tracing: mark user_events as BROKEN

After being merged, user_events become more visible to a wider audience
that have concerns with the current API.

It is too late to fix this for this release, but instead of a full
revert, just mark it as BROKEN (which prevents it from being selected in
make config).  Then we can work finding a better API.  If that fails,
then it will need to be completely reverted.

To not have the code silently bitrot, still allow building it with
COMPILE_TEST.

And to prevent the uapi header from being installed, then later changed,
and then have an old distro user space see the old version, move the
header file out of the uapi directory.

Surround the include with CONFIG_COMPILE_TEST to the current location,
but when the BROKEN tag is taken off, it will use the uapi directory,
and fail to compile.  This is a good way to remind us to move the header
back.

Link: https://lore.kernel.org/all/20220330155835.5e1f6669@gandalf.local.home
Link: https://lkml.kernel.org/r/20220330201755.29319-1-mathieu.desnoyers@efficios.com
Suggested-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 116 deletions

diff --git a/include/uapi/linux/user_events.h b/include/uapi/linux/user_events.h
deleted file mode 100644
index e570840571e1..000000000000
--- a/include/uapi/linux/user_events.h
+++ /dev/null
@@ -1,116 +0,0 @@
-/* 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 */