988eb7ed71
This interface is modeled after FreeBSD API with the usage.
This replaced previous watchpoint API. The previous one was introduced
recently in NetBSD-current and remove its spurs without any
backward-compatibility.
Design choices for Debug Register accessors:
- exec() (TRAP_EXEC event) must remove debug registers from LWP
- debug registers are only per-LWP, not per-process globally
- debug registers must not be inherited after (v)forking a process
- debug registers must not be inherited after forking a thread
- a debugger is responsible to set global watchpoints/breakpoints with the
debug registers, to achieve this PTRACE_LWP_CREATE/PTRACE_LWP_EXIT event
monitoring function is designed to be used
- debug register traps must generate SIGTRAP with si_code TRAP_DBREG
- debugger is responsible to retrieve debug register state to distinguish
the exact debug register trap (DR6 is Status Register on x86)
- kernel must not remove debug register traps after triggering a trap event
a debugger is responsible to detach this trap with appropriate PT_SETDBREGS
call (DR7 is Control Register on x86)
- debug registers must not be exposed in mcontext
- userland must not be allowed to set a trap on the kernel
Implementation notes on i386 and amd64:
- the initial state of debug register is retrieved on boot and this value is
stored in a local copy (initdbregs), this value is used to initialize dbreg
context after PT_GETDBREGS
- struct dbregs is stored in pcb as a pointer and by default not initialized
- reserved registers (DR4-DR5, DR9-DR15) are ignored
Further ideas:
- restrict this interface with securelevel
Tested on real hardware i386 (Intel Pentium IV) and amd64 (Intel i7).
This commit enables 390 debug register ATF tests in kernel/arch/x86.
All tests are passing.
This commit does not cover netbsd32 compat code. Currently other interface
PT_GET_SIGINFO/PT_SET_SIGINFO is required in netbsd32 compat code in order to
validate reliably PT_GETDBREGS/PT_SETDBREGS.
This implementation does not cover FreeBSD specific defines in their
<x86/reg.h>: DBREG_DR7_LOCAL_ENABLE, DBREG_DR7_GLOBAL_ENABLE, DBREG_DR7_LEN_1
etc. These values tend to be reinvented by each tracer on its own. GNU
Debugger (GDB) works with NetBSD debug registers after adding this patch:
--- gdb/amd64bsd-nat.c.orig 2016-02-10 03:19:39.000000000 +0000
+++ gdb/amd64bsd-nat.c
@@ -167,6 +167,10 @@ amd64bsd_target (void)
#ifdef HAVE_PT_GETDBREGS
+#ifndef DBREG_DRX
+#define DBREG_DRX(d,x) ((d)->dr[(x)])
+#endif
+
static unsigned long
amd64bsd_dr_get (ptid_t ptid, int regnum)
{
Another reason to stop introducing unpopular defines covering machine
specific register macros is that these value varies across generations of
the same CPU family.
GDB demo:
(gdb) c
Continuing.
Watchpoint 2: traceme
Old value = 0
New value = 16
main (argc=1, argv=0x7f7fff79fe30) at test.c:8
8 printf("traceme=%d\n", traceme);
(Currently the GDB interface is not reliable due to NetBSD support bugs)
Sponsored by <The NetBSD Foundation>
219 lines
8.0 KiB
C
219 lines
8.0 KiB
C
/* $NetBSD: sys_ptrace.c,v 1.4 2017/02/23 03:34:22 kamil Exp $ */
|
|
|
|
/*-
|
|
* Copyright (c) 2008, 2009 The NetBSD Foundation, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to The NetBSD Foundation
|
|
* by Andrew Doran.
|
|
*
|
|
* 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
|
|
*/
|
|
|
|
/*-
|
|
* Copyright (c) 1982, 1986, 1989, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
* (c) UNIX System Laboratories, Inc.
|
|
* All or some portions of this file are derived from material licensed
|
|
* to the University of California by American Telephone and Telegraph
|
|
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
|
|
* the permission of UNIX System Laboratories, Inc.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* Jan-Simon Pendry.
|
|
*
|
|
* 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.
|
|
* 3. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
|
|
*
|
|
* from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93
|
|
*/
|
|
|
|
/*-
|
|
* Copyright (c) 1993 Jan-Simon Pendry.
|
|
* Copyright (c) 1994 Christopher G. Demetriou. All rights reserved.
|
|
*
|
|
* This code is derived from software contributed to Berkeley by
|
|
* Jan-Simon Pendry.
|
|
*
|
|
* 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.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. Neither the name of the University nor the names of its contributors
|
|
* may be used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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.
|
|
*
|
|
* from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93
|
|
*/
|
|
|
|
/*
|
|
* References:
|
|
* (1) Bach's "The Design of the UNIX Operating System",
|
|
* (2) sys/miscfs/procfs from UCB's 4.4BSD-Lite distribution,
|
|
* (3) the "4.4BSD Programmer's Reference Manual" published
|
|
* by USENIX and O'Reilly & Associates.
|
|
* The 4.4BSD PRM does a reasonably good job of documenting what the various
|
|
* ptrace() requests should actually do, and its text is quoted several times
|
|
* in this file.
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__KERNEL_RCSID(0, "$NetBSD: sys_ptrace.c,v 1.4 2017/02/23 03:34:22 kamil Exp $");
|
|
|
|
#ifdef _KERNEL_OPT
|
|
#include "opt_ptrace.h"
|
|
#endif
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/systm.h>
|
|
#include <sys/proc.h>
|
|
#include <sys/errno.h>
|
|
#include <sys/exec.h>
|
|
#include <sys/pax.h>
|
|
#include <sys/ptrace.h>
|
|
#include <sys/uio.h>
|
|
#include <sys/ras.h>
|
|
#include <sys/kmem.h>
|
|
#include <sys/kauth.h>
|
|
#include <sys/mount.h>
|
|
#include <sys/syscallargs.h>
|
|
#include <sys/syscallvar.h>
|
|
#include <sys/syscall.h>
|
|
#include <sys/module.h>
|
|
|
|
#include <uvm/uvm_extern.h>
|
|
|
|
#include <machine/reg.h>
|
|
|
|
/*
|
|
* PTRACE methods
|
|
*/
|
|
|
|
static int ptrace_copyinpiod(struct ptrace_io_desc *, const void *);
|
|
static void ptrace_copyoutpiod(const struct ptrace_io_desc *, void *);
|
|
|
|
static int
|
|
ptrace_copyinpiod(struct ptrace_io_desc *piod, const void *addr)
|
|
{
|
|
return copyin(addr, piod, sizeof(*piod));
|
|
}
|
|
|
|
static void
|
|
ptrace_copyoutpiod(const struct ptrace_io_desc *piod, void *addr)
|
|
{
|
|
(void) copyout(piod, addr, sizeof(*piod));
|
|
}
|
|
|
|
static struct ptrace_methods native_ptm = {
|
|
.ptm_copyinpiod = ptrace_copyinpiod,
|
|
.ptm_copyoutpiod = ptrace_copyoutpiod,
|
|
.ptm_doregs = process_doregs,
|
|
.ptm_dofpregs = process_dofpregs,
|
|
.ptm_dodbregs = process_dodbregs,
|
|
};
|
|
|
|
static const struct syscall_package ptrace_syscalls[] = {
|
|
{ SYS_ptrace, 0, (sy_call_t *)sys_ptrace },
|
|
{ 0, 0, NULL },
|
|
};
|
|
|
|
/*
|
|
* Process debugging system call.
|
|
*/
|
|
int
|
|
sys_ptrace(struct lwp *l, const struct sys_ptrace_args *uap, register_t *retval)
|
|
{
|
|
/* {
|
|
syscallarg(int) req;
|
|
syscallarg(pid_t) pid;
|
|
syscallarg(void *) addr;
|
|
syscallarg(int) data;
|
|
} */
|
|
|
|
return do_ptrace(&native_ptm, l, SCARG(uap, req), SCARG(uap, pid),
|
|
SCARG(uap, addr), SCARG(uap, data), retval);
|
|
}
|
|
|
|
#define DEPS "ptrace_common"
|
|
|
|
MODULE(MODULE_CLASS_EXEC, ptrace, DEPS);
|
|
|
|
static int
|
|
ptrace_modcmd(modcmd_t cmd, void *arg)
|
|
{
|
|
int error;
|
|
|
|
switch (cmd) {
|
|
case MODULE_CMD_INIT:
|
|
error = syscall_establish(&emul_netbsd, ptrace_syscalls);
|
|
break;
|
|
case MODULE_CMD_FINI:
|
|
error = syscall_disestablish(&emul_netbsd, ptrace_syscalls);
|
|
break;
|
|
default:
|
|
error = ENOTTY;
|
|
break;
|
|
}
|
|
return error;
|
|
}
|