[PATCH HID v2 05/16] HID: samples: convert the 2 HID-BPF samples into struct_ops

Benjamin Tissoires
2024-06-07T15:28:44Z

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

Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>

---

no changes in v2 but the commit message.
---
samples/hid/Makefile | 5 ++--
samples/hid/hid_bpf_attach.bpf.c | 18 -------------
samples/hid/hid_bpf_attach.h | 14 ----------
samples/hid/hid_mouse.bpf.c | 26 +++++++++++++++----
samples/hid/hid_mouse.c | 39 ++++++++--------------------
samples/hid/hid_surface_dial.bpf.c | 10 +++++--
samples/hid/hid_surface_dial.c | 53 +++++++++++---------------------------
7 files changed, 57 insertions(+), 108 deletions(-)

diff --git a/samples/hid/Makefile b/samples/hid/Makefile
index c128ccd49974..8ea59e9631a3 100644
--- a/samples/hid/Makefile
+++ b/samples/hid/Makefile
@@ -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)))

diff --git a/samples/hid/hid_bpf_attach.bpf.c b/samples/hid/hid_bpf_attach.bpf.c
deleted file mode 100644
index d4dce4ea7c6e..000000000000
--- a/samples/hid/hid_bpf_attach.bpf.c
+++ /dev/null
@@ -1,18 +0,0 @@
-// 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;
-}
diff --git a/samples/hid/hid_bpf_attach.h b/samples/hid/hid_bpf_attach.h
deleted file mode 100644
index 35bb28b49264..000000000000
--- a/samples/hid/hid_bpf_attach.h
+++ /dev/null
@@ -1,14 +0,0 @@
-/* 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 */
diff --git a/samples/hid/hid_mouse.bpf.c b/samples/hid/hid_mouse.bpf.c
index 7c8b453ccb16..bd901fa855c9 100644
--- a/samples/hid/hid_mouse.bpf.c
+++ b/samples/hid/hid_mouse.bpf.c
@@ -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";
diff --git a/samples/hid/hid_mouse.c b/samples/hid/hid_mouse.c
index 018f1185f203..4b80d4e4c154 100644
--- a/samples/hid/hid_mouse.c
+++ b/samples/hid/hid_mouse.c
@@ -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;
@@ -120,27 +112,18 @@ 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);
- return 1;
- }
+ 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);
diff --git a/samples/hid/hid_surface_dial.bpf.c b/samples/hid/hid_surface_dial.bpf.c
index 1f80478c0918..d8d0fb07391f 100644
--- a/samples/hid/hid_surface_dial.bpf.c
+++ b/samples/hid/hid_surface_dial.bpf.c
@@ -10,7 +10,7 @@
#define HID_UP_BUTTON 0x0009
#define HID_GD_WHEEL 0x0038

-SEC("fmod_ret/hid_bpf_device_event")
+SEC("struct_ops/device_event")
int BPF_PROG(hid_event, struct hid_bpf_ctx *hctx)
{
__u8 *data = hid_bpf_get_data(hctx, 0 /* offset */, 9 /* size */);
@@ -101,7 +101,7 @@ int set_haptic(struct haptic_syscall_args *args)
}

/* Convert REL_DIAL into REL_WHEEL */
-SEC("fmod_ret/hid_bpf_rdesc_fixup")
+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 */);
@@ -130,5 +130,11 @@ int BPF_PROG(hid_rdesc_fixup, struct hid_bpf_ctx *hctx)
return 0;
}

+SEC(".struct_ops.link")
+struct hid_bpf_ops surface_dial = {
+ .rdesc_fixup = (void *)hid_rdesc_fixup,
+ .device_event = (void *)hid_event,
+};
+
char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = 1;
diff --git a/samples/hid/hid_surface_dial.c b/samples/hid/hid_surface_dial.c
index 4bc97373a708..9dd363845a85 100644
--- a/samples/hid/hid_surface_dial.c
+++ b/samples/hid/hid_surface_dial.c
@@ -31,7 +31,6 @@
#include <bpf/libbpf.h>

#include "hid_surface_dial.skel.h"
-#include "hid_bpf_attach.h"

static bool running = true;

@@ -86,34 +85,6 @@ static int get_hid_id(const char *path)
return (int)strtol(str_id, NULL, 16);
}

-static int attach_prog(struct hid_surface_dial *skel, struct bpf_program *prog, int hid_id)
-{
- struct attach_prog_args args = {
- .hid = hid_id,
- .retval = -1,
- };
- int attach_fd, err;
- DECLARE_LIBBPF_OPTS(bpf_test_run_opts, tattr,
- .ctx_in = &args,
- .ctx_size_in = sizeof(args),
- );
-
- attach_fd = bpf_program__fd(skel->progs.attach_prog);
- if (attach_fd < 0) {
- fprintf(stderr, "can't locate attach prog: %m\n");
- return 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);
- return 1;
- }
- return 0;
-}
-
static int set_haptic(struct hid_surface_dial *skel, int hid_id)
{
struct haptic_syscall_args args = {
@@ -144,10 +115,10 @@ static int set_haptic(struct hid_surface_dial *skel, int hid_id)
int main(int argc, char **argv)
{
struct hid_surface_dial *skel;
- struct bpf_program *prog;
const char *optstr = "r:";
+ struct bpf_link *link;
const char *sysfs_path;
- int opt, hid_id, resolution = 72;
+ int err, opt, hid_id, resolution = 72;

while ((opt = getopt(argc, argv, optstr)) != -1) {
switch (opt) {
@@ -189,7 +160,7 @@ int main(int argc, char **argv)
return 1;
}

- skel = hid_surface_dial__open_and_load();
+ skel = hid_surface_dial__open();
if (!skel) {
fprintf(stderr, "%s %s:%d", __func__, __FILE__, __LINE__);
return -1;
@@ -201,15 +172,21 @@ int main(int argc, char **argv)
return 1;
}

+ skel->struct_ops.surface_dial->hid_id = hid_id;
+
+ err = hid_surface_dial__load(skel);
+ if (err < 0) {
+ fprintf(stderr, "can not load HID-BPF program: %m\n");
+ return 1;
+ }
+
skel->data->resolution = resolution;
skel->data->physical = (int)(resolution / 72);

- bpf_object__for_each_program(prog, *skel->skeleton->obj) {
- /* ignore syscalls */
- if (bpf_program__get_type(prog) != BPF_PROG_TYPE_TRACING)
- continue;
-
- attach_prog(skel, prog, hid_id);
+ link = bpf_map__attach_struct_ops(skel->maps.surface_dial);
+ if (!link) {
+ fprintf(stderr, "can not attach HID-BPF program: %m\n");
+ return 1;
}

signal(SIGINT, int_exit);

--
2.44.0