[deliverable/linux.git] / arch / x86 / include / asm / vgtod.h

#ifndef _ASM_X86_VGTOD_H
#define _ASM_X86_VGTOD_H

#include <linux/compiler.h>
#include <linux/clocksource.h>

#ifdef BUILD_VDSO32_64
typedef u64 gtod_long_t;
#else
typedef unsigned long gtod_long_t;
#endif
/*
 * vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time
 * so be carefull by modifying this structure.
 */
struct vsyscall_gtod_data {
	unsigned seq;

	int vclock_mode;
	cycle_t	cycle_last;
	cycle_t	mask;
	u32	mult;
	u32	shift;

	/* open coded 'struct timespec' */
	u64		wall_time_snsec;
	gtod_long_t	wall_time_sec;
	gtod_long_t	monotonic_time_sec;
	u64		monotonic_time_snsec;
	gtod_long_t	wall_time_coarse_sec;
	gtod_long_t	wall_time_coarse_nsec;
	gtod_long_t	monotonic_time_coarse_sec;
	gtod_long_t	monotonic_time_coarse_nsec;

	int		tz_minuteswest;
	int		tz_dsttime;
};
extern struct vsyscall_gtod_data vsyscall_gtod_data;

static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s)
{
	unsigned ret;

repeat:
	ret = ACCESS_ONCE(s->seq);
	if (unlikely(ret & 1)) {
		cpu_relax();
		goto repeat;
	}
	smp_rmb();
	return ret;
}

static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
					unsigned start)
{
	smp_rmb();
	return unlikely(s->seq != start);
}

static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
{
	++s->seq;
	smp_wmb();
}

static inline void gtod_write_end(struct vsyscall_gtod_data *s)
{
	smp_wmb();
	++s->seq;
}

#endif /* _ASM_X86_VGTOD_H */
Commit	Line	Data
1965aae3 PA	1	#ifndef _ASM_X86_VGTOD_H
1965aae3 PA	2	#define _ASM_X86_VGTOD_H
2aae950b	3
7c03156f	4	#include <linux/compiler.h>
2aae950b AK	5	#include <linux/clocksource.h>
2aae950b AK	6
7c03156f SS	7	#ifdef BUILD_VDSO32_64
	8	typedef u64 gtod_long_t;
	9	#else
	10	typedef unsigned long gtod_long_t;
	11	#endif
	12	/*
	13	* vsyscall_gtod_data will be accessed by 32 and 64 bit code at the same time
	14	* so be carefull by modifying this structure.
	15	*/
2aae950b	16	struct vsyscall_gtod_data {
7c03156f	17	unsigned seq;
2aae950b	18
7c03156f SS	19	int vclock_mode;
	20	cycle_t cycle_last;
	21	cycle_t mask;
	22	u32 mult;
	23	u32 shift;
91ec87d5 AL	24
91ec87d5 AL	25	/* open coded 'struct timespec' */
650ea024	26	u64 wall_time_snsec;
7c03156f SS	27	gtod_long_t wall_time_sec;
7c03156f SS	28	gtod_long_t monotonic_time_sec;
650ea024	29	u64 monotonic_time_snsec;
7c03156f SS	30	gtod_long_t wall_time_coarse_sec;
	31	gtod_long_t wall_time_coarse_nsec;
	32	gtod_long_t monotonic_time_coarse_sec;
	33	gtod_long_t monotonic_time_coarse_nsec;
91ec87d5	34
7c03156f SS	35	int tz_minuteswest;
7c03156f SS	36	int tz_dsttime;
2aae950b	37	};
2aae950b AK	38	extern struct vsyscall_gtod_data vsyscall_gtod_data;
2aae950b AK	39
7c03156f SS	40	static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s)
	41	{
	42	unsigned ret;
	43
	44	repeat:
	45	ret = ACCESS_ONCE(s->seq);
	46	if (unlikely(ret & 1)) {
	47	cpu_relax();
	48	goto repeat;
	49	}
	50	smp_rmb();
	51	return ret;
	52	}
	53
	54	static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
	55	unsigned start)
	56	{
	57	smp_rmb();
	58	return unlikely(s->seq != start);
	59	}
	60
	61	static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
	62	{
	63	++s->seq;
	64	smp_wmb();
	65	}
	66
	67	static inline void gtod_write_end(struct vsyscall_gtod_data *s)
	68	{
	69	smp_wmb();
	70	++s->seq;
	71	}
	72
1965aae3	73	#endif /* _ASM_X86_VGTOD_H */