Comment and whitespace changes

This commit merges the comments and whitespace in the common
parts of i386-linux-nat.c and amd64-linux-nat.c.

gdb/
2014-07-11  Gary Benson  <gbenson@redhat.com>

	* amd64-linux-nat.c: Comment and whitespace changes.
	* i386-linux-nat.c: Comment and whitespace changes.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 46ec2af..490e652 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2014-07-11  Gary Benson  <gbenson@redhat.com>
 
+       * amd64-linux-nat.c: Comment and whitespace changes.
+       * i386-linux-nat.c: Comment and whitespace changes.
+
+2014-07-11  Gary Benson  <gbenson@redhat.com>
+
        * amd64-linux-nat.c (x86_linux_create_target): New function.
        (x86_linux_add_target): Likewise.
        (_initialize_amd64_linux_nat): Delegate to the above new functions.

diff --git a/gdb/amd64-linux-nat.c b/gdb/amd64-linux-nat.c
index d3a09d3..42af924 100644 (file)
--- a/gdb/amd64-linux-nat.c
+++ b/gdb/amd64-linux-nat.c
@@ -277,8 +277,11 @@ amd64_linux_store_inferior_registers (struct target_ops *ops,
     }
 }
 \f
+
 /* Support for debug registers.  */
 
+/* Get debug register REGNUM value from only the one LWP of PTID.  */
+
 static unsigned long
 x86_linux_dr_get (ptid_t ptid, int regnum)
 {

diff --git a/gdb/i386-linux-nat.c b/gdb/i386-linux-nat.c
index f4d8d5f..1ee7503 100644 (file)
--- a/gdb/i386-linux-nat.c
+++ b/gdb/i386-linux-nat.c
@@ -732,7 +732,7 @@ update_debug_registers_callback (struct lwp_info *lwp, void *arg)
   return 0;
 }
 
-/* Set DR_CONTROL to ADDR in all LWPs of the current inferior.  */
+/* Set DR_CONTROL to CONTROL in all LWPs of the current inferior.  */
 
 static void
 x86_linux_dr_set_control (unsigned long control)
@@ -775,9 +775,16 @@ x86_linux_prepare_to_resume (struct lwp_info *lwp)
        = i386_debug_reg_state (ptid_get_pid (lwp->ptid));
       int i;
 
-      /* See amd64_linux_prepare_to_resume for Linux kernel note on
-        i386_linux_dr_set calls ordering.  */
+      /* On Linux kernel before 2.6.33 commit
+        72f674d203cd230426437cdcf7dd6f681dad8b0d
+        if you enable a breakpoint by the DR_CONTROL bits you need to have
+        already written the corresponding DR_FIRSTADDR...DR_LASTADDR registers.
 
+        Ensure DR_CONTROL gets written as the very last register here.  */
+
+      /* Clear DR_CONTROL first.  In some cases, setting DR0-3 to a
+        value that doesn't match what is enabled in DR_CONTROL
+        results in EINVAL.  */
       x86_linux_dr_set (lwp->ptid, DR_CONTROL, 0);
 
       for (i = DR_FIRSTADDR; i <= DR_LASTADDR; i++)
@@ -792,6 +799,8 @@ x86_linux_prepare_to_resume (struct lwp_info *lwp)
            clear_status = 1;
          }
 
+      /* If DR_CONTROL is supposed to be zero, we've already set it
+        above.  */
       if (state->dr_control_mirror != 0)
        x86_linux_dr_set (lwp->ptid, DR_CONTROL, state->dr_control_mirror);