[PATCH RFC 1/3] timekeeping: Remove support for old vsyscalls

From: Miroslav Lichvar
Date: Wed May 17 2017 - 12:13:51 EST


As the last users of CONFIG_GENERIC_TIME_VSYSCALL_OLD have been updated,
the support can be removed from the timekeeping code.

Cc: John Stultz <john.stultz@xxxxxxxxxx>
Cc: Prarit Bhargava <prarit@xxxxxxxxxx>
Cc: Richard Cochran <richardcochran@xxxxxxxxx>
Signed-off-by: Miroslav Lichvar <mlichvar@xxxxxxxxxx>
---
include/linux/timekeeper_internal.h | 7 ------
kernel/time/Kconfig | 4 ----
kernel/time/timekeeping.c | 44 -------------------------------------
3 files changed, 55 deletions(-)

diff --git a/include/linux/timekeeper_internal.h b/include/linux/timekeeper_internal.h
index 110f453..b7ae5b0 100644
--- a/include/linux/timekeeper_internal.h
+++ b/include/linux/timekeeper_internal.h
@@ -132,13 +132,6 @@ struct timekeeper {
extern void update_vsyscall(struct timekeeper *tk);
extern void update_vsyscall_tz(void);

-#elif defined(CONFIG_GENERIC_TIME_VSYSCALL_OLD)
-
-extern void update_vsyscall_old(struct timespec *ts, struct timespec *wtm,
- struct clocksource *c, u32 mult,
- u64 cycle_last);
-extern void update_vsyscall_tz(void);
-
#else

static inline void update_vsyscall(struct timekeeper *tk)
diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig
index 4008d9f..55d61a3 100644
--- a/kernel/time/Kconfig
+++ b/kernel/time/Kconfig
@@ -21,10 +21,6 @@ config CLOCKSOURCE_VALIDATE_LAST_CYCLE
config GENERIC_TIME_VSYSCALL
bool

-# Timekeeping vsyscall support
-config GENERIC_TIME_VSYSCALL_OLD
- bool
-
# Old style timekeeping
config ARCH_USES_GETTIMEOFFSET
bool
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 8fd77c6..ff542dd 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -487,44 +487,6 @@ static void halt_fast_timekeeper(struct timekeeper *tk)
update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
}

-#ifdef CONFIG_GENERIC_TIME_VSYSCALL_OLD
-
-static inline void update_vsyscall(struct timekeeper *tk)
-{
- struct timespec xt, wm;
-
- xt = timespec64_to_timespec(tk_xtime(tk));
- wm = timespec64_to_timespec(tk->wall_to_monotonic);
- update_vsyscall_old(&xt, &wm, tk->tkr_mono.clock, tk->tkr_mono.mult,
- tk->tkr_mono.cycle_last);
-}
-
-static inline void old_vsyscall_fixup(struct timekeeper *tk)
-{
- s64 remainder;
-
- /*
- * Store only full nanoseconds into xtime_nsec after rounding
- * it up and add the remainder to the error difference.
- * XXX - This is necessary to avoid small 1ns inconsistnecies caused
- * by truncating the remainder in vsyscalls. However, it causes
- * additional work to be done in timekeeping_adjust(). Once
- * the vsyscall implementations are converted to use xtime_nsec
- * (shifted nanoseconds), and CONFIG_GENERIC_TIME_VSYSCALL_OLD
- * users are removed, this can be killed.
- */
- remainder = tk->tkr_mono.xtime_nsec & ((1ULL << tk->tkr_mono.shift) - 1);
- if (remainder != 0) {
- tk->tkr_mono.xtime_nsec -= remainder;
- tk->tkr_mono.xtime_nsec += 1ULL << tk->tkr_mono.shift;
- tk->ntp_error += remainder << tk->ntp_error_shift;
- tk->ntp_error -= (1ULL << tk->tkr_mono.shift) << tk->ntp_error_shift;
- }
-}
-#else
-#define old_vsyscall_fixup(tk)
-#endif
-
static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);

static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
@@ -2065,12 +2027,6 @@ void update_wall_time(void)
timekeeping_adjust(tk, offset);

/*
- * XXX This can be killed once everyone converts
- * to the new update_vsyscall.
- */
- old_vsyscall_fixup(tk);
-
- /*
* Finally, make sure that after the rounding
* xtime_nsec isn't larger than NSEC_PER_SEC
*/
--
2.9.3