diff options
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/hid.h | 5 | ||||
-rw-r--r-- | include/linux/hid_bpf.h | 117 |
2 files changed, 122 insertions, 0 deletions
diff --git a/include/linux/hid.h b/include/linux/hid.h index 8677ae38599e..cd3c52fae7b1 100644 --- a/include/linux/hid.h +++ b/include/linux/hid.h @@ -26,6 +26,7 @@ #include <linux/mutex.h> #include <linux/power_supply.h> #include <uapi/linux/hid.h> +#include <linux/hid_bpf.h> /* * We parse each description item into this structure. Short items data @@ -651,6 +652,10 @@ struct hid_device { /* device report descriptor */ wait_queue_head_t debug_wait; unsigned int id; /* system unique id */ + +#ifdef CONFIG_BPF + struct hid_bpf bpf; /* hid-bpf data */ +#endif /* CONFIG_BPF */ }; #define to_hid_device(pdev) \ diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h new file mode 100644 index 000000000000..de3fb1c376d2 --- /dev/null +++ b/include/linux/hid_bpf.h @@ -0,0 +1,117 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ + +#ifndef __HID_BPF_H +#define __HID_BPF_H + +#include <linux/spinlock.h> +#include <uapi/linux/hid.h> + +struct hid_device; + +/* + * The following is the user facing HID BPF API. + * + * Extra care should be taken when editing this part, as + * it might break existing out of the tree bpf programs. + */ + +/** + * 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; +}; + +/** + * enum hid_bpf_attach_flags - flags used when attaching a HIF-BPF program + * + * @HID_BPF_FLAG_NONE: no specific flag is used, the kernel choses where to + * insert the program + * @HID_BPF_FLAG_INSERT_HEAD: insert the given program before any other program + * currently attached to the device. This doesn't + * guarantee that this program will always be first + * @HID_BPF_FLAG_MAX: sentinel value, not to be used by the callers + */ +enum hid_bpf_attach_flags { + HID_BPF_FLAG_NONE = 0, + HID_BPF_FLAG_INSERT_HEAD = _BITUL(0), + HID_BPF_FLAG_MAX, +}; + +/* 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 */ |