[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;

extern int vclocks_used;
static inline bool vclock_was_used(int vclock)
{
	return READ_ONCE(vclocks_used) & (1 << vclock);
}

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;
}

#ifdef CONFIG_X86_64

#define VGETCPU_CPU_MASK 0xfff

static inline unsigned int __getcpu(void)
{
	unsigned int p;

	/*
	 * Load per CPU data from GDT.  LSL is faster than RDTSCP and
	 * works on all CPUs.  This is volatile so that it orders
	 * correctly wrt barrier() and to keep gcc from cleverly
	 * hoisting it out of the calling function.
	 */
	asm volatile ("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));

	return p;
}

#endif /* CONFIG_X86_64 */

#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
bd902c53 AL	40	extern int vclocks_used;
	41	static inline bool vclock_was_used(int vclock)
	42	{
	43	return READ_ONCE(vclocks_used) & (1 << vclock);
	44	}
	45
7c03156f SS	46	static inline unsigned gtod_read_begin(const struct vsyscall_gtod_data *s)
	47	{
	48	unsigned ret;
	49
	50	repeat:
	51	ret = ACCESS_ONCE(s->seq);
	52	if (unlikely(ret & 1)) {
	53	cpu_relax();
	54	goto repeat;
	55	}
	56	smp_rmb();
	57	return ret;
	58	}
	59
	60	static inline int gtod_read_retry(const struct vsyscall_gtod_data *s,
	61	unsigned start)
	62	{
	63	smp_rmb();
	64	return unlikely(s->seq != start);
	65	}
	66
	67	static inline void gtod_write_begin(struct vsyscall_gtod_data *s)
	68	{
	69	++s->seq;
	70	smp_wmb();
	71	}
	72
	73	static inline void gtod_write_end(struct vsyscall_gtod_data *s)
	74	{
	75	smp_wmb();
	76	++s->seq;
	77	}
	78
e76b027e AL	79	#ifdef CONFIG_X86_64
	80
	81	#define VGETCPU_CPU_MASK 0xfff
	82
	83	static inline unsigned int __getcpu(void)
	84	{
	85	unsigned int p;
	86
	87	/*
	88	* Load per CPU data from GDT. LSL is faster than RDTSCP and
1ddf0b1b AL	89	* works on all CPUs. This is volatile so that it orders
	90	* correctly wrt barrier() and to keep gcc from cleverly
	91	* hoisting it out of the calling function.
e76b027e	92	*/
1ddf0b1b	93	asm volatile ("lsl %1,%0" : "=r" (p) : "r" (__PER_CPU_SEG));
e76b027e AL	94
	95	return p;
	96	}
	97
	98	#endif /* CONFIG_X86_64 */
	99
1965aae3	100	#endif /* _ASM_X86_VGTOD_H */