Merge 'Linux v3.0' into Litmus

Some notes:
* Litmus^RT scheduling class is the topmost scheduling class
  (above stop_sched_class).
* scheduler_ipi() function (e.g., in smp_reschedule_interrupt())
  may increase IPI latencies.
* Added path into schedule() to quickly re-evaluate scheduling
  decision without becoming preemptive again. This used to be
  a standard path before the removal of BKL.

Conflicts:
	Makefile
	arch/arm/kernel/calls.S
	arch/arm/kernel/smp.c
	arch/x86/include/asm/unistd_32.h
	arch/x86/kernel/smp.c
	arch/x86/kernel/syscall_table_32.S
	include/linux/hrtimer.h
	kernel/printk.c
	kernel/sched.c
	kernel/sched_fair.c

1 files changed, 445 insertions, 0 deletions

diff --git a/kernel/time/posix-clock.c b/kernel/time/posix-clock.c
new file mode 100644
index 000000000000..c340ca658f37
--- /dev/null
+++ b/kernel/time/posix-clock.c
@@ -0,0 +1,445 @@
+/*
+ * 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/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;
+
+        down_read(&clk->rwsem);
+
+        if (!clk->zombie)
+                return clk;
+
+        up_read(&clk->rwsem);
+
+        return NULL;
+}
+
+static void put_posix_clock(struct posix_clock *clk)
+{
+        up_read(&clk->rwsem);
+}
+
+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);
+
+        down_read(&clk->rwsem);
+
+        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:
+        up_read(&clk->rwsem);
+        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);
+        init_rwsem(&clk->rwsem);
+
+        cdev_init(&clk->cdev, &posix_clock_file_operations);
+        clk->cdev.owner = clk->ops.owner;
+        err = cdev_add(&clk->cdev, devid, 1);
+
+        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);
+
+        if (clk->release)
+                clk->release(clk);
+}
+
+void posix_clock_unregister(struct posix_clock *clk)
+{
+        cdev_del(&clk->cdev);
+
+        down_write(&clk->rwsem);
+        clk->zombie = true;
+        up_write(&clk->rwsem);
+
+        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.fp->f_mode & FMODE_WRITE) == 0) {
+                err = -EACCES;
+                goto out;
+        }
+
+        if (cd.clk->ops.clock_adjtime)
+                err = cd.clk->ops.clock_adjtime(cd.clk, tx);
+        else
+                err = -EOPNOTSUPP;
+out:
+        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.fp->f_mode & FMODE_WRITE) == 0) {
+                err = -EACCES;
+                goto out;
+        }
+
+        if (cd.clk->ops.clock_settime)
+                err = cd.clk->ops.clock_settime(cd.clk, ts);
+        else
+                err = -EOPNOTSUPP;
+out:
+        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,
+};