diff options
Diffstat (limited to 'kernel/time.c')
| -rw-r--r-- | kernel/time.c | 46 |
1 files changed, 34 insertions, 12 deletions
diff --git a/kernel/time.c b/kernel/time.c index 4064c0566e7..a5ec013b6c8 100644 --- a/kernel/time.c +++ b/kernel/time.c @@ -39,6 +39,8 @@ #include <asm/uaccess.h> #include <asm/unistd.h> +#include "timeconst.h" + /* * The timezone where the local system is located. Used as a default by some * programs who obtain this value by using gettimeofday. @@ -93,7 +95,8 @@ asmlinkage long sys_stime(time_t __user *tptr) #endif /* __ARCH_WANT_SYS_TIME */ -asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __user *tz) +asmlinkage long sys_gettimeofday(struct timeval __user *tv, + struct timezone __user *tz) { if (likely(tv != NULL)) { struct timeval ktv; @@ -118,7 +121,7 @@ asmlinkage long sys_gettimeofday(struct timeval __user *tv, struct timezone __us * hard to make the program warp the clock precisely n hours) or * compile in the timezone information into the kernel. Bad, bad.... * - * - TYT, 1992-01-01 + * - TYT, 1992-01-01 * * The best thing to do is to keep the CMOS clock in universal time (UTC) * as real UNIX machines always do it. This avoids all headaches about @@ -240,7 +243,11 @@ unsigned int inline jiffies_to_msecs(const unsigned long j) #elif HZ > MSEC_PER_SEC && !(HZ % MSEC_PER_SEC) return (j + (HZ / MSEC_PER_SEC) - 1)/(HZ / MSEC_PER_SEC); #else - return (j * MSEC_PER_SEC) / HZ; +# if BITS_PER_LONG == 32 + return ((u64)HZ_TO_MSEC_MUL32 * j) >> HZ_TO_MSEC_SHR32; +# else + return (j * HZ_TO_MSEC_NUM) / HZ_TO_MSEC_DEN; +# endif #endif } EXPORT_SYMBOL(jiffies_to_msecs); @@ -252,7 +259,11 @@ unsigned int inline jiffies_to_usecs(const unsigned long j) #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) return (j + (HZ / USEC_PER_SEC) - 1)/(HZ / USEC_PER_SEC); #else - return (j * USEC_PER_SEC) / HZ; +# if BITS_PER_LONG == 32 + return ((u64)HZ_TO_USEC_MUL32 * j) >> HZ_TO_USEC_SHR32; +# else + return (j * HZ_TO_USEC_NUM) / HZ_TO_USEC_DEN; +# endif #endif } EXPORT_SYMBOL(jiffies_to_usecs); @@ -267,7 +278,7 @@ EXPORT_SYMBOL(jiffies_to_usecs); * * This function should be only used for timestamps returned by * current_kernel_time() or CURRENT_TIME, not with do_gettimeofday() because - * it doesn't handle the better resolution of the later. + * it doesn't handle the better resolution of the latter. */ struct timespec timespec_trunc(struct timespec t, unsigned gran) { @@ -315,7 +326,7 @@ EXPORT_SYMBOL_GPL(getnstimeofday); * This algorithm was first published by Gauss (I think). * * WARNING: this function will overflow on 2106-02-07 06:28:16 on - * machines were long is 32-bit! (However, as time_t is signed, we + * machines where long is 32-bit! (However, as time_t is signed, we * will already get problems at other places on 2038-01-19 03:14:08) */ unsigned long @@ -352,7 +363,7 @@ EXPORT_SYMBOL(mktime); * normalize to the timespec storage format * * Note: The tv_nsec part is always in the range of - * 0 <= tv_nsec < NSEC_PER_SEC + * 0 <= tv_nsec < NSEC_PER_SEC * For negative values only the tv_sec field is negative ! */ void set_normalized_timespec(struct timespec *ts, time_t sec, long nsec) @@ -453,12 +464,13 @@ unsigned long msecs_to_jiffies(const unsigned int m) /* * Generic case - multiply, round and divide. But first * check that if we are doing a net multiplication, that - * we wouldnt overflow: + * we wouldn't overflow: */ if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET)) return MAX_JIFFY_OFFSET; - return (m * HZ + MSEC_PER_SEC - 1) / MSEC_PER_SEC; + return ((u64)MSEC_TO_HZ_MUL32 * m + MSEC_TO_HZ_ADJ32) + >> MSEC_TO_HZ_SHR32; #endif } EXPORT_SYMBOL(msecs_to_jiffies); @@ -472,7 +484,8 @@ unsigned long usecs_to_jiffies(const unsigned int u) #elif HZ > USEC_PER_SEC && !(HZ % USEC_PER_SEC) return u * (HZ / USEC_PER_SEC); #else - return (u * HZ + USEC_PER_SEC - 1) / USEC_PER_SEC; + return ((u64)USEC_TO_HZ_MUL32 * u + USEC_TO_HZ_ADJ32) + >> USEC_TO_HZ_SHR32; #endif } EXPORT_SYMBOL(usecs_to_jiffies); @@ -566,7 +579,11 @@ EXPORT_SYMBOL(jiffies_to_timeval); clock_t jiffies_to_clock_t(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 u64 tmp = (u64)x * TICK_NSEC; do_div(tmp, (NSEC_PER_SEC / USER_HZ)); @@ -599,7 +616,14 @@ 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 *= USER_HZ; + do_div(x, HZ); +# elif HZ > USER_HZ do_div(x, HZ / USER_HZ); +# else + /* Nothing to do */ +# endif #else /* * There are better ways that don't overflow early, @@ -611,7 +635,6 @@ u64 jiffies_64_to_clock_t(u64 x) #endif return x; } - EXPORT_SYMBOL(jiffies_64_to_clock_t); u64 nsec_to_clock_t(u64 x) @@ -646,7 +669,6 @@ u64 get_jiffies_64(void) } while (read_seqretry(&xtime_lock, seq)); return ret; } - EXPORT_SYMBOL(get_jiffies_64); #endif |