Commit 46bc0823 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google) Committed by Steven Rostedt (Google)
Browse files

fprobe: Use ftrace_regs in fprobe entry handler 

This allows fprobes to be available with CONFIG_DYNAMIC_FTRACE_WITH_ARGS
instead of CONFIG_DYNAMIC_FTRACE_WITH_REGS, then we can enable fprobe
on arm64.

Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
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>
Link: https://lore.kernel.org/173518994037.391279.2786805566359674586.stgit@devnote2


Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: default avatarFlorent Revest <revest@chromium.org>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent 2ca8c112

include/linux/fprobe.h

+1 −1
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ 
struct fprobe;



typedef int (*fprobe_entry_cb)(struct fprobe *fp, unsigned long entry_ip,

			       unsigned long ret_ip, struct pt_regs *regs,

			       unsigned long ret_ip, struct ftrace_regs *regs,

			       void *entry_data);



typedef void (*fprobe_exit_cb)(struct fprobe *fp, unsigned long entry_ip,

kernel/trace/Kconfig

+2 −1
Original line number Diff line number Diff line
@@ -297,7 +297,7 @@ config DYNAMIC_FTRACE_WITH_ARGS 
config FPROBE

	bool "Kernel Function Probe (fprobe)"

	depends on FUNCTION_TRACER

	depends on DYNAMIC_FTRACE_WITH_REGS

	depends on DYNAMIC_FTRACE_WITH_REGS || DYNAMIC_FTRACE_WITH_ARGS

	depends on HAVE_RETHOOK

	select RETHOOK

	default n
@@ -682,6 +682,7 @@ config FPROBE_EVENTS 
	select TRACING

	select PROBE_EVENTS

	select DYNAMIC_EVENTS

	depends on DYNAMIC_FTRACE_WITH_REGS

	default y

	help

	  This allows user to add tracing events on the function entry and

kernel/trace/bpf_trace.c

+7 −3
Original line number Diff line number Diff line
@@ -2561,7 +2561,7 @@ struct bpf_session_run_ctx { 
	void *data;

};



#ifdef CONFIG_FPROBE

#if defined(CONFIG_FPROBE) && defined(CONFIG_DYNAMIC_FTRACE_WITH_REGS)

struct bpf_kprobe_multi_link {

	struct bpf_link link;

	struct fprobe fp;
@@ -2813,12 +2813,16 @@ kprobe_multi_link_prog_run(struct bpf_kprobe_multi_link *link, 


static int

kprobe_multi_link_handler(struct fprobe *fp, unsigned long fentry_ip,

			  unsigned long ret_ip, struct pt_regs *regs,

			  unsigned long ret_ip, struct ftrace_regs *fregs,

			  void *data)

{

	struct pt_regs *regs = ftrace_get_regs(fregs);

	struct bpf_kprobe_multi_link *link;

	int err;



	if (!regs)

		return 0;



	link = container_of(fp, struct bpf_kprobe_multi_link, fp);

	err = kprobe_multi_link_prog_run(link, get_entry_ip(fentry_ip), regs, false, data);

	return is_kprobe_session(link->link.prog) ? err : 0;
@@ -3093,7 +3097,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr 
	kvfree(cookies);

	return err;

}

#else /* !CONFIG_FPROBE */

#else /* !CONFIG_FPROBE || !CONFIG_DYNAMIC_FTRACE_WITH_REGS */

int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)

{

	return -EOPNOTSUPP;

kernel/trace/fprobe.c

+2 −1
Original line number Diff line number Diff line
@@ -46,7 +46,7 @@ static inline void __fprobe_handler(unsigned long ip, unsigned long parent_ip, 
	}



	if (fp->entry_handler)

		ret = fp->entry_handler(fp, ip, parent_ip, ftrace_get_regs(fregs), entry_data);

		ret = fp->entry_handler(fp, ip, parent_ip, fregs, entry_data);



	/* If entry_handler returns !0, nmissed is not counted. */

	if (rh) {
@@ -182,6 +182,7 @@ static void fprobe_init(struct fprobe *fp) 
		fp->ops.func = fprobe_kprobe_handler;

	else

		fp->ops.func = fprobe_handler;



	fp->ops.flags |= FTRACE_OPS_FL_SAVE_REGS;

}

kernel/trace/trace_fprobe.c

+8 −3
Original line number Diff line number Diff line
@@ -217,12 +217,13 @@ NOKPROBE_SYMBOL(fentry_trace_func); 


/* function exit handler */

static int trace_fprobe_entry_handler(struct fprobe *fp, unsigned long entry_ip,

				unsigned long ret_ip, struct pt_regs *regs,

				unsigned long ret_ip, struct ftrace_regs *fregs,

				void *entry_data)

{

	struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);

	struct pt_regs *regs = ftrace_get_regs(fregs);



	if (tf->tp.entry_arg)

	if (regs && tf->tp.entry_arg)

		store_trace_entry_data(entry_data, &tf->tp, regs);



	return 0;
@@ -339,12 +340,16 @@ NOKPROBE_SYMBOL(fexit_perf_func); 
#endif	/* CONFIG_PERF_EVENTS */



static int fentry_dispatcher(struct fprobe *fp, unsigned long entry_ip,

			     unsigned long ret_ip, struct pt_regs *regs,

			     unsigned long ret_ip, struct ftrace_regs *fregs,

			     void *entry_data)

{

	struct trace_fprobe *tf = container_of(fp, struct trace_fprobe, fp);

	struct pt_regs *regs = ftrace_get_regs(fregs);

	int ret = 0;



	if (!regs)

		return 0;



	if (trace_probe_test_flag(&tf->tp, TP_FLAG_TRACE))

		fentry_trace_func(tf, entry_ip, regs);

#ifdef CONFIG_PERF_EVENTS