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Commit 4f911b0d authored by Michal Simek's avatar Michal Simek
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microblaze: ftrace: Add dynamic function graph tracer 



This patch add support for dynamic function graph tracer.

There is one my expactation that I can do flush_icache after
all code modification. On microblaze is this safer than do
flush for every entry. For icache is used name flush but
correct should be invalidation - this will be fix in upcomming
new cache implementaion and WB support.

Signed-off-by: default avatarMichal Simek <monstr@monstr.eu>
parent a0d3e665

arch/microblaze/kernel/ftrace.c

+28 −0
Original line number Diff line number Diff line
@@ -206,4 +206,32 @@ int ftrace_update_ftrace_func(ftrace_func_t func) 
	return ret;

}



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

unsigned int old_jump; /* saving place for jump instruction */



int ftrace_enable_ftrace_graph_caller(void)

{

	unsigned int ret;

	unsigned long ip = (unsigned long)(&ftrace_call_graph);



	old_jump = *(unsigned int *)ip; /* save jump over instruction */

	ret = ftrace_modify_code(ip, MICROBLAZE_NOP);

	flush_icache();



	pr_debug("%s: Replace instruction: 0x%x\n", __func__, old_jump);

	return ret;

}



int ftrace_disable_ftrace_graph_caller(void)

{

	unsigned int ret;

	unsigned long ip = (unsigned long)(&ftrace_call_graph);



	ret = ftrace_modify_code(ip, old_jump);

	flush_icache();



	pr_debug("%s\n", __func__);

	return ret;

}

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

#endif /* CONFIG_DYNAMIC_FTRACE */

arch/microblaze/kernel/mcount.S

+6 −0
Original line number Diff line number Diff line
@@ -97,6 +97,7 @@ ENTRY(ftrace_caller) 
	nop;

	/* MS: HAVE_FUNCTION_TRACE_MCOUNT_TEST end of checking */

#ifdef CONFIG_FUNCTION_GRAPH_TRACER

#ifndef CONFIG_DYNAMIC_FTRACE

	lwi	r5, r0, ftrace_graph_return;

	addik	r6, r0, ftrace_stub; /* asm implementation */

	cmpu	r5, r5, r6; /* ftrace_graph_return != ftrace_stub */
@@ -108,6 +109,11 @@ ENTRY(ftrace_caller) 
	cmpu	r5, r5, r6; /* ftrace_graph_entry != ftrace_graph_entry_stub */

	beqid	r5, end_graph_tracer;

	nop;

#else /* CONFIG_DYNAMIC_FTRACE */

NOALIGN_ENTRY(ftrace_call_graph)

	/* MS: jump over graph function - replaced from C code */

	bri	end_graph_tracer

#endif /* CONFIG_DYNAMIC_FTRACE */

	addik	r5, r1, 120; /* MS: load parent addr */

	addik	r6, r15, 0; /* MS: load current function addr */

	bralid	r15, prepare_ftrace_return;