From f1f1d5ebd10ffa4242bce7a90a56a222d6b7bc77 Mon Sep 17 00:00:00 2001 From: Richard Cochran Date: Tue, 1 Feb 2011 13:52:26 +0000 Subject: [PATCH] posix-timers: Introduce a syscall for clock tuning. A new syscall is introduced that allows tuning of a POSIX clock. The new call, clock_adjtime, takes two parameters, the clock ID and a pointer to a struct timex. Any ADJTIMEX(2) operation may be requested via this system call, but various POSIX clocks may or may not support tuning. [ tglx: Adapted to the posix-timer cleanup series. Avoid copy_to_user in the error case ] Signed-off-by: Richard Cochran Acked-by: John Stultz LKML-Reference: <20110201134419.869804645@linutronix.de> Signed-off-by: Thomas Gleixner --- include/linux/posix-timers.h | 2 ++ include/linux/syscalls.h | 2 ++ kernel/compat.c | 23 +++++++++++++++++++++++ kernel/posix-timers.c | 30 ++++++++++++++++++++++++++++++ 4 files changed, 57 insertions(+) diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h index 8206255a547c..79a1cea7f6ed 100644 --- a/include/linux/posix-timers.h +++ b/include/linux/posix-timers.h @@ -4,6 +4,7 @@ #include #include #include +#include union cpu_time_count { cputime_t cpu; @@ -71,6 +72,7 @@ struct k_clock { int (*clock_set) (const clockid_t which_clock, const struct timespec *tp); int (*clock_get) (const clockid_t which_clock, struct timespec * tp); + int (*clock_adj) (const clockid_t which_clock, struct timex *tx); int (*timer_create) (struct k_itimer *timer); int (*nsleep) (const clockid_t which_clock, int flags, struct timespec *, struct timespec __user *); diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index 18cd0684fc4e..bfacab921239 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -311,6 +311,8 @@ asmlinkage long sys_clock_settime(clockid_t which_clock, const struct timespec __user *tp); asmlinkage long sys_clock_gettime(clockid_t which_clock, struct timespec __user *tp); +asmlinkage long sys_clock_adjtime(clockid_t which_clock, + struct timex __user *tx); asmlinkage long sys_clock_getres(clockid_t which_clock, struct timespec __user *tp); asmlinkage long sys_clock_nanosleep(clockid_t which_clock, int flags, diff --git a/kernel/compat.c b/kernel/compat.c index 449e853cf41d..38b1d2c1cbe8 100644 --- a/kernel/compat.c +++ b/kernel/compat.c @@ -675,6 +675,29 @@ long compat_sys_clock_gettime(clockid_t which_clock, return err; } +long compat_sys_clock_adjtime(clockid_t which_clock, + struct compat_timex __user *utp) +{ + struct timex txc; + mm_segment_t oldfs; + int err, ret; + + err = compat_get_timex(&txc, utp); + if (err) + return err; + + oldfs = get_fs(); + set_fs(KERNEL_DS); + ret = sys_clock_adjtime(which_clock, (struct timex __user *) &txc); + set_fs(oldfs); + + err = compat_put_timex(utp, &txc); + if (err) + return err; + + return ret; +} + long compat_sys_clock_getres(clockid_t which_clock, struct compat_timespec __user *tp) { diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c index a3fdfd4be0ec..5a5a4f1c0971 100644 --- a/kernel/posix-timers.c +++ b/kernel/posix-timers.c @@ -170,6 +170,12 @@ static int posix_clock_realtime_set(const clockid_t which_clock, return do_sys_settimeofday(tp, NULL); } +static int posix_clock_realtime_adj(const clockid_t which_clock, + struct timex *t) +{ + return do_adjtimex(t); +} + /* * Get monotonic time for posix timers */ @@ -216,6 +222,7 @@ static __init int init_posix_timers(void) .clock_getres = hrtimer_get_res, .clock_get = posix_clock_realtime_get, .clock_set = posix_clock_realtime_set, + .clock_adj = posix_clock_realtime_adj, .nsleep = common_nsleep, .nsleep_restart = hrtimer_nanosleep_restart, .timer_create = common_timer_create, @@ -948,6 +955,29 @@ SYSCALL_DEFINE2(clock_gettime, const clockid_t, which_clock, return error; } +SYSCALL_DEFINE2(clock_adjtime, const clockid_t, which_clock, + struct timex __user *, utx) +{ + struct k_clock *kc = clockid_to_kclock(which_clock); + struct timex ktx; + int err; + + if (!kc) + return -EINVAL; + if (!kc->clock_adj) + return -EOPNOTSUPP; + + if (copy_from_user(&ktx, utx, sizeof(ktx))) + return -EFAULT; + + err = kc->clock_adj(which_clock, &ktx); + + if (!err && copy_to_user(utx, &ktx, sizeof(ktx))) + return -EFAULT; + + return err; +} + SYSCALL_DEFINE2(clock_getres, const clockid_t, which_clock, struct timespec __user *, tp) { -- 2.39.5