Merge tag 'for-linus-2024071601' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid

Pull HID updates from Benjamin Tissoires:

 - rewrite of the HID-BPF internal implementation to use bpf struct_ops
   instead of a tracing endpoint (Benjamin Tissoires)

 - add two new HID-BPF hooks to be able to intercept userspace calls
   targeting a HID device and filtering them (Benjamin Tissoires)

 - add support for various new devices through HID-BPF filters (Benjamin
   Tissoires)

 - add support for the magic keyboard backlight (Orlando Chamberlain)

 - add the missing MODULE_DESCRIPTION() macros in HID drivers (Jeff
   Johnson)

 - use of kvzalloc in case memory gets too fragmented (Hailong Liu)

 - retrieve the device firmware node in the child HID device (Danny
   Kaehn)

 - some hid-uclogic improvements (José Expósito)

 - some more typos, trivial fixes, kernel doctext and unused functions
   cleanups

* tag 'for-linus-2024071601' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid: (60 commits)
  HID: hid-steam: Fix typo in goto label
  HID: mcp2221: Remove unnecessary semicolon
  HID: Fix spelling mistakes "Kensigton" -> "Kensington"
  HID: add more missing MODULE_DESCRIPTION() macros
  HID: samples: fix the 2 struct_ops definitions
  HID: fix for amples in for-6.11/bpf
  HID: apple: Add support for magic keyboard backlight on T2 Macs
  HID: bpf: Thrustmaster TCA Yoke Boeing joystick fix
  HID: bpf: Add Huion Dial 2 bpf fixup
  HID: bpf: Add support for the XP-PEN Deco Mini 4
  HID: bpf: move the BIT() macro to hid_bpf_helpers.h
  HID: bpf: add a driver for the Huion Inspiroy 2S (H641P)
  HID: bpf: Add a HID report composition helper macros
  HID: bpf: doc fixes for hid_hw_request() hooks
  HID: bpf: doc fixes for hid_hw_request() hooks
  HID: bpf: fix gcc warning and unify __u64 into u64
  selftests/hid: ensure CKI can compile our new tests on old kernels
  selftests/hid: add an infinite loop test for hid_bpf_try_input_report
  selftests/hid: add another test for injecting an event from an event hook
  HID: bpf: allow hid_device_event hooks to inject input reports on self
  ...

2 files changed, 146 insertions, 63 deletions

diff --git a/include/linux/hid.h b/include/linux/hid.h
index 8e06d89698e6..1533c9dcd3a6 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -1125,6 +1125,13 @@ int __must_check hid_hw_open(struct hid_device *hdev);
 void hid_hw_close(struct hid_device *hdev);
 void hid_hw_request(struct hid_device *hdev,
 		    struct hid_report *report, enum hid_class_request reqtype);
+int __hid_hw_raw_request(struct hid_device *hdev,
+			 unsigned char reportnum, __u8 *buf,
+			 size_t len, enum hid_report_type rtype,
+			 enum hid_class_request reqtype,
+			 __u64 source, bool from_bpf);
+int __hid_hw_output_report(struct hid_device *hdev, __u8 *buf, size_t len, __u64 source,
+			   bool from_bpf);
 int hid_hw_raw_request(struct hid_device *hdev,
 		       unsigned char reportnum, __u8 *buf,
 		       size_t len, enum hid_report_type rtype,
diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h
index eec2592dec12..9ca96fc90449 100644
--- a/include/linux/hid_bpf.h
+++ b/include/linux/hid_bpf.h
@@ -4,7 +4,8 @@
 #define __HID_BPF_H
 
 #include <linux/bpf.h>
-#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/srcu.h>
 #include <uapi/linux/hid.h>
 
 struct hid_device;
@@ -20,15 +21,9 @@ struct hid_device;
  * 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.
+ * 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()``
+ * @hid: the &struct hid_device representing the device itself
  * @allocated_size: Allocated size of data.
  *
  *                  This is how much memory is available and can be requested
@@ -45,76 +40,147 @@ struct hid_device;
  *        ``size`` must always be less or equal than ``allocated_size`` (it is enforced
  *        once all BPF programs have been run).
  * @retval: Return value of the previous program.
+ *
+ * ``hid`` and ``allocated_size`` are read-only, ``size`` and ``retval`` are read-write.
  */
 struct hid_bpf_ctx {
-	__u32 index;
-	const struct hid_device *hid;
+	struct hid_device *hid;
 	__u32 allocated_size;
-	enum hid_report_type report_type;
 	union {
 		__s32 retval;
 		__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);
-int hid_bpf_rdesc_fixup(struct hid_bpf_ctx *ctx);
-
 /*
  * 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_RDESC_FIXUP,
-	HID_BPF_PROG_TYPE_MAX,
-};
 
 struct hid_report_enum;
 
-struct hid_bpf_ops {
+struct hid_ops {
 	struct hid_report *(*hid_get_report)(struct hid_report_enum *report_enum, const u8 *data);
 	int (*hid_hw_raw_request)(struct hid_device *hdev,
 				  unsigned char reportnum, __u8 *buf,
 				  size_t len, enum hid_report_type rtype,
-				  enum hid_class_request reqtype);
-	int (*hid_hw_output_report)(struct hid_device *hdev, __u8 *buf, size_t len);
+				  enum hid_class_request reqtype,
+				  u64 source, bool from_bpf);
+	int (*hid_hw_output_report)(struct hid_device *hdev, __u8 *buf, size_t len,
+				    u64 source, bool from_bpf);
 	int (*hid_input_report)(struct hid_device *hid, enum hid_report_type type,
-				u8 *data, u32 size, int interrupt);
+				u8 *data, u32 size, int interrupt, u64 source, bool from_bpf,
+				bool lock_already_taken);
 	struct module *owner;
 	const struct bus_type *bus_type;
 };
 
-extern struct hid_bpf_ops *hid_bpf_ops;
+extern struct hid_ops *hid_ops;
 
-struct hid_bpf_prog_list {
-	u16 prog_idx[HID_BPF_MAX_PROGS_PER_DEV];
-	u8 prog_cnt;
+/**
+ * struct hid_bpf_ops - A BPF struct_ops of callbacks allowing to attach HID-BPF
+ *			programs to a HID device
+ * @hid_id: the HID uniq ID to attach to. This is writeable before ``load()``, and
+ *	    cannot be changed after
+ * @flags: flags used while attaching the struct_ops to the device. Currently only
+ *	   available value is %0 or ``BPF_F_BEFORE``.
+ *	   Writeable only before ``load()``
+ */
+struct hid_bpf_ops {
+	/* hid_id needs to stay first so we can easily change it
+	 * from userspace.
+	 */
+	int			hid_id;
+	u32			flags;
+
+	/* private: do not show up in the docs */
+	struct list_head	list;
+
+	/* public: rest should show up in the docs */
+
+	/**
+	 * @hid_device_event: called whenever an event is coming in from the device
+	 *
+	 * It has the following arguments:
+	 *
+	 * ``ctx``: The HID-BPF context as &struct hid_bpf_ctx
+	 *
+	 * Return: %0 on success and keep processing; a positive
+	 * value to change the incoming size buffer; a negative
+	 * error code to interrupt the processing of this event
+	 *
+	 * Context: Interrupt context.
+	 */
+	int (*hid_device_event)(struct hid_bpf_ctx *ctx, enum hid_report_type report_type,
+				u64 source);
+
+	/**
+	 * @hid_rdesc_fixup: called when the probe function parses the report descriptor
+	 * of the HID device
+	 *
+	 * It has the following arguments:
+	 *
+	 * ``ctx``: The HID-BPF context as &struct hid_bpf_ctx
+	 *
+	 * Return: %0 on success and keep processing; a positive
+	 * value to change the incoming size buffer; a negative
+	 * error code to interrupt the processing of this device
+	 */
+	int (*hid_rdesc_fixup)(struct hid_bpf_ctx *ctx);
+
+	/**
+	 * @hid_hw_request: called whenever a hid_hw_raw_request() call is emitted
+	 * on the HID device
+	 *
+	 * It has the following arguments:
+	 *
+	 * ``ctx``: The HID-BPF context as &struct hid_bpf_ctx
+	 *
+	 * ``reportnum``: the report number, as in hid_hw_raw_request()
+	 *
+	 * ``rtype``: the report type (``HID_INPUT_REPORT``, ``HID_FEATURE_REPORT``,
+	 * ``HID_OUTPUT_REPORT``)
+	 *
+	 * ``reqtype``: the request
+	 *
+	 * ``source``: a u64 referring to a uniq but identifiable source. If %0, the
+	 * kernel itself emitted that call. For hidraw, ``source`` is set
+	 * to the associated ``struct file *``.
+	 *
+	 * Return: %0 to keep processing the request by hid-core; any other value
+	 * stops hid-core from processing that event. A positive value should be
+	 * returned with the number of bytes returned in the incoming buffer; a
+	 * negative error code interrupts the processing of this call.
+	 */
+	int (*hid_hw_request)(struct hid_bpf_ctx *ctx, unsigned char reportnum,
+			       enum hid_report_type rtype, enum hid_class_request reqtype,
+			       u64 source);
+
+	/**
+	 * @hid_hw_output_report: called whenever a hid_hw_output_report() call is emitted
+	 * on the HID device
+	 *
+	 * It has the following arguments:
+	 *
+	 * ``ctx``: The HID-BPF context as &struct hid_bpf_ctx
+	 *
+	 * ``source``: a u64 referring to a uniq but identifiable source. If %0, the
+	 * kernel itself emitted that call. For hidraw, ``source`` is set
+	 * to the associated ``struct file *``.
+	 *
+	 * Return: %0 to keep processing the request by hid-core; any other value
+	 * stops hid-core from processing that event. A positive value should be
+	 * returned with the number of bytes written to the device; a negative error
+	 * code interrupts the processing of this call.
+	 */
+	int (*hid_hw_output_report)(struct hid_bpf_ctx *ctx, u64 source);
+
+
+	/* private: do not show up in the docs */
+	struct hid_device *hdev;
 };
 
 /* stored in each device */
@@ -124,34 +190,44 @@ struct hid_bpf {
 					 * to this HID device
 					 */
 	u32 allocated_data;
-
-	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 */
-};
-
-/* specific HID-BPF link when a program is attached to a device */
-struct hid_bpf_link {
-	struct bpf_link link;
-	int hid_table_index;
+	struct hid_bpf_ops *rdesc_ops;
+	struct list_head prog_list;
+	struct mutex prog_list_lock;	/* protects prog_list update */
+	struct srcu_struct srcu;	/* protects prog_list read-only access */
 };
 
 #ifdef CONFIG_HID_BPF
 u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, u8 *data,
-				  u32 *size, int interrupt);
+				  u32 *size, int interrupt, u64 source, bool from_bpf);
+int dispatch_hid_bpf_raw_requests(struct hid_device *hdev,
+				  unsigned char reportnum, __u8 *buf,
+				  u32 size, enum hid_report_type rtype,
+				  enum hid_class_request reqtype,
+				  u64 source, bool from_bpf);
+int dispatch_hid_bpf_output_report(struct hid_device *hdev, __u8 *buf, u32 size,
+				   u64 source, bool from_bpf);
 int hid_bpf_connect_device(struct hid_device *hdev);
 void hid_bpf_disconnect_device(struct hid_device *hdev);
 void hid_bpf_destroy_device(struct hid_device *hid);
-void hid_bpf_device_init(struct hid_device *hid);
+int hid_bpf_device_init(struct hid_device *hid);
 u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size);
 #else /* CONFIG_HID_BPF */
 static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type,
-						u8 *data, u32 *size, int interrupt) { return data; }
+						u8 *data, u32 *size, int interrupt,
+						u64 source, bool from_bpf) { return data; }
+static inline int dispatch_hid_bpf_raw_requests(struct hid_device *hdev,
+						unsigned char reportnum, u8 *buf,
+						u32 size, enum hid_report_type rtype,
+						enum hid_class_request reqtype,
+						u64 source, bool from_bpf) { return 0; }
+static inline int dispatch_hid_bpf_output_report(struct hid_device *hdev, __u8 *buf, u32 size,
+						 u64 source, bool from_bpf) { return 0; }
 static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; }
 static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {}
 static inline void hid_bpf_destroy_device(struct hid_device *hid) {}
-static inline void hid_bpf_device_init(struct hid_device *hid) {}
+static inline int hid_bpf_device_init(struct hid_device *hid) { return 0; }
 #define call_hid_bpf_rdesc_fixup(_hdev, _rdesc, _size)	\
 		((u8 *)kmemdup(_rdesc, *(_size), GFP_KERNEL))