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-rw-r--r--include/linux/user_events.h116
1 files changed, 116 insertions, 0 deletions
diff --git a/include/linux/user_events.h b/include/linux/user_events.h
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+++ b/include/linux/user_events.h
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+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+/*
+ * Copyright (c) 2021, Microsoft Corporation.
+ *
+ * Authors:
+ * Beau Belgrave <beaub@linux.microsoft.com>
+ */
+#ifndef _UAPI_LINUX_USER_EVENTS_H
+#define _UAPI_LINUX_USER_EVENTS_H
+
+#include <linux/types.h>
+#include <linux/ioctl.h>
+
+#ifdef __KERNEL__
+#include <linux/uio.h>
+#else
+#include <sys/uio.h>
+#endif
+
+#define USER_EVENTS_SYSTEM "user_events"
+#define USER_EVENTS_PREFIX "u:"
+
+/* Bits 0-6 are for known probe types, Bit 7 is for unknown probes */
+#define EVENT_BIT_FTRACE 0
+#define EVENT_BIT_PERF 1
+#define EVENT_BIT_OTHER 7
+
+#define EVENT_STATUS_FTRACE (1 << EVENT_BIT_FTRACE)
+#define EVENT_STATUS_PERF (1 << EVENT_BIT_PERF)
+#define EVENT_STATUS_OTHER (1 << EVENT_BIT_OTHER)
+
+/* Create dynamic location entry within a 32-bit value */
+#define DYN_LOC(offset, size) ((size) << 16 | (offset))
+
+/* Use raw iterator for attached BPF program(s), no affect on ftrace/perf */
+#define FLAG_BPF_ITER (1 << 0)
+
+/*
+ * Describes an event registration and stores the results of the registration.
+ * This structure is passed to the DIAG_IOCSREG ioctl, callers at a minimum
+ * must set the size and name_args before invocation.
+ */
+struct user_reg {
+
+ /* Input: Size of the user_reg structure being used */
+ __u32 size;
+
+ /* Input: Pointer to string with event name, description and flags */
+ __u64 name_args;
+
+ /* Output: Byte index of the event within the status page */
+ __u32 status_index;
+
+ /* Output: Index of the event to use when writing data */
+ __u32 write_index;
+};
+
+#define DIAG_IOC_MAGIC '*'
+
+/* Requests to register a user_event */
+#define DIAG_IOCSREG _IOWR(DIAG_IOC_MAGIC, 0, struct user_reg*)
+
+/* Requests to delete a user_event */
+#define DIAG_IOCSDEL _IOW(DIAG_IOC_MAGIC, 1, char*)
+
+/* Data type that was passed to the BPF program */
+enum {
+ /* Data resides in kernel space */
+ USER_BPF_DATA_KERNEL,
+
+ /* Data resides in user space */
+ USER_BPF_DATA_USER,
+
+ /* Data is a pointer to a user_bpf_iter structure */
+ USER_BPF_DATA_ITER,
+};
+
+/*
+ * Describes an iovec iterator that BPF programs can use to access data for
+ * a given user_event write() / writev() call.
+ */
+struct user_bpf_iter {
+
+ /* Offset of the data within the first iovec */
+ __u32 iov_offset;
+
+ /* Number of iovec structures */
+ __u32 nr_segs;
+
+ /* Pointer to iovec structures */
+ const struct iovec *iov;
+};
+
+/* Context that BPF programs receive when attached to a user_event */
+struct user_bpf_context {
+
+ /* Data type being passed (see union below) */
+ __u32 data_type;
+
+ /* Length of the data */
+ __u32 data_len;
+
+ /* Pointer to data, varies by data type */
+ union {
+ /* Kernel data (data_type == USER_BPF_DATA_KERNEL) */
+ void *kdata;
+
+ /* User data (data_type == USER_BPF_DATA_USER) */
+ void *udata;
+
+ /* Direct iovec (data_type == USER_BPF_DATA_ITER) */
+ struct user_bpf_iter *iter;
+ };
+};
+
+#endif /* _UAPI_LINUX_USER_EVENTS_H */