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Diffstat (limited to 'include/linux/ring_buffer.h')
| -rw-r--r-- | include/linux/ring_buffer.h | 329 |
1 files changed, 329 insertions, 0 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h new file mode 100644 index 000000000..eac3e9080 --- /dev/null +++ b/include/linux/ring_buffer.h @@ -0,0 +1,329 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_RING_BUFFER_H +#define _LINUX_RING_BUFFER_H + +#include <linux/mm.h> +#include <linux/poll.h> +#include <linux/ring_buffer_types.h> +#include <linux/seq_file.h> + +#include <uapi/linux/trace_mmap.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); + +struct trace_buffer *__ring_buffer_alloc_range(unsigned long size, unsigned flags, + int order, unsigned long start, + unsigned long range_size, + unsigned long scratch_size, + struct lock_class_key *key); + +void *ring_buffer_meta_scratch(struct trace_buffer *buffer, unsigned int *size); + +/* + * 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); \ +}) + +/* + * 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_range(size, flags, order, start, range_size, s_size) \ +({ \ + static struct lock_class_key __key; \ + __ring_buffer_alloc_range((size), (flags), (order), (start), \ + (range_size), (s_size), &__key); \ +}) + +typedef bool (*ring_buffer_cond_fn)(void *data); +int ring_buffer_wait(struct trace_buffer *buffer, int cpu, int full, + ring_buffer_cond_fn cond, void *data); +__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); +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); + +DEFINE_GUARD(ring_buffer_nest, struct trace_buffer *, + ring_buffer_nest_start(_T), ring_buffer_nest_end(_T)) + +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_start(struct trace_buffer *buffer, int cpu, gfp_t flags); +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); +unsigned long ring_buffer_max_event_size(struct trace_buffer *buffer); + +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); +bool ring_buffer_record_is_on_cpu(struct trace_buffer *buffer, int cpu); +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_dirty_pages(struct trace_buffer *buffer, int cpu); + +struct buffer_data_read_page; +int ring_buffer_alloc_read_page(struct trace_buffer *buffer, int cpu, + struct buffer_data_read_page **rpage); +void ring_buffer_free_read_page(struct trace_buffer *buffer, int cpu, + struct buffer_data_read_page *page); +int ring_buffer_read_page(struct trace_buffer *buffer, + struct buffer_data_read_page *data_page, + size_t len, int cpu, int full); +void *ring_buffer_read_page_data(struct buffer_data_read_page *page); +unsigned int ring_buffer_read_page_size(struct buffer_data_read_page *rpage); + +struct trace_seq; + +int ring_buffer_print_entry_header(struct trace_seq *s); +int ring_buffer_print_page_header(struct trace_buffer *buffer, struct trace_seq *s); + +int ring_buffer_subbuf_order_get(struct trace_buffer *buffer); +int ring_buffer_subbuf_order_set(struct trace_buffer *buffer, int order); +int ring_buffer_subbuf_size_get(struct trace_buffer *buffer); + +enum ring_buffer_flags { + RB_FL_OVERWRITE = 1 << 0, + RB_FL_TESTING = 1 << 1, +}; + +#ifdef CONFIG_RING_BUFFER +int trace_rb_cpu_prepare(unsigned int cpu, struct hlist_node *node); +#else +#define trace_rb_cpu_prepare NULL +#endif + +int ring_buffer_map(struct trace_buffer *buffer, int cpu, + struct vm_area_struct *vma); +void ring_buffer_map_dup(struct trace_buffer *buffer, int cpu); +int ring_buffer_unmap(struct trace_buffer *buffer, int cpu); +int ring_buffer_map_get_reader(struct trace_buffer *buffer, int cpu); + +struct ring_buffer_desc { + int cpu; + unsigned int nr_page_va; /* excludes the meta page */ + unsigned long meta_va; + unsigned long page_va[] __counted_by(nr_page_va); +}; + +struct trace_buffer_desc { + int nr_cpus; + size_t struct_len; + char __data[]; /* list of ring_buffer_desc */ +}; + +static inline struct ring_buffer_desc *__next_ring_buffer_desc(struct ring_buffer_desc *desc) +{ + size_t len = struct_size(desc, page_va, desc->nr_page_va); + + return (struct ring_buffer_desc *)((void *)desc + len); +} + +static inline struct ring_buffer_desc *__first_ring_buffer_desc(struct trace_buffer_desc *desc) +{ + return (struct ring_buffer_desc *)(&desc->__data[0]); +} + +/* + * Returns the number of pages for a ring_buffer_desc. The caller must ensure it + * does not overflow ring_buffer_desc::nr_page_va. + */ +static inline unsigned long __calc_nr_pages_ring_buffer_desc(size_t size) +{ + /* Takes into account the reader page */ + return max(DIV_ROUND_UP(size, PAGE_SIZE - BUF_PAGE_HDR_SIZE), 2UL) + 1; +} + +static inline size_t trace_buffer_desc_size(size_t buffer_size, unsigned int nr_cpus) +{ + unsigned long nr_pages = __calc_nr_pages_ring_buffer_desc(buffer_size); + struct ring_buffer_desc *rbdesc; + + /* Capped by ring_buffer_desc::nr_page_va */ + if (nr_pages > UINT_MAX) + return SIZE_MAX; + + return size_add(offsetof(struct trace_buffer_desc, __data), + size_mul(nr_cpus, struct_size(rbdesc, page_va, nr_pages))); +} + +#define for_each_ring_buffer_desc(__pdesc, __cpu, __trace_pdesc) \ + for (__pdesc = __first_ring_buffer_desc(__trace_pdesc), __cpu = 0; \ + (__cpu) < (__trace_pdesc)->nr_cpus; \ + (__cpu)++, __pdesc = __next_ring_buffer_desc(__pdesc)) + +struct ring_buffer_remote { + struct trace_buffer_desc *desc; + int (*swap_reader_page)(unsigned int cpu, void *priv); + int (*reset)(unsigned int cpu, void *priv); + void *priv; +}; + +int ring_buffer_poll_remote(struct trace_buffer *buffer, int cpu); + +struct trace_buffer * +__ring_buffer_alloc_remote(struct ring_buffer_remote *remote, + struct lock_class_key *key); + +#define ring_buffer_alloc_remote(remote) \ +({ \ + static struct lock_class_key __key; \ + __ring_buffer_alloc_remote(remote, &__key); \ +}) +#endif /* _LINUX_RING_BUFFER_H */ |