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authorPaul Mackerras <paulus@samba.org>2006-03-16 20:01:19 -0500
committerPaul Mackerras <paulus@samba.org>2006-03-16 20:01:19 -0500
commit23dd64011285010ac291f7dddf6e287bdb43a0ad (patch)
tree0e4f4569d38d82f4dceb4150d5ad940e0fd5f24f /arch/powerpc/kernel/time.c
parent516450179454de9e689e0a53ed8f34b896e8651c (diff)
parent485ff09990416c75ae9593ddc71619939ab9dd51 (diff)
Merge ../linux-2.6
Diffstat (limited to 'arch/powerpc/kernel/time.c')
-rw-r--r--arch/powerpc/kernel/time.c48
1 files changed, 34 insertions, 14 deletions
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 4f20a5f15d49..4a27218a086c 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -503,9 +503,9 @@ static inline void update_gtod(u64 new_tb_stamp, u64 new_stamp_xsec,
503 * the two values of tb_update_count match and are even then the 503 * the two values of tb_update_count match and are even then the
504 * tb_to_xs and stamp_xsec values are consistent. If not, then it 504 * tb_to_xs and stamp_xsec values are consistent. If not, then it
505 * loops back and reads them again until this criteria is met. 505 * loops back and reads them again until this criteria is met.
506 * We expect the caller to have done the first increment of
507 * vdso_data->tb_update_count already.
506 */ 508 */
507 ++(vdso_data->tb_update_count);
508 smp_wmb();
509 vdso_data->tb_orig_stamp = new_tb_stamp; 509 vdso_data->tb_orig_stamp = new_tb_stamp;
510 vdso_data->stamp_xsec = new_stamp_xsec; 510 vdso_data->stamp_xsec = new_stamp_xsec;
511 vdso_data->tb_to_xs = new_tb_to_xs; 511 vdso_data->tb_to_xs = new_tb_to_xs;
@@ -530,20 +530,15 @@ static __inline__ void timer_recalc_offset(u64 cur_tb)
530 unsigned long offset; 530 unsigned long offset;
531 u64 new_stamp_xsec; 531 u64 new_stamp_xsec;
532 u64 tlen, t2x; 532 u64 tlen, t2x;
533 u64 tb, xsec_old, xsec_new;
534 struct gettimeofday_vars *varp;
533 535
534 if (__USE_RTC()) 536 if (__USE_RTC())
535 return; 537 return;
536 tlen = current_tick_length(); 538 tlen = current_tick_length();
537 offset = cur_tb - do_gtod.varp->tb_orig_stamp; 539 offset = cur_tb - do_gtod.varp->tb_orig_stamp;
538 if (tlen == last_tick_len && offset < 0x80000000u) { 540 if (tlen == last_tick_len && offset < 0x80000000u)
539 /* check that we're still in sync; if not, resync */ 541 return;
540 struct timeval tv;
541 __do_gettimeofday(&tv, cur_tb);
542 if (tv.tv_sec <= xtime.tv_sec &&
543 (tv.tv_sec < xtime.tv_sec ||
544 tv.tv_usec * 1000 <= xtime.tv_nsec))
545 return;
546 }
547 if (tlen != last_tick_len) { 542 if (tlen != last_tick_len) {
548 t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs); 543 t2x = mulhdu(tlen << TICKLEN_SHIFT, ticklen_to_xs);
549 last_tick_len = tlen; 544 last_tick_len = tlen;
@@ -552,6 +547,21 @@ static __inline__ void timer_recalc_offset(u64 cur_tb)
552 new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC; 547 new_stamp_xsec = (u64) xtime.tv_nsec * XSEC_PER_SEC;
553 do_div(new_stamp_xsec, 1000000000); 548 do_div(new_stamp_xsec, 1000000000);
554 new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC; 549 new_stamp_xsec += (u64) xtime.tv_sec * XSEC_PER_SEC;
550
551 ++vdso_data->tb_update_count;
552 smp_mb();
553
554 /*
555 * Make sure time doesn't go backwards for userspace gettimeofday.
556 */
557 tb = get_tb();
558 varp = do_gtod.varp;
559 xsec_old = mulhdu(tb - varp->tb_orig_stamp, varp->tb_to_xs)
560 + varp->stamp_xsec;
561 xsec_new = mulhdu(tb - cur_tb, t2x) + new_stamp_xsec;
562 if (xsec_new < xsec_old)
563 new_stamp_xsec += xsec_old - xsec_new;
564
555 update_gtod(cur_tb, new_stamp_xsec, t2x); 565 update_gtod(cur_tb, new_stamp_xsec, t2x);
556} 566}
557 567
@@ -800,6 +810,10 @@ int do_settimeofday(struct timespec *tv)
800 } 810 }
801#endif 811#endif
802 812
813 /* Make userspace gettimeofday spin until we're done. */
814 ++vdso_data->tb_update_count;
815 smp_mb();
816
803 /* 817 /*
804 * Subtract off the number of nanoseconds since the 818 * Subtract off the number of nanoseconds since the
805 * beginning of the last tick. 819 * beginning of the last tick.
@@ -961,10 +975,16 @@ void __init time_init(void)
961 * It is computed as: 975 * It is computed as:
962 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9) 976 * ticklen_to_xs = 2^N / (tb_ticks_per_jiffy * 1e9)
963 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT 977 * where N = 64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT
964 * so as to give the result as a 0.64 fixed-point fraction. 978 * which turns out to be N = 51 - SHIFT_HZ.
979 * This gives the result as a 0.64 fixed-point fraction.
980 * That value is reduced by an offset amounting to 1 xsec per
981 * 2^31 timebase ticks to avoid problems with time going backwards
982 * by 1 xsec when we do timer_recalc_offset due to losing the
983 * fractional xsec. That offset is equal to ppc_tb_freq/2^51
984 * since there are 2^20 xsec in a second.
965 */ 985 */
966 div128_by_32(1ULL << (64 + 20 - TICKLEN_SCALE - TICKLEN_SHIFT), 0, 986 div128_by_32((1ULL << 51) - ppc_tb_freq, 0,
967 tb_ticks_per_jiffy, &res); 987 tb_ticks_per_jiffy << SHIFT_HZ, &res);
968 div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res); 988 div128_by_32(res.result_high, res.result_low, NSEC_PER_SEC, &res);
969 ticklen_to_xs = res.result_low; 989 ticklen_to_xs = res.result_low;
970 990