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Commit 1e9b14c0 authored by Zong Li's avatar Zong Li Committed by Greentime Hu
Browse files

nds32/ftrace: Support static function graph tracer 



This patch contains implementation of static function graph tracer.

Signed-off-by: default avatarZong Li <zong@andestech.com>
Acked-by: default avatarGreentime Hu <greentime@andestech.com>
Signed-off-by: default avatarGreentime Hu <greentime@andestech.com>
parent a1808257

arch/nds32/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -41,6 +41,7 @@ config NDS32 
	select RTC_LIB

	select THREAD_INFO_IN_TASK

	select HAVE_FUNCTION_TRACER

	select HAVE_FUNCTION_GRAPH_TRACER

	help

	  Andes(nds32) Linux support.

arch/nds32/kernel/ftrace.c

+69 −0
Original line number Diff line number Diff line
@@ -6,6 +6,8 @@ 


extern void (*ftrace_trace_function)(unsigned long, unsigned long,

				     struct ftrace_ops*, struct pt_regs*);

extern int ftrace_graph_entry_stub(struct ftrace_graph_ent *trace);

extern void ftrace_graph_caller(void);



noinline void __naked ftrace_stub(unsigned long ip, unsigned long parent_ip,

				  struct ftrace_ops *op, struct pt_regs *regs)
@@ -23,6 +25,73 @@ noinline void _mcount(unsigned long parent_ip) 
		ftrace_trace_function(ip - MCOUNT_INSN_SIZE, parent_ip,

				      NULL, NULL);



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	if (ftrace_graph_return != (trace_func_graph_ret_t)ftrace_stub

	    || ftrace_graph_entry != ftrace_graph_entry_stub)

		ftrace_graph_caller();

#endif



	/* restore all state by the compiler epilogue */

}

EXPORT_SYMBOL(_mcount);



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

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

			   unsigned long frame_pointer)

{

	unsigned long return_hooker = (unsigned long)&return_to_handler;

	struct ftrace_graph_ent trace;

	unsigned long old;

	int err;



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

		return;



	old = *parent;



	trace.func = self_addr;

	trace.depth = current->curr_ret_stack + 1;



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

	if (!ftrace_graph_entry(&trace))

		return;



	err = ftrace_push_return_trace(old, self_addr, &trace.depth,

				       frame_pointer, NULL);



	if (err == -EBUSY)

		return;



	*parent = return_hooker;

}



noinline void ftrace_graph_caller(void)

{

	unsigned long *parent_ip =

		(unsigned long *)(__builtin_frame_address(2) - 4);



	unsigned long selfpc =

		(unsigned long)(__builtin_return_address(1) - MCOUNT_INSN_SIZE);



	unsigned long frame_pointer =

		(unsigned long)__builtin_frame_address(3);



	prepare_ftrace_return(parent_ip, selfpc, frame_pointer);

}



extern unsigned long ftrace_return_to_handler(unsigned long frame_pointer);

void __naked return_to_handler(void)

{

	__asm__ __volatile__ (

		/* save state needed by the ABI     */

		"smw.adm $r0,[$sp],$r1,#0x0  \n\t"



		/* get original return address      */

		"move $r0, $fp               \n\t"

		"bal ftrace_return_to_handler\n\t"

		"move $lp, $r0               \n\t"



		/* restore state nedded by the ABI  */

		"lmw.bim $r0,[$sp],$r1,#0x0  \n\t");

}

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */