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Message-ID: <20071014231616.GA24519@kryten>
Date: Sun, 14 Oct 2007 18:16:16 -0500
From: Anton Blanchard <anton@...ba.org>
To: Arnd Bergmann <arnd@...db.de>
Cc: linuxppc-dev@...abs.org, mingo@...e.hu, tglx@...utronix.de,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Hook compat_sys_nanosleep up to high res timer code
Hi Arnd,
> 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 <anton@...ba.org>
---
diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 540799b..7a9398e 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -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);
diff --git a/kernel/compat.c b/kernel/compat.c
index 3bae374..44abfce 100644
--- a/kernel/compat.c
+++ b/kernel/compat.c
@@ -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) {
+ if (put_compat_timespec(&rmt, rmtp))
return -EFAULT;
}
- restart = ¤t_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,
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index dc8a445..095e09e 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -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 = ¤t_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;
}
/*
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index 7a15afb..fc7dac2 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -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
-
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