1 files changed, 215 insertions, 0 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
new file mode 100644
index 000000000..3c7d29574
--- /dev/null
+++ b/include/linux/ring_buffer.h
@@ -0,0 +1,215 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_RING_BUFFER_H
+#define _LINUX_RING_BUFFER_H
+
+#include <linux/mm.h>
+#include <linux/seq_file.h>
+#include <linux/poll.h>
+
+struct trace_buffer;
+struct ring_buffer_iter;
+
+/*
+ * Don't refer to this struct directly, use functions below.
+ */
+struct ring_buffer_event {
+	u32		type_len:5, time_delta:27;
+
+	u32		array[];
+};
+
+/**
+ * enum ring_buffer_type - internal ring buffer types
+ *
+ * @RINGBUF_TYPE_PADDING:	Left over page padding or discarded event
+ *				 If time_delta is 0:
+ *				  array is ignored
+ *				  size is variable depending on how much
+ *				  padding is needed
+ *				 If time_delta is non zero:
+ *				  array[0] holds the actual length
+ *				  size = 4 + length (bytes)
+ *
+ * @RINGBUF_TYPE_TIME_EXTEND:	Extend the time delta
+ *				 array[0] = time delta (28 .. 59)
+ *				 size = 8 bytes
+ *
+ * @RINGBUF_TYPE_TIME_STAMP:	Absolute timestamp
+ *				 Same format as TIME_EXTEND except that the
+ *				 value is an absolute timestamp, not a delta
+ *				 event.time_delta contains bottom 27 bits
+ *				 array[0] = top (28 .. 59) bits
+ *				 size = 8 bytes
+ *
+ * <= @RINGBUF_TYPE_DATA_TYPE_LEN_MAX:
+ *				Data record
+ *				 If type_len is zero:
+ *				  array[0] holds the actual length
+ *				  array[1..(length+3)/4] holds data
+ *				  size = 4 + length (bytes)
+ *				 else
+ *				  length = type_len << 2
+ *				  array[0..(length+3)/4-1] holds data
+ *				  size = 4 + length (bytes)
+ */
+enum ring_buffer_type {
+	RINGBUF_TYPE_DATA_TYPE_LEN_MAX = 28,
+	RINGBUF_TYPE_PADDING,
+	RINGBUF_TYPE_TIME_EXTEND,
+	RINGBUF_TYPE_TIME_STAMP,
+};
+
+unsigned ring_buffer_event_length(struct ring_buffer_event *event);
+void *ring_buffer_event_data(struct ring_buffer_event *event);
+u64 ring_buffer_event_time_stamp(struct trace_buffer *buffer,
+				 struct ring_buffer_event *event);
+
+/*
+ * ring_buffer_discard_commit will remove an event that has not
+ *   been committed yet. If this is used, then ring_buffer_unlock_commit
+ *   must not be called on the discarded event. This function
+ *   will try to remove the event from the ring buffer completely
+ *   if another event has not been written after it.
+ *
+ * Example use:
+ *
+ *  if (some_condition)
+ *    ring_buffer_discard_commit(buffer, event);
+ *  else
+ *    ring_buffer_unlock_commit(buffer, event);
+ */
+void ring_buffer_discard_commit(struct trace_buffer *buffer,
+				struct ring_buffer_event *event);
+
+/*
+ * size is in bytes for each per CPU buffer.
+ */
+struct trace_buffer *
+__ring_buffer_alloc(unsigned long size, unsigned flags, struct lock_class_key *key);
+
+/*
+ * Because the ring buffer is generic, if other users of the ring buffer get
+ * traced by ftrace, it can produce lockdep warnings. We need to keep each
+ * ring buffer's lock class separate.
+ */
+#define ring_buffer_alloc(size, flags)			\
+({							\
+	static struct lock_class_key __key;		\
+	__ring_buffer_alloc((size), (flags), &__key);	\
+})
+
+int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full);
+__poll_t ring_buffer_poll_wait(struct trace_buffer *buffer, int cpu,
+			  struct file *filp, poll_table *poll_table, int full);
+void ring_buffer_wake_waiters(struct trace_buffer *buffer, int cpu);
+
+#define RING_BUFFER_ALL_CPUS -1
+
+void ring_buffer_free(struct trace_buffer *buffer);
+
+int ring_buffer_resize(struct trace_buffer *buffer, unsigned long size, int cpu);
+
+void ring_buffer_change_overwrite(struct trace_buffer *buffer, int val);
+
+struct ring_buffer_event *ring_buffer_lock_reserve(struct trace_buffer *buffer,
+						   unsigned long length);
+int ring_buffer_unlock_commit(struct trace_buffer *buffer,
+			      struct ring_buffer_event *event);
+int ring_buffer_write(struct trace_buffer *buffer,
+		      unsigned long length, void *data);
+
+void ring_buffer_nest_start(struct trace_buffer *buffer);
+void ring_buffer_nest_end(struct trace_buffer *buffer);
+
+struct ring_buffer_event *
+ring_buffer_peek(struct trace_buffer *buffer, int cpu, u64 *ts,
+		 unsigned long *lost_events);
+struct ring_buffer_event *
+ring_buffer_consume(struct trace_buffer *buffer, int cpu, u64 *ts,
+		    unsigned long *lost_events);
+
+struct ring_buffer_iter *
+ring_buffer_read_prepare(struct trace_buffer *buffer, int cpu, gfp_t flags);
+void ring_buffer_read_prepare_sync(void);
+void ring_buffer_read_start(struct ring_buffer_iter *iter);
+void ring_buffer_read_finish(struct ring_buffer_iter *iter);
+
+struct ring_buffer_event *
+ring_buffer_iter_peek(struct ring_buffer_iter *iter, u64 *ts);
+void ring_buffer_iter_advance(struct ring_buffer_iter *iter);
+void ring_buffer_iter_reset(struct ring_buffer_iter *iter);
+int ring_buffer_iter_empty(struct ring_buffer_iter *iter);
+bool ring_buffer_iter_dropped(struct ring_buffer_iter *iter);
+
+unsigned long ring_buffer_size(struct trace_buffer *buffer, int cpu);
+
+void ring_buffer_reset_cpu(struct trace_buffer *buffer, int cpu);
+void ring_buffer_reset_online_cpus(struct trace_buffer *buffer);
+void ring_buffer_reset(struct trace_buffer *buffer);
+
+#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP
+int ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
+			 struct trace_buffer *buffer_b, int cpu);
+#else
+static inline int
+ring_buffer_swap_cpu(struct trace_buffer *buffer_a,
+		     struct trace_buffer *buffer_b, int cpu)
+{
+	return -ENODEV;
+}
+#endif
+
+bool ring_buffer_empty(struct trace_buffer *buffer);
+bool ring_buffer_empty_cpu(struct trace_buffer *buffer, int cpu);
+
+void ring_buffer_record_disable(struct trace_buffer *buffer);
+void ring_buffer_record_enable(struct trace_buffer *buffer);
+void ring_buffer_record_off(struct trace_buffer *buffer);
+void ring_buffer_record_on(struct trace_buffer *buffer);
+bool ring_buffer_record_is_on(struct trace_buffer *buffer);
+bool ring_buffer_record_is_set_on(struct trace_buffer *buffer);
+void ring_buffer_record_disable_cpu(struct trace_buffer *buffer, int cpu);
+void ring_buffer_record_enable_cpu(struct trace_buffer *buffer, int cpu);
+
+u64 ring_buffer_oldest_event_ts(struct trace_buffer *buffer, int cpu);
+unsigned long ring_buffer_bytes_cpu(struct trace_buffer *buffer, int cpu);
+unsigned long ring_buffer_entries(struct trace_buffer *buffer);
+unsigned long ring_buffer_overruns(struct trace_buffer *buffer);
+unsigned long ring_buffer_entries_cpu(struct trace_buffer *buffer, int cpu);
+unsigned long ring_buffer_overrun_cpu(struct trace_buffer *buffer, int cpu);
+unsigned long ring_buffer_commit_overrun_cpu(struct trace_buffer *buffer, int cpu);
+unsigned long ring_buffer_dropped_events_cpu(struct trace_buffer *buffer, int cpu);
+unsigned long ring_buffer_read_events_cpu(struct trace_buffer *buffer, int cpu);
+
+u64 ring_buffer_time_stamp(struct trace_buffer *buffer);
+void ring_buffer_normalize_time_stamp(struct trace_buffer *buffer,
+				      int cpu, u64 *ts);
+void ring_buffer_set_clock(struct trace_buffer *buffer,
+			   u64 (*clock)(void));
+void ring_buffer_set_time_stamp_abs(struct trace_buffer *buffer, bool abs);
+bool ring_buffer_time_stamp_abs(struct trace_buffer *buffer);
+
+size_t ring_buffer_nr_pages(struct trace_buffer *buffer, int cpu);
+size_t ring_buffer_nr_dirty_pages(struct trace_buffer *buffer, int cpu);
+
+void *ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu);
+void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, void *data);
+int ring_buffer_read_page(struct trace_buffer *buffer, void **data_page,
+			  size_t len, int cpu, int full);
+
+struct trace_seq;
+
+int ring_buffer_print_entry_header(struct trace_seq *s);
+int ring_buffer_print_page_header(struct trace_seq *s);
+
+enum ring_buffer_flags {
+	RB_FL_OVERWRITE		= 1 << 0,
+};
+
+#ifdef CONFIG_RING_BUFFER
+int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node);
+#else
+#define trace_rb_cpu_prepare	NULL
+#endif
+
+#endif /* _LINUX_RING_BUFFER_H */