[linux-2.6-block.git] / arch / x86 / vdso / vclock_gettime.c

/*
 * Copyright 2006 Andi Kleen, SUSE Labs.
 * Subject to the GNU Public License, v.2
 *
 * Fast user context implementation of clock_gettime, gettimeofday, and time.
 *
 * 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
 *  sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
 *
 * The code should have no internal unresolved relocations.
 * Check with readelf after changing.
 */

#include <uapi/linux/time.h>
#include <asm/vgtod.h>
#include <asm/hpet.h>
#include <asm/vvar.h>
#include <asm/unistd.h>
#include <asm/msr.h>
#include <linux/math64.h>
#include <linux/time.h>

#define gtod (&VVAR(vsyscall_gtod_data))

extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
extern int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz);
extern time_t __vdso_time(time_t *t);

#ifdef CONFIG_HPET_TIMER
extern u8 hpet_page
	__attribute__((visibility("hidden")));

static notrace cycle_t vread_hpet(void)
{
	return *(const volatile u32 *)(&hpet_page + HPET_COUNTER);
}
#endif

#ifndef BUILD_VDSO32

#include <linux/kernel.h>
#include <asm/vsyscall.h>
#include <asm/fixmap.h>
#include <asm/pvclock.h>

notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
{
	long ret;
	asm("syscall" : "=a" (ret) :
	    "0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
	return ret;
}

notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
{
	long ret;

	asm("syscall" : "=a" (ret) :
	    "0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
	return ret;
}

#ifdef CONFIG_PARAVIRT_CLOCK

static notrace const struct pvclock_vsyscall_time_info *get_pvti(int cpu)
{
	const struct pvclock_vsyscall_time_info *pvti_base;
	int idx = cpu / (PAGE_SIZE/PVTI_SIZE);
	int offset = cpu % (PAGE_SIZE/PVTI_SIZE);

	BUG_ON(PVCLOCK_FIXMAP_BEGIN + idx > PVCLOCK_FIXMAP_END);

	pvti_base = (struct pvclock_vsyscall_time_info *)
		    __fix_to_virt(PVCLOCK_FIXMAP_BEGIN+idx);

	return &pvti_base[offset];
}

static notrace cycle_t vread_pvclock(int *mode)
{
	const struct pvclock_vsyscall_time_info *pvti;
	cycle_t ret;
	u64 last;
	u32 version;
	u8 flags;
	unsigned cpu, cpu1;


	/*
	 * Note: hypervisor must guarantee that:
	 * 1. cpu ID number maps 1:1 to per-CPU pvclock time info.
	 * 2. that per-CPU pvclock time info is updated if the
	 *    underlying CPU changes.
	 * 3. that version is increased whenever underlying CPU
	 *    changes.
	 *
	 */
	do {
		cpu = __getcpu() & VGETCPU_CPU_MASK;
		/* TODO: We can put vcpu id into higher bits of pvti.version.
		 * This will save a couple of cycles by getting rid of
		 * __getcpu() calls (Gleb).
		 */

		pvti = get_pvti(cpu);

		version = __pvclock_read_cycles(&pvti->pvti, &ret, &flags);

		/*
		 * Test we're still on the cpu as well as the version.
		 * We could have been migrated just after the first
		 * vgetcpu but before fetching the version, so we
		 * wouldn't notice a version change.
		 */
		cpu1 = __getcpu() & VGETCPU_CPU_MASK;
	} while (unlikely(cpu != cpu1 ||
			  (pvti->pvti.version & 1) ||
			  pvti->pvti.version != version));

	if (unlikely(!(flags & PVCLOCK_TSC_STABLE_BIT)))
		*mode = VCLOCK_NONE;

	/* refer to tsc.c read_tsc() comment for rationale */
	last = gtod->cycle_last;

	if (likely(ret >= last))
		return ret;

	return last;
}
#endif

#else

notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
{
	long ret;

	asm(
		"mov %%ebx, %%edx \n"
		"mov %2, %%ebx \n"
		"call __kernel_vsyscall \n"
		"mov %%edx, %%ebx \n"
		: "=a" (ret)
		: "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
		: "memory", "edx");
	return ret;
}

notrace static long vdso_fallback_gtod(struct timeval *tv, struct timezone *tz)
{
	long ret;

	asm(
		"mov %%ebx, %%edx \n"
		"mov %2, %%ebx \n"
		"call __kernel_vsyscall \n"
		"mov %%edx, %%ebx \n"
		: "=a" (ret)
		: "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
		: "memory", "edx");
	return ret;
}

#ifdef CONFIG_PARAVIRT_CLOCK

static notrace cycle_t vread_pvclock(int *mode)
{
	*mode = VCLOCK_NONE;
	return 0;
}
#endif

#endif

notrace static cycle_t vread_tsc(void)
{
	cycle_t ret;
	u64 last;

	/*
	 * Empirically, a fence (of type that depends on the CPU)
	 * before rdtsc is enough to ensure that rdtsc is ordered
	 * with respect to loads.  The various CPU manuals are unclear
	 * as to whether rdtsc can be reordered with later loads,
	 * but no one has ever seen it happen.
	 */
	rdtsc_barrier();
	ret = (cycle_t)__native_read_tsc();

	last = gtod->cycle_last;

	if (likely(ret >= last))
		return ret;

	/*
	 * GCC likes to generate cmov here, but this branch is extremely
	 * predictable (it's just a funciton of time and the likely is
	 * very likely) and there's a data dependence, so force GCC
	 * to generate a branch instead.  I don't barrier() because
	 * we don't actually need a barrier, and if this function
	 * ever gets inlined it will generate worse code.
	 */
	asm volatile ("");
	return last;
}

notrace static inline u64 vgetsns(int *mode)
{
	u64 v;
	cycles_t cycles;

	if (gtod->vclock_mode == VCLOCK_TSC)
		cycles = vread_tsc();
#ifdef CONFIG_HPET_TIMER
	else if (gtod->vclock_mode == VCLOCK_HPET)
		cycles = vread_hpet();
#endif
#ifdef CONFIG_PARAVIRT_CLOCK
	else if (gtod->vclock_mode == VCLOCK_PVCLOCK)
		cycles = vread_pvclock(mode);
#endif
	else
		return 0;
	v = (cycles - gtod->cycle_last) & gtod->mask;
	return v * gtod->mult;
}

/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
notrace static int __always_inline do_realtime(struct timespec *ts)
{
	unsigned long seq;
	u64 ns;
	int mode;

	do {
		seq = gtod_read_begin(gtod);
		mode = gtod->vclock_mode;
		ts->tv_sec = gtod->wall_time_sec;
		ns = gtod->wall_time_snsec;
		ns += vgetsns(&mode);
		ns >>= gtod->shift;
	} while (unlikely(gtod_read_retry(gtod, seq)));

	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
	ts->tv_nsec = ns;

	return mode;
}

notrace static int __always_inline do_monotonic(struct timespec *ts)
{
	unsigned long seq;
	u64 ns;
	int mode;

	do {
		seq = gtod_read_begin(gtod);
		mode = gtod->vclock_mode;
		ts->tv_sec = gtod->monotonic_time_sec;
		ns = gtod->monotonic_time_snsec;
		ns += vgetsns(&mode);
		ns >>= gtod->shift;
	} while (unlikely(gtod_read_retry(gtod, seq)));

	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
	ts->tv_nsec = ns;

	return mode;
}

notrace static void do_realtime_coarse(struct timespec *ts)
{
	unsigned long seq;
	do {
		seq = gtod_read_begin(gtod);
		ts->tv_sec = gtod->wall_time_coarse_sec;
		ts->tv_nsec = gtod->wall_time_coarse_nsec;
	} while (unlikely(gtod_read_retry(gtod, seq)));
}

notrace static void do_monotonic_coarse(struct timespec *ts)
{
	unsigned long seq;
	do {
		seq = gtod_read_begin(gtod);
		ts->tv_sec = gtod->monotonic_time_coarse_sec;
		ts->tv_nsec = gtod->monotonic_time_coarse_nsec;
	} while (unlikely(gtod_read_retry(gtod, seq)));
}

notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
{
	switch (clock) {
	case CLOCK_REALTIME:
		if (do_realtime(ts) == VCLOCK_NONE)
			goto fallback;
		break;
	case CLOCK_MONOTONIC:
		if (do_monotonic(ts) == VCLOCK_NONE)
			goto fallback;
		break;
	case CLOCK_REALTIME_COARSE:
		do_realtime_coarse(ts);
		break;
	case CLOCK_MONOTONIC_COARSE:
		do_monotonic_coarse(ts);
		break;
	default:
		goto fallback;
	}

	return 0;
fallback:
	return vdso_fallback_gettime(clock, ts);
}
int clock_gettime(clockid_t, struct timespec *)
	__attribute__((weak, alias("__vdso_clock_gettime")));

notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
	if (likely(tv != NULL)) {
		if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
			return vdso_fallback_gtod(tv, tz);
		tv->tv_usec /= 1000;
	}
	if (unlikely(tz != NULL)) {
		tz->tz_minuteswest = gtod->tz_minuteswest;
		tz->tz_dsttime = gtod->tz_dsttime;
	}

	return 0;
}
int gettimeofday(struct timeval *, struct timezone *)
	__attribute__((weak, alias("__vdso_gettimeofday")));

/*
 * This will break when the xtime seconds get inaccurate, but that is
 * unlikely
 */
notrace time_t __vdso_time(time_t *t)
{
	/* This is atomic on x86 so we don't need any locks. */
	time_t result = ACCESS_ONCE(gtod->wall_time_sec);

	if (t)
		*t = result;
	return result;
}
int time(time_t *t)
	__attribute__((weak, alias("__vdso_time")));
Commit	Line	Data
2aae950b AK	1	/*
	2	* Copyright 2006 Andi Kleen, SUSE Labs.
	3	* Subject to the GNU Public License, v.2
	4	*
f144a6b4	5	* Fast user context implementation of clock_gettime, gettimeofday, and time.
2aae950b	6	*
7a59ed41 SS	7	* 32 Bit compat layer by Stefani Seibold <stefani@seibold.net>
	8	* sponsored by Rohde & Schwarz GmbH & Co. KG Munich/Germany
	9	*
2aae950b AK	10	* The code should have no internal unresolved relocations.
2aae950b AK	11	* Check with readelf after changing.
2aae950b AK	12	*/
2aae950b AK	13
7a59ed41	14	#include <uapi/linux/time.h>
2aae950b	15	#include <asm/vgtod.h>
2aae950b	16	#include <asm/hpet.h>
7c03156f	17	#include <asm/vvar.h>
2aae950b	18	#include <asm/unistd.h>
7c03156f SS	19	#include <asm/msr.h>
	20	#include <linux/math64.h>
	21	#include <linux/time.h>
2aae950b	22
8c49d9a7	23	#define gtod (&VVAR(vsyscall_gtod_data))
2aae950b	24
7a59ed41 SS	25	extern int __vdso_clock_gettime(clockid_t clock, struct timespec *ts);
	26	extern int __vdso_gettimeofday(struct timeval tv, struct timezone tz);
	27	extern time_t __vdso_time(time_t *t);
	28
7c03156f	29	#ifdef CONFIG_HPET_TIMER
f40c3300 AL	30	extern u8 hpet_page
	31	__attribute__((visibility("hidden")));
	32
	33	static notrace cycle_t vread_hpet(void)
7c03156f	34	{
f40c3300	35	return (const volatile u32 )(&hpet_page + HPET_COUNTER);
7c03156f SS	36	}
	37	#endif
	38
7a59ed41 SS	39	#ifndef BUILD_VDSO32
7a59ed41 SS	40
7c03156f SS	41	#include <linux/kernel.h>
	42	#include <asm/vsyscall.h>
	43	#include <asm/fixmap.h>
	44	#include <asm/pvclock.h>
	45
411f790c SS	46	notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
	47	{
	48	long ret;
	49	asm("syscall" : "=a" (ret) :
	50	"0" (__NR_clock_gettime), "D" (clock), "S" (ts) : "memory");
	51	return ret;
98d0ac38 AL	52	}
98d0ac38 AL	53
411f790c	54	notrace static long vdso_fallback_gtod(struct timeval tv, struct timezone tz)
98d0ac38	55	{
411f790c SS	56	long ret;
	57
	58	asm("syscall" : "=a" (ret) :
	59	"0" (__NR_gettimeofday), "D" (tv), "S" (tz) : "memory");
	60	return ret;
98d0ac38 AL	61	}
98d0ac38 AL	62
51c19b4f MT	63	#ifdef CONFIG_PARAVIRT_CLOCK
	64
	65	static notrace const struct pvclock_vsyscall_time_info *get_pvti(int cpu)
	66	{
	67	const struct pvclock_vsyscall_time_info *pvti_base;
	68	int idx = cpu / (PAGE_SIZE/PVTI_SIZE);
	69	int offset = cpu % (PAGE_SIZE/PVTI_SIZE);
	70
	71	BUG_ON(PVCLOCK_FIXMAP_BEGIN + idx > PVCLOCK_FIXMAP_END);
	72
	73	pvti_base = (struct pvclock_vsyscall_time_info *)
	74	__fix_to_virt(PVCLOCK_FIXMAP_BEGIN+idx);
	75
	76	return &pvti_base[offset];
	77	}
	78
	79	static notrace cycle_t vread_pvclock(int *mode)
	80	{
	81	const struct pvclock_vsyscall_time_info *pvti;
	82	cycle_t ret;
	83	u64 last;
	84	u32 version;
51c19b4f MT	85	u8 flags;
	86	unsigned cpu, cpu1;
	87
	88
	89	/*
73459e2a PB	90	* Note: hypervisor must guarantee that:
	91	* 1. cpu ID number maps 1:1 to per-CPU pvclock time info.
	92	* 2. that per-CPU pvclock time info is updated if the
	93	* underlying CPU changes.
	94	* 3. that version is increased whenever underlying CPU
	95	* changes.
	96	*
51c19b4f MT	97	*/
	98	do {
	99	cpu = __getcpu() & VGETCPU_CPU_MASK;
	100	/* TODO: We can put vcpu id into higher bits of pvti.version.
	101	* This will save a couple of cycles by getting rid of
	102	* __getcpu() calls (Gleb).
	103	*/
	104
73459e2a	105	pvti = get_pvti(cpu);
0a4e6be9	106
51c19b4f MT	107	version = __pvclock_read_cycles(&pvti->pvti, &ret, &flags);
	108
	109	/*
	110	* Test we're still on the cpu as well as the version.
73459e2a PB	111	* We could have been migrated just after the first
	112	* vgetcpu but before fetching the version, so we
	113	* wouldn't notice a version change.
51c19b4f	114	*/
73459e2a PB	115	cpu1 = __getcpu() & VGETCPU_CPU_MASK;
	116	} while (unlikely(cpu != cpu1 \|\|
	117	(pvti->pvti.version & 1) \|\|
	118	pvti->pvti.version != version));
51c19b4f MT	119
	120	if (unlikely(!(flags & PVCLOCK_TSC_STABLE_BIT)))
	121	*mode = VCLOCK_NONE;
	122
	123	/* refer to tsc.c read_tsc() comment for rationale */
7c03156f	124	last = gtod->cycle_last;
51c19b4f MT	125
	126	if (likely(ret >= last))
	127	return ret;
	128
	129	return last;
	130	}
	131	#endif
	132
7a59ed41 SS	133	#else
7a59ed41 SS	134
7a59ed41 SS	135	notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
	136	{
	137	long ret;
	138
	139	asm(
	140	"mov %%ebx, %%edx \n"
	141	"mov %2, %%ebx \n"
6f121e54	142	"call __kernel_vsyscall \n"
7a59ed41 SS	143	"mov %%edx, %%ebx \n"
	144	: "=a" (ret)
	145	: "0" (__NR_clock_gettime), "g" (clock), "c" (ts)
	146	: "memory", "edx");
	147	return ret;
	148	}
	149
	150	notrace static long vdso_fallback_gtod(struct timeval tv, struct timezone tz)
	151	{
	152	long ret;
	153
	154	asm(
	155	"mov %%ebx, %%edx \n"
	156	"mov %2, %%ebx \n"
6f121e54	157	"call __kernel_vsyscall \n"
7a59ed41 SS	158	"mov %%edx, %%ebx \n"
	159	: "=a" (ret)
	160	: "0" (__NR_gettimeofday), "g" (tv), "c" (tz)
	161	: "memory", "edx");
	162	return ret;
	163	}
	164
	165	#ifdef CONFIG_PARAVIRT_CLOCK
	166
	167	static notrace cycle_t vread_pvclock(int *mode)
	168	{
	169	*mode = VCLOCK_NONE;
	170	return 0;
	171	}
	172	#endif
	173
	174	#endif
	175
411f790c	176	notrace static cycle_t vread_tsc(void)
2aae950b	177	{
411f790c SS	178	cycle_t ret;
411f790c SS	179	u64 last;
2aae950b	180
411f790c SS	181	/*
	182	* Empirically, a fence (of type that depends on the CPU)
	183	* before rdtsc is enough to ensure that rdtsc is ordered
	184	* with respect to loads. The various CPU manuals are unclear
	185	* as to whether rdtsc can be reordered with later loads,
	186	* but no one has ever seen it happen.
	187	*/
	188	rdtsc_barrier();
7a59ed41	189	ret = (cycle_t)__native_read_tsc();
a939e817	190
7c03156f	191	last = gtod->cycle_last;
a939e817	192
411f790c SS	193	if (likely(ret >= last))
	194	return ret;
	195
	196	/*
	197	* GCC likes to generate cmov here, but this branch is extremely
	198	* predictable (it's just a funciton of time and the likely is
	199	* very likely) and there's a data dependence, so force GCC
	200	* to generate a branch instead. I don't barrier() because
	201	* we don't actually need a barrier, and if this function
	202	* ever gets inlined it will generate worse code.
	203	*/
	204	asm volatile ("");
	205	return last;
	206	}
a939e817	207
51c19b4f	208	notrace static inline u64 vgetsns(int *mode)
2aae950b	209	{
7a59ed41	210	u64 v;
98d0ac38	211	cycles_t cycles;
7c03156f SS	212
7c03156f SS	213	if (gtod->vclock_mode == VCLOCK_TSC)
98d0ac38	214	cycles = vread_tsc();
7a59ed41	215	#ifdef CONFIG_HPET_TIMER
7c03156f	216	else if (gtod->vclock_mode == VCLOCK_HPET)
98d0ac38	217	cycles = vread_hpet();
7a59ed41	218	#endif
51c19b4f	219	#ifdef CONFIG_PARAVIRT_CLOCK
7c03156f	220	else if (gtod->vclock_mode == VCLOCK_PVCLOCK)
51c19b4f MT	221	cycles = vread_pvclock(mode);
51c19b4f MT	222	#endif
a939e817 JS	223	else
a939e817 JS	224	return 0;
7c03156f SS	225	v = (cycles - gtod->cycle_last) & gtod->mask;
7c03156f SS	226	return v * gtod->mult;
2aae950b AK	227	}
2aae950b AK	228
5f293474 AL	229	/* Code size doesn't matter (vdso is 4k anyway) and this is faster. */
5f293474 AL	230	notrace static int __always_inline do_realtime(struct timespec *ts)
2aae950b	231	{
650ea024 JS	232	unsigned long seq;
650ea024 JS	233	u64 ns;
a939e817 JS	234	int mode;
a939e817 JS	235
2aae950b	236	do {
7c03156f SS	237	seq = gtod_read_begin(gtod);
7c03156f SS	238	mode = gtod->vclock_mode;
2aae950b	239	ts->tv_sec = gtod->wall_time_sec;
650ea024	240	ns = gtod->wall_time_snsec;
51c19b4f	241	ns += vgetsns(&mode);
7c03156f SS	242	ns >>= gtod->shift;
	243	} while (unlikely(gtod_read_retry(gtod, seq)));
	244
	245	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
	246	ts->tv_nsec = ns;
a939e817	247
a939e817	248	return mode;
2aae950b AK	249	}
2aae950b AK	250
7a59ed41	251	notrace static int __always_inline do_monotonic(struct timespec *ts)
2aae950b	252	{
650ea024 JS	253	unsigned long seq;
650ea024 JS	254	u64 ns;
a939e817 JS	255	int mode;
a939e817 JS	256
2aae950b	257	do {
7c03156f SS	258	seq = gtod_read_begin(gtod);
7c03156f SS	259	mode = gtod->vclock_mode;
91ec87d5	260	ts->tv_sec = gtod->monotonic_time_sec;
650ea024	261	ns = gtod->monotonic_time_snsec;
51c19b4f	262	ns += vgetsns(&mode);
7c03156f SS	263	ns >>= gtod->shift;
	264	} while (unlikely(gtod_read_retry(gtod, seq)));
	265
	266	ts->tv_sec += __iter_div_u64_rem(ns, NSEC_PER_SEC, &ns);
	267	ts->tv_nsec = ns;
0f51f285	268
a939e817	269	return mode;
2aae950b AK	270	}
2aae950b AK	271
ce39c640	272	notrace static void do_realtime_coarse(struct timespec *ts)
da15cfda	273	{
	274	unsigned long seq;
	275	do {
7c03156f SS	276	seq = gtod_read_begin(gtod);
	277	ts->tv_sec = gtod->wall_time_coarse_sec;
	278	ts->tv_nsec = gtod->wall_time_coarse_nsec;
	279	} while (unlikely(gtod_read_retry(gtod, seq)));
da15cfda	280	}
da15cfda	281
ce39c640	282	notrace static void do_monotonic_coarse(struct timespec *ts)
da15cfda	283	{
91ec87d5	284	unsigned long seq;
da15cfda	285	do {
7c03156f SS	286	seq = gtod_read_begin(gtod);
	287	ts->tv_sec = gtod->monotonic_time_coarse_sec;
	288	ts->tv_nsec = gtod->monotonic_time_coarse_nsec;
	289	} while (unlikely(gtod_read_retry(gtod, seq)));
da15cfda	290	}
da15cfda	291
23adec55	292	notrace int __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
2aae950b	293	{
0d7b8547 AL	294	switch (clock) {
0d7b8547 AL	295	case CLOCK_REALTIME:
ce39c640 SS	296	if (do_realtime(ts) == VCLOCK_NONE)
ce39c640 SS	297	goto fallback;
0d7b8547 AL	298	break;
0d7b8547 AL	299	case CLOCK_MONOTONIC:
ce39c640 SS	300	if (do_monotonic(ts) == VCLOCK_NONE)
ce39c640 SS	301	goto fallback;
0d7b8547 AL	302	break;
0d7b8547 AL	303	case CLOCK_REALTIME_COARSE:
ce39c640 SS	304	do_realtime_coarse(ts);
ce39c640 SS	305	break;
0d7b8547	306	case CLOCK_MONOTONIC_COARSE:
ce39c640 SS	307	do_monotonic_coarse(ts);
	308	break;
	309	default:
	310	goto fallback;
0d7b8547 AL	311	}
0d7b8547 AL	312
a939e817	313	return 0;
ce39c640 SS	314	fallback:
ce39c640 SS	315	return vdso_fallback_gettime(clock, ts);
2aae950b AK	316	}
	317	int clock_gettime(clockid_t, struct timespec *)
	318	__attribute__((weak, alias("__vdso_clock_gettime")));
	319
23adec55	320	notrace int __vdso_gettimeofday(struct timeval tv, struct timezone tz)
2aae950b	321	{
a939e817	322	if (likely(tv != NULL)) {
0df1ea2b SS	323	if (unlikely(do_realtime((struct timespec *)tv) == VCLOCK_NONE))
0df1ea2b SS	324	return vdso_fallback_gtod(tv, tz);
a939e817	325	tv->tv_usec /= 1000;
2aae950b	326	}
a939e817	327	if (unlikely(tz != NULL)) {
7c03156f SS	328	tz->tz_minuteswest = gtod->tz_minuteswest;
7c03156f SS	329	tz->tz_dsttime = gtod->tz_dsttime;
a939e817 JS	330	}
a939e817 JS	331
a939e817	332	return 0;
2aae950b AK	333	}
	334	int gettimeofday(struct timeval , struct timezone )
	335	__attribute__((weak, alias("__vdso_gettimeofday")));
f144a6b4	336
0d7b8547 AL	337	/*
	338	* This will break when the xtime seconds get inaccurate, but that is
	339	* unlikely
	340	*/
f144a6b4 AL	341	notrace time_t __vdso_time(time_t *t)
f144a6b4 AL	342	{
7a59ed41	343	/* This is atomic on x86 so we don't need any locks. */
af8c93d8	344	time_t result = ACCESS_ONCE(gtod->wall_time_sec);
f144a6b4 AL	345
	346	if (t)
	347	*t = result;
	348	return result;
	349	}
	350	int time(time_t *t)
	351	__attribute__((weak, alias("__vdso_time")));