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authorRichard Cochran <richardcochran@gmail.com>2011-02-01 16:52:26 +0300
committerThomas Gleixner <tglx@linutronix.de>2011-02-02 17:28:19 +0300
commitf1f1d5ebd10ffa4242bce7a90a56a222d6b7bc77 (patch)
treeca04ea979512e0037c52bca855dbf050b1b08360
parent65f5d80bdf83ec0d7f3887db10153bf3f36ed73c (diff)
downloadlinux-f1f1d5ebd10ffa4242bce7a90a56a222d6b7bc77.tar.xz
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 <richard.cochran@omicron.at> Acked-by: John Stultz <johnstul@us.ibm.com> LKML-Reference: <20110201134419.869804645@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--include/linux/posix-timers.h2
-rw-r--r--include/linux/syscalls.h2
-rw-r--r--kernel/compat.c23
-rw-r--r--kernel/posix-timers.c30
4 files changed, 57 insertions, 0 deletions
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 <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sched.h>
+#include <linux/timex.h>
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)
{