Commit 41705c42 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google) Committed by Steven Rostedt (Google)
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fgraph: Pass ftrace_regs to entryfunc 



Pass ftrace_regs to the fgraph_ops::entryfunc(). If ftrace_regs is not
available, it passes a NULL instead. User callback function can access
some registers (including return address) via this ftrace_regs.

Note that the ftrace_regs can be NULL when the arch does NOT define:
HAVE_DYNAMIC_FTRACE_WITH_ARGS or HAVE_DYNAMIC_FTRACE_WITH_REGS.
More specifically, if HAVE_DYNAMIC_FTRACE_WITH_REGS is defined but
not the HAVE_DYNAMIC_FTRACE_WITH_ARGS, and the ftrace ops used to
register the function callback does not set FTRACE_OPS_FL_SAVE_REGS.
In this case, ftrace_regs can be NULL in user callback.

Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
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: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
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: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
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/173518990044.391279.17406984900626078579.stgit@devnote2


Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent d576aec2

arch/arm64/kernel/ftrace.c

+14 −1
Original line number Diff line number Diff line
@@ -481,7 +481,20 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, 
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,

		       struct ftrace_ops *op, struct ftrace_regs *fregs)

{

	prepare_ftrace_return(ip, &arch_ftrace_regs(fregs)->lr, arch_ftrace_regs(fregs)->fp);

	unsigned long return_hooker = (unsigned long)&return_to_handler;

	unsigned long frame_pointer = arch_ftrace_regs(fregs)->fp;

	unsigned long *parent = &arch_ftrace_regs(fregs)->lr;

	unsigned long old;



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

		return;



	old = *parent;



	if (!function_graph_enter_regs(old, ip, frame_pointer,

				       (void *)frame_pointer, fregs)) {

		*parent = return_hooker;

	}

}

#else

/*

arch/loongarch/kernel/ftrace_dyn.c

+9 −1
Original line number Diff line number Diff line
@@ -243,8 +243,16 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, 
{

	struct pt_regs *regs = &arch_ftrace_regs(fregs)->regs;

	unsigned long *parent = (unsigned long *)&regs->regs[1];

	unsigned long return_hooker = (unsigned long)&return_to_handler;

	unsigned long old;



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

		return;



	old = *parent;



	prepare_ftrace_return(ip, (unsigned long *)parent);

	if (!function_graph_enter_regs(old, ip, 0, parent, fregs))

		*parent = return_hooker;

}

#else

static int ftrace_modify_graph_caller(bool enable)

arch/powerpc/kernel/trace/ftrace.c

+1 −1
Original line number Diff line number Diff line
@@ -665,7 +665,7 @@ void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, 
	if (unlikely(atomic_read(&current->tracing_graph_pause)))

		goto out;



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

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

		parent_ip = ppc_function_entry(return_to_handler);



out:

arch/powerpc/kernel/trace/ftrace_64_pg.c

+6 −4
Original line number Diff line number Diff line
@@ -787,7 +787,8 @@ int ftrace_disable_ftrace_graph_caller(void) 
 * 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)

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

			struct ftrace_regs *fregs)

{

	unsigned long return_hooker;
@@ -799,7 +800,7 @@ __prepare_ftrace_return(unsigned long parent, unsigned long ip, unsigned long sp 


	return_hooker = ppc_function_entry(return_to_handler);



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

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

		parent = return_hooker;



out:
@@ -810,13 +811,14 @@ __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)

{

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

	arch_ftrace_regs(fregs)->regs.link = __prepare_ftrace_return(parent_ip, ip,

						arch_ftrace_regs(fregs)->regs.gpr[1], fregs);

}

#else

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

				    unsigned long sp)

{

	return __prepare_ftrace_return(parent, ip, sp);

	return __prepare_ftrace_return(parent, ip, sp, NULL);

}

#endif

#endif /* CONFIG_FUNCTION_GRAPH_TRACER */

arch/riscv/kernel/ftrace.c

+16 −1
Original line number Diff line number Diff line
@@ -214,7 +214,22 @@ void prepare_ftrace_return(unsigned long *parent, unsigned long self_addr, 
void ftrace_graph_func(unsigned long ip, unsigned long parent_ip,

		       struct ftrace_ops *op, struct ftrace_regs *fregs)

{

	prepare_ftrace_return(&arch_ftrace_regs(fregs)->ra, ip, arch_ftrace_regs(fregs)->s0);

	unsigned long return_hooker = (unsigned long)&return_to_handler;

	unsigned long frame_pointer = arch_ftrace_regs(fregs)->s0;

	unsigned long *parent = &arch_ftrace_regs(fregs)->ra;

	unsigned long old;



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

		return;



	/*

	 * We don't suffer access faults, so no extra fault-recovery assembly

	 * is needed here.

	 */

	old = *parent;



	if (!function_graph_enter_regs(old, ip, frame_pointer, parent, fregs))

		*parent = return_hooker;

}

#else /* CONFIG_DYNAMIC_FTRACE_WITH_ARGS */

extern void ftrace_graph_call(void);