Commit e342d6f6 authored by Benjamin Tissoires's avatar Benjamin Tissoires
Browse files

HID: samples: convert the 2 HID-BPF samples into struct_ops 

This is mostly mechanical: attach_prog is dropped, and
the SEC are converted into struct_ops.

Link: https://lore.kernel.org/r/20240608-hid_bpf_struct_ops-v3-5-6ac6ade58329@kernel.org


Signed-off-by: default avatarBenjamin Tissoires <bentiss@kernel.org>
parent d7696738

samples/hid/Makefile

+2 −3
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ LIBBPF_DESTDIR = $(LIBBPF_OUTPUT) 
LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include

LIBBPF = $(LIBBPF_OUTPUT)/libbpf.a



EXTRA_HEADERS := hid_bpf_attach.h

EXTRA_BPF_HEADERS := hid_bpf_helpers.h



hid_mouse-objs := hid_mouse.o
@@ -207,8 +206,8 @@ $(obj)/%.bpf.o: $(src)/%.bpf.c $(EXTRA_BPF_HEADERS_SRC) $(obj)/vmlinux.h 
LINKED_SKELS := hid_mouse.skel.h hid_surface_dial.skel.h

clean-files += $(LINKED_SKELS)



hid_mouse.skel.h-deps := hid_mouse.bpf.o hid_bpf_attach.bpf.o

hid_surface_dial.skel.h-deps := hid_surface_dial.bpf.o hid_bpf_attach.bpf.o

hid_mouse.skel.h-deps := hid_mouse.bpf.o

hid_surface_dial.skel.h-deps := hid_surface_dial.bpf.o



LINKED_BPF_SRCS := $(patsubst %.bpf.o,%.bpf.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps)))

samples/hid/hid_bpf_attach.bpf.c

deleted100644 → 0
+0 −18
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0-only

/* Copyright (c) 2022 Benjamin Tissoires

 */



#include "vmlinux.h"

#include <bpf/bpf_helpers.h>

#include <bpf/bpf_tracing.h>

#include "hid_bpf_attach.h"

#include "hid_bpf_helpers.h"



SEC("syscall")

int attach_prog(struct attach_prog_args *ctx)

{

	ctx->retval = hid_bpf_attach_prog(ctx->hid,

					  ctx->prog_fd,

					  0);

	return 0;

}

samples/hid/hid_bpf_attach.h

deleted100644 → 0
+0 −14
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

/* Copyright (c) 2022 Benjamin Tissoires

 */



#ifndef __HID_BPF_ATTACH_H

#define __HID_BPF_ATTACH_H



struct attach_prog_args {

	int prog_fd;

	unsigned int hid;

	int retval;

};



#endif /* __HID_BPF_ATTACH_H */

samples/hid/hid_mouse.bpf.c

+21 −5
Original line number Diff line number Diff line
@@ -5,8 +5,7 @@ 
#include <bpf/bpf_tracing.h>

#include "hid_bpf_helpers.h"



SEC("fmod_ret/hid_bpf_device_event")

int BPF_PROG(hid_y_event, struct hid_bpf_ctx *hctx)

static int hid_y_event(struct hid_bpf_ctx *hctx)

{

	s16 y;

	__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */);
@@ -51,8 +50,7 @@ int BPF_PROG(hid_y_event, struct hid_bpf_ctx *hctx) 
	return 0;

}



SEC("fmod_ret/hid_bpf_device_event")

int BPF_PROG(hid_x_event, struct hid_bpf_ctx *hctx)

static int hid_x_event(struct hid_bpf_ctx *hctx)

{

	s16 x;

	__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */);
@@ -69,7 +67,19 @@ int BPF_PROG(hid_x_event, struct hid_bpf_ctx *hctx) 
	return 0;

}



SEC("fmod_ret/hid_bpf_rdesc_fixup")

SEC("struct_ops/device_event")

int BPF_PROG(hid_event, struct hid_bpf_ctx *hctx, enum hid_report_type type)

{

	int ret = hid_y_event(hctx);



	if (ret)

		return ret;



	return hid_x_event(hctx);

}





SEC("struct_ops/rdesc_fixup")

int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx)

{

	__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 4096 /* size */);
@@ -109,4 +119,10 @@ int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx) 
	return 0;

}



SEC(".struct_ops.link")

struct hid_bpf_ops mouse_invert = {

	.rdesc_fixup = (void *)hid_rdesc_fixup,

	.device_event = (void *)hid_event,

};



char _license[] SEC("license") = "GPL";

samples/hid/hid_mouse.c

+11 −28
Original line number Diff line number Diff line
@@ -29,7 +29,6 @@ 
#include <bpf/libbpf.h>



#include "hid_mouse.skel.h"

#include "hid_bpf_attach.h"



static bool running = true;
@@ -76,18 +75,11 @@ static int get_hid_id(const char *path) 
int main(int argc, char **argv)

{

	struct hid_mouse *skel;

	struct bpf_program *prog;

	struct bpf_link *link;

	int err;

	const char *optstr = "";

	const char *sysfs_path;

	int opt, hid_id, attach_fd;

	struct attach_prog_args args = {

		.retval = -1,

	};

	DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,

			    .ctx_in = &args,

			    .ctx_size_in = sizeof(args),

	);

	int opt, hid_id;



	while ((opt = getopt(argc, argv, optstr)) != -1) {

		switch (opt) {
@@ -108,7 +100,7 @@ int main(int argc, char **argv) 
		return 1;

	}



	skel = hid_mouse__open_and_load();

	skel = hid_mouse__open();

	if (!skel) {

		fprintf(stderr, "%s  %s:%d", __func__, __FILE__, __LINE__);

		return -1;
@@ -120,28 +112,19 @@ int main(int argc, char **argv) 
		fprintf(stderr, "can not open HID device: %m\n");

		return 1;

	}

	args.hid = hid_id;

	skel->struct_ops.mouse_invert->hid_id = hid_id;



	attach_fd = bpf_program__fd(skel->progs.attach_prog);

	if (attach_fd < 0) {

		fprintf(stderr, "can't locate attach prog: %m\n");

	err = hid_mouse__load(skel);

	if (err < 0) {

		fprintf(stderr, "can not load HID-BPF program: %m\n");

		return 1;

	}



	bpf_object__for_each_program(prog, *skel->skeleton->obj) {

		/* ignore syscalls */

		if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING)

			continue;



		args.retval = -1;

		args.prog_fd = bpf_program__fd(prog);

		err = bpf_prog_test_run_opts(attach_fd, &tattr);

		if (err) {

			fprintf(stderr, "can't attach prog to hid device %d: %m (err: %d)\n",

				hid_id, err);

	link = bpf_map__attach_struct_ops(skel->maps.mouse_invert);

	if (!link) {

		fprintf(stderr, "can not attach HID-BPF program: %m\n");

		return 1;

	}

	}



	signal(SIGINT, int_exit);

	signal(SIGTERM, int_exit);