Subversion Repositories or1k_soc_on_altera_embedded_dev_kit

/*

 * linux/kernel/futex_compat.c

 *

 * Futex compatibililty routines.

 *

 * Copyright 2006, Red Hat, Inc., Ingo Molnar

 */

#include <linux/linkage.h>

#include <linux/compat.h>

#include <linux/nsproxy.h>

#include <linux/futex.h>

#include <asm/uaccess.h>

/*

 * Fetch a robust-list pointer. Bit 0 signals PI futexes:

 */

static inline int

fetch_robust_entry(compat_uptr_t *uentry, struct robust_list __user **entry,

                   compat_uptr_t __user *head, int *pi)

{

        if (get_user(*uentry, head))

                return -EFAULT;

        *entry = compat_ptr((*uentry) & ~1);

        *pi = (unsigned int)(*uentry) & 1;

        return 0;

}

static void __user *futex_uaddr(struct robust_list *entry,

                                compat_long_t futex_offset)

{

        compat_uptr_t base = ptr_to_compat(entry);

        void __user *uaddr = compat_ptr(base + futex_offset);

        return uaddr;

}

/*

 * Walk curr->robust_list (very carefully, it's a userspace list!)

 * and mark any locks found there dead, and notify any waiters.

 *

 * We silently return on any sign of list-walking problem.

 */

void compat_exit_robust_list(struct task_struct *curr)

{

        struct compat_robust_list_head __user *head = curr->compat_robust_list;

        struct robust_list __user *entry, *next_entry, *pending;

        unsigned int limit = ROBUST_LIST_LIMIT, pi, next_pi, pip;

        compat_uptr_t uentry, next_uentry, upending;

        compat_long_t futex_offset;

        int rc;

        /*

         * Fetch the list head (which was registered earlier, via

         * sys_set_robust_list()):

         */

        if (fetch_robust_entry(&uentry, &entry, &head->list.next, &pi))

                return;

        /*

         * Fetch the relative futex offset:

         */

        if (get_user(futex_offset, &head->futex_offset))

                return;

        /*

         * Fetch any possibly pending lock-add first, and handle it

         * if it exists:

         */

        if (fetch_robust_entry(&upending, &pending,

                               &head->list_op_pending, &pip))

                return;

        next_entry = NULL;      /* avoid warning with gcc */

        while (entry != (struct robust_list __user *) &head->list) {

                /*

                 * Fetch the next entry in the list before calling

                 * handle_futex_death:

                 */

                rc = fetch_robust_entry(&next_uentry, &next_entry,

                        (compat_uptr_t __user *)&entry->next, &next_pi);

                /*

                 * A pending lock might already be on the list, so

                 * dont process it twice:

                 */

                if (entry != pending) {

                        void __user *uaddr = futex_uaddr(entry, futex_offset);

                        if (handle_futex_death(uaddr, curr, pi))

                                return;

                }

                if (rc)

                        return;

                uentry = next_uentry;

                entry = next_entry;

                pi = next_pi;

                /*

                 * Avoid excessively long or circular lists:

                 */

                if (!--limit)

                        break;

                cond_resched();

        }

        if (pending) {

                void __user *uaddr = futex_uaddr(pending, futex_offset);

                handle_futex_death(uaddr, curr, pip);

        }

}

asmlinkage long

compat_sys_set_robust_list(struct compat_robust_list_head __user *head,

                           compat_size_t len)

{

        if (unlikely(len != sizeof(*head)))

                return -EINVAL;

        current->compat_robust_list = head;

        return 0;

}

asmlinkage long

compat_sys_get_robust_list(int pid, compat_uptr_t __user *head_ptr,

                           compat_size_t __user *len_ptr)

{

        struct compat_robust_list_head __user *head;

        unsigned long ret;

        if (!pid)

                head = current->compat_robust_list;

        else {

                struct task_struct *p;

                ret = -ESRCH;

                read_lock(&tasklist_lock);

                p = find_task_by_vpid(pid);

                if (!p)

                        goto err_unlock;

                ret = -EPERM;

                if ((current->euid != p->euid) && (current->euid != p->uid) &&

                                !capable(CAP_SYS_PTRACE))

                        goto err_unlock;

                head = p->compat_robust_list;

                read_unlock(&tasklist_lock);

        }

        if (put_user(sizeof(*head), len_ptr))

                return -EFAULT;

        return put_user(ptr_to_compat(head), head_ptr);

err_unlock:

        read_unlock(&tasklist_lock);

        return ret;

}

asmlinkage long compat_sys_futex(u32 __user *uaddr, int op, u32 val,

                struct compat_timespec __user *utime, u32 __user *uaddr2,

                u32 val3)

{

        struct timespec ts;

        ktime_t t, *tp = NULL;

        int val2 = 0;

        int cmd = op & FUTEX_CMD_MASK;

        if (utime && (cmd == FUTEX_WAIT || cmd == FUTEX_LOCK_PI)) {

                if (get_compat_timespec(&ts, utime))

                        return -EFAULT;

                if (!timespec_valid(&ts))

                        return -EINVAL;

                t = timespec_to_ktime(ts);

                if (cmd == FUTEX_WAIT)

                        t = ktime_add(ktime_get(), t);

                tp = &t;

        }

        if (cmd == FUTEX_REQUEUE || cmd == FUTEX_CMP_REQUEUE)

                val2 = (int) (unsigned long) utime;

        return do_futex(uaddr, op, val, tp, uaddr2, val2, val3);

}