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Commit 1ee76d7e authored by Mike Frysinger's avatar Mike Frysinger
Browse files

Blackfin: initial support for ftrace grapher 



Signed-off-by: default avatarMike Frysinger <vapier@gentoo.org>
parent 1c873be7

arch/blackfin/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ config RWSEM_XCHGADD_ALGORITHM 


config BLACKFIN

	def_bool y

	select HAVE_FUNCTION_GRAPH_TRACER

	select HAVE_FUNCTION_TRACER

	select HAVE_IDE

	select HAVE_KERNEL_GZIP

arch/blackfin/kernel/Makefile

+3 −0
Original line number Diff line number Diff line
@@ -16,6 +16,9 @@ else 
endif



obj-$(CONFIG_FUNCTION_TRACER)        += ftrace-entry.o

obj-$(CONFIG_FUNCTION_GRAPH_TRACER)  += ftrace.o

CFLAGS_REMOVE_ftrace.o = -pg



obj-$(CONFIG_IPIPE)                  += ipipe.o

obj-$(CONFIG_IPIPE_TRACE_MCOUNT)     += mcount.o

obj-$(CONFIG_BFIN_GPTIMERS)          += gptimers.o

arch/blackfin/kernel/ftrace-entry.S

+68 −0
Original line number Diff line number Diff line
@@ -35,6 +35,28 @@ ENTRY(__mcount) 
	cc = r2 == r3;

	if ! cc jump .Ldo_trace;



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	/* if the ftrace_graph_return function pointer is not set to

	 * the ftrace_stub entry, call prepare_ftrace_return().

	 */

	p0.l = _ftrace_graph_return;

	p0.h = _ftrace_graph_return;

	r3 = [p0];

	cc = r2 == r3;

	if ! cc jump _ftrace_graph_caller;



	/* similarly, if the ftrace_graph_entry function pointer is not

	 * set to the ftrace_graph_entry_stub entry, ...

	 */

	p0.l = _ftrace_graph_entry;

	p0.h = _ftrace_graph_entry;

	r2.l = _ftrace_graph_entry_stub;

	r2.h = _ftrace_graph_entry_stub;

	r3 = [p0];

	cc = r2 == r3;

	if ! cc jump _ftrace_graph_caller;

#endif



	r2 = [sp++];

	rts;
@@ -61,6 +83,7 @@ ENTRY(__mcount) 
	call (p0);



	/* restore state and get out of dodge */

.Lfinish_trace:

	rets = [sp++];

	r1 = [sp++];

	r0 = [sp++];
@@ -70,3 +93,48 @@ ENTRY(__mcount) 
_ftrace_stub:

	rts;

ENDPROC(__mcount)



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

/* The prepare_ftrace_return() function is similar to the trace function

 * except it takes a pointer to the location of the frompc.  This is so

 * the prepare_ftrace_return() can hijack it temporarily for probing

 * purposes.

 */

ENTRY(_ftrace_graph_caller)

	/* save first/second function arg and the return register */

	[--sp] = r0;

	[--sp] = r1;

	[--sp] = rets;



	r0 = fp;

	r1 = rets;

	r0 += 4;

	r1 += -MCOUNT_INSN_SIZE;

	call _prepare_ftrace_return;



	jump .Lfinish_trace;

ENDPROC(_ftrace_graph_caller)



/* Undo the rewrite caused by ftrace_graph_caller().  The common function

 * ftrace_return_to_handler() will return the original rets so we can

 * restore it and be on our way.

 */

ENTRY(_return_to_handler)

	/* make sure original return values are saved */

	[--sp] = p0;

	[--sp] = r0;

	[--sp] = r1;



	/* get original return address */

	call _ftrace_return_to_handler;

	rets = r0;



	/* anomaly 05000371 - make sure we have at least three instructions

	 * between rets setting and the return

	 */

	r1 = [sp++];

	r0 = [sp++];

	p0 = [sp++];

	rts;

ENDPROC(_return_to_handler)

#endif

arch/blackfin/kernel/ftrace.c

0 → 100644
+42 −0
Original line number Diff line number Diff line 
/*

 * ftrace graph code

 *

 * Copyright (C) 2009 Analog Devices Inc.

 * Licensed under the GPL-2 or later.

 */



#include <linux/ftrace.h>

#include <linux/kernel.h>

#include <linux/sched.h>

#include <asm/atomic.h>



#ifdef CONFIG_FUNCTION_GRAPH_TRACER



/*

 * Hook the return address and push it in the stack of return addrs

 * in current thread info.

 */

void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr)

{

	struct ftrace_graph_ent trace;

	unsigned long return_hooker = (unsigned long)&return_to_handler;



	if (unlikely(atomic_read(&current->tracing_graph_pause)))

		return;



	if (ftrace_push_return_trace(*parent, self_addr, &trace.depth) == -EBUSY)

		return;



	trace.func = self_addr;



	/* Only trace if the calling function expects to */

	if (!ftrace_graph_entry(&trace)) {

		current->curr_ret_stack--;

		return;

	}



	/* all is well in the world !  hijack RETS ... */

	*parent = return_hooker;

}



#endif

arch/blackfin/kernel/vmlinux.lds.S

+1 −0
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ SECTIONS 
		SCHED_TEXT

#endif

		LOCK_TEXT

		IRQENTRY_TEXT

		KPROBES_TEXT

		*(.text.*)

		*(.fixup)