Commit 98f29261 authored by Sven Schnelle's avatar Sven Schnelle Committed by Helge Deller
Browse files

parisc/ftrace: use static key to enable/disable function graph tracer 



This avoids using dereference_function_descriptor in the ftrace code
path, and it's also faster.

Signed-off-by: default avatarSven Schnelle <svens@stackframe.org>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
parent 44382af8

arch/parisc/kernel/ftrace.c

+6 −3
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ 
#include <linux/uaccess.h>

#include <linux/kprobes.h>

#include <linux/ptrace.h>

#include <linux/jump_label.h>



#include <asm/assembly.h>

#include <asm/sections.h>
@@ -24,6 +25,8 @@ 
#define __hot __section(".text.hot")



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

static DEFINE_STATIC_KEY_FALSE(ftrace_graph_enable);



/*

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

 * in current thread info.
@@ -60,9 +63,7 @@ void notrace __hot ftrace_function_trampoline(unsigned long parent, 
	ftrace_func(self_addr, parent, function_trace_op, fregs);



#ifdef CONFIG_FUNCTION_GRAPH_TRACER

	if (dereference_function_descriptor(ftrace_graph_return) !=

	    dereference_function_descriptor(ftrace_stub) ||

	    ftrace_graph_entry != ftrace_graph_entry_stub) {

	if (static_branch_unlikely(&ftrace_graph_enable)) {

		unsigned long *parent_rp;



		/* calculate pointer to %rp in stack */
@@ -80,11 +81,13 @@ void notrace __hot ftrace_function_trampoline(unsigned long parent, 
#ifdef CONFIG_FUNCTION_GRAPH_TRACER

int ftrace_enable_ftrace_graph_caller(void)

{

	static_key_enable(&ftrace_graph_enable.key);

	return 0;

}



int ftrace_disable_ftrace_graph_caller(void)

{

	static_key_enable(&ftrace_graph_enable.key);

	return 0;

}

#endif