From: Richard Cochran <[email protected]>
This patch adds support for adding and removing posix clocks. The
clock lifetime cycle is patterned after usb devices. Each clock is
represented by a standard character device. In addition, the driver
may optionally implement custom character device operations.
The posix clock and timer system calls listed below now work with
dynamic posix clocks, as well as the traditional static clocks.
The following system calls are affected:
- clock_adjtime (brand new syscall)
- clock_gettime
- clock_getres
- clock_settime
- timer_create
- timer_delete
- timer_gettime
- timer_settime
[ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic
to posix-clock.c and made all referenced functions static ]
Signed-off-by: Richard Cochran <[email protected]>
Cc: John Stultz <[email protected]>
LKML-Reference: <21258f45fcc5e08a595f411c7760f3ccc18964bb.1296124770.git.richard.cochran@omicron.at>
Signed-off-by: Thomas Gleixner <[email protected]>
---
include/linux/posix-clock.h | 150 ++++++++++++++
include/linux/posix-timers.h | 6
kernel/posix-timers.c | 4
kernel/time/Makefile | 3
kernel/time/posix-clock.c | 441 +++++++++++++++++++++++++++++++++++++++++++
5 files changed, 601 insertions(+), 3 deletions(-)
create mode 100644 include/linux/posix-clock.h
create mode 100644 kernel/time/posix-clock-syscalls.h
create mode 100644 kernel/time/posix-clock.c
Index: linux-2.6-tip/include/linux/posix-clock.h
===================================================================
--- /dev/null
+++ linux-2.6-tip/include/linux/posix-clock.h
@@ -0,0 +1,150 @@
+/*
+ * posix-clock.h - support for dynamic clock devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#ifndef _LINUX_POSIX_CLOCK_H_
+#define _LINUX_POSIX_CLOCK_H_
+
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/posix-timers.h>
+
+struct posix_clock;
+
+/**
+ * struct posix_clock_operations - functional interface to the clock
+ *
+ * Every posix clock is represented by a character device. Drivers may
+ * optionally offer extended capabilities by implementing the
+ * character device methods. The character device file operations are
+ * first handled by the clock device layer, then passed on to the
+ * driver by calling these functions.
+ *
+ * @owner: The clock driver should set to THIS_MODULE
+ * @clock_adjtime: Adjust the clock
+ * @clock_gettime: Read the current time
+ * @clock_getres: Get the clock resolution
+ * @clock_settime: Set the current time value
+ * @timer_create: Create a new timer
+ * @timer_delete: Remove a previously created timer
+ * @timer_gettime: Get remaining time and interval of a timer
+ * @timer_setttime: Set a timer's initial expiration and interval
+ * @fasync: Optional character device fasync method
+ * @mmap: Optional character device mmap method
+ * @open: Optional character device open method
+ * @release: Optional character device release method
+ * @ioctl: Optional character device ioctl method
+ * @read: Optional character device read method
+ * @poll: Optional character device poll method
+ */
+struct posix_clock_operations {
+ struct module *owner;
+
+ int (*clock_adjtime)(struct posix_clock *pc, struct timex *tx);
+
+ int (*clock_gettime)(struct posix_clock *pc, struct timespec *ts);
+
+ int (*clock_getres) (struct posix_clock *pc, struct timespec *ts);
+
+ int (*clock_settime)(struct posix_clock *pc,
+ const struct timespec *ts);
+
+ int (*timer_create) (struct posix_clock *pc, struct k_itimer *kit);
+
+ int (*timer_delete) (struct posix_clock *pc, struct k_itimer *kit);
+
+ void (*timer_gettime)(struct posix_clock *pc,
+ struct k_itimer *kit, struct itimerspec *tsp);
+
+ int (*timer_settime)(struct posix_clock *pc,
+ struct k_itimer *kit, int flags,
+ struct itimerspec *tsp, struct itimerspec *old);
+ /*
+ * Optional character device methods:
+ */
+ int (*fasync) (struct posix_clock *pc,
+ int fd, struct file *file, int on);
+
+ long (*ioctl) (struct posix_clock *pc,
+ unsigned int cmd, unsigned long arg);
+
+ int (*mmap) (struct posix_clock *pc,
+ struct vm_area_struct *vma);
+
+ int (*open) (struct posix_clock *pc, fmode_t f_mode);
+
+ uint (*poll) (struct posix_clock *pc,
+ struct file *file, poll_table *wait);
+
+ int (*release) (struct posix_clock *pc);
+
+ ssize_t (*read) (struct posix_clock *pc,
+ uint flags, char __user *buf, size_t cnt);
+};
+
+/**
+ * struct posix_clock - represents a dynamic posix clock
+ *
+ * @ops: Functional interface to the clock
+ * @cdev: Character device instance for this clock
+ * @kref: Reference count.
+ * @mutex: Protects the 'zombie' field from concurrent access.
+ * @zombie: If 'zombie' is true, then the hardware has disappeared.
+ * @release: A function to free the structure when the reference count reaches
+ * zero. May be NULL if structure is statically allocated.
+ *
+ * Drivers should embed their struct posix_clock within a private
+ * structure, obtaining a reference to it during callbacks using
+ * container_of().
+ */
+struct posix_clock {
+ struct posix_clock_operations ops;
+ struct cdev cdev;
+ struct kref kref;
+ struct mutex mutex;
+ bool zombie;
+ void (*release)(struct posix_clock *clk);
+};
+
+/**
+ * posix_clock_register() - register a new clock
+ * @clk: Pointer to the clock. Caller must provide 'ops' and 'release'
+ * @devid: Allocated device id
+ *
+ * A clock driver calls this function to register itself with the
+ * clock device subsystem. If 'clk' points to dynamically allocated
+ * memory, then the caller must provide a 'release' function to free
+ * that memory.
+ *
+ * Returns zero on success, non-zero otherwise.
+ */
+int posix_clock_register(struct posix_clock *clk, dev_t devid);
+
+/**
+ * posix_clock_unregister() - unregister a clock
+ * @clk: Clock instance previously registered via posix_clock_register()
+ *
+ * A clock driver calls this function to remove itself from the clock
+ * device subsystem. The posix_clock itself will remain (in an
+ * inactive state) until its reference count drops to zero, at which
+ * point it will be deallocated with its 'release' method.
+ */
+void posix_clock_unregister(struct posix_clock *clk);
+
+#endif
Index: linux-2.6-tip/include/linux/posix-timers.h
===================================================================
--- linux-2.6-tip.orig/include/linux/posix-timers.h
+++ linux-2.6-tip/include/linux/posix-timers.h
@@ -32,7 +32,7 @@ struct cpu_timer_list {
#define CPUCLOCK_PID(clock) ((pid_t) ~((clock) >> 3))
#define CPUCLOCK_PERTHREAD(clock) \
(((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
-#define CPUCLOCK_PID_MASK 7
+
#define CPUCLOCK_PERTHREAD_MASK 4
#define CPUCLOCK_WHICH(clock) ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
#define CPUCLOCK_CLOCK_MASK 3
@@ -48,6 +48,9 @@ struct cpu_timer_list {
#define MAKE_THREAD_CPUCLOCK(tid, clock) \
MAKE_PROCESS_CPUCLOCK((tid), (clock) | CPUCLOCK_PERTHREAD_MASK)
+#define FD_TO_CLOCKID(fd) ((~(clockid_t) (fd) << 3) | CLOCKFD)
+#define CLOCKID_TO_FD(clk) ((unsigned int) ~((clk) >> 3))
+
/* POSIX.1b interval timer structure. */
struct k_itimer {
struct list_head list; /* free/ allocate list */
@@ -100,6 +103,7 @@ struct k_clock {
};
extern struct k_clock clock_posix_cpu;
+extern struct k_clock clock_posix_dynamic;
void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock);
Index: linux-2.6-tip/kernel/posix-timers.c
===================================================================
--- linux-2.6-tip.orig/kernel/posix-timers.c
+++ linux-2.6-tip/kernel/posix-timers.c
@@ -41,6 +41,7 @@
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/idr.h>
+#include <linux/posix-clock.h>
#include <linux/posix-timers.h>
#include <linux/syscalls.h>
#include <linux/wait.h>
@@ -477,7 +478,8 @@ static void release_posix_timer(struct k
static struct k_clock *clockid_to_kclock(const clockid_t id)
{
if (id < 0)
- return (id & CLOCKFD_MASK) == CLOCKFD ? NULL : &clock_posix_cpu;
+ return (id & CLOCKFD_MASK) == CLOCKFD ?
+ &clock_posix_dynamic : &clock_posix_cpu;
if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
return NULL;
Index: linux-2.6-tip/kernel/time/Makefile
===================================================================
--- linux-2.6-tip.orig/kernel/time/Makefile
+++ linux-2.6-tip/kernel/time/Makefile
@@ -1,4 +1,5 @@
-obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o timeconv.o
+obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o
+obj-y += timeconv.o posix-clock.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD) += clockevents.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o
Index: linux-2.6-tip/kernel/time/posix-clock.c
===================================================================
--- /dev/null
+++ linux-2.6-tip/kernel/time/posix-clock.c
@@ -0,0 +1,441 @@
+/*
+ * posix-clock.c - support for dynamic clock devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <linux/device.h>
+#include <linux/file.h>
+#include <linux/mutex.h>
+#include <linux/posix-clock.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+
+static void delete_clock(struct kref *kref);
+
+/*
+ * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
+ */
+static struct posix_clock *get_posix_clock(struct file *fp)
+{
+ struct posix_clock *clk = fp->private_data;
+
+ mutex_lock(&clk->mutex);
+
+ if (!clk->zombie)
+ return clk;
+
+ mutex_unlock(&clk->mutex);
+
+ return NULL;
+}
+
+static void put_posix_clock(struct posix_clock *clk)
+{
+ mutex_unlock(&clk->mutex);
+}
+
+static ssize_t posix_clock_read(struct file *fp, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -EINVAL;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.read)
+ err = clk->ops.read(clk, fp->f_flags, buf, count);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int result = 0;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.poll)
+ result = clk->ops.poll(clk, fp, wait);
+
+ put_posix_clock(clk);
+
+ return result;
+}
+
+static int posix_clock_fasync(int fd, struct file *fp, int on)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = 0;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.fasync)
+ err = clk->ops.fasync(clk, fd, fp, on);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENODEV;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.mmap)
+ err = clk->ops.mmap(clk, vma);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static long posix_clock_ioctl(struct file *fp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENOTTY;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.ioctl)
+ err = clk->ops.ioctl(clk, cmd, arg);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+#ifdef CONFIG_COMPAT
+static long posix_clock_compat_ioctl(struct file *fp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENOTTY;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.ioctl)
+ err = clk->ops.ioctl(clk, cmd, arg);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+#endif
+
+static int posix_clock_open(struct inode *inode, struct file *fp)
+{
+ int err;
+ struct posix_clock *clk =
+ container_of(inode->i_cdev, struct posix_clock, cdev);
+
+ mutex_lock(&clk->mutex);
+
+ if (clk->zombie) {
+ err = -ENODEV;
+ goto out;
+ }
+ if (clk->ops.open)
+ err = clk->ops.open(clk, fp->f_mode);
+ else
+ err = 0;
+
+ if (!err) {
+ kref_get(&clk->kref);
+ fp->private_data = clk;
+ }
+out:
+ mutex_unlock(&clk->mutex);
+ return err;
+}
+
+static int posix_clock_release(struct inode *inode, struct file *fp)
+{
+ struct posix_clock *clk = fp->private_data;
+ int err = 0;
+
+ if (clk->ops.release)
+ err = clk->ops.release(clk);
+
+ kref_put(&clk->kref, delete_clock);
+
+ fp->private_data = NULL;
+
+ return err;
+}
+
+static const struct file_operations posix_clock_file_operations = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = posix_clock_read,
+ .poll = posix_clock_poll,
+ .unlocked_ioctl = posix_clock_ioctl,
+ .open = posix_clock_open,
+ .release = posix_clock_release,
+ .fasync = posix_clock_fasync,
+ .mmap = posix_clock_mmap,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = posix_clock_compat_ioctl,
+#endif
+};
+
+int posix_clock_register(struct posix_clock *clk, dev_t devid)
+{
+ int err;
+
+ kref_init(&clk->kref);
+ mutex_init(&clk->mutex);
+
+ cdev_init(&clk->cdev, &posix_clock_file_operations);
+ clk->cdev.owner = clk->ops.owner;
+ err = cdev_add(&clk->cdev, devid, 1);
+ if (err)
+ goto no_cdev;
+
+ return err;
+no_cdev:
+ mutex_destroy(&clk->mutex);
+ return err;
+}
+EXPORT_SYMBOL_GPL(posix_clock_register);
+
+static void delete_clock(struct kref *kref)
+{
+ struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
+ mutex_destroy(&clk->mutex);
+ if (clk->release)
+ clk->release(clk);
+}
+
+void posix_clock_unregister(struct posix_clock *clk)
+{
+ cdev_del(&clk->cdev);
+
+ mutex_lock(&clk->mutex);
+ clk->zombie = true;
+ mutex_unlock(&clk->mutex);
+
+ kref_put(&clk->kref, delete_clock);
+}
+EXPORT_SYMBOL_GPL(posix_clock_unregister);
+
+struct posix_clock_desc {
+ struct file *fp;
+ struct posix_clock *clk;
+};
+
+static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
+{
+ struct file *fp = fget(CLOCKID_TO_FD(id));
+ int err = -EINVAL;
+
+ if (!fp)
+ return err;
+
+ if (fp->f_op->open != posix_clock_open || !fp->private_data)
+ goto out;
+
+ cd->fp = fp;
+ cd->clk = get_posix_clock(fp);
+
+ err = cd->clk ? 0 : -ENODEV;
+out:
+ if (err)
+ fput(fp);
+ return err;
+}
+
+static void put_clock_desc(struct posix_clock_desc *cd)
+{
+ put_posix_clock(cd->clk);
+ fput(cd->fp);
+}
+
+static int pc_clock_adjtime(clockid_t id, struct timex *tx)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_adjtime)
+ err = cd.clk->ops.clock_adjtime(cd.clk, tx);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_clock_gettime(clockid_t id, struct timespec *ts)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_gettime)
+ err = cd.clk->ops.clock_gettime(cd.clk, ts);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_clock_getres(clockid_t id, struct timespec *ts)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_getres)
+ err = cd.clk->ops.clock_getres(cd.clk, ts);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_clock_settime(clockid_t id, const struct timespec *ts)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_settime)
+ err = cd.clk->ops.clock_settime(cd.clk, ts);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_timer_create(struct k_itimer *kit)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_create)
+ err = cd.clk->ops.timer_create(cd.clk, kit);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_timer_delete(struct k_itimer *kit)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_delete)
+ err = cd.clk->ops.timer_delete(cd.clk, kit);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+
+ if (get_clock_desc(id, &cd))
+ return;
+
+ if (cd.clk->ops.timer_gettime)
+ cd.clk->ops.timer_gettime(cd.clk, kit, ts);
+
+ put_clock_desc(&cd);
+}
+
+static int pc_timer_settime(struct k_itimer *kit, int flags,
+ struct itimerspec *ts, struct itimerspec *old)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_settime)
+ err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+struct k_clock clock_posix_dynamic = {
+ .clock_getres = pc_clock_getres,
+ .clock_set = pc_clock_settime,
+ .clock_get = pc_clock_gettime,
+ .clock_adj = pc_clock_adjtime,
+ .timer_create = pc_timer_create,
+ .timer_set = pc_timer_settime,
+ .timer_del = pc_timer_delete,
+ .timer_get = pc_timer_gettime,
+};
On Tue, 2011-02-01 at 13:52 +0000, Thomas Gleixner wrote:
> plain text document attachment
> (posix-clocks-introduce-dynamic-clocks.patch)
> From: Richard Cochran <[email protected]>
>
> This patch adds support for adding and removing posix clocks. The
> clock lifetime cycle is patterned after usb devices. Each clock is
> represented by a standard character device. In addition, the driver
> may optionally implement custom character device operations.
>
> The posix clock and timer system calls listed below now work with
> dynamic posix clocks, as well as the traditional static clocks.
> The following system calls are affected:
>
> - clock_adjtime (brand new syscall)
> - clock_gettime
> - clock_getres
> - clock_settime
> - timer_create
> - timer_delete
> - timer_gettime
> - timer_settime
>
> [ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic
> to posix-clock.c and made all referenced functions static ]
I sort of worry about the naming collision with the term posix-clock, as
this is just one type of posix clock (I suspect most folks think of a
posix clock as the clockid passed to the existing posix api).
Could we maybe use posix-dynclock or posix-fdclock or something? I know
its already been changed from clkdev, so sorry for being finicky here
and not catching this earlier.
thanks
-john
On Tue, 1 Feb 2011, john stultz wrote:
> On Tue, 2011-02-01 at 13:52 +0000, Thomas Gleixner wrote:
> > plain text document attachment
> > (posix-clocks-introduce-dynamic-clocks.patch)
> > From: Richard Cochran <[email protected]>
> >
> > This patch adds support for adding and removing posix clocks. The
> > clock lifetime cycle is patterned after usb devices. Each clock is
> > represented by a standard character device. In addition, the driver
> > may optionally implement custom character device operations.
> >
> > The posix clock and timer system calls listed below now work with
> > dynamic posix clocks, as well as the traditional static clocks.
> > The following system calls are affected:
> >
> > - clock_adjtime (brand new syscall)
> > - clock_gettime
> > - clock_getres
> > - clock_settime
> > - timer_create
> > - timer_delete
> > - timer_gettime
> > - timer_settime
> >
> > [ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic
> > to posix-clock.c and made all referenced functions static ]
>
> I sort of worry about the naming collision with the term posix-clock, as
> this is just one type of posix clock (I suspect most folks think of a
> posix clock as the clockid passed to the existing posix api).
Well that's kernel internal and not the posix-timer syscalls.
> Could we maybe use posix-dynclock or posix-fdclock or something? I know
> its already been changed from clkdev, so sorry for being finicky here
> and not catching this earlier.
I'm fine with the name as is and it's well documented.
Thanks,
tglx
On Tue, Feb 01, 2011 at 01:49:47PM -0800, john stultz wrote:
> I sort of worry about the naming collision with the term posix-clock, as
> this is just one type of posix clock (I suspect most folks think of a
> posix clock as the clockid passed to the existing posix api).
>
> Could we maybe use posix-dynclock or posix-fdclock or something? I know
> its already been changed from clkdev, so sorry for being finicky here
> and not catching this earlier.
A rose by any other name...
I agree that naming (even internal APIs) is important and have no
objection to changing the name. I did spend a bit of time considering
various alternatives, and now I'm out of ideas.
So, please do change the name if you have a better one.
Thanks,
Richard
On Wed, 2 Feb 2011, Richard Cochran wrote:
> On Tue, Feb 01, 2011 at 01:49:47PM -0800, john stultz wrote:
> > I sort of worry about the naming collision with the term posix-clock, as
> > this is just one type of posix clock (I suspect most folks think of a
> > posix clock as the clockid passed to the existing posix api).
> >
> > Could we maybe use posix-dynclock or posix-fdclock or something? I know
> > its already been changed from clkdev, so sorry for being finicky here
> > and not catching this earlier.
>
> A rose by any other name...
>
> I agree that naming (even internal APIs) is important and have no
> objection to changing the name. I did spend a bit of time considering
> various alternatives, and now I'm out of ideas.
>
> So, please do change the name if you have a better one.
We have a clear distinction between posix-timers and those new
posix-clocks. Adding some artificial "fd", "dyn" or whatever will not
make it much better.
Thanks,
tglx
On Wed, 2 Feb 2011, Thomas Gleixner wrote:
> On Wed, 2 Feb 2011, Richard Cochran wrote:
>
> > On Tue, Feb 01, 2011 at 01:49:47PM -0800, john stultz wrote:
> > > I sort of worry about the naming collision with the term posix-clock, as
> > > this is just one type of posix clock (I suspect most folks think of a
> > > posix clock as the clockid passed to the existing posix api).
> > >
> > > Could we maybe use posix-dynclock or posix-fdclock or something? I know
> > > its already been changed from clkdev, so sorry for being finicky here
> > > and not catching this earlier.
> >
> > A rose by any other name...
> >
> > I agree that naming (even internal APIs) is important and have no
> > objection to changing the name. I did spend a bit of time considering
> > various alternatives, and now I'm out of ideas.
> >
> > So, please do change the name if you have a better one.
>
> We have a clear distinction between posix-timers and those new
> posix-clocks. Adding some artificial "fd", "dyn" or whatever will not
> make it much better.
There is only one function visible outside of posix-timers.c which
uses the posix_clock namespace: register_posix_clock(). That needs to
be cleaned up. See patch below.
Thanks,
tglx
Subject: posix-timers: Cleanup namespace
From: Thomas Gleixner <[email protected]>
Date: Wed, 02 Feb 2011 12:10:09 +0100
Rename register_posix_clock() to posix_timers_register_clock(). That's
what the function really does. As a side effect this cleans up the
posix_clock namespace for the upcoming dynamic posix_clock
infrastructure.
Signed-off-by: Thomas Gleixner <[email protected]>
---
drivers/char/mmtimer.c | 2 +-
include/linux/posix-timers.h | 2 +-
kernel/posix-cpu-timers.c | 4 ++--
kernel/posix-timers.c | 15 ++++++++-------
4 files changed, 12 insertions(+), 11 deletions(-)
Index: linux-2.6-tip/drivers/char/mmtimer.c
===================================================================
--- linux-2.6-tip.orig/drivers/char/mmtimer.c
+++ linux-2.6-tip/drivers/char/mmtimer.c
@@ -840,7 +840,7 @@ static int __init mmtimer_init(void)
}
sgi_clock_period = NSEC_PER_SEC / sn_rtc_cycles_per_second;
- register_posix_clock(CLOCK_SGI_CYCLE, &sgi_clock);
+ posix_timers_register_clock(CLOCK_SGI_CYCLE, &sgi_clock);
printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
sn_rtc_cycles_per_second/(unsigned long)1E6);
Index: linux-2.6-tip/include/linux/posix-timers.h
===================================================================
--- linux-2.6-tip.orig/include/linux/posix-timers.h
+++ linux-2.6-tip/include/linux/posix-timers.h
@@ -101,7 +101,7 @@ struct k_clock {
extern struct k_clock clock_posix_cpu;
-void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock);
+void posix_timers_register_clock(const clockid_t clock_id, struct k_clock *new_clock);
/* function to call to trigger timer event */
int posix_timer_event(struct k_itimer *timr, int si_private);
Index: linux-2.6-tip/kernel/posix-cpu-timers.c
===================================================================
--- linux-2.6-tip.orig/kernel/posix-cpu-timers.c
+++ linux-2.6-tip/kernel/posix-cpu-timers.c
@@ -1618,8 +1618,8 @@ static __init int init_posix_cpu_timers(
};
struct timespec ts;
- register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
- register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
+ posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
+ posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
cputime_to_timespec(cputime_one_jiffy, &ts);
onecputick = ts.tv_nsec;
Index: linux-2.6-tip/kernel/posix-timers.c
===================================================================
--- linux-2.6-tip.orig/kernel/posix-timers.c
+++ linux-2.6-tip/kernel/posix-timers.c
@@ -253,11 +253,11 @@ static __init int init_posix_timers(void
.clock_get = posix_get_monotonic_coarse,
};
- register_posix_clock(CLOCK_REALTIME, &clock_realtime);
- register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
- register_posix_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
- register_posix_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
- register_posix_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
+ posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime);
+ posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic);
+ posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
+ posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
+ posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
posix_timers_cache = kmem_cache_create("posix_timers_cache",
sizeof (struct k_itimer), 0, SLAB_PANIC,
@@ -433,7 +433,8 @@ static struct pid *good_sigevent(sigeven
return task_pid(rtn);
}
-void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock)
+void posix_timers_register_clock(const clockid_t clock_id,
+ struct k_clock *new_clock)
{
if ((unsigned) clock_id >= MAX_CLOCKS) {
printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
@@ -454,7 +455,7 @@ void register_posix_clock(const clockid_
posix_clocks[clock_id] = *new_clock;
}
-EXPORT_SYMBOL_GPL(register_posix_clock);
+EXPORT_SYMBOL_GPL(posix_timers_register_clock);
static struct k_itimer * alloc_posix_timer(void)
{
Commit-ID: 527087374faa488776a789375a7d6ea74fda6f71
Gitweb: http://git.kernel.org/tip/527087374faa488776a789375a7d6ea74fda6f71
Author: Thomas Gleixner <[email protected]>
AuthorDate: Wed, 2 Feb 2011 12:10:09 +0100
Committer: Thomas Gleixner <[email protected]>
CommitDate: Wed, 2 Feb 2011 15:28:19 +0100
posix-timers: Cleanup namespace
Rename register_posix_clock() to posix_timers_register_clock(). That's
what the function really does. As a side effect this cleans up the
posix_clock namespace for the upcoming dynamic posix_clock
infrastructure.
Signed-off-by: Thomas Gleixner <[email protected]>
Tested-by: Richard Cochran <[email protected]>
Cc: John Stultz <[email protected]>
LKML-Reference: <[email protected]>
---
drivers/char/mmtimer.c | 2 +-
include/linux/posix-timers.h | 2 +-
kernel/posix-cpu-timers.c | 4 ++--
kernel/posix-timers.c | 15 ++++++++-------
4 files changed, 12 insertions(+), 11 deletions(-)
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index ff41eb3..33dc229 100644
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -840,7 +840,7 @@ static int __init mmtimer_init(void)
}
sgi_clock_period = NSEC_PER_SEC / sn_rtc_cycles_per_second;
- register_posix_clock(CLOCK_SGI_CYCLE, &sgi_clock);
+ posix_timers_register_clock(CLOCK_SGI_CYCLE, &sgi_clock);
printk(KERN_INFO "%s: v%s, %ld MHz\n", MMTIMER_DESC, MMTIMER_VERSION,
sn_rtc_cycles_per_second/(unsigned long)1E6);
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 88b9256..9d6ffe2 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -101,7 +101,7 @@ struct k_clock {
extern struct k_clock clock_posix_cpu;
-void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock);
+void posix_timers_register_clock(const clockid_t clock_id, struct k_clock *new_clock);
/* function to call to trigger timer event */
int posix_timer_event(struct k_itimer *timr, int si_private);
diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index 609e187..67fea9d 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -1618,8 +1618,8 @@ static __init int init_posix_cpu_timers(void)
};
struct timespec ts;
- register_posix_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
- register_posix_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
+ posix_timers_register_clock(CLOCK_PROCESS_CPUTIME_ID, &process);
+ posix_timers_register_clock(CLOCK_THREAD_CPUTIME_ID, &thread);
cputime_to_timespec(cputime_one_jiffy, &ts);
onecputick = ts.tv_nsec;
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index df629d8..af936fd 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -253,11 +253,11 @@ static __init int init_posix_timers(void)
.clock_get = posix_get_monotonic_coarse,
};
- register_posix_clock(CLOCK_REALTIME, &clock_realtime);
- register_posix_clock(CLOCK_MONOTONIC, &clock_monotonic);
- register_posix_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
- register_posix_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
- register_posix_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
+ posix_timers_register_clock(CLOCK_REALTIME, &clock_realtime);
+ posix_timers_register_clock(CLOCK_MONOTONIC, &clock_monotonic);
+ posix_timers_register_clock(CLOCK_MONOTONIC_RAW, &clock_monotonic_raw);
+ posix_timers_register_clock(CLOCK_REALTIME_COARSE, &clock_realtime_coarse);
+ posix_timers_register_clock(CLOCK_MONOTONIC_COARSE, &clock_monotonic_coarse);
posix_timers_cache = kmem_cache_create("posix_timers_cache",
sizeof (struct k_itimer), 0, SLAB_PANIC,
@@ -433,7 +433,8 @@ static struct pid *good_sigevent(sigevent_t * event)
return task_pid(rtn);
}
-void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock)
+void posix_timers_register_clock(const clockid_t clock_id,
+ struct k_clock *new_clock)
{
if ((unsigned) clock_id >= MAX_CLOCKS) {
printk(KERN_WARNING "POSIX clock register failed for clock_id %d\n",
@@ -454,7 +455,7 @@ void register_posix_clock(const clockid_t clock_id, struct k_clock *new_clock)
posix_clocks[clock_id] = *new_clock;
}
-EXPORT_SYMBOL_GPL(register_posix_clock);
+EXPORT_SYMBOL_GPL(posix_timers_register_clock);
static struct k_itimer * alloc_posix_timer(void)
{
Commit-ID: 0606f422b453f76c31ab2b1bd52943ff06a2dcf2
Gitweb: http://git.kernel.org/tip/0606f422b453f76c31ab2b1bd52943ff06a2dcf2
Author: Richard Cochran <[email protected]>
AuthorDate: Tue, 1 Feb 2011 13:52:35 +0000
Committer: Thomas Gleixner <[email protected]>
CommitDate: Wed, 2 Feb 2011 15:28:20 +0100
posix clocks: Introduce dynamic clocks
This patch adds support for adding and removing posix clocks. The
clock lifetime cycle is patterned after usb devices. Each clock is
represented by a standard character device. In addition, the driver
may optionally implement custom character device operations.
The posix clock and timer system calls listed below now work with
dynamic posix clocks, as well as the traditional static clocks.
The following system calls are affected:
- clock_adjtime (brand new syscall)
- clock_gettime
- clock_getres
- clock_settime
- timer_create
- timer_delete
- timer_gettime
- timer_settime
[ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic
to posix-clock.c and made all referenced functions static ]
Signed-off-by: Richard Cochran <[email protected]>
Acked-by: John Stultz <[email protected]>
LKML-Reference: <[email protected]>
Signed-off-by: Thomas Gleixner <[email protected]>
---
include/linux/posix-clock.h | 150 ++++++++++++++
include/linux/posix-timers.h | 6 +-
kernel/posix-timers.c | 4 +-
kernel/time/Makefile | 3 +-
kernel/time/posix-clock.c | 441 ++++++++++++++++++++++++++++++++++++++++++
5 files changed, 601 insertions(+), 3 deletions(-)
diff --git a/include/linux/posix-clock.h b/include/linux/posix-clock.h
new file mode 100644
index 0000000..369e19d
--- /dev/null
+++ b/include/linux/posix-clock.h
@@ -0,0 +1,150 @@
+/*
+ * posix-clock.h - support for dynamic clock devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#ifndef _LINUX_POSIX_CLOCK_H_
+#define _LINUX_POSIX_CLOCK_H_
+
+#include <linux/cdev.h>
+#include <linux/fs.h>
+#include <linux/poll.h>
+#include <linux/posix-timers.h>
+
+struct posix_clock;
+
+/**
+ * struct posix_clock_operations - functional interface to the clock
+ *
+ * Every posix clock is represented by a character device. Drivers may
+ * optionally offer extended capabilities by implementing the
+ * character device methods. The character device file operations are
+ * first handled by the clock device layer, then passed on to the
+ * driver by calling these functions.
+ *
+ * @owner: The clock driver should set to THIS_MODULE
+ * @clock_adjtime: Adjust the clock
+ * @clock_gettime: Read the current time
+ * @clock_getres: Get the clock resolution
+ * @clock_settime: Set the current time value
+ * @timer_create: Create a new timer
+ * @timer_delete: Remove a previously created timer
+ * @timer_gettime: Get remaining time and interval of a timer
+ * @timer_setttime: Set a timer's initial expiration and interval
+ * @fasync: Optional character device fasync method
+ * @mmap: Optional character device mmap method
+ * @open: Optional character device open method
+ * @release: Optional character device release method
+ * @ioctl: Optional character device ioctl method
+ * @read: Optional character device read method
+ * @poll: Optional character device poll method
+ */
+struct posix_clock_operations {
+ struct module *owner;
+
+ int (*clock_adjtime)(struct posix_clock *pc, struct timex *tx);
+
+ int (*clock_gettime)(struct posix_clock *pc, struct timespec *ts);
+
+ int (*clock_getres) (struct posix_clock *pc, struct timespec *ts);
+
+ int (*clock_settime)(struct posix_clock *pc,
+ const struct timespec *ts);
+
+ int (*timer_create) (struct posix_clock *pc, struct k_itimer *kit);
+
+ int (*timer_delete) (struct posix_clock *pc, struct k_itimer *kit);
+
+ void (*timer_gettime)(struct posix_clock *pc,
+ struct k_itimer *kit, struct itimerspec *tsp);
+
+ int (*timer_settime)(struct posix_clock *pc,
+ struct k_itimer *kit, int flags,
+ struct itimerspec *tsp, struct itimerspec *old);
+ /*
+ * Optional character device methods:
+ */
+ int (*fasync) (struct posix_clock *pc,
+ int fd, struct file *file, int on);
+
+ long (*ioctl) (struct posix_clock *pc,
+ unsigned int cmd, unsigned long arg);
+
+ int (*mmap) (struct posix_clock *pc,
+ struct vm_area_struct *vma);
+
+ int (*open) (struct posix_clock *pc, fmode_t f_mode);
+
+ uint (*poll) (struct posix_clock *pc,
+ struct file *file, poll_table *wait);
+
+ int (*release) (struct posix_clock *pc);
+
+ ssize_t (*read) (struct posix_clock *pc,
+ uint flags, char __user *buf, size_t cnt);
+};
+
+/**
+ * struct posix_clock - represents a dynamic posix clock
+ *
+ * @ops: Functional interface to the clock
+ * @cdev: Character device instance for this clock
+ * @kref: Reference count.
+ * @mutex: Protects the 'zombie' field from concurrent access.
+ * @zombie: If 'zombie' is true, then the hardware has disappeared.
+ * @release: A function to free the structure when the reference count reaches
+ * zero. May be NULL if structure is statically allocated.
+ *
+ * Drivers should embed their struct posix_clock within a private
+ * structure, obtaining a reference to it during callbacks using
+ * container_of().
+ */
+struct posix_clock {
+ struct posix_clock_operations ops;
+ struct cdev cdev;
+ struct kref kref;
+ struct mutex mutex;
+ bool zombie;
+ void (*release)(struct posix_clock *clk);
+};
+
+/**
+ * posix_clock_register() - register a new clock
+ * @clk: Pointer to the clock. Caller must provide 'ops' and 'release'
+ * @devid: Allocated device id
+ *
+ * A clock driver calls this function to register itself with the
+ * clock device subsystem. If 'clk' points to dynamically allocated
+ * memory, then the caller must provide a 'release' function to free
+ * that memory.
+ *
+ * Returns zero on success, non-zero otherwise.
+ */
+int posix_clock_register(struct posix_clock *clk, dev_t devid);
+
+/**
+ * posix_clock_unregister() - unregister a clock
+ * @clk: Clock instance previously registered via posix_clock_register()
+ *
+ * A clock driver calls this function to remove itself from the clock
+ * device subsystem. The posix_clock itself will remain (in an
+ * inactive state) until its reference count drops to zero, at which
+ * point it will be deallocated with its 'release' method.
+ */
+void posix_clock_unregister(struct posix_clock *clk);
+
+#endif
diff --git a/include/linux/posix-timers.h b/include/linux/posix-timers.h
index 9d6ffe2..d51243a 100644
--- a/include/linux/posix-timers.h
+++ b/include/linux/posix-timers.h
@@ -32,7 +32,7 @@ struct cpu_timer_list {
#define CPUCLOCK_PID(clock) ((pid_t) ~((clock) >> 3))
#define CPUCLOCK_PERTHREAD(clock) \
(((clock) & (clockid_t) CPUCLOCK_PERTHREAD_MASK) != 0)
-#define CPUCLOCK_PID_MASK 7
+
#define CPUCLOCK_PERTHREAD_MASK 4
#define CPUCLOCK_WHICH(clock) ((clock) & (clockid_t) CPUCLOCK_CLOCK_MASK)
#define CPUCLOCK_CLOCK_MASK 3
@@ -48,6 +48,9 @@ struct cpu_timer_list {
#define MAKE_THREAD_CPUCLOCK(tid, clock) \
MAKE_PROCESS_CPUCLOCK((tid), (clock) | CPUCLOCK_PERTHREAD_MASK)
+#define FD_TO_CLOCKID(fd) ((~(clockid_t) (fd) << 3) | CLOCKFD)
+#define CLOCKID_TO_FD(clk) ((unsigned int) ~((clk) >> 3))
+
/* POSIX.1b interval timer structure. */
struct k_itimer {
struct list_head list; /* free/ allocate list */
@@ -100,6 +103,7 @@ struct k_clock {
};
extern struct k_clock clock_posix_cpu;
+extern struct k_clock clock_posix_dynamic;
void posix_timers_register_clock(const clockid_t clock_id, struct k_clock *new_clock);
diff --git a/kernel/posix-timers.c b/kernel/posix-timers.c
index af936fd..44fcff1 100644
--- a/kernel/posix-timers.c
+++ b/kernel/posix-timers.c
@@ -41,6 +41,7 @@
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/idr.h>
+#include <linux/posix-clock.h>
#include <linux/posix-timers.h>
#include <linux/syscalls.h>
#include <linux/wait.h>
@@ -489,7 +490,8 @@ static void release_posix_timer(struct k_itimer *tmr, int it_id_set)
static struct k_clock *clockid_to_kclock(const clockid_t id)
{
if (id < 0)
- return (id & CLOCKFD_MASK) == CLOCKFD ? NULL : &clock_posix_cpu;
+ return (id & CLOCKFD_MASK) == CLOCKFD ?
+ &clock_posix_dynamic : &clock_posix_cpu;
if (id >= MAX_CLOCKS || !posix_clocks[id].clock_getres)
return NULL;
diff --git a/kernel/time/Makefile b/kernel/time/Makefile
index ee26662..b042599 100644
--- a/kernel/time/Makefile
+++ b/kernel/time/Makefile
@@ -1,4 +1,5 @@
-obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o timeconv.o
+obj-y += timekeeping.o ntp.o clocksource.o jiffies.o timer_list.o timecompare.o
+obj-y += timeconv.o posix-clock.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS_BUILD) += clockevents.o
obj-$(CONFIG_GENERIC_CLOCKEVENTS) += tick-common.o
diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
new file mode 100644
index 0000000..04498cb
--- /dev/null
+++ b/kernel/time/posix-clock.c
@@ -0,0 +1,441 @@
+/*
+ * posix-clock.c - support for dynamic clock devices
+ *
+ * Copyright (C) 2010 OMICRON electronics GmbH
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+#include <linux/device.h>
+#include <linux/file.h>
+#include <linux/mutex.h>
+#include <linux/posix-clock.h>
+#include <linux/slab.h>
+#include <linux/syscalls.h>
+#include <linux/uaccess.h>
+
+static void delete_clock(struct kref *kref);
+
+/*
+ * Returns NULL if the posix_clock instance attached to 'fp' is old and stale.
+ */
+static struct posix_clock *get_posix_clock(struct file *fp)
+{
+ struct posix_clock *clk = fp->private_data;
+
+ mutex_lock(&clk->mutex);
+
+ if (!clk->zombie)
+ return clk;
+
+ mutex_unlock(&clk->mutex);
+
+ return NULL;
+}
+
+static void put_posix_clock(struct posix_clock *clk)
+{
+ mutex_unlock(&clk->mutex);
+}
+
+static ssize_t posix_clock_read(struct file *fp, char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -EINVAL;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.read)
+ err = clk->ops.read(clk, fp->f_flags, buf, count);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static unsigned int posix_clock_poll(struct file *fp, poll_table *wait)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int result = 0;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.poll)
+ result = clk->ops.poll(clk, fp, wait);
+
+ put_posix_clock(clk);
+
+ return result;
+}
+
+static int posix_clock_fasync(int fd, struct file *fp, int on)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = 0;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.fasync)
+ err = clk->ops.fasync(clk, fd, fp, on);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static int posix_clock_mmap(struct file *fp, struct vm_area_struct *vma)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENODEV;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.mmap)
+ err = clk->ops.mmap(clk, vma);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+static long posix_clock_ioctl(struct file *fp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENOTTY;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.ioctl)
+ err = clk->ops.ioctl(clk, cmd, arg);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+
+#ifdef CONFIG_COMPAT
+static long posix_clock_compat_ioctl(struct file *fp,
+ unsigned int cmd, unsigned long arg)
+{
+ struct posix_clock *clk = get_posix_clock(fp);
+ int err = -ENOTTY;
+
+ if (!clk)
+ return -ENODEV;
+
+ if (clk->ops.ioctl)
+ err = clk->ops.ioctl(clk, cmd, arg);
+
+ put_posix_clock(clk);
+
+ return err;
+}
+#endif
+
+static int posix_clock_open(struct inode *inode, struct file *fp)
+{
+ int err;
+ struct posix_clock *clk =
+ container_of(inode->i_cdev, struct posix_clock, cdev);
+
+ mutex_lock(&clk->mutex);
+
+ if (clk->zombie) {
+ err = -ENODEV;
+ goto out;
+ }
+ if (clk->ops.open)
+ err = clk->ops.open(clk, fp->f_mode);
+ else
+ err = 0;
+
+ if (!err) {
+ kref_get(&clk->kref);
+ fp->private_data = clk;
+ }
+out:
+ mutex_unlock(&clk->mutex);
+ return err;
+}
+
+static int posix_clock_release(struct inode *inode, struct file *fp)
+{
+ struct posix_clock *clk = fp->private_data;
+ int err = 0;
+
+ if (clk->ops.release)
+ err = clk->ops.release(clk);
+
+ kref_put(&clk->kref, delete_clock);
+
+ fp->private_data = NULL;
+
+ return err;
+}
+
+static const struct file_operations posix_clock_file_operations = {
+ .owner = THIS_MODULE,
+ .llseek = no_llseek,
+ .read = posix_clock_read,
+ .poll = posix_clock_poll,
+ .unlocked_ioctl = posix_clock_ioctl,
+ .open = posix_clock_open,
+ .release = posix_clock_release,
+ .fasync = posix_clock_fasync,
+ .mmap = posix_clock_mmap,
+#ifdef CONFIG_COMPAT
+ .compat_ioctl = posix_clock_compat_ioctl,
+#endif
+};
+
+int posix_clock_register(struct posix_clock *clk, dev_t devid)
+{
+ int err;
+
+ kref_init(&clk->kref);
+ mutex_init(&clk->mutex);
+
+ cdev_init(&clk->cdev, &posix_clock_file_operations);
+ clk->cdev.owner = clk->ops.owner;
+ err = cdev_add(&clk->cdev, devid, 1);
+ if (err)
+ goto no_cdev;
+
+ return err;
+no_cdev:
+ mutex_destroy(&clk->mutex);
+ return err;
+}
+EXPORT_SYMBOL_GPL(posix_clock_register);
+
+static void delete_clock(struct kref *kref)
+{
+ struct posix_clock *clk = container_of(kref, struct posix_clock, kref);
+ mutex_destroy(&clk->mutex);
+ if (clk->release)
+ clk->release(clk);
+}
+
+void posix_clock_unregister(struct posix_clock *clk)
+{
+ cdev_del(&clk->cdev);
+
+ mutex_lock(&clk->mutex);
+ clk->zombie = true;
+ mutex_unlock(&clk->mutex);
+
+ kref_put(&clk->kref, delete_clock);
+}
+EXPORT_SYMBOL_GPL(posix_clock_unregister);
+
+struct posix_clock_desc {
+ struct file *fp;
+ struct posix_clock *clk;
+};
+
+static int get_clock_desc(const clockid_t id, struct posix_clock_desc *cd)
+{
+ struct file *fp = fget(CLOCKID_TO_FD(id));
+ int err = -EINVAL;
+
+ if (!fp)
+ return err;
+
+ if (fp->f_op->open != posix_clock_open || !fp->private_data)
+ goto out;
+
+ cd->fp = fp;
+ cd->clk = get_posix_clock(fp);
+
+ err = cd->clk ? 0 : -ENODEV;
+out:
+ if (err)
+ fput(fp);
+ return err;
+}
+
+static void put_clock_desc(struct posix_clock_desc *cd)
+{
+ put_posix_clock(cd->clk);
+ fput(cd->fp);
+}
+
+static int pc_clock_adjtime(clockid_t id, struct timex *tx)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_adjtime)
+ err = cd.clk->ops.clock_adjtime(cd.clk, tx);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_clock_gettime(clockid_t id, struct timespec *ts)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_gettime)
+ err = cd.clk->ops.clock_gettime(cd.clk, ts);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_clock_getres(clockid_t id, struct timespec *ts)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_getres)
+ err = cd.clk->ops.clock_getres(cd.clk, ts);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_clock_settime(clockid_t id, const struct timespec *ts)
+{
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.clock_settime)
+ err = cd.clk->ops.clock_settime(cd.clk, ts);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_timer_create(struct k_itimer *kit)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_create)
+ err = cd.clk->ops.timer_create(cd.clk, kit);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static int pc_timer_delete(struct k_itimer *kit)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_delete)
+ err = cd.clk->ops.timer_delete(cd.clk, kit);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+static void pc_timer_gettime(struct k_itimer *kit, struct itimerspec *ts)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+
+ if (get_clock_desc(id, &cd))
+ return;
+
+ if (cd.clk->ops.timer_gettime)
+ cd.clk->ops.timer_gettime(cd.clk, kit, ts);
+
+ put_clock_desc(&cd);
+}
+
+static int pc_timer_settime(struct k_itimer *kit, int flags,
+ struct itimerspec *ts, struct itimerspec *old)
+{
+ clockid_t id = kit->it_clock;
+ struct posix_clock_desc cd;
+ int err;
+
+ err = get_clock_desc(id, &cd);
+ if (err)
+ return err;
+
+ if (cd.clk->ops.timer_settime)
+ err = cd.clk->ops.timer_settime(cd.clk, kit, flags, ts, old);
+ else
+ err = -EOPNOTSUPP;
+
+ put_clock_desc(&cd);
+
+ return err;
+}
+
+struct k_clock clock_posix_dynamic = {
+ .clock_getres = pc_clock_getres,
+ .clock_set = pc_clock_settime,
+ .clock_get = pc_clock_gettime,
+ .clock_adj = pc_clock_adjtime,
+ .timer_create = pc_timer_create,
+ .timer_set = pc_timer_settime,
+ .timer_del = pc_timer_delete,
+ .timer_get = pc_timer_gettime,
+};
On Tue, Feb 01, 2011 at 01:52:35PM -0000, Thomas Gleixner wrote:
> From: Richard Cochran <[email protected]>
>
> This patch adds support for adding and removing posix clocks. The
> clock lifetime cycle is patterned after usb devices. Each clock is
> represented by a standard character device. In addition, the driver
> may optionally implement custom character device operations.
>
> The posix clock and timer system calls listed below now work with
> dynamic posix clocks, as well as the traditional static clocks.
> The following system calls are affected:
>
> - clock_adjtime (brand new syscall)
> - clock_gettime
> - clock_getres
> - clock_settime
> - timer_create
> - timer_delete
> - timer_gettime
> - timer_settime
>
> [ tglx: Adapted to the posix-timer cleanup. Moved clock_posix_dynamic
> to posix-clock.c and made all referenced functions static ]
>
> Signed-off-by: Richard Cochran <[email protected]>
> Cc: John Stultz <[email protected]>
> LKML-Reference: <21258f45fcc5e08a595f411c7760f3ccc18964bb.1296124770.git.richard.cochran@omicron.at>
> Signed-off-by: Thomas Gleixner <[email protected]>
> ---
> include/linux/posix-clock.h | 150 ++++++++++++++
> include/linux/posix-timers.h | 6
> kernel/posix-timers.c | 4
> kernel/time/Makefile | 3
> kernel/time/posix-clock.c | 441 +++++++++++++++++++++++++++++++++++++++++++
> 5 files changed, 601 insertions(+), 3 deletions(-)
> create mode 100644 include/linux/posix-clock.h
> create mode 100644 kernel/time/posix-clock-syscalls.h
> create mode 100644 kernel/time/posix-clock.c
>
> +
> +static int pc_clock_adjtime(clockid_t id, struct timex *tx)
> +{
> + struct posix_clock_desc cd;
> + int err;
> +
> + err = get_clock_desc(id, &cd);
> + if (err)
> + return err;
there is no permission check here.
if i get the clock fd in READ mode, i can still adjtime.
same for settime.
> +
> + if (cd.clk->ops.clock_adjtime)
> + err = cd.clk->ops.clock_adjtime(cd.clk, tx);
> + else
> + err = -EOPNOTSUPP;
> +
> + put_clock_desc(&cd);
> +
> + return err;
> +}
--
torben Hohn
On Thu, Mar 03, 2011 at 03:50:08PM +0100, torbenh wrote:
> On Tue, Feb 01, 2011 at 01:52:35PM -0000, Thomas Gleixner wrote:
> > +static int pc_clock_adjtime(clockid_t id, struct timex *tx)
> > +{
> > + struct posix_clock_desc cd;
> > + int err;
> > +
> > + err = get_clock_desc(id, &cd);
> > + if (err)
> > + return err;
>
> there is no permission check here.
> if i get the clock fd in READ mode, i can still adjtime.
> same for settime.
You are right, but I think the check should be for the capability
instead. Checking the file mode for RDWR seems a bit pedantic to me.
For the normal system timer, clock_settime calls security_settime, but
adjtimex calls capable(CAP_SYS_TIME) directly. Perhaps adjtimex should
also use the security call, too.
Thanks,
Richard
On Thu, Mar 03, 2011 at 05:01:14PM +0100, Richard Cochran wrote:
> On Thu, Mar 03, 2011 at 03:50:08PM +0100, torbenh wrote:
> > On Tue, Feb 01, 2011 at 01:52:35PM -0000, Thomas Gleixner wrote:
> > > +static int pc_clock_adjtime(clockid_t id, struct timex *tx)
> > > +{
> > > + struct posix_clock_desc cd;
> > > + int err;
> > > +
> > > + err = get_clock_desc(id, &cd);
> > > + if (err)
> > > + return err;
> >
> > there is no permission check here.
> > if i get the clock fd in READ mode, i can still adjtime.
> > same for settime.
>
> You are right, but I think the check should be for the capability
> instead. Checking the file mode for RDWR seems a bit pedantic to me.
i dont see, why an fd based clock, which already has associated permissions,
should check against the capability.
why should the ptpd be running as root ?
changing the permissions of /dev/ptp0 to allow ptpd to set the
clock should be enough.
>
> For the normal system timer, clock_settime calls security_settime, but
> adjtimex calls capable(CAP_SYS_TIME) directly. Perhaps adjtimex should
> also use the security call, too.
probably yes.
>
> Thanks,
>
> Richard
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
torben Hohn
On Thu, Mar 03, 2011 at 06:07:59PM +0100, torbenh wrote:
> On Thu, Mar 03, 2011 at 05:01:14PM +0100, Richard Cochran wrote:
> >
> > You are right, but I think the check should be for the capability
> > instead. Checking the file mode for RDWR seems a bit pedantic to me.
>
> i dont see, why an fd based clock, which already has associated permissions,
> should check against the capability.
> why should the ptpd be running as root ?
> changing the permissions of /dev/ptp0 to allow ptpd to set the
> clock should be enough.
Thinking a bit more about this, I can see three options:
1. Enfore CAP_SYS_TIME in the posix dynamic clock layer.
2. Defer the CAP_SYS_TIME check to the underlying dynamic clock. That
puts the decision of whether a clock counts as a "system clock" to
the author of the driver.
3. As you suggest, just use file read/write as get/set permissions.
The admin can still restrict device node ownership and read access in
any case. You could event combine these methods (1 and 3, or 1 and 2)
but I think that would only lead to user confusion.
I am not opinionated about this, but I would like to gather some
feedback before going forward. The implementation is easy in any case.
Thanks,
Richard