Commit 96d7a136 authored by Naveen N Rao's avatar Naveen N Rao Committed by Michael Ellerman
Browse files

powerpc/ftrace: Simplify function_graph support in ftrace.c 



Since we now support DYNAMIC_FTRACE_WITH_ARGS across ppc32 and ppc64
ELFv2, we can simplify function_graph tracer support code in ftrace.c

Signed-off-by: default avatarNaveen N Rao <naveen@kernel.org>
Reviewed-by: default avatarChristophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/4dc92c4b1ed444dc62b748ae7327acdb9e096864.1687166935.git.naveen@kernel.org
parent 7f7797b3

arch/powerpc/kernel/trace/ftrace.c

+7 −57
Original line number Diff line number Diff line
@@ -790,44 +790,10 @@ int __init ftrace_dyn_arch_init(void) 
#endif



#ifdef CONFIG_FUNCTION_GRAPH_TRACER



extern void ftrace_graph_call(void);

extern void ftrace_graph_stub(void);



static int ftrace_modify_ftrace_graph_caller(bool enable)

{

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

	unsigned long addr = (unsigned long)(&ftrace_graph_caller);

	unsigned long stub = (unsigned long)(&ftrace_graph_stub);

	ppc_inst_t old, new;



	if (IS_ENABLED(CONFIG_DYNAMIC_FTRACE_WITH_ARGS))

		return 0;



	old = ftrace_call_replace(ip, enable ? stub : addr, 0);

	new = ftrace_call_replace(ip, enable ? addr : stub, 0);



	return ftrace_modify_code(ip, old, new);

}



int ftrace_enable_ftrace_graph_caller(void)

{

	return ftrace_modify_ftrace_graph_caller(true);

}



int ftrace_disable_ftrace_graph_caller(void)

{

	return ftrace_modify_ftrace_graph_caller(false);

}



/*

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

 * in current thread info. Return the address we want to divert to.

 */

static unsigned long

__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp)

void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,

		       struct ftrace_ops *op, struct ftrace_regs *fregs)

{

	unsigned long return_hooker;

	unsigned long sp = fregs->regs.gpr[1];

	int bit;



	if (unlikely(ftrace_graph_is_dead()))
@@ -836,31 +802,15 @@ __prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp 
	if (unlikely(atomic_read(&current->tracing_graph_pause)))

		goto out;



	bit = ftrace_test_recursion_trylock(ip, parent);

	bit = ftrace_test_recursion_trylock(ip, parent_ip);

	if (bit < 0)

		goto out;



	return_hooker = ppc_function_entry(return_to_handler);



	if (!function_graph_enter(parent, ip, 0, (unsigned long *)sp))

		parent = return_hooker;

	if (!function_graph_enter(parent_ip, ip, 0, (unsigned long *)sp))

		parent_ip = ppc_function_entry(return_to_handler);



	ftrace_test_recursion_unlock(bit);

out:

	return parent;

	fregs->regs.link = parent_ip;

}



#ifdef CONFIG_DYNAMIC_FTRACE_WITH_ARGS

void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,

		       struct ftrace_ops *op, struct ftrace_regs *fregs)

{

	fregs->regs.link = __prepare_ftrace_return(parent_ip, ip, fregs->regs.gpr[1]);

}

#else

unsigned long prepare_ftrace_return(unsigned long parent, unsigned long ip,

				    unsigned long sp)

{

	return __prepare_ftrace_return(parent, ip, sp);

}

#endif

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */