1 files changed, 89 insertions, 41 deletions

diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index c673965..288160b 100644
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -64,6 +64,14 @@
 #define PTRACE_SETREGSET	0x4205
 #endif
 
+/* Per-thread arch-specific data we want to keep.  */
+
+struct arch_lwp_info
+{
+  /* Non-zero if our copy differs from what's recorded in the thread.  */
+  int debug_registers_changed;
+};
+
 /* Does the current host support PTRACE_GETREGSET?  */
 static int have_ptrace_getregset = -1;
 
@@ -265,8 +273,6 @@ amd64_linux_store_inferior_registers (struct target_ops *ops,
 
 /* Support for debug registers.  */
 
-static unsigned long amd64_linux_dr[DR_CONTROL + 1];
-
 static unsigned long
 amd64_linux_dr_get (ptid_t ptid, int regnum)
 {
@@ -304,75 +310,116 @@ amd64_linux_dr_set (ptid_t ptid, int regnum, unsigned long value)
     perror_with_name (_("Couldn't write debug register"));
 }
 
-/* Set DR_CONTROL to ADDR in all LWPs of LWP_LIST.  */
+/* Return the inferior's debug register REGNUM.  */
 
-static void
-amd64_linux_dr_set_control (unsigned long control)
+static CORE_ADDR
+amd64_linux_dr_get_addr (int regnum)
 {
-  struct lwp_info *lp;
+  /* DR6 and DR7 are retrieved with some other way.  */
+  gdb_assert (DR_FIRSTADDR <= regnum && regnum <= DR_LASTADDR);
 
-  amd64_linux_dr[DR_CONTROL] = control;
-  ALL_LWPS (lp)
-    amd64_linux_dr_set (lp->ptid, DR_CONTROL, control);
+  return amd64_linux_dr_get (inferior_ptid, regnum);
 }
 
-/* Set address REGNUM (zero based) to ADDR in all LWPs of LWP_LIST.  */
+/* Return the inferior's DR7 debug control register.  */
 
-static void
-amd64_linux_dr_set_addr (int regnum, CORE_ADDR addr)
+static unsigned long
+amd64_linux_dr_get_control (void)
 {
-  struct lwp_info *lp;
+  return amd64_linux_dr_get (inferior_ptid, DR_CONTROL);
+}
 
-  gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
+/* Get DR_STATUS from only the one LWP of INFERIOR_PTID.  */
+
+static unsigned long
+amd64_linux_dr_get_status (void)
+{
+  return amd64_linux_dr_get (inferior_ptid, DR_STATUS);
+}
+
+/* Callback for iterate_over_lwps.  Update the debug registers of
+   LWP.  */
+
+static int
+update_debug_registers_callback (struct lwp_info *lwp, void *arg)
+{
+  /* The actual update is done later just before resuming the lwp, we
+     just mark that the registers need updating.  */
+  lwp->arch_private->debug_registers_changed = 1;
+
+  /* If the lwp isn't stopped, force it to momentarily pause, so we
+     can update its debug registers.  */
+  if (!lwp->stopped)
+    linux_stop_lwp (lwp);
 
-  amd64_linux_dr[DR_FIRSTADDR + regnum] = addr;
-  ALL_LWPS (lp)
-    amd64_linux_dr_set (lp->ptid, DR_FIRSTADDR + regnum, addr);
+  return 0;
 }
 
-/* Set address REGNUM (zero based) to zero in all LWPs of LWP_LIST.  */
+/* Set DR_CONTROL to CONTROL in all LWPs of the current inferior.  */
 
 static void
-amd64_linux_dr_reset_addr (int regnum)
+amd64_linux_dr_set_control (unsigned long control)
 {
-  amd64_linux_dr_set_addr (regnum, 0);
+  ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
+
+  iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
 }
 
-/* Get DR_STATUS from only the one LWP of INFERIOR_PTID.  */
+/* Set address REGNUM (zero based) to ADDR in all LWPs of the current
+   inferior.  */
 
-static unsigned long
-amd64_linux_dr_get_status (void)
+static void
+amd64_linux_dr_set_addr (int regnum, CORE_ADDR addr)
 {
-  return amd64_linux_dr_get (inferior_ptid, DR_STATUS);
+  ptid_t pid_ptid = pid_to_ptid (ptid_get_pid (inferior_ptid));
+
+  gdb_assert (regnum >= 0 && regnum <= DR_LASTADDR - DR_FIRSTADDR);
+
+  iterate_over_lwps (pid_ptid, update_debug_registers_callback, NULL);
 }
 
-/* Unset MASK bits in DR_STATUS in all LWPs of LWP_LIST.  */
+/* Called when resuming a thread.
+   If the debug regs have changed, update the thread's copies.  */
 
 static void
-amd64_linux_dr_unset_status (unsigned long mask)
+amd64_linux_prepare_to_resume (struct lwp_info *lwp)
 {
-  struct lwp_info *lp;
+  int clear_status = 0;
 
-  ALL_LWPS (lp)
+  if (lwp->arch_private->debug_registers_changed)
     {
-      unsigned long value;
-      
-      value = amd64_linux_dr_get (lp->ptid, DR_STATUS);
-      value &= ~mask;
-      amd64_linux_dr_set (lp->ptid, DR_STATUS, value);
+      struct i386_debug_reg_state *state = i386_debug_reg_state ();
+      int i;
+
+      for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
+	if (state->dr_ref_count[i] > 0)
+	  {
+	    amd64_linux_dr_set (lwp->ptid, i, state->dr_mirror[i]);
+
+	    /* If we're setting a watchpoint, any change the inferior
+	       had done itself to the debug registers needs to be
+	       discarded, otherwise, i386_stopped_data_address can get
+	       confused.  */
+	    clear_status = 1;
+	  }
+
+      amd64_linux_dr_set (lwp->ptid, DR_CONTROL, state->dr_control_mirror);
+
+      lwp->arch_private->debug_registers_changed = 0;
     }
-}
 
+  if (clear_status || lwp->stopped_by_watchpoint)
+    amd64_linux_dr_set (lwp->ptid, DR_STATUS, 0);
+}
 
 static void
-amd64_linux_new_thread (ptid_t ptid)
+amd64_linux_new_thread (struct lwp_info *lp)
 {
-  int i;
+  struct arch_lwp_info *info = XCNEW (struct arch_lwp_info);
 
-  for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
-    amd64_linux_dr_set (ptid, i, amd64_linux_dr[i]);
+  info->debug_registers_changed = 1;
 
-  amd64_linux_dr_set (ptid, DR_CONTROL, amd64_linux_dr[DR_CONTROL]);
+  lp->arch_private = info;
 }
 
 
@@ -785,9 +832,9 @@ _initialize_amd64_linux_nat (void)
 
   i386_dr_low.set_control = amd64_linux_dr_set_control;
   i386_dr_low.set_addr = amd64_linux_dr_set_addr;
-  i386_dr_low.reset_addr = amd64_linux_dr_reset_addr;
+  i386_dr_low.get_addr = amd64_linux_dr_get_addr;
   i386_dr_low.get_status = amd64_linux_dr_get_status;
-  i386_dr_low.unset_status = amd64_linux_dr_unset_status;
+  i386_dr_low.get_control = amd64_linux_dr_get_control;
   i386_set_debug_register_length (8);
 
   /* Override the GNU/Linux inferior startup hook.  */
@@ -804,4 +851,5 @@ _initialize_amd64_linux_nat (void)
   linux_nat_add_target (t);
   linux_nat_set_new_thread (t, amd64_linux_new_thread);
   linux_nat_set_siginfo_fixup (t, amd64_linux_siginfo_fixup);
+  linux_nat_set_prepare_to_resume (t, amd64_linux_prepare_to_resume);
 }