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[PATCH]: Make Linux use the new unified x86 watchpoint support


FYI, I checked this in.  HJ can finally be happy now (although things
probably won't work correctly for multithreaded programs).

Mark


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

	Make Linux use the new unified support for hardware breakpoints
	and watchpoints on x86 targets.
	* i386-linux-nat.c: Doc fixes.  Include "gdb_assert.h".
	[HAVE_SYS_DEBUGREG_H]: Include <sys/debugreg.h>.
	(DR_FIRSTADDR, DR_LASTADDR, DR_STATUS, DR_CONTROL): Define to
	appropriate value if not already defined.
	(register_u_addr): New function.
	(kernel_u_size): New function.
	(i386_linux_dr_get, i386_linux_dr_set): New functions.
	(i386_linux_dr_set_control, i386_linux_dr_set_addr,
	i386_linux_reset_addr, i386_linux_dr_get_status): New functions.
	* config/i386/nm-linux.h: Don't include "nm-i386v.h".
	(I386_USE_GENERIC_WATCHPOINTS): Define and include "nm-i386.h".
	(TARGET_HAS_HARDWARE_WATCHPOINTS,
	TARGET_CAN_USE_HARDWARE_WATCHPOINTS, HAVE_CONTINUABLE_WATCHPOINT,
	STOPPED_BY_WATCHPOINT, target_insert_watchpoint,
	target_remove_watchpoint): Remove macros.
	(i386_stopped_by_watchpoint, i386_insert_watchpoint,
	i386_remove_watchpoint): Remove prototypes.
	(register_u_addr): New prototype.
	(REGISTER_U_ADDR): Define in terms of register_u_addr.
	(i386_linux_dr_set_control, i386_linux_dr_set_addr,
	i386_linux_reset_addr, i386_linux_dr_get_status): New prototypes.
	(I386_DR_LOW_SET_CONTROL, I386_DR_LOW_SET_ADDR,
	I386_DR_LOW_RESET_ADDR, I386_DR_LOW_GET_STATUS): New macros.
	* config/i386/linux.mh (NATDEPFILES): Replace i386v-nat.o with
	i386-nat.o.

Index: i386-linux-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-linux-nat.c,v
retrieving revision 1.23
diff -u -p -r1.23 i386-linux-nat.c
--- i386-linux-nat.c 2001/03/13 23:31:13 1.23
+++ i386-linux-nat.c 2001/03/21 21:20:21
@@ -23,6 +23,7 @@
 #include "gdbcore.h"
 #include "regcache.h"
 
+#include "gdb_assert.h"
 #include <sys/ptrace.h>
 #include <sys/user.h>
 #include <sys/procfs.h>
@@ -31,6 +32,26 @@
 #include <sys/reg.h>
 #endif
 
+#ifdef HAVE_SYS_DEBUGREG_H
+#include <sys/debugreg.h>
+#endif
+
+#ifndef DR_FIRSTADDR
+#define DR_FIRSTADDR 0
+#endif
+
+#ifndef DR_LASTADDR
+#define DR_LASTADDR 3
+#endif
+
+#ifndef DR_STATUS
+#define DR_STATUS 6
+#endif
+
+#ifndef DR_CONTROL
+#define DR_CONTROL 7
+#endif
+
 /* Prototypes for supply_gregset etc.  */
 #include "gregset.h"
 
@@ -110,6 +131,26 @@ int have_ptrace_getfpxregs =
 ;
 
 
+/* Support for the user struct.  */
+
+/* Return the address of register REGNUM.  BLOCKEND is the value of
+   u.u_ar0, which should point to the registers.  */
+
+CORE_ADDR
+register_u_addr (CORE_ADDR blockend, int regnum)
+{
+  return (blockend + 4 * regmap[regnum]);
+}
+
+/* Return the size of the user struct.  */
+
+int
+kernel_u_size (void)
+{
+  return (sizeof (struct user));
+}
+
+
 /* Fetching registers directly from the U area, one at a time.  */
 
 /* FIXME: kettenis/2000-03-05: This duplicates code from `inptrace.c'.
@@ -657,6 +698,72 @@ store_inferior_registers (int regno)
 
   internal_error (__FILE__, __LINE__,
 		  "Got request to store bad register number %d.", regno);
+}
+
+
+static long
+i386_linux_dr_get (int regnum)
+{
+  int tid;
+  long value;
+
+  /* FIXME: kettenis/2001-01-29: It's not clear what we should do with
+     multi-threaded processes here.  For now, pretend there is just
+     one thread.  */
+  tid = PIDGET (inferior_pid);
+
+  errno = 0;
+  value = ptrace (PT_READ_U, tid,
+		  offsetof (struct user, u_debugreg[regnum]), 0);
+  if (errno != 0)
+    perror_with_name ("Couldn't read debug register");
+
+  return value;
+}
+
+static void
+i386_linux_dr_set (int regnum, long value)
+{
+  int tid;
+
+  /* FIXME: kettenis/2001-01-29: It's not clear what we should do with
+     multi-threaded processes here.  For now, pretend there is just
+     one thread.  */
+  tid = PIDGET (inferior_pid);
+
+  errno = 0;
+  ptrace (PT_WRITE_U, tid,
+	  offsetof (struct user, u_debugreg[regnum]), value);
+  if (errno != 0)
+    perror_with_name ("Couldn't write debug register");
+}
+
+void
+i386_linux_dr_set_control (long control)
+{
+  i386_linux_dr_set (DR_CONTROL, control);
+}
+
+void
+i386_linux_dr_set_addr (int regnum, CORE_ADDR addr)
+{
+  gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
+
+  i386_linux_dr_set (DR_FIRSTADDR + regnum, addr);
+}
+
+void
+i386_linux_dr_reset_addr (int regnum)
+{
+  gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
+
+  i386_linux_dr_set (DR_FIRSTADDR + regnum, 0L);
+}
+
+long
+i386_linux_dr_get_status (void)
+{
+  return i386_linux_dr_get (DR_STATUS);
 }
 
 
Index: config/i386/nm-linux.h
===================================================================
RCS file: /cvs/src/src/gdb/config/i386/nm-linux.h,v
retrieving revision 1.8
diff -u -p -r1.8 nm-linux.h
--- config/i386/nm-linux.h 2001/03/06 08:21:28 1.8
+++ config/i386/nm-linux.h 2001/03/21 21:20:21
@@ -1,6 +1,6 @@
 /* Native support for Linux/x86.
    Copyright 1986, 1987, 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000
+   1999, 2000, 2001
    Free Software Foundation, Inc.
 
    This file is part of GDB.
@@ -23,52 +23,56 @@
 #ifndef NM_LINUX_H
 #define NM_LINUX_H
 
-#include "i386/nm-i386v.h"
+/* GNU/Linux supports the i386 hardware debugging registers.  */
+#define I386_USE_GENERIC_WATCHPOINTS
+
+#include "i386/nm-i386.h"
 #include "nm-linux.h"
 
-/* Return sizeof user struct to callers in less machine dependent routines */
+/* Return sizeof user struct to callers in less machine dependent
+   routines.  */
 
-#define KERNEL_U_SIZE kernel_u_size()
 extern int kernel_u_size (void);
+#define KERNEL_U_SIZE kernel_u_size()
 
 #define U_REGS_OFFSET 0
-
-/* GNU/Linux supports the 386 hardware debugging registers.  */
-
-#define TARGET_HAS_HARDWARE_WATCHPOINTS
-
-#define TARGET_CAN_USE_HARDWARE_WATCHPOINT(type, cnt, ot) 1
 
-/* After a watchpoint trap, the PC points to the instruction after
-   the one that caused the trap.  Therefore we don't need to step over it.
-   But we do need to reset the status register to avoid another trap.  */
-#define HAVE_CONTINUABLE_WATCHPOINT
+extern CORE_ADDR register_u_addr (CORE_ADDR blockend, int regnum);
+#define REGISTER_U_ADDR(addr, blockend, regnum) \
+  (addr) = register_u_addr (blockend, regnum)
+
+/* Provide access to the i386 hardware debugging registers.  */
+
+extern void i386_linux_dr_set_control (long control);
+#define I386_DR_LOW_SET_CONTROL(control) \
+  i386_linux_dr_set_control (control)
+
+extern void i386_linux_dr_set_addr (int regnum, CORE_ADDR addr);
+#define I386_DR_LOW_SET_ADDR(regnum, addr) \
+  i386_linux_dr_set_addr (regnum, addr)
+
+extern void i386_linux_dr_reset_addr (int regnum);
+#define I386_DR_LOW_RESET_ADDR(regnum) \
+  i386_linux_dr_reset_addr (regnum)
+
+extern long i386_linux_dr_get_status (void);
+#define I386_DR_LOW_GET_STATUS() \
+  i386_linux_dr_get_status ()
 
-#define STOPPED_BY_WATCHPOINT(W)  \
-  i386_stopped_by_watchpoint (inferior_pid)
+/* We define this if link.h is available, because with ELF we use SVR4
+   style shared libraries.  */
 
-/* Use these macros for watchpoint insertion/removal.  */
-
-#define target_insert_watchpoint(addr, len, type)  \
-  i386_insert_watchpoint (inferior_pid, addr, len, type)
-
-#define target_remove_watchpoint(addr, len, type)  \
-  i386_remove_watchpoint (inferior_pid, addr, len)
-
-/* We define this if link.h is available, because with ELF we use SVR4 style
-   shared libraries. */
-
 #ifdef HAVE_LINK_H
 #define SVR4_SHARED_LIBS
-#include "solib.h"		/* Support for shared libraries. */
+#include "solib.h"		/* Support for shared libraries.  */
 #endif
 
 /* Override copies of {fetch,store}_inferior_registers in `infptrace.c'.  */
 #define FETCH_INFERIOR_REGISTERS
 
-/* Nevertheless, define CANNOT_{FETCH,STORE}_REGISTER, because we might fall
-   back on the code `infptrace.c' (well a copy of that code in
-   `i386-linux-nat.c' for now) and we can access only the
+/* Nevertheless, define CANNOT_{FETCH,STORE}_REGISTER, because we
+   might fall back on the code `infptrace.c' (well a copy of that code
+   in `i386-linux-nat.c' for now) and we can access only the
    general-purpose registers in that way.  */
 extern int cannot_fetch_register (int regno);
 extern int cannot_store_register (int regno);
@@ -77,10 +81,6 @@ extern int cannot_store_register (int re
 
 /* Override child_resume in `infptrace.c'.  */
 #define CHILD_RESUME
-
-extern CORE_ADDR i386_stopped_by_watchpoint (int);
-extern int i386_insert_watchpoint (int pid, CORE_ADDR addr, int len, int rw);
-extern int i386_remove_watchpoint (int pid, CORE_ADDR addr, int len);
 
 /* FIXME: kettenis/2000-09-03: This should be moved to ../nm-linux.h
    once we have converted all Linux targets to use the new threads
Index: config/i386/linux.mh
===================================================================
RCS file: /cvs/src/src/gdb/config/i386/linux.mh,v
retrieving revision 1.6
diff -u -p -r1.6 linux.mh
--- config/i386/linux.mh 2000/10/30 22:33:32 1.6
+++ config/i386/linux.mh 2001/03/21 21:20:21
@@ -5,7 +5,7 @@ XDEPFILES=
 
 NAT_FILE= nm-linux.h
 NATDEPFILES= infptrace.o inftarg.o fork-child.o corelow.o \
-	core-aout.o i386v-nat.o i386-linux-nat.o i387-nat.o \
+	core-aout.o i386-nat.o i386-linux-nat.o i387-nat.o \
 	proc-service.o thread-db.o lin-lwp.o
 
 LOADLIBES = -ldl -rdynamic


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