arch/sparc/vdso/vclock_gettime.c - linux - Git at Google

 /*
  * Copyright 2006 Andi Kleen, SUSE Labs.
  * Subject to the GNU Public License, v.2
  *
  * Fast user context implementation of clock_gettime, gettimeofday, and time.
  *
  * The code should have no internal unresolved relocations.
  * Check with readelf after changing.
  * Also alternative() doesn't work.
  */
 /*
  * Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
  */

 #include <linux/kernel.h>
 #include <linux/time.h>
 #include <linux/string.h>
 #include <asm/io.h>
 #include <asm/unistd.h>
 #include <asm/timex.h>
 #include <asm/clocksource.h>
 #include <asm/vvar.h>

 #ifdef	CONFIG_SPARC64
 #define SYSCALL_STRING							\
 	"ta	0x6d;"							\
 	"bcs,a	1f;"							\
 	" sub	%%g0, %%o0, %%o0;"					\
 	"1:"
 #else
 #define SYSCALL_STRING							\
 	"ta	0x10;"							\
 	"bcs,a	1f;"							\
 	" sub	%%g0, %%o0, %%o0;"					\
 	"1:"
 #endif

 #define SYSCALL_CLOBBERS						\
 	"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7",			\
 	"f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15",		\
 	"f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23",		\
 	"f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31",		\
 	"f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46",		\
 	"f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62",		\
 	"cc", "memory"

 /*
  * Compute the vvar page's address in the process address space, and return it
  * as a pointer to the vvar_data.
  */
 notrace static __always_inline struct vvar_data *get_vvar_data(void)
 {
 	unsigned long ret;

 	/*
 	 * vdso data page is the first vDSO page so grab the PC
 	 * and move up a page to get to the data page.
 	 */
 	__asm__("rd %%pc, %0" : "=r" (ret));
 	ret &= ~(8192 - 1);
 	ret -= 8192;

 	return (struct vvar_data *) ret;
 }

 notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
 {
 	register long num __asm__("g1") = __NR_clock_gettime;
 	register long o0 __asm__("o0") = clock;
 	register long o1 __asm__("o1") = (long) ts;

 	__asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
 			     "0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
 	return o0;
 }

 notrace static long vdso_fallback_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
 	register long num __asm__("g1") = __NR_gettimeofday;
 	register long o0 __asm__("o0") = (long) tv;
 	register long o1 __asm__("o1") = (long) tz;

 	__asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
 			     "0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
 	return o0;
 }

 #ifdef	CONFIG_SPARC64
 notrace static __always_inline u64 vread_tick(void)
 {
 	u64	ret;

 	__asm__ __volatile__("rd %%tick, %0" : "=r" (ret));
 	return ret;
 }

 notrace static __always_inline u64 vread_tick_stick(void)
 {
 	u64	ret;

 	__asm__ __volatile__("rd %%asr24, %0" : "=r" (ret));
 	return ret;
 }
 #else
 notrace static __always_inline u64 vread_tick(void)
 {
 	register unsigned long long ret asm("o4");

 	__asm__ __volatile__("rd %%tick, %L0\n\t"
 			     "srlx %L0, 32, %H0"
 			     : "=r" (ret));
 	return ret;
 }

 notrace static __always_inline u64 vread_tick_stick(void)
 {
 	register unsigned long long ret asm("o4");

 	__asm__ __volatile__("rd %%asr24, %L0\n\t"
 			     "srlx %L0, 32, %H0"
 			     : "=r" (ret));
 	return ret;
 }
 #endif

 notrace static __always_inline u64 vgetsns(struct vvar_data *vvar)
 {
 	u64 v;
 	u64 cycles;

 	cycles = vread_tick();
 	v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
 	return v * vvar->clock.mult;
 }

 notrace static __always_inline u64 vgetsns_stick(struct vvar_data *vvar)
 {
 	u64 v;
 	u64 cycles;

 	cycles = vread_tick_stick();
 	v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
 	return v * vvar->clock.mult;
 }

 notrace static __always_inline int do_realtime(struct vvar_data *vvar,
 					       struct timespec *ts)
 {
 	unsigned long seq;
 	u64 ns;

 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->wall_time_sec;
 		ns = vvar->wall_time_snsec;
 		ns += vgetsns(vvar);
 		ns >>= vvar->clock.shift;
 	} while (unlikely(vvar_read_retry(vvar, seq)));

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

 	return 0;
 }

 notrace static __always_inline int do_realtime_stick(struct vvar_data *vvar,
 						     struct timespec *ts)
 {
 	unsigned long seq;
 	u64 ns;

 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->wall_time_sec;
 		ns = vvar->wall_time_snsec;
 		ns += vgetsns_stick(vvar);
 		ns >>= vvar->clock.shift;
 	} while (unlikely(vvar_read_retry(vvar, seq)));

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

 	return 0;
 }

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

 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->monotonic_time_sec;
 		ns = vvar->monotonic_time_snsec;
 		ns += vgetsns(vvar);
 		ns >>= vvar->clock.shift;
 	} while (unlikely(vvar_read_retry(vvar, seq)));

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

 	return 0;
 }

 notrace static __always_inline int do_monotonic_stick(struct vvar_data *vvar,
 						      struct timespec *ts)
 {
 	unsigned long seq;
 	u64 ns;

 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->monotonic_time_sec;
 		ns = vvar->monotonic_time_snsec;
 		ns += vgetsns_stick(vvar);
 		ns >>= vvar->clock.shift;
 	} while (unlikely(vvar_read_retry(vvar, seq)));

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

 	return 0;
 }

 notrace static int do_realtime_coarse(struct vvar_data *vvar,
 				      struct timespec *ts)
 {
 	unsigned long seq;

 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->wall_time_coarse_sec;
 		ts->tv_nsec = vvar->wall_time_coarse_nsec;
 	} while (unlikely(vvar_read_retry(vvar, seq)));
 	return 0;
 }

 notrace static int do_monotonic_coarse(struct vvar_data *vvar,
 				       struct timespec *ts)
 {
 	unsigned long seq;

 	do {
 		seq = vvar_read_begin(vvar);
 		ts->tv_sec = vvar->monotonic_time_coarse_sec;
 		ts->tv_nsec = vvar->monotonic_time_coarse_nsec;
 	} while (unlikely(vvar_read_retry(vvar, seq)));

 	return 0;
 }

 notrace int
 __vdso_clock_gettime(clockid_t clock, struct timespec *ts)
 {
 	struct vvar_data *vvd = get_vvar_data();

 	switch (clock) {
 	case CLOCK_REALTIME:
 		if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
 			break;
 		return do_realtime(vvd, ts);
 	case CLOCK_MONOTONIC:
 		if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
 			break;
 		return do_monotonic(vvd, ts);
 	case CLOCK_REALTIME_COARSE:
 		return do_realtime_coarse(vvd, ts);
 	case CLOCK_MONOTONIC_COARSE:
 		return do_monotonic_coarse(vvd, ts);
 	}
 	/*
 	 * Unknown clock ID ? Fall back to the syscall.
 	 */
 	return vdso_fallback_gettime(clock, ts);
 }
 int
 clock_gettime(clockid_t, struct timespec *)
 	__attribute__((weak, alias("__vdso_clock_gettime")));

 notrace int
 __vdso_clock_gettime_stick(clockid_t clock, struct timespec *ts)
 {
 	struct vvar_data *vvd = get_vvar_data();

 	switch (clock) {
 	case CLOCK_REALTIME:
 		if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
 			break;
 		return do_realtime_stick(vvd, ts);
 	case CLOCK_MONOTONIC:
 		if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
 			break;
 		return do_monotonic_stick(vvd, ts);
 	case CLOCK_REALTIME_COARSE:
 		return do_realtime_coarse(vvd, ts);
 	case CLOCK_MONOTONIC_COARSE:
 		return do_monotonic_coarse(vvd, ts);
 	}
 	/*
 	 * Unknown clock ID ? Fall back to the syscall.
 	 */
 	return vdso_fallback_gettime(clock, ts);
 }

 notrace int
 __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
 {
 	struct vvar_data *vvd = get_vvar_data();

 	if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
 		if (likely(tv != NULL)) {
 			union tstv_t {
 				struct timespec ts;
 				struct timeval tv;
 			} *tstv = (union tstv_t *) tv;
 			do_realtime(vvd, &tstv->ts);
 			/*
 			 * Assign before dividing to ensure that the division is
 			 * done in the type of tv_usec, not tv_nsec.
 			 *
 			 * There cannot be > 1 billion usec in a second:
 			 * do_realtime() has already distributed such overflow
 			 * into tv_sec.  So we can assign it to an int safely.
 			 */
 			tstv->tv.tv_usec = tstv->ts.tv_nsec;
 			tstv->tv.tv_usec /= 1000;
 		}
 		if (unlikely(tz != NULL)) {
 			/* Avoid memcpy. Some old compilers fail to inline it */
 			tz->tz_minuteswest = vvd->tz_minuteswest;
 			tz->tz_dsttime = vvd->tz_dsttime;
 		}
 		return 0;
 	}
 	return vdso_fallback_gettimeofday(tv, tz);
 }
 int
 gettimeofday(struct timeval *, struct timezone *)
 	__attribute__((weak, alias("__vdso_gettimeofday")));

 notrace int
 __vdso_gettimeofday_stick(struct timeval *tv, struct timezone *tz)
 {
 	struct vvar_data *vvd = get_vvar_data();

 	if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
 		if (likely(tv != NULL)) {
 			union tstv_t {
 				struct timespec ts;
 				struct timeval tv;
 			} *tstv = (union tstv_t *) tv;
 			do_realtime_stick(vvd, &tstv->ts);
 			/*
 			 * Assign before dividing to ensure that the division is
 			 * done in the type of tv_usec, not tv_nsec.
 			 *
 			 * There cannot be > 1 billion usec in a second:
 			 * do_realtime() has already distributed such overflow
 			 * into tv_sec.  So we can assign it to an int safely.
 			 */
 			tstv->tv.tv_usec = tstv->ts.tv_nsec;
 			tstv->tv.tv_usec /= 1000;
 		}
 		if (unlikely(tz != NULL)) {
 			/* Avoid memcpy. Some old compilers fail to inline it */
 			tz->tz_minuteswest = vvd->tz_minuteswest;
 			tz->tz_dsttime = vvd->tz_dsttime;
 		}
 		return 0;
 	}
 	return vdso_fallback_gettimeofday(tv, tz);
 }
	/*
	* Copyright 2006 Andi Kleen, SUSE Labs.
	* Subject to the GNU Public License, v.2
	*
	* Fast user context implementation of clock_gettime, gettimeofday, and time.
	*
	* The code should have no internal unresolved relocations.
	* Check with readelf after changing.
	* Also alternative() doesn't work.
	*/
	/*
	* Copyright (c) 2017 Oracle and/or its affiliates. All rights reserved.
	*/

	#include <linux/kernel.h>
	#include <linux/time.h>
	#include <linux/string.h>
	#include <asm/io.h>
	#include <asm/unistd.h>
	#include <asm/timex.h>
	#include <asm/clocksource.h>
	#include <asm/vvar.h>

	#ifdef CONFIG_SPARC64
	#define SYSCALL_STRING \
	"ta 0x6d;" \
	"bcs,a 1f;" \
	" sub %%g0, %%o0, %%o0;" \
	"1:"
	#else
	#define SYSCALL_STRING \
	"ta 0x10;" \
	"bcs,a 1f;" \
	" sub %%g0, %%o0, %%o0;" \
	"1:"
	#endif

	#define SYSCALL_CLOBBERS \
	"f0", "f1", "f2", "f3", "f4", "f5", "f6", "f7", \
	"f8", "f9", "f10", "f11", "f12", "f13", "f14", "f15", \
	"f16", "f17", "f18", "f19", "f20", "f21", "f22", "f23", \
	"f24", "f25", "f26", "f27", "f28", "f29", "f30", "f31", \
	"f32", "f34", "f36", "f38", "f40", "f42", "f44", "f46", \
	"f48", "f50", "f52", "f54", "f56", "f58", "f60", "f62", \
	"cc", "memory"

	/*
	* Compute the vvar page's address in the process address space, and return it
	* as a pointer to the vvar_data.
	*/
	notrace static __always_inline struct vvar_data *get_vvar_data(void)
	{
	unsigned long ret;

	/*
	* vdso data page is the first vDSO page so grab the PC
	* and move up a page to get to the data page.
	*/
	__asm__("rd %%pc, %0" : "=r" (ret));
	ret &= ~(8192 - 1);
	ret -= 8192;

	return (struct vvar_data *) ret;
	}

	notrace static long vdso_fallback_gettime(long clock, struct timespec *ts)
	{
	register long num __asm__("g1") = __NR_clock_gettime;
	register long o0 __asm__("o0") = clock;
	register long o1 __asm__("o1") = (long) ts;

	__asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
	"0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
	return o0;
	}

	notrace static long vdso_fallback_gettimeofday(struct timeval tv, struct timezone tz)
	{
	register long num __asm__("g1") = __NR_gettimeofday;
	register long o0 __asm__("o0") = (long) tv;
	register long o1 __asm__("o1") = (long) tz;

	__asm__ __volatile__(SYSCALL_STRING : "=r" (o0) : "r" (num),
	"0" (o0), "r" (o1) : SYSCALL_CLOBBERS);
	return o0;
	}

	#ifdef CONFIG_SPARC64
	notrace static __always_inline u64 vread_tick(void)
	{
	u64 ret;

	__asm__ __volatile__("rd %%tick, %0" : "=r" (ret));
	return ret;
	}

	notrace static __always_inline u64 vread_tick_stick(void)
	{
	u64 ret;

	__asm__ __volatile__("rd %%asr24, %0" : "=r" (ret));
	return ret;
	}
	#else
	notrace static __always_inline u64 vread_tick(void)
	{
	register unsigned long long ret asm("o4");

	__asm__ __volatile__("rd %%tick, %L0\n\t"
	"srlx %L0, 32, %H0"
	: "=r" (ret));
	return ret;
	}

	notrace static __always_inline u64 vread_tick_stick(void)
	{
	register unsigned long long ret asm("o4");

	__asm__ __volatile__("rd %%asr24, %L0\n\t"
	"srlx %L0, 32, %H0"
	: "=r" (ret));
	return ret;
	}
	#endif

	notrace static __always_inline u64 vgetsns(struct vvar_data *vvar)
	{
	u64 v;
	u64 cycles;

	cycles = vread_tick();
	v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
	return v * vvar->clock.mult;
	}

	notrace static __always_inline u64 vgetsns_stick(struct vvar_data *vvar)
	{
	u64 v;
	u64 cycles;

	cycles = vread_tick_stick();
	v = (cycles - vvar->clock.cycle_last) & vvar->clock.mask;
	return v * vvar->clock.mult;
	}

	notrace static __always_inline int do_realtime(struct vvar_data *vvar,
	struct timespec *ts)
	{
	unsigned long seq;
	u64 ns;

	do {
	seq = vvar_read_begin(vvar);
	ts->tv_sec = vvar->wall_time_sec;
	ns = vvar->wall_time_snsec;
	ns += vgetsns(vvar);
	ns >>= vvar->clock.shift;
	} while (unlikely(vvar_read_retry(vvar, seq)));

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

	return 0;
	}

	notrace static __always_inline int do_realtime_stick(struct vvar_data *vvar,
	struct timespec *ts)
	{
	unsigned long seq;
	u64 ns;

	do {
	seq = vvar_read_begin(vvar);
	ts->tv_sec = vvar->wall_time_sec;
	ns = vvar->wall_time_snsec;
	ns += vgetsns_stick(vvar);
	ns >>= vvar->clock.shift;
	} while (unlikely(vvar_read_retry(vvar, seq)));

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

	return 0;
	}

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

	do {
	seq = vvar_read_begin(vvar);
	ts->tv_sec = vvar->monotonic_time_sec;
	ns = vvar->monotonic_time_snsec;
	ns += vgetsns(vvar);
	ns >>= vvar->clock.shift;
	} while (unlikely(vvar_read_retry(vvar, seq)));

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

	return 0;
	}

	notrace static __always_inline int do_monotonic_stick(struct vvar_data *vvar,
	struct timespec *ts)
	{
	unsigned long seq;
	u64 ns;

	do {
	seq = vvar_read_begin(vvar);
	ts->tv_sec = vvar->monotonic_time_sec;
	ns = vvar->monotonic_time_snsec;
	ns += vgetsns_stick(vvar);
	ns >>= vvar->clock.shift;
	} while (unlikely(vvar_read_retry(vvar, seq)));

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

	return 0;
	}

	notrace static int do_realtime_coarse(struct vvar_data *vvar,
	struct timespec *ts)
	{
	unsigned long seq;

	do {
	seq = vvar_read_begin(vvar);
	ts->tv_sec = vvar->wall_time_coarse_sec;
	ts->tv_nsec = vvar->wall_time_coarse_nsec;
	} while (unlikely(vvar_read_retry(vvar, seq)));
	return 0;
	}

	notrace static int do_monotonic_coarse(struct vvar_data *vvar,
	struct timespec *ts)
	{
	unsigned long seq;

	do {
	seq = vvar_read_begin(vvar);
	ts->tv_sec = vvar->monotonic_time_coarse_sec;
	ts->tv_nsec = vvar->monotonic_time_coarse_nsec;
	} while (unlikely(vvar_read_retry(vvar, seq)));

	return 0;
	}

	notrace int
	__vdso_clock_gettime(clockid_t clock, struct timespec *ts)
	{
	struct vvar_data *vvd = get_vvar_data();

	switch (clock) {
	case CLOCK_REALTIME:
	if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
	break;
	return do_realtime(vvd, ts);
	case CLOCK_MONOTONIC:
	if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
	break;
	return do_monotonic(vvd, ts);
	case CLOCK_REALTIME_COARSE:
	return do_realtime_coarse(vvd, ts);
	case CLOCK_MONOTONIC_COARSE:
	return do_monotonic_coarse(vvd, ts);
	}
	/*
	* Unknown clock ID ? Fall back to the syscall.
	*/
	return vdso_fallback_gettime(clock, ts);
	}
	int
	clock_gettime(clockid_t, struct timespec *)
	__attribute__((weak, alias("__vdso_clock_gettime")));

	notrace int
	__vdso_clock_gettime_stick(clockid_t clock, struct timespec *ts)
	{
	struct vvar_data *vvd = get_vvar_data();

	switch (clock) {
	case CLOCK_REALTIME:
	if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
	break;
	return do_realtime_stick(vvd, ts);
	case CLOCK_MONOTONIC:
	if (unlikely(vvd->vclock_mode == VCLOCK_NONE))
	break;
	return do_monotonic_stick(vvd, ts);
	case CLOCK_REALTIME_COARSE:
	return do_realtime_coarse(vvd, ts);
	case CLOCK_MONOTONIC_COARSE:
	return do_monotonic_coarse(vvd, ts);
	}
	/*
	* Unknown clock ID ? Fall back to the syscall.
	*/
	return vdso_fallback_gettime(clock, ts);
	}

	notrace int
	__vdso_gettimeofday(struct timeval tv, struct timezone tz)
	{
	struct vvar_data *vvd = get_vvar_data();

	if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
	if (likely(tv != NULL)) {
	union tstv_t {
	struct timespec ts;
	struct timeval tv;
	} tstv = (union tstv_t ) tv;
	do_realtime(vvd, &tstv->ts);
	/*
	* Assign before dividing to ensure that the division is
	* done in the type of tv_usec, not tv_nsec.
	*
	* There cannot be > 1 billion usec in a second:
	* do_realtime() has already distributed such overflow
	* into tv_sec. So we can assign it to an int safely.
	*/
	tstv->tv.tv_usec = tstv->ts.tv_nsec;
	tstv->tv.tv_usec /= 1000;
	}
	if (unlikely(tz != NULL)) {
	/* Avoid memcpy. Some old compilers fail to inline it */
	tz->tz_minuteswest = vvd->tz_minuteswest;
	tz->tz_dsttime = vvd->tz_dsttime;
	}
	return 0;
	}
	return vdso_fallback_gettimeofday(tv, tz);
	}
	int
	gettimeofday(struct timeval , struct timezone )
	__attribute__((weak, alias("__vdso_gettimeofday")));

	notrace int
	__vdso_gettimeofday_stick(struct timeval tv, struct timezone tz)
	{
	struct vvar_data *vvd = get_vvar_data();

	if (likely(vvd->vclock_mode != VCLOCK_NONE)) {
	if (likely(tv != NULL)) {
	union tstv_t {
	struct timespec ts;
	struct timeval tv;
	} tstv = (union tstv_t ) tv;
	do_realtime_stick(vvd, &tstv->ts);
	/*
	* Assign before dividing to ensure that the division is
	* done in the type of tv_usec, not tv_nsec.
	*
	* There cannot be > 1 billion usec in a second:
	* do_realtime() has already distributed such overflow
	* into tv_sec. So we can assign it to an int safely.
	*/
	tstv->tv.tv_usec = tstv->ts.tv_nsec;
	tstv->tv.tv_usec /= 1000;
	}
	if (unlikely(tz != NULL)) {
	/* Avoid memcpy. Some old compilers fail to inline it */
	tz->tz_minuteswest = vvd->tz_minuteswest;
	tz->tz_dsttime = vvd->tz_dsttime;
	}
	return 0;
	}
	return vdso_fallback_gettimeofday(tv, tz);
	}