[PATCH]: Add hardware watchpoint/breakpoint support for FreeBSD/i386

[Mark Kettenis <kettenis at wins dot uva dot nl>]

Checked in.

Mark


Index: ChangeLog
from  Mark Kettenis  <kettenis@gnu.org>

	* i386bsd-nat.c: Include "gdb_assert.h".
	[HAVE_PT_GETDBREGS] (DBREG_DRX): Define if not
	already defined.
	[HAVE_PT_GETDBREGS] (i386bsd_dr_set, i386bsd_dr_set_control,
	i386bsd_dr_set_addr, i386bsd_dr_reset_addr,
	i386bsd_dr_get_status): New functions.
	* config/i386/nm-fbsd.h [HAVE_PT_GETDBREGS]
	(I386_USE_GENERIC_WATCHPOINTS): Define.
	Include "i386/nm-i386.h".
	(I386_DR_LOW_SET_CONTROL, I386_DR_LOW_SET_ADDR,
	I386_DR_LOW_RESET_ADDR, I386_DR_LOW_GET_STATUS): New macros.
	(i386bsd_dr_set_control, i386bsd_dr_set_addr,
	i386bsd_dr_reset_addr, i386bsd_dr_get_status): New prototypes.
	* acconfig.h (HAVE_PT_GETDBREGS): New configure macro.
	* configure.in: Cleanup a few comments.  Check for PT_GETDBREGS
	ptrace request.
	* config.in, configure: Regenerate.

Index: acconfig.h
===================================================================
RCS file: /cvs/src/src/gdb/acconfig.h,v
retrieving revision 1.15
diff -u -p -r1.15 acconfig.h
--- acconfig.h 2001/03/19 05:46:26 1.15
+++ acconfig.h 2001/03/31 18:03:40
@@ -147,6 +147,9 @@
 /* Define if <sys/ptrace.h> defines the PTRACE_GETFPXREGS request.  */
 #undef HAVE_PTRACE_GETFPXREGS
 
+/* Define if <sys/ptrace.h> defines the PT_GETDBREGS request.  */
+#undef HAVE_PT_GETDBREGS
+
 /* Define if gnu-regex.c included with GDB should be used. */
 #undef USE_INCLUDED_REGEX
 
Index: configure.in
===================================================================
RCS file: /cvs/src/src/gdb/configure.in,v
retrieving revision 1.62
diff -u -p -r1.62 configure.in
--- configure.in 2001/03/28 21:42:31 1.62
+++ configure.in 2001/03/31 18:03:40
@@ -135,7 +135,7 @@ AC_CHECK_FUNCS(setpgid sbrk sigaction is
 AC_FUNC_VFORK
 AC_FUNC_ALLOCA
 
-# See if machine/reg.h supports the %fs and %gs i386 segment registers.
+# See if <machine/reg.h> supports the %fs and %gs i386 segment registers.
 # Older i386 BSD's don't have the r_fs and r_gs members of `struct reg'.
 AC_CACHE_CHECK([for r_fs in struct reg], gdb_cv_struct_reg_r_fs,
 [AC_TRY_COMPILE([#include <machine/reg.h>], [struct reg r; r.r_fs;],
@@ -150,7 +150,7 @@ if test $gdb_cv_struct_reg_r_gs = yes; t
   AC_DEFINE(HAVE_STRUCT_REG_R_GS)
 fi
 
-dnl See if ptrace.h provides the PTRACE_GETREGS request.
+# See if <sys/ptrace.h> provides the PTRACE_GETREGS request.
 AC_MSG_CHECKING(for PTRACE_GETREGS)
 AC_CACHE_VAL(gdb_cv_have_ptrace_getregs,
 [AC_TRY_COMPILE([#include <sys/ptrace.h>],
@@ -162,7 +162,7 @@ if test $gdb_cv_have_ptrace_getregs = ye
   AC_DEFINE(HAVE_PTRACE_GETREGS)
 fi
 
-dnl See if ptrace.h provides the PTRACE_GETFPXREGS request.
+# See if <sys/ptrace.h> provides the PTRACE_GETFPXREGS request.
 AC_MSG_CHECKING(for PTRACE_GETFPXREGS)
 AC_CACHE_VAL(gdb_cv_have_ptrace_getfpxregs,
 [AC_TRY_COMPILE([#include <sys/ptrace.h>],
@@ -173,6 +173,20 @@ AC_MSG_RESULT($gdb_cv_have_ptrace_getfpx
 if test $gdb_cv_have_ptrace_getfpxregs = yes; then
   AC_DEFINE(HAVE_PTRACE_GETFPXREGS)
 fi
+
+# See if <sys/ptrace.h> provides the PT_GETDBREGS request.
+AC_MSG_CHECKING(for PT_GETDBREGS)
+AC_CACHE_VAL(gdb_cv_have_pt_getdbregs,
+[AC_TRY_COMPILE([#include <sys/types.h>
+#include <sys/ptrace.h>],
+		[PT_GETDBREGS;],
+		[gdb_cv_have_pt_getdbregs=yes],
+		[gdb_cv_have_pt_getdbregs=no])])
+AC_MSG_RESULT($gdb_cv_have_pt_getdbregs)
+if test $gdb_cv_have_pt_getdbregs = yes; then
+  AC_DEFINE(HAVE_PT_GETDBREGS)
+fi
+
 
 AC_CHECK_LIB(socket, socketpair)
 AC_CHECK_FUNCS(socketpair)
Index: i386bsd-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/i386bsd-nat.c,v
retrieving revision 1.5
diff -u -p -r1.5 i386bsd-nat.c
--- i386bsd-nat.c 2001/03/01 01:39:20 1.5
+++ i386bsd-nat.c 2001/03/31 18:03:40
@@ -22,6 +22,7 @@
 #include "inferior.h"
 #include "regcache.h"
 
+#include "gdb_assert.h"
 #include <sys/types.h>
 #include <sys/ptrace.h>
 #include <machine/reg.h>
@@ -213,6 +214,80 @@ store_inferior_registers (int regno)
 	perror_with_name ("Couldn't write floating point status");
     }
 }
+
+
+/* Support for debug registers.  */
+
+#ifdef HAVE_PT_GETDBREGS
+
+/* Not all versions of FreeBSD/i386 that support the debug registers
+   have this macro.  */
+#ifndef DBREG_DRX
+#define DBREG_DRX(d, x) ((&d->dr0)[x])
+#endif
+
+static void
+i386bsd_dr_set (int regnum, unsigned int value)
+{
+  struct dbreg dbregs;
+
+  if (ptrace (PT_GETDBREGS, inferior_pid, (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
+    perror_with_name ("Couldn't get debug registers");
+
+  /* For some mysterious reason, some of the reserved bits in the
+     debug control register get set.  Mask these off, otherwise the
+     ptrace call below will fail.  */
+  dbregs.dr7 &= ~(0x0000fc00);
+
+  DBREG_DRX ((&dbregs), regnum) = value;
+
+  if (ptrace (PT_SETDBREGS, inferior_pid, (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
+    perror_with_name ("Couldn't write debug registers");
+}
+
+void
+i386bsd_dr_set_control (unsigned long control)
+{
+  i386bsd_dr_set (7, control);
+}
+
+void
+i386bsd_dr_set_addr (int regnum, CORE_ADDR addr)
+{
+  gdb_assert (regnum >= 0 && regnum <= 4);
+
+  i386bsd_dr_set (regnum, addr);
+}
+
+void
+i386bsd_dr_reset_addr (int regnum)
+{
+  gdb_assert (regnum >= 0 && regnum <= 4);
+
+  i386bsd_dr_set (regnum, 0);
+}
+
+unsigned long
+i386bsd_dr_get_status (void)
+{
+  struct dbreg dbregs;
+
+  /* FIXME: kettenis/2001-03-31: Calling perror_with_name if the
+     ptrace call fails breaks debugging remote targets.  The correct
+     way to fix this is to add the hardware breakpoint and watchpoint
+     stuff to the target vectore.  For now, just return zero if the
+     ptrace call fails.  */
+  if (ptrace (PT_GETDBREGS, inferior_pid, (PTRACE_ARG3_TYPE) &dbregs, 0) == -1)
+#if 0
+    perror_with_name ("Couldn't read debug registers");
+#else
+    return 0;
+#endif
+
+  return dbregs.dr6;
+}
+
+#endif /* PT_GETDBREGS */
 
 
 /* Support for the user struct.  */
Index: config/i386/nm-fbsd.h
===================================================================
RCS file: /cvs/src/src/gdb/config/i386/nm-fbsd.h,v
retrieving revision 1.3
diff -u -p -r1.3 nm-fbsd.h
--- config/i386/nm-fbsd.h 2001/03/06 08:21:28 1.3
+++ config/i386/nm-fbsd.h 2001/03/31 18:03:40
@@ -1,5 +1,5 @@
 /* Native-dependent definitions for FreeBSD/i386.
-   Copyright 1986, 1987, 1989, 1992, 1994, 1996, 1997, 2000
+   Copyright 1986, 1987, 1989, 1992, 1994, 1996, 1997, 2000, 2001
    Free Software Foundation, Inc.
 
    This file is part of GDB.
@@ -21,6 +21,31 @@
 
 #ifndef NM_FBSD_H
 #define NM_FBSD_H
+
+#ifdef HAVE_PT_GETDBREGS
+#define I386_USE_GENERIC_WATCHPOINTS
+#endif
+
+#include "i386/nm-i386.h"
+
+/* Provide access to the i386 hardware debugging registers.  */
+
+#define I386_DR_LOW_SET_CONTROL(control) \
+  i386bsd_dr_set_control (control)
+extern void i386bsd_dr_set_control (unsigned long control);
+
+#define I386_DR_LOW_SET_ADDR(regnum, addr) \
+  i386bsd_dr_set_addr (regnum, addr)
+extern void i386bsd_dr_set_addr (int regnum, CORE_ADDR addr);
+
+#define I386_DR_LOW_RESET_ADDR(regnum) \
+  i386bsd_dr_reset_addr (regnum)
+extern void i386bsd_dr_reset_addr (int regnum);
+
+#define I386_DR_LOW_GET_STATUS() \
+  i386bsd_dr_get_status ()
+extern unsigned long i386bsd_dr_get_status (void);
+
 
 /* Type of the third argument to the `ptrace' system call.  */
 #define PTRACE_ARG3_TYPE caddr_t