[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-utils.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;

/*
 * 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(). */
	struct lttng_ust_lib_ring_buffer_channel *chan; /* channel */
	void *priv;				/* client private data */
	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 */
	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 *buf;	/*
						 * buffer corresponding to processor id
						 * for this channel
						 */
	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);
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)
{
	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->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
3d3a2bb8 MJ	18	#include <lttng/ust-tracer.h>
eae3c729	19	#include <lttng/ust-utils.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;
0f3a182f MD	25
	26	/*
	27	* ring buffer context
	28	*
	29	* Context passed to lib_ring_buffer_reserve(), lib_ring_buffer_commit(),
	30	* lib_ring_buffer_try_discard_reserve(), lib_ring_buffer_align_ctx() and
	31	* lib_ring_buffer_write().
	32	*
	33	* IMPORTANT: this structure is part of the ABI between the probe and
	34	* UST. Fields need to be only added at the end, never reordered, never
	35	* removed.
	36	*
	37	* The field @struct_size should be used to determine the size of the
	38	* structure. It should be queried before using additional fields added
	39	* at the end of the structure.
	40	*/
	41	struct lttng_ust_lib_ring_buffer_ctx {
07539b34	42	uint32_t struct_size; /* Size of this structure. */
0f3a182f	43
07539b34	44	/* input received by lib_ring_buffer_reserve(). */
0f3a182f	45	struct lttng_ust_lib_ring_buffer_channel chan; / channel */
07539b34 MD	46	void priv; / client private data */
	47	size_t data_size; /* size of payload */
	48	int largest_align; /*
	49	* alignment of the largest element
	50	* in the payload
	51	*/
0f3a182f MD	52
0f3a182f MD	53	/* output from lib_ring_buffer_reserve() */
07539b34 MD	54	int reserve_cpu; /* processor id updated by the reserve */
	55	size_t slot_size; /* size of the reserved slot */
	56	unsigned long buf_offset; /* offset following the record header */
	57	unsigned long pre_offset; /*
	58	* Initial offset position _before_
	59	* the record is written. Positioned
	60	* prior to record header alignment
	61	* padding.
	62	*/
	63	uint64_t tsc; /* time-stamp counter value */
	64	unsigned int rflags; /* reservation flags */
	65	void ip; / caller ip address */
	66
0f3a182f	67	struct lttng_ust_lib_ring_buffer buf; /
07539b34 MD	68	* buffer corresponding to processor id
	69	* for this channel
	70	*/
0f3a182f MD	71	struct lttng_ust_lib_ring_buffer_backend_pages *backend_pages;
	72
	73	/* End of base ABI. Fields below should be used after checking struct_size. */
	74	};
	75
	76	/**
	77	* lib_ring_buffer_ctx_init - initialize ring buffer context
	78	* @ctx: ring buffer context to initialize
	79	* @chan: channel
	80	* @priv: client private data
	81	* @data_size: size of record data payload
	82	* @largest_align: largest alignment within data payload types
0f3a182f MD	83	*/
	84	static inline lttng_ust_notrace
	85	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	86	struct lttng_ust_lib_ring_buffer_channel *chan,
aab8b172	87	void *priv, size_t data_size, int largest_align);
0f3a182f MD	88	static inline
	89	void lib_ring_buffer_ctx_init(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	90	struct lttng_ust_lib_ring_buffer_channel *chan,
aab8b172	91	void *priv, size_t data_size, int largest_align)
0f3a182f MD	92	{
	93	ctx->struct_size = sizeof(struct lttng_ust_lib_ring_buffer_ctx);
	94	ctx->chan = chan;
	95	ctx->priv = priv;
	96	ctx->data_size = data_size;
7489fcb4	97	ctx->reserve_cpu = -1;
0f3a182f	98	ctx->largest_align = largest_align;
0f3a182f	99	ctx->rflags = 0;
0f3a182f MD	100	ctx->ip = 0;
	101	}
	102
	103	/*
	104	* We need to define RING_BUFFER_ALIGN_ATTR so it is known early at
	105	* compile-time. We have to duplicate the "config->align" information and the
	106	* definition here because config->align is used both in the slow and fast
	107	* paths, but RING_BUFFER_ALIGN_ATTR is only available for the client code.
	108	*/
	109	#ifdef RING_BUFFER_ALIGN
	110
	111	# define RING_BUFFER_ALIGN_ATTR /* Default arch alignment */
	112
	113	/*
	114	* Calculate the offset needed to align the type.
	115	* size_of_type must be non-zero.
	116	*/
	117	static inline lttng_ust_notrace
	118	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
	119	static inline
	120	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	121	{
	122	return lttng_ust_offset_align(align_drift, size_of_type);
	123	}
	124
	125	#else
	126
	127	# define RING_BUFFER_ALIGN_ATTR __attribute__((packed))
	128
	129	/*
	130	* Calculate the offset needed to align the type.
	131	* size_of_type must be non-zero.
	132	*/
	133	static inline lttng_ust_notrace
	134	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type);
	135	static inline
	136	unsigned int lib_ring_buffer_align(size_t align_drift, size_t size_of_type)
	137	{
	138	return 0;
	139	}
	140
	141	#endif
	142
	143	/**
	144	* lib_ring_buffer_align_ctx - Align context offset on "alignment"
	145	* @ctx: ring buffer context.
	146	*/
	147	static inline lttng_ust_notrace
	148	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	149	size_t alignment);
	150	static inline
	151	void lib_ring_buffer_align_ctx(struct lttng_ust_lib_ring_buffer_ctx *ctx,
	152	size_t alignment)
	153	{
	154	ctx->buf_offset += lib_ring_buffer_align(ctx->buf_offset,
	155	alignment);
	156	}
	157
	158	#endif /* _LTTNG_RING_BUFFER_CONTEXT_H */