forked from luck/tmp_suning_uos_patched
7c0f6ba682
This was entirely automated, using the script by Al:
PATT='^[[:blank:]]*#[[:blank:]]*include[[:blank:]]*<asm/uaccess.h>'
sed -i -e "s!$PATT!#include <linux/uaccess.h>!" \
$(git grep -l "$PATT"|grep -v ^include/linux/uaccess.h)
to do the replacement at the end of the merge window.
Requested-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
793 lines
21 KiB
C
793 lines
21 KiB
C
/*
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* linux/kernel/time.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* This file contains the interface functions for the various
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* time related system calls: time, stime, gettimeofday, settimeofday,
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* adjtime
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*/
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/*
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* Modification history kernel/time.c
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*
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* 1993-09-02 Philip Gladstone
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* Created file with time related functions from sched/core.c and adjtimex()
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* 1993-10-08 Torsten Duwe
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* adjtime interface update and CMOS clock write code
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* 1995-08-13 Torsten Duwe
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* kernel PLL updated to 1994-12-13 specs (rfc-1589)
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* 1999-01-16 Ulrich Windl
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* Introduced error checking for many cases in adjtimex().
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* Updated NTP code according to technical memorandum Jan '96
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* "A Kernel Model for Precision Timekeeping" by Dave Mills
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* Allow time_constant larger than MAXTC(6) for NTP v4 (MAXTC == 10)
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* (Even though the technical memorandum forbids it)
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* 2004-07-14 Christoph Lameter
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* Added getnstimeofday to allow the posix timer functions to return
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* with nanosecond accuracy
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*/
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#include <linux/export.h>
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#include <linux/timex.h>
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#include <linux/capability.h>
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#include <linux/timekeeper_internal.h>
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#include <linux/errno.h>
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#include <linux/syscalls.h>
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#include <linux/security.h>
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#include <linux/fs.h>
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#include <linux/math64.h>
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#include <linux/ptrace.h>
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#include <linux/uaccess.h>
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#include <asm/unistd.h>
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#include <generated/timeconst.h>
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#include "timekeeping.h"
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/*
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* The timezone where the local system is located. Used as a default by some
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* programs who obtain this value by using gettimeofday.
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*/
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struct timezone sys_tz;
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EXPORT_SYMBOL(sys_tz);
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#ifdef __ARCH_WANT_SYS_TIME
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/*
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* sys_time() can be implemented in user-level using
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* sys_gettimeofday(). Is this for backwards compatibility? If so,
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* why not move it into the appropriate arch directory (for those
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* architectures that need it).
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*/
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SYSCALL_DEFINE1(time, time_t __user *, tloc)
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{
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time_t i = get_seconds();
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if (tloc) {
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if (put_user(i,tloc))
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return -EFAULT;
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}
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force_successful_syscall_return();
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return i;
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}
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/*
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* sys_stime() can be implemented in user-level using
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* sys_settimeofday(). Is this for backwards compatibility? If so,
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* why not move it into the appropriate arch directory (for those
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* architectures that need it).
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*/
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SYSCALL_DEFINE1(stime, time_t __user *, tptr)
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{
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struct timespec tv;
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int err;
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if (get_user(tv.tv_sec, tptr))
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return -EFAULT;
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tv.tv_nsec = 0;
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err = security_settime(&tv, NULL);
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if (err)
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return err;
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do_settimeofday(&tv);
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return 0;
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}
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#endif /* __ARCH_WANT_SYS_TIME */
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SYSCALL_DEFINE2(gettimeofday, struct timeval __user *, tv,
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struct timezone __user *, tz)
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{
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if (likely(tv != NULL)) {
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struct timeval ktv;
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do_gettimeofday(&ktv);
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if (copy_to_user(tv, &ktv, sizeof(ktv)))
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return -EFAULT;
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}
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if (unlikely(tz != NULL)) {
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if (copy_to_user(tz, &sys_tz, sizeof(sys_tz)))
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return -EFAULT;
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}
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return 0;
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}
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/*
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* Indicates if there is an offset between the system clock and the hardware
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* clock/persistent clock/rtc.
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*/
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int persistent_clock_is_local;
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/*
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* Adjust the time obtained from the CMOS to be UTC time instead of
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* local time.
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*
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* This is ugly, but preferable to the alternatives. Otherwise we
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* would either need to write a program to do it in /etc/rc (and risk
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* confusion if the program gets run more than once; it would also be
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* hard to make the program warp the clock precisely n hours) or
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* compile in the timezone information into the kernel. Bad, bad....
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*
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* - TYT, 1992-01-01
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*
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* The best thing to do is to keep the CMOS clock in universal time (UTC)
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* as real UNIX machines always do it. This avoids all headaches about
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* daylight saving times and warping kernel clocks.
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*/
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static inline void warp_clock(void)
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{
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if (sys_tz.tz_minuteswest != 0) {
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struct timespec adjust;
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persistent_clock_is_local = 1;
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adjust.tv_sec = sys_tz.tz_minuteswest * 60;
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adjust.tv_nsec = 0;
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timekeeping_inject_offset(&adjust);
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}
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}
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/*
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* In case for some reason the CMOS clock has not already been running
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* in UTC, but in some local time: The first time we set the timezone,
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* we will warp the clock so that it is ticking UTC time instead of
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* local time. Presumably, if someone is setting the timezone then we
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* are running in an environment where the programs understand about
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* timezones. This should be done at boot time in the /etc/rc script,
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* as soon as possible, so that the clock can be set right. Otherwise,
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* various programs will get confused when the clock gets warped.
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*/
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int do_sys_settimeofday64(const struct timespec64 *tv, const struct timezone *tz)
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{
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static int firsttime = 1;
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int error = 0;
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if (tv && !timespec64_valid(tv))
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return -EINVAL;
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error = security_settime64(tv, tz);
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if (error)
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return error;
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if (tz) {
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/* Verify we're witin the +-15 hrs range */
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if (tz->tz_minuteswest > 15*60 || tz->tz_minuteswest < -15*60)
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return -EINVAL;
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sys_tz = *tz;
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update_vsyscall_tz();
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if (firsttime) {
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firsttime = 0;
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if (!tv)
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warp_clock();
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}
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}
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if (tv)
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return do_settimeofday64(tv);
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return 0;
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}
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SYSCALL_DEFINE2(settimeofday, struct timeval __user *, tv,
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struct timezone __user *, tz)
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{
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struct timeval user_tv;
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struct timespec new_ts;
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struct timezone new_tz;
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if (tv) {
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if (copy_from_user(&user_tv, tv, sizeof(*tv)))
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return -EFAULT;
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if (!timeval_valid(&user_tv))
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return -EINVAL;
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new_ts.tv_sec = user_tv.tv_sec;
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new_ts.tv_nsec = user_tv.tv_usec * NSEC_PER_USEC;
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}
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if (tz) {
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if (copy_from_user(&new_tz, tz, sizeof(*tz)))
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return -EFAULT;
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}
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return do_sys_settimeofday(tv ? &new_ts : NULL, tz ? &new_tz : NULL);
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}
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SYSCALL_DEFINE1(adjtimex, struct timex __user *, txc_p)
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{
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struct timex txc; /* Local copy of parameter */
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int ret;
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/* Copy the user data space into the kernel copy
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* structure. But bear in mind that the structures
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* may change
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*/
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if(copy_from_user(&txc, txc_p, sizeof(struct timex)))
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return -EFAULT;
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ret = do_adjtimex(&txc);
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return copy_to_user(txc_p, &txc, sizeof(struct timex)) ? -EFAULT : ret;
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}
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/**
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* current_fs_time - Return FS time
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* @sb: Superblock.
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*
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* Return the current time truncated to the time granularity supported by
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* the fs.
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*/
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struct timespec current_fs_time(struct super_block *sb)
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{
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struct timespec now = current_kernel_time();
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return timespec_trunc(now, sb->s_time_gran);
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}
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EXPORT_SYMBOL(current_fs_time);
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/*
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* Convert jiffies to milliseconds and back.
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*
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* Avoid unnecessary multiplications/divisions in the
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* two most common HZ cases:
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*/
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unsigned int jiffies_to_msecs(const unsigned long j)
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{
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#if HZ <= MSEC_PER_SEC && !(MSEC_PER_SEC % HZ)
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return (MSEC_PER_SEC / HZ) * j;
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#elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC)
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return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC);
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#else
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# if BITS_PER_LONG == 32
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return (HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32;
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# else
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return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN;
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# endif
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#endif
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}
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EXPORT_SYMBOL(jiffies_to_msecs);
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unsigned int jiffies_to_usecs(const unsigned long j)
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{
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/*
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* Hz usually doesn't go much further MSEC_PER_SEC.
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* jiffies_to_usecs() and usecs_to_jiffies() depend on that.
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*/
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BUILD_BUG_ON(HZ > USEC_PER_SEC);
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#if !(USEC_PER_SEC % HZ)
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return (USEC_PER_SEC / HZ) * j;
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#else
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# if BITS_PER_LONG == 32
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return (HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32;
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# else
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return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN;
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# endif
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#endif
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}
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EXPORT_SYMBOL(jiffies_to_usecs);
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/**
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* timespec_trunc - Truncate timespec to a granularity
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* @t: Timespec
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* @gran: Granularity in ns.
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*
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* Truncate a timespec to a granularity. Always rounds down. gran must
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* not be 0 nor greater than a second (NSEC_PER_SEC, or 10^9 ns).
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*/
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struct timespec timespec_trunc(struct timespec t, unsigned gran)
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{
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/* Avoid division in the common cases 1 ns and 1 s. */
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if (gran == 1) {
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/* nothing */
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} else if (gran == NSEC_PER_SEC) {
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t.tv_nsec = 0;
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} else if (gran > 1 && gran < NSEC_PER_SEC) {
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t.tv_nsec -= t.tv_nsec % gran;
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} else {
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WARN(1, "illegal file time granularity: %u", gran);
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}
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return t;
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}
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EXPORT_SYMBOL(timespec_trunc);
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/*
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* mktime64 - Converts date to seconds.
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* Converts Gregorian date to seconds since 1970-01-01 00:00:00.
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* Assumes input in normal date format, i.e. 1980-12-31 23:59:59
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* => year=1980, mon=12, day=31, hour=23, min=59, sec=59.
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*
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* [For the Julian calendar (which was used in Russia before 1917,
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* Britain & colonies before 1752, anywhere else before 1582,
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* and is still in use by some communities) leave out the
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* -year/100+year/400 terms, and add 10.]
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*
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* This algorithm was first published by Gauss (I think).
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*
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* A leap second can be indicated by calling this function with sec as
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* 60 (allowable under ISO 8601). The leap second is treated the same
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* as the following second since they don't exist in UNIX time.
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*
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* An encoding of midnight at the end of the day as 24:00:00 - ie. midnight
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* tomorrow - (allowable under ISO 8601) is supported.
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*/
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time64_t mktime64(const unsigned int year0, const unsigned int mon0,
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const unsigned int day, const unsigned int hour,
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const unsigned int min, const unsigned int sec)
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{
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unsigned int mon = mon0, year = year0;
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/* 1..12 -> 11,12,1..10 */
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if (0 >= (int) (mon -= 2)) {
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mon += 12; /* Puts Feb last since it has leap day */
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year -= 1;
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}
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return ((((time64_t)
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(year/4 - year/100 + year/400 + 367*mon/12 + day) +
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year*365 - 719499
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)*24 + hour /* now have hours - midnight tomorrow handled here */
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)*60 + min /* now have minutes */
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)*60 + sec; /* finally seconds */
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}
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EXPORT_SYMBOL(mktime64);
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/**
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* set_normalized_timespec - set timespec sec and nsec parts and normalize
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*
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* @ts: pointer to timespec variable to be set
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* @sec: seconds to set
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* @nsec: nanoseconds to set
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*
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* Set seconds and nanoseconds field of a timespec variable and
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* normalize to the timespec storage format
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*
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* Note: The tv_nsec part is always in the range of
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* 0 <= tv_nsec < NSEC_PER_SEC
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* For negative values only the tv_sec field is negative !
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*/
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void set_normalized_timespec(struct timespec *ts, time_t sec, s64 nsec)
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{
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while (nsec >= NSEC_PER_SEC) {
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/*
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* The following asm() prevents the compiler from
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* optimising this loop into a modulo operation. See
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* also __iter_div_u64_rem() in include/linux/time.h
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*/
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asm("" : "+rm"(nsec));
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nsec -= NSEC_PER_SEC;
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++sec;
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}
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while (nsec < 0) {
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asm("" : "+rm"(nsec));
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nsec += NSEC_PER_SEC;
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--sec;
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}
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ts->tv_sec = sec;
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ts->tv_nsec = nsec;
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}
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EXPORT_SYMBOL(set_normalized_timespec);
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/**
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* ns_to_timespec - Convert nanoseconds to timespec
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* @nsec: the nanoseconds value to be converted
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*
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* Returns the timespec representation of the nsec parameter.
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*/
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struct timespec ns_to_timespec(const s64 nsec)
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{
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struct timespec ts;
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s32 rem;
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if (!nsec)
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return (struct timespec) {0, 0};
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ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
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if (unlikely(rem < 0)) {
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ts.tv_sec--;
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rem += NSEC_PER_SEC;
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}
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ts.tv_nsec = rem;
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return ts;
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}
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EXPORT_SYMBOL(ns_to_timespec);
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/**
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* ns_to_timeval - Convert nanoseconds to timeval
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* @nsec: the nanoseconds value to be converted
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*
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* Returns the timeval representation of the nsec parameter.
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*/
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struct timeval ns_to_timeval(const s64 nsec)
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{
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struct timespec ts = ns_to_timespec(nsec);
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struct timeval tv;
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tv.tv_sec = ts.tv_sec;
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tv.tv_usec = (suseconds_t) ts.tv_nsec / 1000;
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return tv;
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}
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EXPORT_SYMBOL(ns_to_timeval);
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#if BITS_PER_LONG == 32
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/**
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* set_normalized_timespec - set timespec sec and nsec parts and normalize
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*
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* @ts: pointer to timespec variable to be set
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* @sec: seconds to set
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* @nsec: nanoseconds to set
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*
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* Set seconds and nanoseconds field of a timespec variable and
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* normalize to the timespec storage format
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*
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* Note: The tv_nsec part is always in the range of
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* 0 <= tv_nsec < NSEC_PER_SEC
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* For negative values only the tv_sec field is negative !
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*/
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void set_normalized_timespec64(struct timespec64 *ts, time64_t sec, s64 nsec)
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{
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while (nsec >= NSEC_PER_SEC) {
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/*
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* The following asm() prevents the compiler from
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* optimising this loop into a modulo operation. See
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* also __iter_div_u64_rem() in include/linux/time.h
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*/
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asm("" : "+rm"(nsec));
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nsec -= NSEC_PER_SEC;
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++sec;
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}
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while (nsec < 0) {
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asm("" : "+rm"(nsec));
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nsec += NSEC_PER_SEC;
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--sec;
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}
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ts->tv_sec = sec;
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ts->tv_nsec = nsec;
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}
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EXPORT_SYMBOL(set_normalized_timespec64);
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/**
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* ns_to_timespec64 - Convert nanoseconds to timespec64
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* @nsec: the nanoseconds value to be converted
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*
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* Returns the timespec64 representation of the nsec parameter.
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*/
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struct timespec64 ns_to_timespec64(const s64 nsec)
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{
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struct timespec64 ts;
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s32 rem;
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if (!nsec)
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return (struct timespec64) {0, 0};
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ts.tv_sec = div_s64_rem(nsec, NSEC_PER_SEC, &rem);
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if (unlikely(rem < 0)) {
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ts.tv_sec--;
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rem += NSEC_PER_SEC;
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}
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ts.tv_nsec = rem;
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return ts;
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}
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EXPORT_SYMBOL(ns_to_timespec64);
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#endif
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/**
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* msecs_to_jiffies: - convert milliseconds to jiffies
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* @m: time in milliseconds
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*
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* conversion is done as follows:
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*
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* - negative values mean 'infinite timeout' (MAX_JIFFY_OFFSET)
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*
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* - 'too large' values [that would result in larger than
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* MAX_JIFFY_OFFSET values] mean 'infinite timeout' too.
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*
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* - all other values are converted to jiffies by either multiplying
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|
* the input value by a factor or dividing it with a factor and
|
|
* handling any 32-bit overflows.
|
|
* for the details see __msecs_to_jiffies()
|
|
*
|
|
* msecs_to_jiffies() checks for the passed in value being a constant
|
|
* via __builtin_constant_p() allowing gcc to eliminate most of the
|
|
* code, __msecs_to_jiffies() is called if the value passed does not
|
|
* allow constant folding and the actual conversion must be done at
|
|
* runtime.
|
|
* the _msecs_to_jiffies helpers are the HZ dependent conversion
|
|
* routines found in include/linux/jiffies.h
|
|
*/
|
|
unsigned long __msecs_to_jiffies(const unsigned int m)
|
|
{
|
|
/*
|
|
* Negative value, means infinite timeout:
|
|
*/
|
|
if ((int)m < 0)
|
|
return MAX_JIFFY_OFFSET;
|
|
return _msecs_to_jiffies(m);
|
|
}
|
|
EXPORT_SYMBOL(__msecs_to_jiffies);
|
|
|
|
unsigned long __usecs_to_jiffies(const unsigned int u)
|
|
{
|
|
if (u > jiffies_to_usecs(MAX_JIFFY_OFFSET))
|
|
return MAX_JIFFY_OFFSET;
|
|
return _usecs_to_jiffies(u);
|
|
}
|
|
EXPORT_SYMBOL(__usecs_to_jiffies);
|
|
|
|
/*
|
|
* The TICK_NSEC - 1 rounds up the value to the next resolution. Note
|
|
* that a remainder subtract here would not do the right thing as the
|
|
* resolution values don't fall on second boundries. I.e. the line:
|
|
* nsec -= nsec % TICK_NSEC; is NOT a correct resolution rounding.
|
|
* Note that due to the small error in the multiplier here, this
|
|
* rounding is incorrect for sufficiently large values of tv_nsec, but
|
|
* well formed timespecs should have tv_nsec < NSEC_PER_SEC, so we're
|
|
* OK.
|
|
*
|
|
* Rather, we just shift the bits off the right.
|
|
*
|
|
* The >> (NSEC_JIFFIE_SC - SEC_JIFFIE_SC) converts the scaled nsec
|
|
* value to a scaled second value.
|
|
*/
|
|
static unsigned long
|
|
__timespec64_to_jiffies(u64 sec, long nsec)
|
|
{
|
|
nsec = nsec + TICK_NSEC - 1;
|
|
|
|
if (sec >= MAX_SEC_IN_JIFFIES){
|
|
sec = MAX_SEC_IN_JIFFIES;
|
|
nsec = 0;
|
|
}
|
|
return ((sec * SEC_CONVERSION) +
|
|
(((u64)nsec * NSEC_CONVERSION) >>
|
|
(NSEC_JIFFIE_SC - SEC_JIFFIE_SC))) >> SEC_JIFFIE_SC;
|
|
|
|
}
|
|
|
|
static unsigned long
|
|
__timespec_to_jiffies(unsigned long sec, long nsec)
|
|
{
|
|
return __timespec64_to_jiffies((u64)sec, nsec);
|
|
}
|
|
|
|
unsigned long
|
|
timespec64_to_jiffies(const struct timespec64 *value)
|
|
{
|
|
return __timespec64_to_jiffies(value->tv_sec, value->tv_nsec);
|
|
}
|
|
EXPORT_SYMBOL(timespec64_to_jiffies);
|
|
|
|
void
|
|
jiffies_to_timespec64(const unsigned long jiffies, struct timespec64 *value)
|
|
{
|
|
/*
|
|
* Convert jiffies to nanoseconds and separate with
|
|
* one divide.
|
|
*/
|
|
u32 rem;
|
|
value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
|
|
NSEC_PER_SEC, &rem);
|
|
value->tv_nsec = rem;
|
|
}
|
|
EXPORT_SYMBOL(jiffies_to_timespec64);
|
|
|
|
/*
|
|
* We could use a similar algorithm to timespec_to_jiffies (with a
|
|
* different multiplier for usec instead of nsec). But this has a
|
|
* problem with rounding: we can't exactly add TICK_NSEC - 1 to the
|
|
* usec value, since it's not necessarily integral.
|
|
*
|
|
* We could instead round in the intermediate scaled representation
|
|
* (i.e. in units of 1/2^(large scale) jiffies) but that's also
|
|
* perilous: the scaling introduces a small positive error, which
|
|
* combined with a division-rounding-upward (i.e. adding 2^(scale) - 1
|
|
* units to the intermediate before shifting) leads to accidental
|
|
* overflow and overestimates.
|
|
*
|
|
* At the cost of one additional multiplication by a constant, just
|
|
* use the timespec implementation.
|
|
*/
|
|
unsigned long
|
|
timeval_to_jiffies(const struct timeval *value)
|
|
{
|
|
return __timespec_to_jiffies(value->tv_sec,
|
|
value->tv_usec * NSEC_PER_USEC);
|
|
}
|
|
EXPORT_SYMBOL(timeval_to_jiffies);
|
|
|
|
void jiffies_to_timeval(const unsigned long jiffies, struct timeval *value)
|
|
{
|
|
/*
|
|
* Convert jiffies to nanoseconds and separate with
|
|
* one divide.
|
|
*/
|
|
u32 rem;
|
|
|
|
value->tv_sec = div_u64_rem((u64)jiffies * TICK_NSEC,
|
|
NSEC_PER_SEC, &rem);
|
|
value->tv_usec = rem / NSEC_PER_USEC;
|
|
}
|
|
EXPORT_SYMBOL(jiffies_to_timeval);
|
|
|
|
/*
|
|
* Convert jiffies/jiffies_64 to clock_t and back.
|
|
*/
|
|
clock_t jiffies_to_clock_t(unsigned long x)
|
|
{
|
|
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
|
|
# if HZ < USER_HZ
|
|
return x * (USER_HZ / HZ);
|
|
# else
|
|
return x / (HZ / USER_HZ);
|
|
# endif
|
|
#else
|
|
return div_u64((u64)x * TICK_NSEC, NSEC_PER_SEC / USER_HZ);
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL(jiffies_to_clock_t);
|
|
|
|
unsigned long clock_t_to_jiffies(unsigned long x)
|
|
{
|
|
#if (HZ % USER_HZ)==0
|
|
if (x >= ~0UL / (HZ / USER_HZ))
|
|
return ~0UL;
|
|
return x * (HZ / USER_HZ);
|
|
#else
|
|
/* Don't worry about loss of precision here .. */
|
|
if (x >= ~0UL / HZ * USER_HZ)
|
|
return ~0UL;
|
|
|
|
/* .. but do try to contain it here */
|
|
return div_u64((u64)x * HZ, USER_HZ);
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL(clock_t_to_jiffies);
|
|
|
|
u64 jiffies_64_to_clock_t(u64 x)
|
|
{
|
|
#if (TICK_NSEC % (NSEC_PER_SEC / USER_HZ)) == 0
|
|
# if HZ < USER_HZ
|
|
x = div_u64(x * USER_HZ, HZ);
|
|
# elif HZ > USER_HZ
|
|
x = div_u64(x, HZ / USER_HZ);
|
|
# else
|
|
/* Nothing to do */
|
|
# endif
|
|
#else
|
|
/*
|
|
* There are better ways that don't overflow early,
|
|
* but even this doesn't overflow in hundreds of years
|
|
* in 64 bits, so..
|
|
*/
|
|
x = div_u64(x * TICK_NSEC, (NSEC_PER_SEC / USER_HZ));
|
|
#endif
|
|
return x;
|
|
}
|
|
EXPORT_SYMBOL(jiffies_64_to_clock_t);
|
|
|
|
u64 nsec_to_clock_t(u64 x)
|
|
{
|
|
#if (NSEC_PER_SEC % USER_HZ) == 0
|
|
return div_u64(x, NSEC_PER_SEC / USER_HZ);
|
|
#elif (USER_HZ % 512) == 0
|
|
return div_u64(x * USER_HZ / 512, NSEC_PER_SEC / 512);
|
|
#else
|
|
/*
|
|
* max relative error 5.7e-8 (1.8s per year) for USER_HZ <= 1024,
|
|
* overflow after 64.99 years.
|
|
* exact for HZ=60, 72, 90, 120, 144, 180, 300, 600, 900, ...
|
|
*/
|
|
return div_u64(x * 9, (9ull * NSEC_PER_SEC + (USER_HZ / 2)) / USER_HZ);
|
|
#endif
|
|
}
|
|
|
|
/**
|
|
* nsecs_to_jiffies64 - Convert nsecs in u64 to jiffies64
|
|
*
|
|
* @n: nsecs in u64
|
|
*
|
|
* Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
|
|
* And this doesn't return MAX_JIFFY_OFFSET since this function is designed
|
|
* for scheduler, not for use in device drivers to calculate timeout value.
|
|
*
|
|
* note:
|
|
* NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
|
|
* ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
|
|
*/
|
|
u64 nsecs_to_jiffies64(u64 n)
|
|
{
|
|
#if (NSEC_PER_SEC % HZ) == 0
|
|
/* Common case, HZ = 100, 128, 200, 250, 256, 500, 512, 1000 etc. */
|
|
return div_u64(n, NSEC_PER_SEC / HZ);
|
|
#elif (HZ % 512) == 0
|
|
/* overflow after 292 years if HZ = 1024 */
|
|
return div_u64(n * HZ / 512, NSEC_PER_SEC / 512);
|
|
#else
|
|
/*
|
|
* Generic case - optimized for cases where HZ is a multiple of 3.
|
|
* overflow after 64.99 years, exact for HZ = 60, 72, 90, 120 etc.
|
|
*/
|
|
return div_u64(n * 9, (9ull * NSEC_PER_SEC + HZ / 2) / HZ);
|
|
#endif
|
|
}
|
|
EXPORT_SYMBOL(nsecs_to_jiffies64);
|
|
|
|
/**
|
|
* nsecs_to_jiffies - Convert nsecs in u64 to jiffies
|
|
*
|
|
* @n: nsecs in u64
|
|
*
|
|
* Unlike {m,u}secs_to_jiffies, type of input is not unsigned int but u64.
|
|
* And this doesn't return MAX_JIFFY_OFFSET since this function is designed
|
|
* for scheduler, not for use in device drivers to calculate timeout value.
|
|
*
|
|
* note:
|
|
* NSEC_PER_SEC = 10^9 = (5^9 * 2^9) = (1953125 * 512)
|
|
* ULLONG_MAX ns = 18446744073.709551615 secs = about 584 years
|
|
*/
|
|
unsigned long nsecs_to_jiffies(u64 n)
|
|
{
|
|
return (unsigned long)nsecs_to_jiffies64(n);
|
|
}
|
|
EXPORT_SYMBOL_GPL(nsecs_to_jiffies);
|
|
|
|
/*
|
|
* Add two timespec values and do a safety check for overflow.
|
|
* It's assumed that both values are valid (>= 0)
|
|
*/
|
|
struct timespec timespec_add_safe(const struct timespec lhs,
|
|
const struct timespec rhs)
|
|
{
|
|
struct timespec res;
|
|
|
|
set_normalized_timespec(&res, lhs.tv_sec + rhs.tv_sec,
|
|
lhs.tv_nsec + rhs.tv_nsec);
|
|
|
|
if (res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)
|
|
res.tv_sec = TIME_T_MAX;
|
|
|
|
return res;
|
|
}
|
|
|
|
/*
|
|
* Add two timespec64 values and do a safety check for overflow.
|
|
* It's assumed that both values are valid (>= 0).
|
|
* And, each timespec64 is in normalized form.
|
|
*/
|
|
struct timespec64 timespec64_add_safe(const struct timespec64 lhs,
|
|
const struct timespec64 rhs)
|
|
{
|
|
struct timespec64 res;
|
|
|
|
set_normalized_timespec64(&res, (timeu64_t) lhs.tv_sec + rhs.tv_sec,
|
|
lhs.tv_nsec + rhs.tv_nsec);
|
|
|
|
if (unlikely(res.tv_sec < lhs.tv_sec || res.tv_sec < rhs.tv_sec)) {
|
|
res.tv_sec = TIME64_MAX;
|
|
res.tv_nsec = 0;
|
|
}
|
|
|
|
return res;
|
|
}
|