[lttng-ust.git] / include / lttng / ringbuffer-context.h

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2010-2021 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Ring buffer context header.
 */

#ifndef _LTTNG_RING_BUFFER_CONTEXT_H
#define _LTTNG_RING_BUFFER_CONTEXT_H

#include <errno.h>
#include <stdint.h>
#include <stddef.h>
#include <urcu/arch.h>
#include <string.h>

#include <lttng/ust-tracer.h>
#include <lttng/ust-align.h>
#include <lttng/ust-compiler.h>

struct lttng_ust_lib_ring_buffer;
struct lttng_ust_lib_ring_buffer_channel;
struct lttng_ust_lib_ring_buffer_ctx;
struct lttng_ust_shm_handle;

/*
 * ring buffer context
 *
 * Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
 * lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
 * lib_ring_buffer_write().
 *
 * IMPORTANT: this structure is part of the ABI between the probe and
 * UST. Fields need to be only added at the end, never reordered, never
 * removed.
 *
 * The field @struct_size should be used to determine the size of the
 * structure. It should be queried before using additional fields added
 * at the end of the structure.
 */
struct lttng_ust_lib_ring_buffer_ctx {
	uint32_t struct_size;		/* Size of this structure. */

	/* input received by lib_ring_buffer_reserve(), saved here. */
	struct lttng_ust_lib_ring_buffer_channel *chan; /* channel */
	void *priv;			/* client private data */
	struct lttng_ust_shm_handle *handle;	/* shared-memory handle */
	size_t data_size;		/* size of payload */
	int largest_align;		/*
					 * alignment of the largest element
					 * in the payload
					 */

	/* output from lib_ring_buffer_reserve() */
	int reserve_cpu;		/* processor id updated by the reserve */
	struct lttng_ust_lib_ring_buffer *buf;	/*
					 * buffer corresponding to processor id
					 * for this channel
					 */
	size_t slot_size;		/* size of the reserved slot */
	unsigned long buf_offset;	/* offset following the record header */
	unsigned long pre_offset;	/*
					 * Initial offset position _before_
					 * the record is written. Positioned
					 * prior to record header alignment
					 * padding.
					 */
	uint64_t tsc;			/* time-stamp counter value */
	unsigned int rflags;		/* reservation flags */
	void *ip;			/* caller ip address */
	struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;

	/* End of base ABI. Fields below should be used after checking struct_size. */
};

/**
 * lib_ring_buffer_ctx_init - initialize ring buffer context
 * @ctx: ring buffer context to initialize
 * @chan: channel
 * @priv: client private data
 * @data_size: size of record data payload
 * @largest_align: largest alignment within data payload types
 */
static inline lttng_ust_notrace
void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			      struct lttng_ust_lib_ring_buffer_channel *chan,
			      void *priv, size_t data_size, int largest_align,
			      struct lttng_ust_shm_handle *handle);
static inline
void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			      struct lttng_ust_lib_ring_buffer_channel *chan,
			      void *priv, size_t data_size, int largest_align,
			      struct lttng_ust_shm_handle *handle)
{
	ctx->struct_size = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
	ctx->chan = chan;
	ctx->priv = priv;
	ctx->data_size = data_size;
	ctx->reserve_cpu = -1;
	ctx->largest_align = largest_align;
	ctx->rflags = 0;
	ctx->handle = handle;
	ctx->ip = 0;
}

/*
 * We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
 * compile-time. We have to duplicate the "config->align" information and the
 * definition here because config->align is used both in the slow and fast
 * paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
 */
#ifdef RING_BUFFER_ALIGN

# define RING_BUFFER_ALIGN_ATTR		/* Default arch alignment */

/*
 * Calculate the offset needed to align the type.
 * size_of_type must be non-zero.
 */
static inline lttng_ust_notrace
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
static inline
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
{
	return lttng_ust_offset_align(align_drift, size_of_type);
}

#else

# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))

/*
 * Calculate the offset needed to align the type.
 * size_of_type must be non-zero.
 */
static inline lttng_ust_notrace
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
static inline
unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
{
	return 0;
}

#endif

/**
 * lib_ring_buffer_align_ctx - Align context offset on "alignment"
 * @ctx: ring buffer context.
 */
static inline lttng_ust_notrace
void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			   size_t alignment);
static inline
void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
			   size_t alignment)
{
	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
						 alignment);
}

#endif /* _LTTNG_RING_BUFFER_CONTEXT_H */
Commit	Line	Data
0f3a182f MD	1	/*
	2	* SPDX-License-Identifier: MIT
	3	*
	4	* Copyright (C) 2010-2021 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*
	6	* Ring buffer context header.
	7	*/
	8
	9	#ifndef _LTTNG_RING_BUFFER_CONTEXT_H
	10	#define _LTTNG_RING_BUFFER_CONTEXT_H
	11
	12	#include <errno.h>
0f3a182f MD	13	#include <stdint.h>
	14	#include <stddef.h>
	15	#include <urcu/arch.h>
	16	#include <string.h>
3d3a2bb8 MJ	17
	18	#include <lttng/ust-tracer.h>
	19	#include <lttng/ust-align.h>
0f3a182f MD	20	#include <lttng/ust-compiler.h>
	21
	22	struct lttng_ust_lib_ring_buffer;
	23	struct lttng_ust_lib_ring_buffer_channel;
	24	struct lttng_ust_lib_ring_buffer_ctx;
	25	struct lttng_ust_shm_handle;
	26
	27	/*
	28	* ring buffer context
	29	*
	30	* Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
	31	* lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
	32	* lib_ring_buffer_write().
	33	*
	34	* IMPORTANT: this structure is part of the ABI between the probe and
	35	* UST. Fields need to be only added at the end, never reordered, never
	36	* removed.
	37	*
	38	* The field @struct_size should be used to determine the size of the
	39	* structure. It should be queried before using additional fields added
	40	* at the end of the structure.
	41	*/
	42	struct lttng_ust_lib_ring_buffer_ctx {
	43	uint32_t struct_size; /* Size of this structure. */
	44
	45	/* input received by lib_ring_buffer_reserve(), saved here. */
	46	struct lttng_ust_lib_ring_buffer_channel chan; / channel */
	47	void priv; / client private data */
	48	struct lttng_ust_shm_handle handle; / shared-memory handle */
	49	size_t data_size; /* size of payload */
	50	int largest_align; /*
	51	* alignment of the largest element
	52	* in the payload
	53	*/
0f3a182f MD	54
0f3a182f MD	55	/* output from lib_ring_buffer_reserve() */
7489fcb4	56	int reserve_cpu; /* processor id updated by the reserve */
0f3a182f MD	57	struct lttng_ust_lib_ring_buffer buf; /
	58	* buffer corresponding to processor id
	59	* for this channel
	60	*/
	61	size_t slot_size; /* size of the reserved slot */
	62	unsigned long buf_offset; /* offset following the record header */
	63	unsigned long pre_offset; /*
	64	* Initial offset position _before_
	65	* the record is written. Positioned
	66	* prior to record header alignment
	67	* padding.
	68	*/
	69	uint64_t tsc; /* time-stamp counter value */
	70	unsigned int rflags; /* reservation flags */
	71	void ip; / caller ip address */
	72	struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
	73
	74	/* End of base ABI. Fields below should be used after checking struct_size. */
	75	};
	76
	77	/**
	78	* lib_ring_buffer_ctx_init - initialize ring buffer context
	79	* @ctx: ring buffer context to initialize
	80	* @chan: channel
	81	* @priv: client private data
	82	* @data_size: size of record data payload
	83	* @largest_align: largest alignment within data payload types
0f3a182f MD	84	*/
	85	static inline lttng_ust_notrace
	86	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	87	struct lttng_ust_lib_ring_buffer_channel *chan,
	88	void *priv, size_t data_size, int largest_align,
7489fcb4	89	struct lttng_ust_shm_handle *handle);
0f3a182f MD	90	static inline
	91	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	92	struct lttng_ust_lib_ring_buffer_channel *chan,
	93	void *priv, size_t data_size, int largest_align,
7489fcb4	94	struct lttng_ust_shm_handle *handle)
0f3a182f MD	95	{
	96	ctx->struct_size = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
	97	ctx->chan = chan;
	98	ctx->priv = priv;
	99	ctx->data_size = data_size;
7489fcb4	100	ctx->reserve_cpu = -1;
0f3a182f	101	ctx->largest_align = largest_align;
0f3a182f MD	102	ctx->rflags = 0;
	103	ctx->handle = handle;
	104	ctx->ip = 0;
	105	}
	106
	107	/*
	108	* We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
	109	* compile-time. We have to duplicate the "config->align" information and the
	110	* definition here because config->align is used both in the slow and fast
	111	* paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
	112	*/
	113	#ifdef RING_BUFFER_ALIGN
	114
	115	# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
	116
	117	/*
	118	* Calculate the offset needed to align the type.
	119	* size_of_type must be non-zero.
	120	*/
	121	static inline lttng_ust_notrace
	122	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
	123	static inline
	124	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	125	{
	126	return lttng_ust_offset_align(align_drift, size_of_type);
	127	}
	128
	129	#else
	130
	131	# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
	132
	133	/*
	134	* Calculate the offset needed to align the type.
	135	* size_of_type must be non-zero.
	136	*/
	137	static inline lttng_ust_notrace
	138	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
	139	static inline
	140	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	141	{
	142	return 0;
	143	}
	144
	145	#endif
	146
	147	/**
	148	* lib_ring_buffer_align_ctx - Align context offset on "alignment"
	149	* @ctx: ring buffer context.
	150	*/
	151	static inline lttng_ust_notrace
	152	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	153	size_t alignment);
	154	static inline
	155	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	156	size_t alignment)
	157	{
	158	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
	159	alignment);
	160	}
	161
	162	#endif /* _LTTNG_RING_BUFFER_CONTEXT_H */