xref: /linux/include/linux/user_events.h (revision 6c8c1406)
1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /*
3  * Copyright (c) 2021, Microsoft Corporation.
4  *
5  * Authors:
6  *   Beau Belgrave <beaub@linux.microsoft.com>
7  */
8 #ifndef _UAPI_LINUX_USER_EVENTS_H
9 #define _UAPI_LINUX_USER_EVENTS_H
10 
11 #include <linux/types.h>
12 #include <linux/ioctl.h>
13 
14 #ifdef __KERNEL__
15 #include <linux/uio.h>
16 #else
17 #include <sys/uio.h>
18 #endif
19 
20 #define USER_EVENTS_SYSTEM "user_events"
21 #define USER_EVENTS_PREFIX "u:"
22 
23 /* Create dynamic location entry within a 32-bit value */
24 #define DYN_LOC(offset, size) ((size) << 16 | (offset))
25 
26 /*
27  * Describes an event registration and stores the results of the registration.
28  * This structure is passed to the DIAG_IOCSREG ioctl, callers at a minimum
29  * must set the size and name_args before invocation.
30  */
31 struct user_reg {
32 
33 	/* Input: Size of the user_reg structure being used */
34 	__u32 size;
35 
36 	/* Input: Pointer to string with event name, description and flags */
37 	__u64 name_args;
38 
39 	/* Output: Bitwise index of the event within the status page */
40 	__u32 status_bit;
41 
42 	/* Output: Index of the event to use when writing data */
43 	__u32 write_index;
44 } __attribute__((__packed__));
45 
46 #define DIAG_IOC_MAGIC '*'
47 
48 /* Requests to register a user_event */
49 #define DIAG_IOCSREG _IOWR(DIAG_IOC_MAGIC, 0, struct user_reg*)
50 
51 /* Requests to delete a user_event */
52 #define DIAG_IOCSDEL _IOW(DIAG_IOC_MAGIC, 1, char*)
53 
54 #endif /* _UAPI_LINUX_USER_EVENTS_H */
55