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Hook compat_sys_nanosleep up to high res timer code

PATCH In review Anton Blanchard 3 participants 9 messages Oct 14, 2007 – Oct 15, 2007 High-resolution timers, timer wheel, clockevents

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Anton Blanchard

author
#0 lore raw

PATCH 1/1 Hook compat_sys_nanosleep up to high res timer code

Now we have high res timers on ppc64 I thought Id test them. It turns out compat_sys_nanosleep hasnt been converted to the hrtimer code and so is limited to HZ resolution.

The following patch makes compat_sys_nanosleep call hrtimer_nanosleep and uses compat_alloc_user_space to avoid setting KERNEL_DS.

Signed-off-by Anton Blanchard <[email protected]>

---

kernel/compat.c +13 -46
index 3bae374..46795ac 100644
@@ -40,62 +40,29 @@ int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user
 			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
 }
 
-static long compat_nanosleep_restart(struct restart_block *restart)
-{
-	unsigned long expire = restart->arg0, now = jiffies;
-	struct compat_timespec __user *rmtp;
-
-	/* Did it expire while we handled signals? */
-	if (!time_after(expire, now))
-		return 0;
-
-	expire = schedule_timeout_interruptible(expire - now);
-	if (expire == 0)
-		return 0;
-
-	rmtp = (struct compat_timespec __user *)restart->arg1;
-	if (rmtp) {
-		struct compat_timespec ct;
-		struct timespec t;
-
-		jiffies_to_timespec(expire, &t);
-		ct.tv_sec = t.tv_sec;
-		ct.tv_nsec = t.tv_nsec;
-		if (copy_to_user(rmtp, &ct, sizeof(ct)))
-			return -EFAULT;
-	}
-	/* The 'restart' block is already filled in */
-	return -ERESTART_RESTARTBLOCK;
-}
-
 asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
-		struct compat_timespec __user *rmtp)
+				     struct compat_timespec __user *rmtp)
 {
-	struct timespec t;
-	struct restart_block *restart;
-	unsigned long expire;
+	struct timespec tu;
+	struct timespec __user *rmtp64;
+	long ret;
 
-	if (get_compat_timespec(&t, rqtp))
+	if (get_compat_timespec(&tu, rqtp))
 		return -EFAULT;
 
-	if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0))
+	if (!timespec_valid(&tu))
 		return -EINVAL;
 
-	expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
-	expire = schedule_timeout_interruptible(expire);
-	if (expire == 0)
-		return 0;
+	rmtp64 = compat_alloc_user_space(sizeof(*rmtp64));
+	ret = hrtimer_nanosleep(&tu, rmtp64, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 
-	if (rmtp) {
-		jiffies_to_timespec(expire, &t);
-		if (put_compat_timespec(&t, rmtp))
+	if (ret) {
+		if (copy_from_user(&tu, rmtp64, sizeof(*rmtp64)) ||
+		    put_compat_timespec(&tu, rmtp))
 			return -EFAULT;
 	}
-	restart = &current_thread_info()->restart_block;
-	restart->fn = compat_nanosleep_restart;
-	restart->arg0 = jiffies + expire;
-	restart->arg1 = (unsigned long) rmtp;
-	return -ERESTART_RESTARTBLOCK;
+
+	return ret;
 }
 
 static inline long get_compat_itimerval(struct itimerval *o,
#1 lore raw
Quoted 8 lines · Anton Blanchard

Now we have high res timers on ppc64 I thought Id test them. It turns out compat_sys_nanosleep hasnt been converted to the hrtimer code and so is limited to HZ resolution.

The following patch makes compat_sys_nanosleep call hrtimer_nanosleep and uses compat_alloc_user_space to avoid setting KERNEL_DS.

Signed-off-by Anton Blanchard <[email protected]>

The code looks correct, but I think it would be nicer to change hrtimer_nanosleep to take a kernel pointer and have all three callers (common_nsleep, sys_nanosleep and compat_sys_nanosleep) do the copy_to_user/put_compat_timespec in the caller.

This would also make it possible to get rid of set_fs() in compat_sys_clock_nanosleep().

	Arnd <><
author
#2 lore raw

Hi Arnd,

Quoted 4 lines

The code looks correct, but I think it would be nicer to change hrtimer_nanosleep to take a kernel pointer and have all three callers (common_nsleep, sys_nanosleep and compat_sys_nanosleep) do the copy_to_user/put_compat_timespec in the caller.

Good idea, I had considered that but thought a larger cleanup might run afoul of the merge rules :)

Regardless, here it is. Id appreciate a once over since it does affect more code than the previous patch :)

Anton

--

Now we have high res timers on ppc64 I thought Id test them. It turns out compat_sys_nanosleep hasnt been converted to the hrtimer code and so is limited to HZ resolution.

The following patch pulls the copy_to_user out of hrtimer_nanosleep and into the callers (common_nsleep, sys_nanosleep and compat_sys_nanosleep) thus avoiding any set_fs(KERNEL_DS) or compat_alloc_userspace tricks.

Signed-off-by Anton Blanchard <[email protected]>

---

include/linux/hrtimer.h +1 -1
index 540799b..7a9398e 100644
@@ -300,7 +300,7 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
 
 /* Precise sleep: */
 extern long hrtimer_nanosleep(struct timespec *rqtp,
-			      struct timespec __user *rmtp,
+			      struct timespec *rmtp,
 			      const enum hrtimer_mode mode,
 			      const clockid_t clockid);
 extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
kernel/compat.c +10 -46

72 lines not on this page · raw message

kernel/hrtimer.c +15 -13
index dc8a445..095e09e 100644
@@ -1286,8 +1286,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 {
 	struct hrtimer_sleeper t;
-	struct timespec __user *rmtp;
-	struct timespec tu;
+	struct timespec *rmtp;
 	ktime_t time;
 
 	restart->fn = do_no_restart_syscall;

@@ -1298,14 +1297,12 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	if (do_nanosleep(&t, HRTIMER_MODE_ABS))
 		return 0;
 
-	rmtp = (struct timespec __user *) restart->arg1;
+	rmtp = (struct timespec *)restart->arg1;
 	if (rmtp) {
 		time = ktime_sub(t.timer.expires, t.timer.base->get_time());
 		if (time.tv64 <= 0)
 			return 0;
-		tu = ktime_to_timespec(time);
-		if (copy_to_user(rmtp, &tu, sizeof(tu)))
-			return -EFAULT;
+		*rmtp = ktime_to_timespec(time);
 	}
 
 	restart->fn = hrtimer_nanosleep_restart;

@@ -1314,12 +1311,11 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	return -ERESTART_RESTARTBLOCK;
 }
 
-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
 		       const enum hrtimer_mode mode, const clockid_t clockid)
 {
 	struct restart_block *restart;
 	struct hrtimer_sleeper t;
-	struct timespec tu;
 	ktime_t rem;
 
 	hrtimer_init(&t.timer, clockid, mode);

@@ -1335,9 +1331,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 		rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
 		if (rem.tv64 <= 0)
 			return 0;
-		tu = ktime_to_timespec(rem);
-		if (copy_to_user(rmtp, &tu, sizeof(tu)))
-			return -EFAULT;
+		*rmtp = ktime_to_timespec(rem);
 	}
 
 	restart = &current_thread_info()->restart_block;

@@ -1353,7 +1347,8 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 asmlinkage long
 sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 {
-	struct timespec tu;
+	struct timespec tu, rmt;
+	int ret;
 
 	if (copy_from_user(&tu, rqtp, sizeof(tu)))
 		return -EFAULT;

@@ -1361,7 +1356,14 @@ sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 	if (!timespec_valid(&tu))
 		return -EINVAL;
 
-	return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+	ret = hrtimer_nanosleep(&tu, &rmt, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+
+	if (ret) {
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }
 
 /*
kernel/posix-timers.c +11 -1
index 7a15afb..fc7dac2 100644
@@ -980,9 +980,19 @@ sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp)
 static int common_nsleep(const clockid_t which_clock, int flags,
 			 struct timespec *tsave, struct timespec __user *rmtp)
 {
-	return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
+	struct timespec rmt;
+	int ret;
+
+	ret = hrtimer_nanosleep(tsave, &rmt, flags & TIMER_ABSTIME ?
 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 				 which_clock);
+
+	if (ret) {
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }
 
 asmlinkage long
#3 lore raw
Quoted 9 lines · Anton Blanchard

Hi Arnd,

Quoted 4 lines

The code looks correct, but I think it would be nicer to change hrtimer_nanosleep to take a kernel pointer and have all three callers (common_nsleep, sys_nanosleep and compat_sys_nanosleep) do the copy_to_user/put_compat_timespec in the caller.

Good idea, I had considered that but thought a larger cleanup might run afoul of the merge rules :)

Looks good, except ....

kernel/compat.c int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user · line 41

Quoted 5 lines
kernel/compat.c +0 -0
@@ -40,62 +40,26 @@ int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user
 			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
 }

Can you put this into a separate patch please ?

Quoted 14 lines
kernel/hrtimer.c +2 -1
 	restart = &current_thread_info()->restart_block;

@@ -1353,7 +1347,8 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 asmlinkage long
 sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 {
-	struct timespec tu;
+	struct timespec tu, rmt;
+	int ret;
 
 	if (copy_from_user(&tu, rqtp, sizeof(tu)))
 		return -EFAULT;

kernel/hrtimer.c sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp) · line 1361

Quoted 7 lines
kernel/hrtimer.c +3 -1
@@ -1361,7 +1356,14 @@ sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 	if (!timespec_valid(&tu))
 		return -EINVAL;
 
-	return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+	ret = hrtimer_nanosleep(&tu, &rmt, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+
+	if (ret) {

Can you check for rmtp as well ? rmtp is optional and can be NULL

Quoted 15 lines
kernel/hrtimer.c +5 -0
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }
 
 /*
kernel/posix-timers.c +0 -0
index 7a15afb..fc7dac2 100644
@@ -980,9 +980,19 @@ sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp)
 static int common_nsleep(const clockid_t which_clock, int flags,
 			 struct timespec *tsave, struct timespec __user *rmtp)

kernel/posix-timers.c sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp) · line 990

Quoted 10 lines
kernel/posix-timers.c +6 -1
 {
-	return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
+	struct timespec rmt;
+	int ret;
+
+	ret = hrtimer_nanosleep(tsave, &rmt, flags & TIMER_ABSTIME ?
 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 				 which_clock);
+
+	if (ret) {

Ditto.

kernel/posix-timers.c sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp) · line 996

Quoted 6 lines
kernel/posix-timers.c +5 -0
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }

Thanks,

tglx

author
#4 lore raw

PATCH 1/1 Rework hrtimer_nanosleep to make sys_compat_nanosleep easier

Hi Thomas,

Thanks for the review, updates to follow.

Anton

--

Pull the copy_to_user out of hrtimer_nanosleep and into the callers (common_nsleep, sys_nanosleep) in preparation for converting compat_sys_nanosleep to use hrtimers.

Signed-off-by Anton Blanchard <[email protected]>

---

include/linux/hrtimer.h +1 -1
index 540799b..7a9398e 100644
@@ -300,7 +300,7 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
 
 /* Precise sleep: */
 extern long hrtimer_nanosleep(struct timespec *rqtp,
-			      struct timespec __user *rmtp,
+			      struct timespec *rmtp,
 			      const enum hrtimer_mode mode,
 			      const clockid_t clockid);
 extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
kernel/hrtimer.c +15 -13
index dc8a445..129fead 100644
@@ -1286,8 +1286,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 {
 	struct hrtimer_sleeper t;
-	struct timespec __user *rmtp;
-	struct timespec tu;
+	struct timespec *rmtp;
 	ktime_t time;
 
 	restart->fn = do_no_restart_syscall;

@@ -1298,14 +1297,12 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	if (do_nanosleep(&t, HRTIMER_MODE_ABS))
 		return 0;
 
-	rmtp = (struct timespec __user *) restart->arg1;
+	rmtp = (struct timespec *)restart->arg1;
 	if (rmtp) {
 		time = ktime_sub(t.timer.expires, t.timer.base->get_time());
 		if (time.tv64 <= 0)
 			return 0;
-		tu = ktime_to_timespec(time);
-		if (copy_to_user(rmtp, &tu, sizeof(tu)))
-			return -EFAULT;
+		*rmtp = ktime_to_timespec(time);
 	}
 
 	restart->fn = hrtimer_nanosleep_restart;

@@ -1314,12 +1311,11 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	return -ERESTART_RESTARTBLOCK;
 }
 
-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
 		       const enum hrtimer_mode mode, const clockid_t clockid)
 {
 	struct restart_block *restart;
 	struct hrtimer_sleeper t;
-	struct timespec tu;
 	ktime_t rem;
 
 	hrtimer_init(&t.timer, clockid, mode);

@@ -1335,9 +1331,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 		rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
 		if (rem.tv64 <= 0)
 			return 0;
-		tu = ktime_to_timespec(rem);
-		if (copy_to_user(rmtp, &tu, sizeof(tu)))
-			return -EFAULT;
+		*rmtp = ktime_to_timespec(rem);
 	}
 
 	restart = &current_thread_info()->restart_block;

@@ -1353,7 +1347,8 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 asmlinkage long
 sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 {
-	struct timespec tu;
+	struct timespec tu, rmt;
+	int ret;
 
 	if (copy_from_user(&tu, rqtp, sizeof(tu)))
 		return -EFAULT;

@@ -1361,7 +1356,14 @@ sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 	if (!timespec_valid(&tu))
 		return -EINVAL;
 
-	return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+	ret = hrtimer_nanosleep(&tu, &rmt, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+
+	if (ret && rmtp) {
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }
 
 /*
kernel/posix-timers.c +11 -1
index 57efe04..cce8c75 100644
@@ -980,9 +980,19 @@ sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp)
 static int common_nsleep(const clockid_t which_clock, int flags,
 			 struct timespec *tsave, struct timespec __user *rmtp)
 {
-	return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
+	struct timespec rmt;
+	int ret;
+
+	ret = hrtimer_nanosleep(tsave, &rmt, flags & TIMER_ABSTIME ?
 				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
 				 which_clock);
+
+	if (ret && rmtp) {
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }
 
 asmlinkage long
author
#5 lore raw

PATCH 1/1 Hook compat_sys_nanosleep up to high res timer code

Now we have high res timers on ppc64 I thought Id test them. It turns out compat_sys_nanosleep hasnt been converted to the hrtimer code and so is limited to HZ resolution.

The follow patch converts compat_sys_nanosleep to use high res timers.

Signed-off-by Anton Blanchard <[email protected]>

---

kernel/compat.c +10 -46
index 3bae374..729f63d 100644
@@ -40,62 +40,26 @@ int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user
 			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
 }
 
-static long compat_nanosleep_restart(struct restart_block *restart)
-{
-	unsigned long expire = restart->arg0, now = jiffies;
-	struct compat_timespec __user *rmtp;
-
-	/* Did it expire while we handled signals? */
-	if (!time_after(expire, now))
-		return 0;
-
-	expire = schedule_timeout_interruptible(expire - now);
-	if (expire == 0)
-		return 0;
-
-	rmtp = (struct compat_timespec __user *)restart->arg1;
-	if (rmtp) {
-		struct compat_timespec ct;
-		struct timespec t;
-
-		jiffies_to_timespec(expire, &t);
-		ct.tv_sec = t.tv_sec;
-		ct.tv_nsec = t.tv_nsec;
-		if (copy_to_user(rmtp, &ct, sizeof(ct)))
-			return -EFAULT;
-	}
-	/* The 'restart' block is already filled in */
-	return -ERESTART_RESTARTBLOCK;
-}
-
 asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
-		struct compat_timespec __user *rmtp)
+				     struct compat_timespec __user *rmtp)
 {
-	struct timespec t;
-	struct restart_block *restart;
-	unsigned long expire;
+	struct timespec tu, rmt;
+	long ret;
 
-	if (get_compat_timespec(&t, rqtp))
+	if (get_compat_timespec(&tu, rqtp))
 		return -EFAULT;
 
-	if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0))
+	if (!timespec_valid(&tu))
 		return -EINVAL;
 
-	expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
-	expire = schedule_timeout_interruptible(expire);
-	if (expire == 0)
-		return 0;
+	ret = hrtimer_nanosleep(&tu, &rmt, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
 
-	if (rmtp) {
-		jiffies_to_timespec(expire, &t);
-		if (put_compat_timespec(&t, rmtp))
+	if (ret && rmtp) {
+		if (put_compat_timespec(&rmt, rmtp))
 			return -EFAULT;
 	}
-	restart = &current_thread_info()->restart_block;
-	restart->fn = compat_nanosleep_restart;
-	restart->arg0 = jiffies + expire;
-	restart->arg1 = (unsigned long) rmtp;
-	return -ERESTART_RESTARTBLOCK;
+
+	return ret;
 }
 
 static inline long get_compat_itimerval(struct itimerval *o,
Acked-by on v1 1/1
#6 lore raw

Re: [PATCH] Rework hrtimer_nanosleep to make sys_compat_nanosleep easier

In reply to Anton Blanchard
Quoted 3 lines · Anton Blanchard

Pull the copy_to_user out of hrtimer_nanosleep and into the callers (common_nsleep, sys_nanosleep) in preparation for converting compat_sys_nanosleep to use hrtimers.

Looks good, except for two micro-optimization:

Quoted 1 line
Signed-off-by Anton Blanchard <[email protected]>
Acked-by Arnd Bergmann <[email protected]>

Review sys_nanosleep(struct timespec __user *rqtp, struct=

Quoted 1 line
(quoted diff) +0 -0
@@ -1361,7 +1356,14 @@ sys_nanosleep(struct timespec __user *rqtp, struct=

timespec __user *rmtp)

Quoted 4 lines
(quoted diff) +0 -0
 =A0=A0=A0=A0=A0=A0=A0=A0if (!timespec_valid(&tu))
 =A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0return -EINVAL;

=A0
-=A0=A0=A0=A0=A0=A0=A0return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_RE=

L, CLOCK_MONOTONIC);

Quoted 1 line

+=A0=A0=A0=A0=A0=A0=A0ret =3D hrtimer_nanosleep(&tu, &rmt, HRTIMER_MODE_R=

EL, CLOCK_MONOTONIC);

Quoted 3 lines

+

+=A0=A0=A0=A0=A0=A0=A0if (ret && rmtp) {
+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0if (copy_to_user(rmtp, &rmt=

, sizeof(*rmtp)))

Quoted 1 line

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0ret=

urn -EFAULT;

Quoted 5 lines

+=A0=A0=A0=A0=A0=A0=A0}
+
+=A0=A0=A0=A0=A0=A0=A0return ret;
=A0}
=A0

If it's common to call sys_nanosleep with a NULL rmtp argument, we could sa= ve a
few cycles using=20

	return hrtimer_nanosleep(&tu, rmtp ? &rmp : NULL, HRTIMER_MODE_REL,
								 CLOCK_MONOTONIC);

kernel/posix-timers.c sys_clock_getres(const clockid_t which_clock, struct=

Quoted 5 lines
kernel/posix-timers.c +0 -0
index 57efe04..cce8c75 100644
@@ -980,9 +980,19 @@ sys_clock_getres(const clockid_t which_clock, struct=

timespec __user *tp)

Quoted 2 lines
kernel/posix-timers.c +0 -0
 =A0static int common_nsleep(const clockid_t which_clock, int flags,

=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0 =

struct timespec *tsave, struct timespec __user *rmtp)

Quoted 2 lines

=A0{
-=A0=A0=A0=A0=A0=A0=A0return hrtimer_nanosleep(tsave, rmtp, flags & TIMER=

_ABSTIME ?

Quoted 4 lines
+=A0=A0=A0=A0=A0=A0=A0struct timespec rmt;
+=A0=A0=A0=A0=A0=A0=A0int ret;

+
+=A0=A0=A0=A0=A0=A0=A0ret =3D hrtimer_nanosleep(tsave, &rmt, flags & TIME=

R_ABSTIME ?

Quoted 1 line

=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=

=A0=A0=A0=A0=A0=A0=A0=A0 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,

Quoted 1 line

=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=

=A0=A0=A0=A0=A0=A0=A0=A0 which_clock);

Quoted 3 lines

+

+=A0=A0=A0=A0=A0=A0=A0if (ret && rmtp) {
+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0if (copy_to_user(rmtp, &rmt=

, sizeof(*rmtp)))

Quoted 1 line

+=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0=A0ret=

urn -EFAULT;

Quoted 4 lines

+=A0=A0=A0=A0=A0=A0=A0}
+
+=A0=A0=A0=A0=A0=A0=A0return ret;
=A0}

I think it would be better here to propagate the move to a kernel *rmtp down to sys_clock_nanosleep so we get the same optimization in compat_sys_clock_nanosleep. That should probably also be a separate patch. I can do one if you don't do it first.

	Arnd <><
author
#7 lore raw

PATCH 1/1 Rework hrtimer_nanosleep to make sys_compat_nanosleep easier

Hi,

Quoted 5 lines

If it's common to call sys_nanosleep with a NULL rmtp argument, we could save a few cycles using

	return hrtimer_nanosleep(&tu, rmtp ? &rmp : NULL, HRTIMER_MODE_REL,
				CLOCK_MONOTONIC);

Good idea, patches updated.

Quoted 4 lines

I think it would be better here to propagate the move to a kernel *rmtp down to sys_clock_nanosleep so we get the same optimization in compat_sys_clock_nanosleep. That should probably also be a separate patch. I can do one if you don't do it first.

I can get to this later in the week, if you feel the urge in the meantime go for it :)

Anton

--

Pull the copy_to_user out of hrtimer_nanosleep and into the callers (common_nsleep, sys_nanosleep) in preparation for converting compat_sys_nanosleep to use hrtimers.

Signed-off-by Anton Blanchard <[email protected]>
Acked-by Arnd Bergmann <[email protected]>

---

include/linux/hrtimer.h +1 -1
index 540799b..7a9398e 100644
@@ -300,7 +300,7 @@ hrtimer_forward(struct hrtimer *timer, ktime_t now, ktime_t interval);
 
 /* Precise sleep: */
 extern long hrtimer_nanosleep(struct timespec *rqtp,
-			      struct timespec __user *rmtp,
+			      struct timespec *rmtp,
 			      const enum hrtimer_mode mode,
 			      const clockid_t clockid);
 extern long hrtimer_nanosleep_restart(struct restart_block *restart_block);
kernel/hrtimer.c +16 -13
index dc8a445..b2b2c2b 100644
@@ -1286,8 +1286,7 @@ static int __sched do_nanosleep(struct hrtimer_sleeper *t, enum hrtimer_mode mod
 long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 {
 	struct hrtimer_sleeper t;
-	struct timespec __user *rmtp;
-	struct timespec tu;
+	struct timespec *rmtp;
 	ktime_t time;
 
 	restart->fn = do_no_restart_syscall;

@@ -1298,14 +1297,12 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	if (do_nanosleep(&t, HRTIMER_MODE_ABS))
 		return 0;
 
-	rmtp = (struct timespec __user *) restart->arg1;
+	rmtp = (struct timespec *)restart->arg1;
 	if (rmtp) {
 		time = ktime_sub(t.timer.expires, t.timer.base->get_time());
 		if (time.tv64 <= 0)
 			return 0;
-		tu = ktime_to_timespec(time);
-		if (copy_to_user(rmtp, &tu, sizeof(tu)))
-			return -EFAULT;
+		*rmtp = ktime_to_timespec(time);
 	}
 
 	restart->fn = hrtimer_nanosleep_restart;

@@ -1314,12 +1311,11 @@ long __sched hrtimer_nanosleep_restart(struct restart_block *restart)
 	return -ERESTART_RESTARTBLOCK;
 }
 
-long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
+long hrtimer_nanosleep(struct timespec *rqtp, struct timespec *rmtp,
 		       const enum hrtimer_mode mode, const clockid_t clockid)
 {
 	struct restart_block *restart;
 	struct hrtimer_sleeper t;
-	struct timespec tu;
 	ktime_t rem;
 
 	hrtimer_init(&t.timer, clockid, mode);

@@ -1335,9 +1331,7 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 		rem = ktime_sub(t.timer.expires, t.timer.base->get_time());
 		if (rem.tv64 <= 0)
 			return 0;
-		tu = ktime_to_timespec(rem);
-		if (copy_to_user(rmtp, &tu, sizeof(tu)))
-			return -EFAULT;
+		*rmtp = ktime_to_timespec(rem);
 	}
 
 	restart = &current_thread_info()->restart_block;

@@ -1353,7 +1347,8 @@ long hrtimer_nanosleep(struct timespec *rqtp, struct timespec __user *rmtp,
 asmlinkage long
 sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 {
-	struct timespec tu;
+	struct timespec tu, rmt;
+	int ret;
 
 	if (copy_from_user(&tu, rqtp, sizeof(tu)))
 		return -EFAULT;

@@ -1361,7 +1356,15 @@ sys_nanosleep(struct timespec __user *rqtp, struct timespec __user *rmtp)
 	if (!timespec_valid(&tu))
 		return -EINVAL;
 
-	return hrtimer_nanosleep(&tu, rmtp, HRTIMER_MODE_REL, CLOCK_MONOTONIC);
+	ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,
+				CLOCK_MONOTONIC);
+
+	if (ret && rmtp) {
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }
 
 /*
kernel/posix-timers.c +14 -3
index 57efe04..56b3d86 100644
@@ -980,9 +980,20 @@ sys_clock_getres(const clockid_t which_clock, struct timespec __user *tp)
 static int common_nsleep(const clockid_t which_clock, int flags,
 			 struct timespec *tsave, struct timespec __user *rmtp)
 {
-	return hrtimer_nanosleep(tsave, rmtp, flags & TIMER_ABSTIME ?
-				 HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
-				 which_clock);
+	struct timespec rmt;
+	int ret;
+
+	ret = hrtimer_nanosleep(tsave, rmtp ? &rmt : NULL,
+				flags & TIMER_ABSTIME ?
+				HRTIMER_MODE_ABS : HRTIMER_MODE_REL,
+				which_clock);
+
+	if (ret && rmtp) {
+		if (copy_to_user(rmtp, &rmt, sizeof(*rmtp)))
+			return -EFAULT;
+	}
+
+	return ret;
 }
 
 asmlinkage long
author
#8 lore raw

PATCH 1/1 Hook compat_sys_nanosleep up to high res timer code

In reply to Arnd Bergmann

Now we have high res timers on ppc64 I thought Id test them. It turns out compat_sys_nanosleep hasnt been converted to the hrtimer code and so is limited to HZ resolution.

The follow patch converts compat_sys_nanosleep to use high res timers.

Signed-off-by Anton Blanchard <[email protected]>

---

kernel/compat.c +11 -46
index 3bae374..252a446 100644
@@ -40,62 +40,27 @@ int put_compat_timespec(const struct timespec *ts, struct compat_timespec __user
 			__put_user(ts->tv_nsec, &cts->tv_nsec)) ? -EFAULT : 0;
 }
 
-static long compat_nanosleep_restart(struct restart_block *restart)
-{
-	unsigned long expire = restart->arg0, now = jiffies;
-	struct compat_timespec __user *rmtp;
-
-	/* Did it expire while we handled signals? */
-	if (!time_after(expire, now))
-		return 0;
-
-	expire = schedule_timeout_interruptible(expire - now);
-	if (expire == 0)
-		return 0;
-
-	rmtp = (struct compat_timespec __user *)restart->arg1;
-	if (rmtp) {
-		struct compat_timespec ct;
-		struct timespec t;
-
-		jiffies_to_timespec(expire, &t);
-		ct.tv_sec = t.tv_sec;
-		ct.tv_nsec = t.tv_nsec;
-		if (copy_to_user(rmtp, &ct, sizeof(ct)))
-			return -EFAULT;
-	}
-	/* The 'restart' block is already filled in */
-	return -ERESTART_RESTARTBLOCK;
-}
-
 asmlinkage long compat_sys_nanosleep(struct compat_timespec __user *rqtp,
-		struct compat_timespec __user *rmtp)
+				     struct compat_timespec __user *rmtp)
 {
-	struct timespec t;
-	struct restart_block *restart;
-	unsigned long expire;
+	struct timespec tu, rmt;
+	long ret;
 
-	if (get_compat_timespec(&t, rqtp))
+	if (get_compat_timespec(&tu, rqtp))
 		return -EFAULT;
 
-	if ((t.tv_nsec >= 1000000000L) || (t.tv_nsec < 0) || (t.tv_sec < 0))
+	if (!timespec_valid(&tu))
 		return -EINVAL;
 
-	expire = timespec_to_jiffies(&t) + (t.tv_sec || t.tv_nsec);
-	expire = schedule_timeout_interruptible(expire);
-	if (expire == 0)
-		return 0;
+	ret = hrtimer_nanosleep(&tu, rmtp ? &rmt : NULL, HRTIMER_MODE_REL,
+				CLOCK_MONOTONIC);
 
-	if (rmtp) {
-		jiffies_to_timespec(expire, &t);
-		if (put_compat_timespec(&t, rmtp))
+	if (ret && rmtp) {
+		if (put_compat_timespec(&rmt, rmtp))
 			return -EFAULT;
 	}
-	restart = &current_thread_info()->restart_block;
-	restart->fn = compat_nanosleep_restart;
-	restart->arg0 = jiffies + expire;
-	restart->arg1 = (unsigned long) rmtp;
-	return -ERESTART_RESTARTBLOCK;
+
+	return ret;
 }
 
 static inline long get_compat_itimerval(struct itimerval *o,