linux-hardened/include/linux/ktime.h
Thomas Gleixner cfd1893477 [PATCH] ktime: Fix signed / unsigned mismatch in ktime_to_ns
The 32 bit implementation of ktime_to_ns returns unsigned value, while the
64 bit version correctly returns an signed value.  There is no current user
affected by this, but it has to be fixed, as ktime values can be negative.

Pointed-out-by: Helmut Duregger <Helmut.Duregger@student.uibk.ac.at>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-07 08:39:37 -08:00

273 lines
7.5 KiB
C

/*
* include/linux/ktime.h
*
* ktime_t - nanosecond-resolution time format.
*
* Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
* Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
*
* data type definitions, declarations, prototypes and macros.
*
* Started by: Thomas Gleixner and Ingo Molnar
*
* Credits:
*
* Roman Zippel provided the ideas and primary code snippets of
* the ktime_t union and further simplifications of the original
* code.
*
* For licencing details see kernel-base/COPYING
*/
#ifndef _LINUX_KTIME_H
#define _LINUX_KTIME_H
#include <linux/time.h>
#include <linux/jiffies.h>
/*
* ktime_t:
*
* On 64-bit CPUs a single 64-bit variable is used to store the hrtimers
* internal representation of time values in scalar nanoseconds. The
* design plays out best on 64-bit CPUs, where most conversions are
* NOPs and most arithmetic ktime_t operations are plain arithmetic
* operations.
*
* On 32-bit CPUs an optimized representation of the timespec structure
* is used to avoid expensive conversions from and to timespecs. The
* endian-aware order of the tv struct members is choosen to allow
* mathematical operations on the tv64 member of the union too, which
* for certain operations produces better code.
*
* For architectures with efficient support for 64/32-bit conversions the
* plain scalar nanosecond based representation can be selected by the
* config switch CONFIG_KTIME_SCALAR.
*/
typedef union {
s64 tv64;
#if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
struct {
# ifdef __BIG_ENDIAN
s32 sec, nsec;
# else
s32 nsec, sec;
# endif
} tv;
#endif
} ktime_t;
#define KTIME_MAX ((s64)~((u64)1 << 63))
#define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC)
/*
* ktime_t definitions when using the 64-bit scalar representation:
*/
#if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
/**
* ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
* @secs: seconds to set
* @nsecs: nanoseconds to set
*
* Return the ktime_t representation of the value
*/
static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
{
#if (BITS_PER_LONG == 64)
if (unlikely(secs >= KTIME_SEC_MAX))
return (ktime_t){ .tv64 = KTIME_MAX };
#endif
return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
}
/* Subtract two ktime_t variables. rem = lhs -rhs: */
#define ktime_sub(lhs, rhs) \
({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
/* Add two ktime_t variables. res = lhs + rhs: */
#define ktime_add(lhs, rhs) \
({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
/*
* Add a ktime_t variable and a scalar nanosecond value.
* res = kt + nsval:
*/
#define ktime_add_ns(kt, nsval) \
({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
/* convert a timespec to ktime_t format: */
static inline ktime_t timespec_to_ktime(struct timespec ts)
{
return ktime_set(ts.tv_sec, ts.tv_nsec);
}
/* convert a timeval to ktime_t format: */
static inline ktime_t timeval_to_ktime(struct timeval tv)
{
return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
}
/* Map the ktime_t to timespec conversion to ns_to_timespec function */
#define ktime_to_timespec(kt) ns_to_timespec((kt).tv64)
/* Map the ktime_t to timeval conversion to ns_to_timeval function */
#define ktime_to_timeval(kt) ns_to_timeval((kt).tv64)
/* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
#define ktime_to_ns(kt) ((kt).tv64)
#else
/*
* Helper macros/inlines to get the ktime_t math right in the timespec
* representation. The macros are sometimes ugly - their actual use is
* pretty okay-ish, given the circumstances. We do all this for
* performance reasons. The pure scalar nsec_t based code was nice and
* simple, but created too many 64-bit / 32-bit conversions and divisions.
*
* Be especially aware that negative values are represented in a way
* that the tv.sec field is negative and the tv.nsec field is greater
* or equal to zero but less than nanoseconds per second. This is the
* same representation which is used by timespecs.
*
* tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
*/
/* Set a ktime_t variable to a value in sec/nsec representation: */
static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
{
return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } };
}
/**
* ktime_sub - subtract two ktime_t variables
* @lhs: minuend
* @rhs: subtrahend
*
* Returns the remainder of the substraction
*/
static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs)
{
ktime_t res;
res.tv64 = lhs.tv64 - rhs.tv64;
if (res.tv.nsec < 0)
res.tv.nsec += NSEC_PER_SEC;
return res;
}
/**
* ktime_add - add two ktime_t variables
* @add1: addend1
* @add2: addend2
*
* Returns the sum of addend1 and addend2
*/
static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2)
{
ktime_t res;
res.tv64 = add1.tv64 + add2.tv64;
/*
* performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
* so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
*
* it's equivalent to:
* tv.nsec -= NSEC_PER_SEC
* tv.sec ++;
*/
if (res.tv.nsec >= NSEC_PER_SEC)
res.tv64 += (u32)-NSEC_PER_SEC;
return res;
}
/**
* ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
* @kt: addend
* @nsec: the scalar nsec value to add
*
* Returns the sum of kt and nsec in ktime_t format
*/
extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);
/**
* timespec_to_ktime - convert a timespec to ktime_t format
* @ts: the timespec variable to convert
*
* Returns a ktime_t variable with the converted timespec value
*/
static inline ktime_t timespec_to_ktime(const struct timespec ts)
{
return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec,
.nsec = (s32)ts.tv_nsec } };
}
/**
* timeval_to_ktime - convert a timeval to ktime_t format
* @tv: the timeval variable to convert
*
* Returns a ktime_t variable with the converted timeval value
*/
static inline ktime_t timeval_to_ktime(const struct timeval tv)
{
return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec,
.nsec = (s32)tv.tv_usec * 1000 } };
}
/**
* ktime_to_timespec - convert a ktime_t variable to timespec format
* @kt: the ktime_t variable to convert
*
* Returns the timespec representation of the ktime value
*/
static inline struct timespec ktime_to_timespec(const ktime_t kt)
{
return (struct timespec) { .tv_sec = (time_t) kt.tv.sec,
.tv_nsec = (long) kt.tv.nsec };
}
/**
* ktime_to_timeval - convert a ktime_t variable to timeval format
* @kt: the ktime_t variable to convert
*
* Returns the timeval representation of the ktime value
*/
static inline struct timeval ktime_to_timeval(const ktime_t kt)
{
return (struct timeval) {
.tv_sec = (time_t) kt.tv.sec,
.tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) };
}
/**
* ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
* @kt: the ktime_t variable to convert
*
* Returns the scalar nanoseconds representation of kt
*/
static inline s64 ktime_to_ns(const ktime_t kt)
{
return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec;
}
#endif
/*
* The resolution of the clocks. The resolution value is returned in
* the clock_getres() system call to give application programmers an
* idea of the (in)accuracy of timers. Timer values are rounded up to
* this resolution values.
*/
#define KTIME_REALTIME_RES (ktime_t){ .tv64 = TICK_NSEC }
#define KTIME_MONOTONIC_RES (ktime_t){ .tv64 = TICK_NSEC }
/* Get the monotonic time in timespec format: */
extern void ktime_get_ts(struct timespec *ts);
/* Get the real (wall-) time in timespec format: */
#define ktime_get_real_ts(ts) getnstimeofday(ts)
#endif