Re: [PATCH -v6 05/13] tracing: enableHAVE_FUNCTION_TRACE_MCOUNT_TEST for MIPS

[Steven Rostedt]

On Mon, 2009-10-26 at 18:41 +0300, Sergei Shtylyov wrote:
> Hello.
> 
> Wu Zhangjin wrote:
> 
> > There is an exisiting common ftrace_test_stop_func() in
> > kernel/trace/ftrace.c, which is used to check the global variable
> > ftrace_trace_stop to determine whether stop the function tracing.
> 
> > This patch implepment the MIPS specific one to speedup the procedure.
> 
> > Thanks goes to Zhang Le for Cleaning it up.
> 
> > Signed-off-by: Wu Zhangjin <wuzhangjin@xxxxxxxxx>
> 
> [...]
> 
> > diff --git a/arch/mips/kernel/mcount.S b/arch/mips/kernel/mcount.S
> > index 0c39bc8..5dfaca8 100644
> > --- a/arch/mips/kernel/mcount.S
> > +++ b/arch/mips/kernel/mcount.S
> > @@ -64,6 +64,10 @@
> >  	.endm
> >  
> >  NESTED(_mcount, PT_SIZE, ra)
> > +	lw	t0, function_trace_stop
> > +	bnez	t0, ftrace_stub
> > +	nop
> 
> 1) unless .set noreorder is specified in this file, explicit nop is not needed;

>From patch 4:

+++ b/arch/mips/kernel/mcount.S
@@ -0,0 +1,89 @@
+/*
+ * MIPS specific _mcount support
+ *
+ * This file is subject to the terms and conditions of the GNU General
Public
+ * License.  See the file "COPYING" in the main directory of this
archive for
+ * more details.
+ *
+ * Copyright (C) 2009 Lemote Inc. & DSLab, Lanzhou University, China
+ * Author: Wu Zhangjin <wuzj@xxxxxxxxxx>
+ */
+
+#include <asm/regdef.h>
+#include <asm/stackframe.h>
+#include <asm/ftrace.h>
+
+       .text
+       .set noreorder
+       .set noat

-- Steve

> 
> 2) delay slot instruction is usually denoted by adding extra space on its 
> left, like this:
> 
> 	bnez	t0, ftrace_stub
> 	 nop




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/