On 7/28/22 16:19, Greg KH wrote:
On Thu, Jul 21, 2022 at 05:36:14PM +0200, Benjamin Tissoires wrote:
--- /dev/null
+++ b/include/linux/hid_bpf.h
@@ -0,0 +1,102 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
This is not a uapi .h file, so the "WITH Linux-syscall-note" should not
be here, right?
thanks, dropping this syscall note from the series.
+
+#ifndef __HID_BPF_H
+#define __HID_BPF_H
+
+#include <linux/spinlock.h>
+#include <uapi/linux/hid.h>
+#include <uapi/linux/hid_bpf.h>
+
+struct hid_device;
+
+/*
+ * The following is the HID BPF API.
+ *
+ * It should be treated as UAPI, so extra care is required
+ * when making change to this file.
So is this uapi? If so, shouldn't it go into a uapi include directory
so we know this and properly track it and maintain it that way?
IMO it's a grey area. It is not "uapi" because it doesn't export
anything that userspace can use. A userspace program can not include
that and use it in other words.
So strictly speaking, it's a normal part of a kernel header file,
because it's a description of what other kernel users (though here, eBPF
programs) can use.
But I really want that part of the API to be considered as "stable" and
give some guarantees to the users that I won't change it at every
release. Thus the "uapi-like".
+ */
+
+/**
+ * struct hid_bpf_ctx - User accessible data for all HID programs
+ *
+ * ``data`` is not directly accessible from the context. We need to issue
+ * a call to ``hid_bpf_get_data()`` in order to get a pointer to that field.
+ *
+ * All of these fields are currently read-only.
+ *
+ * @index: program index in the jump table. No special meaning (a smaller index
+ * doesn't mean the program will be executed before another program with
+ * a bigger index).
+ * @hid: the ``struct hid_device`` representing the device itself
+ * @report_type: used for ``hid_bpf_device_event()``
+ * @size: Valid data in the data field.
+ *
+ * Programs can get the available valid size in data by fetching this field.
+ */
+struct hid_bpf_ctx {
+ __u32 index;
+ const struct hid_device *hid;
+ enum hid_report_type report_type;
+ __s32 size;
+};
+
+/* Following functions are tracepoints that BPF programs can attach to */
+int hid_bpf_device_event(struct hid_bpf_ctx *ctx);
+
+/* Following functions are kfunc that we export to BPF programs */
+/* only available in tracing */
+__u8 *hid_bpf_get_data(struct hid_bpf_ctx *ctx, unsigned int offset, const size_t __sz);
+
+/* only available in syscall */
+int hid_bpf_attach_prog(unsigned int hid_id, int prog_fd, __u32 flags);
+
+/*
+ * Below is HID internal
+ */
+
+/* internal function to call eBPF programs, not to be used by anybody */
+int __hid_bpf_tail_call(struct hid_bpf_ctx *ctx);
+
+#define HID_BPF_MAX_PROGS_PER_DEV 64
+#define HID_BPF_FLAG_MASK (((HID_BPF_FLAG_MAX - 1) << 1) - 1)
+
+/* types of HID programs to attach to */
+enum hid_bpf_prog_type {
+ HID_BPF_PROG_TYPE_UNDEF = -1,
+ HID_BPF_PROG_TYPE_DEVICE_EVENT, /* an event is emitted from the device */
+ HID_BPF_PROG_TYPE_MAX,
+};
+
+struct hid_bpf_ops {
+ struct module *owner;
+ struct bus_type *bus_type;
+};
+
+extern struct hid_bpf_ops *hid_bpf_ops;
+
+struct hid_bpf_prog_list {
+ u16 prog_idx[HID_BPF_MAX_PROGS_PER_DEV];
+ u8 prog_cnt;
+};
+
+/* stored in each device */
+struct hid_bpf {
+ struct hid_bpf_prog_list __rcu *progs[HID_BPF_PROG_TYPE_MAX]; /* attached BPF progs */
+ bool destroyed; /* prevents the assignment of any progs */
+
+ spinlock_t progs_lock; /* protects RCU update of progs */
+};
+
+#ifdef CONFIG_HID_BPF
+int dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data,
+ u32 size, int interrupt);
+void hid_bpf_destroy_device(struct hid_device *hid);
+void hid_bpf_device_init(struct hid_device *hid);
+#else /* CONFIG_HID_BPF */
+static inline int dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data,
+ u32 size, int interrupt) { return 0; }
+static inline void hid_bpf_destroy_device(struct hid_device *hid) {}
+static inline void hid_bpf_device_init(struct hid_device *hid) {}
+#endif /* CONFIG_HID_BPF */
+
+#endif /* __HID_BPF_H */
diff --git a/include/uapi/linux/hid_bpf.h b/include/uapi/linux/hid_bpf.h
new file mode 100644
index 000000000000..ba8caf9b60ee
--- /dev/null
+++ b/include/uapi/linux/hid_bpf.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
This is fine, it is in include/uapi/
Other than those minor comments, this all looks good to me!
Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Great!
And thanks a lot for the other reviews.
I finally managed to get some time to work on it after some time off and
urgent sh**t happening, so I'll send a new version of the series today.
Cheers,
Benjamin
