Current File : //usr/share/virtualbox/src/vboxhost/vboxdrv/r0drv/linux/time-r0drv-linux.c
/* $Id: time-r0drv-linux.c 155244 2023-01-17 14:15:46Z bird $ */
/** @file
* IPRT - Time, Ring-0 Driver, Linux.
*/
/*
* Copyright (C) 2006-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#define LOG_GROUP RTLOGGROUP_TIME
#include "the-linux-kernel.h"
#include "internal/iprt.h"
/* Make sure we have the setting functions we need for RTTimeNow: */
#if RTLNX_VER_MAX(2,6,16)
# define RTTIME_INCL_TIMEVAL
#elif RTLNX_VER_MAX(3,17,0)
# define RTTIME_INCL_TIMESPEC
#endif
#include <iprt/time.h>
#include <iprt/asm.h>
DECLINLINE(uint64_t) rtTimeGetSystemNanoTS(void)
{
#if RTLNX_VER_MIN(5,6,0)
/*
* Starting with kernel version 5.6-rc3 only 64-bit time interfaces
* are allowed in the kernel.
*/
uint64_t u64;
struct timespec64 Ts = { 0, 0 };
ktime_get_ts64(&Ts);
u64 = Ts.tv_sec * RT_NS_1SEC_64 + Ts.tv_nsec;
return u64;
#elif RTLNX_VER_MIN(2,6,16) /* This must match timer-r0drv-linux.c! */
/*
* Use ktime_get_ts, this is also what clock_gettime(CLOCK_MONOTONIC,) is using.
*/
uint64_t u64;
struct timespec Ts = { 0, 0 };
ktime_get_ts(&Ts);
u64 = Ts.tv_sec * RT_NS_1SEC_64 + Ts.tv_nsec;
return u64;
#elif RTLNX_VER_MIN(2,5,60)
/*
* Seems there is no way of getting to the exact source of
* sys_clock_gettime(CLOCK_MONOTONIC, &ts) here, I think. But
* 64-bit jiffies adjusted for the initial value should be pretty
* much the same I hope.
*/
uint64_t u64 = get_jiffies_64();
# ifdef INITIAL_JIFFIES
u64 += INITIAL_JIFFIES;
# endif
u64 *= TICK_NSEC;
return u64;
#else /* < 2.5.60 */
# if BITS_PER_LONG >= 64
/*
* This is the same as above, except that there is no get_jiffies_64()
* here and we rely on long, and therefor jiffies, being 64-bit instead.
*/
uint64_t u64 = jiffies;
# ifdef INITIAL_JIFFIES
u64 += INITIAL_JIFFIES;
# endif
u64 *= TICK_NSEC;
return u64;
# else /* 32 bit jiffies */
/*
* We'll have to try track jiffy rollovers here or we'll be
* in trouble every time it flips.
*
* The high dword of the s_u64Last is the rollover count, the
* low dword is the previous jiffies. Updating is done by
* atomic compare & exchange of course.
*/
static uint64_t volatile s_u64Last = 0;
uint64_t u64;
for (;;)
{
uint64_t u64NewLast;
int32_t iDelta;
uint32_t cRollovers;
uint32_t u32LastJiffies;
/* sample the values */
unsigned long ulNow = jiffies;
uint64_t u64Last = s_u64Last;
if (ulNow != jiffies)
continue; /* try again */
# ifdef INITIAL_JIFFIES
ulNow += INITIAL_JIFFIES;
# endif
u32LastJiffies = (uint32_t)u64Last;
cRollovers = u64Last >> 32;
/*
* Check for rollover and update the static last value.
*
* We have to make sure we update it successfully to rule out
* an underrun because of racing someone.
*/
iDelta = ulNow - u32LastJiffies;
if (iDelta < 0)
{
cRollovers++;
u64NewLast = RT_MAKE_U64(ulNow, cRollovers);
if (!ASMAtomicCmpXchgU64(&s_u64Last, u64NewLast, u64Last))
continue; /* race, try again */
}
else
{
u64NewLast = RT_MAKE_U64(ulNow, cRollovers);
ASMAtomicCmpXchgU64(&s_u64Last, u64NewLast, u64Last);
}
/* calculate the return value */
u64 = ulNow;
u64 *= TICK_NSEC;
u64 += cRollovers * (_4G * TICK_NSEC);
break;
}
return u64;
# endif /* 32 bit jiffies */
#endif /* < 2.5.60 */
}
RTDECL(uint64_t) RTTimeNanoTS(void)
{
return rtTimeGetSystemNanoTS();
}
RT_EXPORT_SYMBOL(RTTimeNanoTS);
RTDECL(uint64_t) RTTimeMilliTS(void)
{
return rtTimeGetSystemNanoTS() / RT_NS_1MS;
}
RT_EXPORT_SYMBOL(RTTimeMilliTS);
RTDECL(uint64_t) RTTimeSystemNanoTS(void)
{
return rtTimeGetSystemNanoTS();
}
RT_EXPORT_SYMBOL(RTTimeSystemNanoTS);
RTDECL(uint64_t) RTTimeSystemMilliTS(void)
{
return rtTimeGetSystemNanoTS() / RT_NS_1MS;
}
RT_EXPORT_SYMBOL(RTTimeSystemMilliTS);
RTDECL(PRTTIMESPEC) RTTimeNow(PRTTIMESPEC pTime)
{
IPRT_LINUX_SAVE_EFL_AC();
#if RTLNX_VER_MIN(3,17,0)
struct timespec64 Ts;
ktime_get_real_ts64(&Ts); /* ktime_get_real_ts64 was added as a macro in 3.17, function since 4.18. */
IPRT_LINUX_RESTORE_EFL_AC();
return RTTimeSpecSetTimespec64(pTime, &Ts);
#elif RTLNX_VER_MIN(2,6,16)
struct timespec Ts;
ktime_get_real_ts(&Ts); /* ktime_get_real_ts was removed in Linux 4.20. */
IPRT_LINUX_RESTORE_EFL_AC();
return RTTimeSpecSetTimespec(pTime, &Ts);
#else /* < 2.6.16 */
struct timeval Tv;
do_gettimeofday(&Tv);
IPRT_LINUX_RESTORE_EFL_AC();
return RTTimeSpecSetTimeval(pTime, &Tv);
#endif
}
RT_EXPORT_SYMBOL(RTTimeNow);
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