Commit d576aec2 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google) Committed by Steven Rostedt (Google)
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fgraph: Get ftrace recursion lock in function_graph_enter 

Get the ftrace recursion lock in the generic function_graph_enter()
instead of each architecture code.
This changes all function_graph tracer callbacks running in
non-preemptive state. On x86 and powerpc, this is by default, but
on the other architecutres, this will be new.

Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://lore.kernel.org/173379653720.973433.18438622234884980494.stgit@devnote2


Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 1d95fd9d

arch/powerpc/kernel/trace/ftrace.c

+0 −6
Original line number Diff line number Diff line
@@ -658,7 +658,6 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, 
		       struct ftrace_ops *op, struct ftrace_regs *fregs)

{

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

	int bit;



	if (unlikely(ftrace_graph_is_dead()))

		goto out;
@@ -666,14 +665,9 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, 
	if (unlikely(atomic_read(&current->tracing_graph_pause)))

		goto out;



	bit = ftrace_test_recursion_trylock(ip, parent_ip);

	if (bit < 0)

		goto out;



	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:

	arch_ftrace_regs(fregs)->regs.link = parent_ip;

}

arch/powerpc/kernel/trace/ftrace_64_pg.c

+0 −6
Original line number Diff line number Diff line
@@ -790,7 +790,6 @@ static unsigned long 
__prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp)

{

	unsigned long return_hooker;

	int bit;



	if (unlikely(ftrace_graph_is_dead()))

		goto out;
@@ -798,16 +797,11 @@ __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);

	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;



	ftrace_test_recursion_unlock(bit);

out:

	return parent;

}

arch/x86/kernel/ftrace.c

+0 −7
Original line number Diff line number Diff line
@@ -615,7 +615,6 @@ void prepare_ftrace_return(unsigned long ip, unsigned long *parent, 
			   unsigned long frame_pointer)

{

	unsigned long return_hooker = (unsigned long)&return_to_handler;

	int bit;



	/*

	 * When resuming from suspend-to-ram, this function can be indirectly
@@ -635,14 +634,8 @@ void prepare_ftrace_return(unsigned long ip, unsigned long *parent, 
	if (unlikely(atomic_read(&current->tracing_graph_pause)))

		return;



	bit = ftrace_test_recursion_trylock(ip, *parent);

	if (bit < 0)

		return;



	if (!function_graph_enter(*parent, ip, frame_pointer, parent))

		*parent = return_hooker;



	ftrace_test_recursion_unlock(bit);

}



#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS

kernel/trace/fgraph.c

+7 −1
Original line number Diff line number Diff line
@@ -650,8 +650,13 @@ int function_graph_enter(unsigned long ret, unsigned long func, 
	struct ftrace_graph_ent trace;

	unsigned long bitmap = 0;

	int offset;

	int bit;

	int i;



	bit = ftrace_test_recursion_trylock(func, ret);

	if (bit < 0)

		return -EBUSY;



	trace.func = func;

	trace.depth = ++current->curr_ret_depth;
@@ -697,12 +702,13 @@ int function_graph_enter(unsigned long ret, unsigned long func, 
	 * flag, set that bit always.

	 */

	set_bitmap(current, offset, bitmap | BIT(0));



	ftrace_test_recursion_unlock(bit);

	return 0;

 out_ret:

	current->curr_ret_stack -= FGRAPH_FRAME_OFFSET + 1;

 out:

	current->curr_ret_depth--;

	ftrace_test_recursion_unlock(bit);

	return -EBUSY;

}