[lttng-ust.git] / include / lttng / align.h

/*
 * SPDX-License-Identifier: MIT
 *
 * Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 */

#ifndef _UST_ALIGN_H
#define _UST_ALIGN_H

#include <lttng/bug.h>
#include <unistd.h>
#include <limits.h>

#ifdef __FreeBSD__
#include <machine/param.h>
#endif

#ifdef _SC_PAGE_SIZE
#define LTTNG_UST_PAGE_SIZE	sysconf(_SC_PAGE_SIZE)
#elif defined(PAGE_SIZE)
#define LTTNG_UST_PAGE_SIZE	PAGE_SIZE
#else
#error "Please add page size detection for your OS."
#endif

#define LTTNG_UST_PAGE_MASK	(~(LTTNG_UST_PAGE_SIZE - 1))

#define __LTTNG_UST_ALIGN_MASK(v, mask)	(((v) + (mask)) & ~(mask))
#define LTTNG_UST_ALIGN(v, align)	__LTTNG_UST_ALIGN_MASK(v, (__typeof__(v)) (align) - 1)
#define LTTNG_UST_PAGE_ALIGN(addr)	LTTNG_UST_ALIGN(addr, LTTNG_UST_PAGE_SIZE)

/**
 * lttng_ust_offset_align - Calculate the offset needed to align an object on
 *                its natural alignment towards higher addresses.
 * @align_drift:  object offset from an "alignment"-aligned address.
 * @alignment:    natural object alignment. Must be non-zero, power of 2.
 *
 * Returns the offset that must be added to align towards higher
 * addresses.
 */
#define lttng_ust_offset_align(align_drift, alignment)			       \
	({								       \
		LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0		       \
				   || ((alignment) & ((alignment) - 1)));      \
		(((alignment) - (align_drift)) & ((alignment) - 1));	       \
	})

/**
 * lttng_ust_offset_align_floor - Calculate the offset needed to align an
 *                object on its natural alignment towards lower addresses.
 * @align_drift:  object offset from an "alignment"-aligned address.
 * @alignment:    natural object alignment. Must be non-zero, power of 2.
 *
 * Returns the offset that must be substracted to align towards lower addresses.
 */
#define lttng_ust_offset_align_floor(align_drift, alignment)		       \
	({								       \
		LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0		       \
				   || ((alignment) & ((alignment) - 1)));      \
		(((align_drift) - (alignment)) & ((alignment) - 1));	       \
	})

/*
 * Non-namespaced defines for backwards compatibility,
 * introduced in 2.13, should be removed in the future.
 */

/* Cygwin limits.h defines its own PAGE_SIZE */
#ifndef PAGE_SIZE
#define PAGE_SIZE	LTTNG_UST_PAGE_SIZE
#endif

/* FreeBSD and macOS defines their own PAGE_MASK. */
#ifndef PAGE_MASK
#define PAGE_MASK	LTTNG_UST_PAGE_MASK
#endif

/* FreeBSD machine/param.h defines its own ALIGN */
#ifndef ALIGN
#define ALIGN		LTTNG_UST_ALIGN
#endif

#ifndef PAGE_ALIGN
#define PAGE_ALIGN	LTTNG_UST_PAGE_ALIGN
#endif

#ifndef offset_align
#define offset_align lttng_ust_offset_align
#endif

#ifndef offset_align_floor
#define offset_align_floor lttng_ust_offset_align_floor
#endif

#endif /* _UST_ALIGN_H */
Commit	Line	Data
	1	/*
	2	* SPDX-License-Identifier: MIT
	3	*
	4	* Copyright (C) 2010-2011 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	5	*/
	6
	7	#ifndef _UST_ALIGN_H
	8	#define _UST_ALIGN_H
	9
	10	#include <lttng/bug.h>
	11	#include <unistd.h>
	12	#include <limits.h>
	13
	14	#ifdef __FreeBSD__
	15	#include <machine/param.h>
	16	#endif
	17
	18	#ifdef _SC_PAGE_SIZE
	19	#define LTTNG_UST_PAGE_SIZE sysconf(_SC_PAGE_SIZE)
	20	#elif defined(PAGE_SIZE)
	21	#define LTTNG_UST_PAGE_SIZE PAGE_SIZE
	22	#else
	23	#error "Please add page size detection for your OS."
	24	#endif
	25
	26	#define LTTNG_UST_PAGE_MASK (~(LTTNG_UST_PAGE_SIZE - 1))
	27
	28	#define __LTTNG_UST_ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
	29	#define LTTNG_UST_ALIGN(v, align) __LTTNG_UST_ALIGN_MASK(v, (__typeof__(v)) (align) - 1)
	30	#define LTTNG_UST_PAGE_ALIGN(addr) LTTNG_UST_ALIGN(addr, LTTNG_UST_PAGE_SIZE)
	31
	32	/**
	33	* lttng_ust_offset_align - Calculate the offset needed to align an object on
	34	* its natural alignment towards higher addresses.
	35	* @align_drift: object offset from an "alignment"-aligned address.
	36	* @alignment: natural object alignment. Must be non-zero, power of 2.
	37	*
	38	* Returns the offset that must be added to align towards higher
	39	* addresses.
	40	*/
	41	#define lttng_ust_offset_align(align_drift, alignment) \
	42	({ \
	43	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	44	\|\| ((alignment) & ((alignment) - 1))); \
	45	(((alignment) - (align_drift)) & ((alignment) - 1)); \
	46	})
	47
	48	/**
	49	* lttng_ust_offset_align_floor - Calculate the offset needed to align an
	50	* object on its natural alignment towards lower addresses.
	51	* @align_drift: object offset from an "alignment"-aligned address.
	52	* @alignment: natural object alignment. Must be non-zero, power of 2.
	53	*
	54	* Returns the offset that must be substracted to align towards lower addresses.
	55	*/
	56	#define lttng_ust_offset_align_floor(align_drift, alignment) \
	57	({ \
	58	LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
	59	\|\| ((alignment) & ((alignment) - 1))); \
	60	(((align_drift) - (alignment)) & ((alignment) - 1)); \
	61	})
	62
	63	/*
	64	* Non-namespaced defines for backwards compatibility,
	65	* introduced in 2.13, should be removed in the future.
	66	*/
	67
	68	/* Cygwin limits.h defines its own PAGE_SIZE */
	69	#ifndef PAGE_SIZE
	70	#define PAGE_SIZE LTTNG_UST_PAGE_SIZE
	71	#endif
	72
	73	/* FreeBSD and macOS defines their own PAGE_MASK. */
	74	#ifndef PAGE_MASK
	75	#define PAGE_MASK LTTNG_UST_PAGE_MASK
	76	#endif
	77
	78	/* FreeBSD machine/param.h defines its own ALIGN */
	79	#ifndef ALIGN
	80	#define ALIGN LTTNG_UST_ALIGN
	81	#endif
	82
	83	#ifndef PAGE_ALIGN
	84	#define PAGE_ALIGN LTTNG_UST_PAGE_ALIGN
	85	#endif
	86
	87	#ifndef offset_align
	88	#define offset_align lttng_ust_offset_align
	89	#endif
	90
	91	#ifndef offset_align_floor
	92	#define offset_align_floor lttng_ust_offset_align_floor
	93	#endif
	94
	95	#endif /* _UST_ALIGN_H */