P((int, union descriptor *, int));
int i386_get_ioperm __P((unsigned int, unsigned int *, int *));
int i386_set_ioperm __P((unsigned int, unsigned int, int));
int i386_vm86 __P((int, void *));
int i386_set_watch __P((int watchnum, unsigned int watchaddr, int size,
int access, struct dbreg * d));
int i386_clr_watch __P((int watchnum, struct dbreg * d));
__END_DECLS
#endif