[PATCH] FRV: debugging fixes

The attached patch fixes three debugging problems in the frv arch:

 (1) Single-stepping in userspace steps through into the kernel-mode interrupt
     handler when a hardware interrupt happens, and sometimes it gets past
     where the debug-mode handler would normally catch it. This patch extends
     the range of detected PC values.

 (2) When setting up the kernel-mode exception frame from the debug-mode
     handler for a userspace debugging event, we weren't setting the LR
     register to generate a return to the exception handler epilogue.

 (3) sys_ptrace() now needs to "put" the inferior task_struct not "free" it as
     was done in 2.4.
Signed-Off-By: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/frv/kernel/break.S

@@ -202,6 +202,10 @@ __break_step:
 	setlo		%lo(__entry_kernel_external_interrupt),gr3
 	subcc		gr2,gr3,gr0,icc0
 	beq		icc0,#2,__break_step_kernel_external_interrupt
+	sethi.p		%hi(__entry_uspace_external_interrupt),gr3
+	setlo		%lo(__entry_uspace_external_interrupt),gr3
+	subcc		gr2,gr3,gr0,icc0
+	beq		icc0,#2,__break_step_uspace_external_interrupt
 
 	LEDS		0x2007,gr2
 
@@ -483,6 +487,9 @@ __break_no_user_sstep:
 	movgs		gr2,bpsr
 
 	# return through remainder of the exception prologue
+	# - need to load gr23 with return handler address
+	sethi.p		%hi(__entry_return_from_user_exception),gr23
+	setlo		%lo(__entry_return_from_user_exception),gr23
 	sethi.p		%hi(__entry_common),gr3
 	setlo		%lo(__entry_common),gr3
 	movgs		gr3,bpcsr

arch/frv/kernel/ptrace.c

@@ -358,7 +358,7 @@ asmlinkage int sys_ptrace(long request, long pid, long addr, long data)
 		break;
 	}
 out_tsk:
-	free_task_struct(child);
+	put_task_struct(child);
 out:
 	unlock_kernel();
 	return ret;