[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 <lttng/ust-tracer.h>
#include <stdint.h>
#include <stddef.h>
#include <urcu/arch.h>
#include <string.h>
#include <lttng/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
					 */
	int cpu;			/* processor id */

	/* output from lib_ring_buffer_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
 * @cpu: processor id
 */
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,
			      int cpu, 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,
			      int cpu, 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->largest_align = largest_align;
	ctx->cpu = cpu;
	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>
	13	#include <lttng/ust-tracer.h>
	14	#include <stdint.h>
	15	#include <stddef.h>
	16	#include <urcu/arch.h>
	17	#include <string.h>
	18	#include <lttng/align.h>
	19	#include <lttng/ust-compiler.h>
	20
	21	struct lttng_ust_lib_ring_buffer;
	22	struct lttng_ust_lib_ring_buffer_channel;
	23	struct lttng_ust_lib_ring_buffer_ctx;
	24	struct lttng_ust_shm_handle;
	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 {
	42	uint32_t struct_size; /* Size of this structure. */
	43
	44	/* input received by lib_ring_buffer_reserve(), saved here. */
	45	struct lttng_ust_lib_ring_buffer_channel chan; / channel */
	46	void priv; / client private data */
	47	struct lttng_ust_shm_handle handle; / shared-memory handle */
	48	size_t data_size; /* size of payload */
	49	int largest_align; /*
	50	* alignment of the largest element
	51	* in the payload
	52	*/
	53	int cpu; /* processor id */
	54
	55	/* output from lib_ring_buffer_reserve() */
	56	struct lttng_ust_lib_ring_buffer buf; /
	57	* buffer corresponding to processor id
	58	* for this channel
	59	*/
	60	size_t slot_size; /* size of the reserved slot */
	61	unsigned long buf_offset; /* offset following the record header */
	62	unsigned long pre_offset; /*
	63	* Initial offset position _before_
	64	* the record is written. Positioned
65	* prior to record header alignment
66	* padding.
67	*/
68	uint64_t tsc; /* time-stamp counter value */
69	unsigned int rflags; /* reservation flags */
70	void ip; / caller ip address */
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
83	* @cpu: processor id
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,
89	int cpu, struct lttng_ust_shm_handle *handle);
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,
94	int cpu, struct lttng_ust_shm_handle *handle)
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;
100	ctx->largest_align = largest_align;
101	ctx->cpu = cpu;
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 */