[linux-2.6-block.git] / kernel / futex / syscalls.c

// SPDX-License-Identifier: GPL-2.0-or-later

#include <linux/syscalls.h>
#include <linux/time_namespace.h>

#include "futex.h"

/*
 * Support for robust futexes: the kernel cleans up held futexes at
 * thread exit time.
 *
 * Implementation: user-space maintains a per-thread list of locks it
 * is holding. Upon do_exit(), the kernel carefully walks this list,
 * and marks all locks that are owned by this thread with the
 * FUTEX_OWNER_DIED bit, and wakes up a waiter (if any). The list is
 * always manipulated with the lock held, so the list is private and
 * per-thread. Userspace also maintains a per-thread 'list_op_pending'
 * field, to allow the kernel to clean up if the thread dies after
 * acquiring the lock, but just before it could have added itself to
 * the list. There can only be one such pending lock.
 */

/**
 * sys_set_robust_list() - Set the robust-futex list head of a task
 * @head:	pointer to the list-head
 * @len:	length of the list-head, as userspace expects
 */
SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
		size_t, len)
{
	/*
	 * The kernel knows only one size for now:
	 */
	if (unlikely(len != sizeof(*head)))
		return -EINVAL;

	current->robust_list = head;

	return 0;
}

/**
 * sys_get_robust_list() - Get the robust-futex list head of a task
 * @pid:	pid of the process [zero for current task]
 * @head_ptr:	pointer to a list-head pointer, the kernel fills it in
 * @len_ptr:	pointer to a length field, the kernel fills in the header size
 */
SYSCALL_DEFINE3(get_robust_list, int, pid,
		struct robust_list_head __user * __user *, head_ptr,
		size_t __user *, len_ptr)
{
	struct robust_list_head __user *head;
	unsigned long ret;
	struct task_struct *p;

	rcu_read_lock();

	ret = -ESRCH;
	if (!pid)
		p = current;
	else {
		p = find_task_by_vpid(pid);
		if (!p)
			goto err_unlock;
	}

	ret = -EPERM;
	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
		goto err_unlock;

	head = p->robust_list;
	rcu_read_unlock();

	if (put_user(sizeof(*head), len_ptr))
		return -EFAULT;
	return put_user(head, head_ptr);

err_unlock:
	rcu_read_unlock();

	return ret;
}

long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
		u32 __user *uaddr2, u32 val2, u32 val3)
{
	unsigned int flags = futex_to_flags(op);
	int cmd = op & FUTEX_CMD_MASK;

	if (flags & FLAGS_CLOCKRT) {
		if (cmd != FUTEX_WAIT_BITSET &&
		    cmd != FUTEX_WAIT_REQUEUE_PI &&
		    cmd != FUTEX_LOCK_PI2)
			return -ENOSYS;
	}

	switch (cmd) {
	case FUTEX_WAIT:
		val3 = FUTEX_BITSET_MATCH_ANY;
		fallthrough;
	case FUTEX_WAIT_BITSET:
		return futex_wait(uaddr, flags, val, timeout, val3);
	case FUTEX_WAKE:
		val3 = FUTEX_BITSET_MATCH_ANY;
		fallthrough;
	case FUTEX_WAKE_BITSET:
		return futex_wake(uaddr, flags, val, val3);
	case FUTEX_REQUEUE:
		return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
	case FUTEX_CMP_REQUEUE:
		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
	case FUTEX_WAKE_OP:
		return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
	case FUTEX_LOCK_PI:
		flags |= FLAGS_CLOCKRT;
		fallthrough;
	case FUTEX_LOCK_PI2:
		return futex_lock_pi(uaddr, flags, timeout, 0);
	case FUTEX_UNLOCK_PI:
		return futex_unlock_pi(uaddr, flags);
	case FUTEX_TRYLOCK_PI:
		return futex_lock_pi(uaddr, flags, NULL, 1);
	case FUTEX_WAIT_REQUEUE_PI:
		val3 = FUTEX_BITSET_MATCH_ANY;
		return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
					     uaddr2);
	case FUTEX_CMP_REQUEUE_PI:
		return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
	}
	return -ENOSYS;
}

static __always_inline bool futex_cmd_has_timeout(u32 cmd)
{
	switch (cmd) {
	case FUTEX_WAIT:
	case FUTEX_LOCK_PI:
	case FUTEX_LOCK_PI2:
	case FUTEX_WAIT_BITSET:
	case FUTEX_WAIT_REQUEUE_PI:
		return true;
	}
	return false;
}

static __always_inline int
futex_init_timeout(u32 cmd, u32 op, struct timespec64 *ts, ktime_t *t)
{
	if (!timespec64_valid(ts))
		return -EINVAL;

	*t = timespec64_to_ktime(*ts);
	if (cmd == FUTEX_WAIT)
		*t = ktime_add_safe(ktime_get(), *t);
	else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
		*t = timens_ktime_to_host(CLOCK_MONOTONIC, *t);
	return 0;
}

SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
		const struct __kernel_timespec __user *, utime,
		u32 __user *, uaddr2, u32, val3)
{
	int ret, cmd = op & FUTEX_CMD_MASK;
	ktime_t t, *tp = NULL;
	struct timespec64 ts;

	if (utime && futex_cmd_has_timeout(cmd)) {
		if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
			return -EFAULT;
		if (get_timespec64(&ts, utime))
			return -EFAULT;
		ret = futex_init_timeout(cmd, op, &ts, &t);
		if (ret)
			return ret;
		tp = &t;
	}

	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
}

#define FUTEX2_VALID_MASK (FUTEX2_SIZE_MASK | FUTEX2_PRIVATE)

/**
 * futex_parse_waitv - Parse a waitv array from userspace
 * @futexv:	Kernel side list of waiters to be filled
 * @uwaitv:     Userspace list to be parsed
 * @nr_futexes: Length of futexv
 *
 * Return: Error code on failure, 0 on success
 */
static int futex_parse_waitv(struct futex_vector *futexv,
			     struct futex_waitv __user *uwaitv,
			     unsigned int nr_futexes)
{
	struct futex_waitv aux;
	unsigned int i;

	for (i = 0; i < nr_futexes; i++) {
		unsigned int flags;

		if (copy_from_user(&aux, &uwaitv[i], sizeof(aux)))
			return -EFAULT;

		if ((aux.flags & ~FUTEX2_VALID_MASK) || aux.__reserved)
			return -EINVAL;

		flags = futex2_to_flags(aux.flags);
		if (!futex_flags_valid(flags))
			return -EINVAL;

		if (!futex_validate_input(flags, aux.val))
			return -EINVAL;

		futexv[i].w.flags = flags;
		futexv[i].w.val = aux.val;
		futexv[i].w.uaddr = aux.uaddr;
		futexv[i].q = futex_q_init;
	}

	return 0;
}

static int futex2_setup_timeout(struct __kernel_timespec __user *timeout,
				clockid_t clockid, struct hrtimer_sleeper *to)
{
	int flag_clkid = 0, flag_init = 0;
	struct timespec64 ts;
	ktime_t time;
	int ret;

	if (!timeout)
		return 0;

	if (clockid == CLOCK_REALTIME) {
		flag_clkid = FLAGS_CLOCKRT;
		flag_init = FUTEX_CLOCK_REALTIME;
	}

	if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC)
		return -EINVAL;

	if (get_timespec64(&ts, timeout))
		return -EFAULT;

	/*
	 * Since there's no opcode for futex_waitv, use
	 * FUTEX_WAIT_BITSET that uses absolute timeout as well
	 */
	ret = futex_init_timeout(FUTEX_WAIT_BITSET, flag_init, &ts, &time);
	if (ret)
		return ret;

	futex_setup_timer(&time, to, flag_clkid, 0);
	return 0;
}

static inline void futex2_destroy_timeout(struct hrtimer_sleeper *to)
{
	hrtimer_cancel(&to->timer);
	destroy_hrtimer_on_stack(&to->timer);
}

/**
 * sys_futex_waitv - Wait on a list of futexes
 * @waiters:    List of futexes to wait on
 * @nr_futexes: Length of futexv
 * @flags:      Flag for timeout (monotonic/realtime)
 * @timeout:	Optional absolute timeout.
 * @clockid:	Clock to be used for the timeout, realtime or monotonic.
 *
 * Given an array of `struct futex_waitv`, wait on each uaddr. The thread wakes
 * if a futex_wake() is performed at any uaddr. The syscall returns immediately
 * if any waiter has *uaddr != val. *timeout is an optional timeout value for
 * the operation. Each waiter has individual flags. The `flags` argument for
 * the syscall should be used solely for specifying the timeout as realtime, if
 * needed. Flags for private futexes, sizes, etc. should be used on the
 * individual flags of each waiter.
 *
 * Returns the array index of one of the woken futexes. No further information
 * is provided: any number of other futexes may also have been woken by the
 * same event, and if more than one futex was woken, the retrned index may
 * refer to any one of them. (It is not necessaryily the futex with the
 * smallest index, nor the one most recently woken, nor...)
 */

SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
		unsigned int, nr_futexes, unsigned int, flags,
		struct __kernel_timespec __user *, timeout, clockid_t, clockid)
{
	struct hrtimer_sleeper to;
	struct futex_vector *futexv;
	int ret;

	/* This syscall supports no flags for now */
	if (flags)
		return -EINVAL;

	if (!nr_futexes || nr_futexes > FUTEX_WAITV_MAX || !waiters)
		return -EINVAL;

	if (timeout && (ret = futex2_setup_timeout(timeout, clockid, &to)))
		return ret;

	futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
	if (!futexv) {
		ret = -ENOMEM;
		goto destroy_timer;
	}

	ret = futex_parse_waitv(futexv, waiters, nr_futexes);
	if (!ret)
		ret = futex_wait_multiple(futexv, nr_futexes, timeout ? &to : NULL);

	kfree(futexv);

destroy_timer:
	if (timeout)
		futex2_destroy_timeout(&to);
	return ret;
}

/*
 * sys_futex_wake - Wake a number of futexes
 * @uaddr:	Address of the futex(es) to wake
 * @mask:	bitmask
 * @nr:		Number of the futexes to wake
 * @flags:	FUTEX2 flags
 *
 * Identical to the traditional FUTEX_WAKE_BITSET op, except it is part of the
 * futex2 family of calls.
 */

SYSCALL_DEFINE4(futex_wake,
		void __user *, uaddr,
		unsigned long, mask,
		int, nr,
		unsigned int, flags)
{
	if (flags & ~FUTEX2_VALID_MASK)
		return -EINVAL;

	flags = futex2_to_flags(flags);
	if (!futex_flags_valid(flags))
		return -EINVAL;

	if (!futex_validate_input(flags, mask))
		return -EINVAL;

	return futex_wake(uaddr, FLAGS_STRICT | flags, nr, mask);
}

/*
 * sys_futex_wait - Wait on a futex
 * @uaddr:	Address of the futex to wait on
 * @val:	Value of @uaddr
 * @mask:	bitmask
 * @flags:	FUTEX2 flags
 * @timeout:	Optional absolute timeout
 * @clockid:	Clock to be used for the timeout, realtime or monotonic
 *
 * Identical to the traditional FUTEX_WAIT_BITSET op, except it is part of the
 * futex2 familiy of calls.
 */

SYSCALL_DEFINE6(futex_wait,
		void __user *, uaddr,
		unsigned long, val,
		unsigned long, mask,
		unsigned int, flags,
		struct __kernel_timespec __user *, timeout,
		clockid_t, clockid)
{
	struct hrtimer_sleeper to;
	int ret;

	if (flags & ~FUTEX2_VALID_MASK)
		return -EINVAL;

	flags = futex2_to_flags(flags);
	if (!futex_flags_valid(flags))
		return -EINVAL;

	if (!futex_validate_input(flags, val) ||
	    !futex_validate_input(flags, mask))
		return -EINVAL;

	if (timeout && (ret = futex2_setup_timeout(timeout, clockid, &to)))
		return ret;

	ret = __futex_wait(uaddr, flags, val, timeout ? &to : NULL, mask);

	if (timeout)
		futex2_destroy_timeout(&to);

	return ret;
}

#ifdef CONFIG_COMPAT
COMPAT_SYSCALL_DEFINE2(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;
}

COMPAT_SYSCALL_DEFINE3(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;
	struct task_struct *p;

	rcu_read_lock();

	ret = -ESRCH;
	if (!pid)
		p = current;
	else {
		p = find_task_by_vpid(pid);
		if (!p)
			goto err_unlock;
	}

	ret = -EPERM;
	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
		goto err_unlock;

	head = p->compat_robust_list;
	rcu_read_unlock();

	if (put_user(sizeof(*head), len_ptr))
		return -EFAULT;
	return put_user(ptr_to_compat(head), head_ptr);

err_unlock:
	rcu_read_unlock();

	return ret;
}
#endif /* CONFIG_COMPAT */

#ifdef CONFIG_COMPAT_32BIT_TIME
SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
		const struct old_timespec32 __user *, utime, u32 __user *, uaddr2,
		u32, val3)
{
	int ret, cmd = op & FUTEX_CMD_MASK;
	ktime_t t, *tp = NULL;
	struct timespec64 ts;

	if (utime && futex_cmd_has_timeout(cmd)) {
		if (get_old_timespec32(&ts, utime))
			return -EFAULT;
		ret = futex_init_timeout(cmd, op, &ts, &t);
		if (ret)
			return ret;
		tp = &t;
	}

	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
}
#endif /* CONFIG_COMPAT_32BIT_TIME */
Commit	Line	Data
af8cc960 PZ	1	// SPDX-License-Identifier: GPL-2.0-or-later
af8cc960 PZ	2
af8cc960 PZ	3	#include <linux/syscalls.h>
	4	#include <linux/time_namespace.h>
	5
	6	#include "futex.h"
	7
	8	/*
	9	* Support for robust futexes: the kernel cleans up held futexes at
	10	* thread exit time.
	11	*
	12	* Implementation: user-space maintains a per-thread list of locks it
	13	* is holding. Upon do_exit(), the kernel carefully walks this list,
	14	* and marks all locks that are owned by this thread with the
	15	* FUTEX_OWNER_DIED bit, and wakes up a waiter (if any). The list is
	16	* always manipulated with the lock held, so the list is private and
	17	* per-thread. Userspace also maintains a per-thread 'list_op_pending'
	18	* field, to allow the kernel to clean up if the thread dies after
	19	* acquiring the lock, but just before it could have added itself to
	20	* the list. There can only be one such pending lock.
	21	*/
	22
	23	/**
	24	* sys_set_robust_list() - Set the robust-futex list head of a task
	25	* @head: pointer to the list-head
	26	* @len: length of the list-head, as userspace expects
	27	*/
	28	SYSCALL_DEFINE2(set_robust_list, struct robust_list_head __user *, head,
	29	size_t, len)
	30	{
af8cc960 PZ	31	/*
	32	* The kernel knows only one size for now:
	33	*/
	34	if (unlikely(len != sizeof(*head)))
	35	return -EINVAL;
	36
	37	current->robust_list = head;
	38
	39	return 0;
	40	}
	41
	42	/**
	43	* sys_get_robust_list() - Get the robust-futex list head of a task
	44	* @pid: pid of the process [zero for current task]
	45	* @head_ptr: pointer to a list-head pointer, the kernel fills it in
	46	* @len_ptr: pointer to a length field, the kernel fills in the header size
	47	*/
	48	SYSCALL_DEFINE3(get_robust_list, int, pid,
	49	struct robust_list_head __user * __user *, head_ptr,
	50	size_t __user *, len_ptr)
	51	{
	52	struct robust_list_head __user *head;
	53	unsigned long ret;
	54	struct task_struct *p;
	55
af8cc960 PZ	56	rcu_read_lock();
	57
	58	ret = -ESRCH;
	59	if (!pid)
	60	p = current;
	61	else {
	62	p = find_task_by_vpid(pid);
	63	if (!p)
	64	goto err_unlock;
	65	}
	66
	67	ret = -EPERM;
	68	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
	69	goto err_unlock;
	70
	71	head = p->robust_list;
	72	rcu_read_unlock();
	73
	74	if (put_user(sizeof(*head), len_ptr))
	75	return -EFAULT;
	76	return put_user(head, head_ptr);
	77
	78	err_unlock:
	79	rcu_read_unlock();
	80
	81	return ret;
	82	}
	83
	84	long do_futex(u32 __user uaddr, int op, u32 val, ktime_t timeout,
	85	u32 __user *uaddr2, u32 val2, u32 val3)
	86	{
5694289c	87	unsigned int flags = futex_to_flags(op);
af8cc960	88	int cmd = op & FUTEX_CMD_MASK;
af8cc960	89
5694289c	90	if (flags & FLAGS_CLOCKRT) {
	91	if (cmd != FUTEX_WAIT_BITSET &&
	92	cmd != FUTEX_WAIT_REQUEUE_PI &&
af8cc960 PZ	93	cmd != FUTEX_LOCK_PI2)
	94	return -ENOSYS;
	95	}
	96
af8cc960 PZ	97	switch (cmd) {
	98	case FUTEX_WAIT:
	99	val3 = FUTEX_BITSET_MATCH_ANY;
	100	fallthrough;
	101	case FUTEX_WAIT_BITSET:
	102	return futex_wait(uaddr, flags, val, timeout, val3);
	103	case FUTEX_WAKE:
	104	val3 = FUTEX_BITSET_MATCH_ANY;
	105	fallthrough;
	106	case FUTEX_WAKE_BITSET:
	107	return futex_wake(uaddr, flags, val, val3);
	108	case FUTEX_REQUEUE:
	109	return futex_requeue(uaddr, flags, uaddr2, val, val2, NULL, 0);
	110	case FUTEX_CMP_REQUEUE:
	111	return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 0);
	112	case FUTEX_WAKE_OP:
	113	return futex_wake_op(uaddr, flags, uaddr2, val, val2, val3);
	114	case FUTEX_LOCK_PI:
	115	flags \|= FLAGS_CLOCKRT;
	116	fallthrough;
	117	case FUTEX_LOCK_PI2:
	118	return futex_lock_pi(uaddr, flags, timeout, 0);
	119	case FUTEX_UNLOCK_PI:
	120	return futex_unlock_pi(uaddr, flags);
	121	case FUTEX_TRYLOCK_PI:
	122	return futex_lock_pi(uaddr, flags, NULL, 1);
	123	case FUTEX_WAIT_REQUEUE_PI:
	124	val3 = FUTEX_BITSET_MATCH_ANY;
	125	return futex_wait_requeue_pi(uaddr, flags, val, timeout, val3,
	126	uaddr2);
	127	case FUTEX_CMP_REQUEUE_PI:
	128	return futex_requeue(uaddr, flags, uaddr2, val, val2, &val3, 1);
	129	}
	130	return -ENOSYS;
	131	}
	132
	133	static __always_inline bool futex_cmd_has_timeout(u32 cmd)
	134	{
	135	switch (cmd) {
	136	case FUTEX_WAIT:
	137	case FUTEX_LOCK_PI:
	138	case FUTEX_LOCK_PI2:
	139	case FUTEX_WAIT_BITSET:
	140	case FUTEX_WAIT_REQUEUE_PI:
	141	return true;
	142	}
	143	return false;
	144	}
	145
	146	static __always_inline int
	147	futex_init_timeout(u32 cmd, u32 op, struct timespec64 ts, ktime_t t)
	148	{
	149	if (!timespec64_valid(ts))
	150	return -EINVAL;
	151
	152	t = timespec64_to_ktime(ts);
	153	if (cmd == FUTEX_WAIT)
	154	t = ktime_add_safe(ktime_get(), t);
	155	else if (cmd != FUTEX_LOCK_PI && !(op & FUTEX_CLOCK_REALTIME))
	156	t = timens_ktime_to_host(CLOCK_MONOTONIC, t);
	157	return 0;
	158	}
	159
	160	SYSCALL_DEFINE6(futex, u32 __user *, uaddr, int, op, u32, val,
161	const struct __kernel_timespec __user *, utime,
162	u32 __user *, uaddr2, u32, val3)
163	{
164	int ret, cmd = op & FUTEX_CMD_MASK;
165	ktime_t t, *tp = NULL;
166	struct timespec64 ts;
167
168	if (utime && futex_cmd_has_timeout(cmd)) {
169	if (unlikely(should_fail_futex(!(op & FUTEX_PRIVATE_FLAG))))
170	return -EFAULT;
171	if (get_timespec64(&ts, utime))
172	return -EFAULT;
173	ret = futex_init_timeout(cmd, op, &ts, &t);
174	if (ret)
175	return ret;
176	tp = &t;
177	}
178
179	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
180	}
181
d6d08d24	182	#define FUTEX2_VALID_MASK (FUTEX2_SIZE_MASK \| FUTEX2_PRIVATE)
bf69bad3 AA	183
	184	/**
	185	* futex_parse_waitv - Parse a waitv array from userspace
	186	* @futexv: Kernel side list of waiters to be filled
	187	* @uwaitv: Userspace list to be parsed
	188	* @nr_futexes: Length of futexv
	189	*
	190	* Return: Error code on failure, 0 on success
	191	*/
	192	static int futex_parse_waitv(struct futex_vector *futexv,
	193	struct futex_waitv __user *uwaitv,
	194	unsigned int nr_futexes)
	195	{
	196	struct futex_waitv aux;
	197	unsigned int i;
	198
	199	for (i = 0; i < nr_futexes; i++) {
5694289c	200	unsigned int flags;
5694289c	201
bf69bad3 AA	202	if (copy_from_user(&aux, &uwaitv[i], sizeof(aux)))
	203	return -EFAULT;
	204
4923954b	205	if ((aux.flags & ~FUTEX2_VALID_MASK) \|\| aux.__reserved)
bf69bad3 AA	206	return -EINVAL;
bf69bad3 AA	207
5694289c	208	flags = futex2_to_flags(aux.flags);
5694289c	209	if (!futex_flags_valid(flags))
bf69bad3 AA	210	return -EINVAL;
bf69bad3 AA	211
698eb826	212	if (!futex_validate_input(flags, aux.val))
	213	return -EINVAL;
	214
5694289c	215	futexv[i].w.flags = flags;
bf69bad3 AA	216	futexv[i].w.val = aux.val;
	217	futexv[i].w.uaddr = aux.uaddr;
	218	futexv[i].q = futex_q_init;
	219	}
	220
	221	return 0;
	222	}
	223
cb8c4312	224	static int futex2_setup_timeout(struct __kernel_timespec __user *timeout,
	225	clockid_t clockid, struct hrtimer_sleeper *to)
	226	{
	227	int flag_clkid = 0, flag_init = 0;
	228	struct timespec64 ts;
	229	ktime_t time;
	230	int ret;
	231
	232	if (!timeout)
	233	return 0;
	234
	235	if (clockid == CLOCK_REALTIME) {
	236	flag_clkid = FLAGS_CLOCKRT;
	237	flag_init = FUTEX_CLOCK_REALTIME;
	238	}
	239
	240	if (clockid != CLOCK_REALTIME && clockid != CLOCK_MONOTONIC)
	241	return -EINVAL;
	242
	243	if (get_timespec64(&ts, timeout))
	244	return -EFAULT;
	245
	246	/*
	247	* Since there's no opcode for futex_waitv, use
	248	* FUTEX_WAIT_BITSET that uses absolute timeout as well
	249	*/
	250	ret = futex_init_timeout(FUTEX_WAIT_BITSET, flag_init, &ts, &time);
	251	if (ret)
	252	return ret;
	253
	254	futex_setup_timer(&time, to, flag_clkid, 0);
	255	return 0;
	256	}
	257
	258	static inline void futex2_destroy_timeout(struct hrtimer_sleeper *to)
	259	{
	260	hrtimer_cancel(&to->timer);
	261	destroy_hrtimer_on_stack(&to->timer);
	262	}
	263
bf69bad3 AA	264	/**
	265	* sys_futex_waitv - Wait on a list of futexes
	266	* @waiters: List of futexes to wait on
	267	* @nr_futexes: Length of futexv
	268	* @flags: Flag for timeout (monotonic/realtime)
	269	* @timeout: Optional absolute timeout.
	270	* @clockid: Clock to be used for the timeout, realtime or monotonic.
	271	*
	272	* Given an array of `struct futex_waitv`, wait on each uaddr. The thread wakes
	273	* if a futex_wake() is performed at any uaddr. The syscall returns immediately
	274	* if any waiter has uaddr != val. timeout is an optional timeout value for
	275	* the operation. Each waiter has individual flags. The `flags` argument for
	276	* the syscall should be used solely for specifying the timeout as realtime, if
	277	* needed. Flags for private futexes, sizes, etc. should be used on the
	278	* individual flags of each waiter.
	279	*
	280	* Returns the array index of one of the woken futexes. No further information
	281	* is provided: any number of other futexes may also have been woken by the
	282	* same event, and if more than one futex was woken, the retrned index may
	283	* refer to any one of them. (It is not necessaryily the futex with the
	284	* smallest index, nor the one most recently woken, nor...)
	285	*/
	286
	287	SYSCALL_DEFINE5(futex_waitv, struct futex_waitv __user *, waiters,
	288	unsigned int, nr_futexes, unsigned int, flags,
	289	struct __kernel_timespec __user *, timeout, clockid_t, clockid)
	290	{
	291	struct hrtimer_sleeper to;
	292	struct futex_vector *futexv;
bf69bad3 AA	293	int ret;
	294
	295	/* This syscall supports no flags for now */
	296	if (flags)
	297	return -EINVAL;
	298
	299	if (!nr_futexes \|\| nr_futexes > FUTEX_WAITV_MAX \|\| !waiters)
	300	return -EINVAL;
	301
cb8c4312	302	if (timeout && (ret = futex2_setup_timeout(timeout, clockid, &to)))
cb8c4312	303	return ret;
bf69bad3 AA	304
bf69bad3 AA	305	futexv = kcalloc(nr_futexes, sizeof(*futexv), GFP_KERNEL);
94cd8fa0 MD	306	if (!futexv) {
	307	ret = -ENOMEM;
	308	goto destroy_timer;
	309	}
bf69bad3 AA	310
	311	ret = futex_parse_waitv(futexv, waiters, nr_futexes);
	312	if (!ret)
	313	ret = futex_wait_multiple(futexv, nr_futexes, timeout ? &to : NULL);
	314
94cd8fa0 MD	315	kfree(futexv);
	316
	317	destroy_timer:
cb8c4312	318	if (timeout)
cb8c4312	319	futex2_destroy_timeout(&to);
bf69bad3 AA	320	return ret;
	321	}
	322
9f6c532f	323	/*
	324	* sys_futex_wake - Wake a number of futexes
	325	* @uaddr: Address of the futex(es) to wake
	326	* @mask: bitmask
	327	* @nr: Number of the futexes to wake
	328	* @flags: FUTEX2 flags
	329	*
	330	* Identical to the traditional FUTEX_WAKE_BITSET op, except it is part of the
	331	* futex2 family of calls.
	332	*/
	333
	334	SYSCALL_DEFINE4(futex_wake,
	335	void __user *, uaddr,
	336	unsigned long, mask,
	337	int, nr,
	338	unsigned int, flags)
	339	{
	340	if (flags & ~FUTEX2_VALID_MASK)
	341	return -EINVAL;
	342
	343	flags = futex2_to_flags(flags);
	344	if (!futex_flags_valid(flags))
	345	return -EINVAL;
	346
	347	if (!futex_validate_input(flags, mask))
	348	return -EINVAL;
	349
43adf844	350	return futex_wake(uaddr, FLAGS_STRICT \| flags, nr, mask);
9f6c532f	351	}
9f6c532f	352
cb8c4312	353	/*
	354	* sys_futex_wait - Wait on a futex
	355	* @uaddr: Address of the futex to wait on
	356	* @val: Value of @uaddr
	357	* @mask: bitmask
	358	* @flags: FUTEX2 flags
	359	* @timeout: Optional absolute timeout
	360	* @clockid: Clock to be used for the timeout, realtime or monotonic
	361	*
	362	* Identical to the traditional FUTEX_WAIT_BITSET op, except it is part of the
	363	* futex2 familiy of calls.
	364	*/
	365
	366	SYSCALL_DEFINE6(futex_wait,
	367	void __user *, uaddr,
	368	unsigned long, val,
	369	unsigned long, mask,
	370	unsigned int, flags,
	371	struct __kernel_timespec __user *, timeout,
	372	clockid_t, clockid)
	373	{
	374	struct hrtimer_sleeper to;
	375	int ret;
	376
	377	if (flags & ~FUTEX2_VALID_MASK)
	378	return -EINVAL;
	379
	380	flags = futex2_to_flags(flags);
	381	if (!futex_flags_valid(flags))
	382	return -EINVAL;
	383
	384	if (!futex_validate_input(flags, val) \|\|
	385	!futex_validate_input(flags, mask))
	386	return -EINVAL;
	387
	388	if (timeout && (ret = futex2_setup_timeout(timeout, clockid, &to)))
	389	return ret;
	390
	391	ret = __futex_wait(uaddr, flags, val, timeout ? &to : NULL, mask);
	392
	393	if (timeout)
	394	futex2_destroy_timeout(&to);
	395
	396	return ret;
	397	}
	398
af8cc960 PZ	399	#ifdef CONFIG_COMPAT
	400	COMPAT_SYSCALL_DEFINE2(set_robust_list,
	401	struct compat_robust_list_head __user *, head,
	402	compat_size_t, len)
	403	{
af8cc960 PZ	404	if (unlikely(len != sizeof(*head)))
	405	return -EINVAL;
	406
	407	current->compat_robust_list = head;
	408
	409	return 0;
	410	}
	411
	412	COMPAT_SYSCALL_DEFINE3(get_robust_list, int, pid,
	413	compat_uptr_t __user *, head_ptr,
	414	compat_size_t __user *, len_ptr)
	415	{
	416	struct compat_robust_list_head __user *head;
	417	unsigned long ret;
	418	struct task_struct *p;
	419
af8cc960 PZ	420	rcu_read_lock();
	421
	422	ret = -ESRCH;
	423	if (!pid)
	424	p = current;
	425	else {
	426	p = find_task_by_vpid(pid);
	427	if (!p)
	428	goto err_unlock;
	429	}
	430
	431	ret = -EPERM;
	432	if (!ptrace_may_access(p, PTRACE_MODE_READ_REALCREDS))
	433	goto err_unlock;
	434
	435	head = p->compat_robust_list;
	436	rcu_read_unlock();
	437
	438	if (put_user(sizeof(*head), len_ptr))
	439	return -EFAULT;
	440	return put_user(ptr_to_compat(head), head_ptr);
	441
	442	err_unlock:
	443	rcu_read_unlock();
	444
	445	return ret;
	446	}
	447	#endif /* CONFIG_COMPAT */
	448
	449	#ifdef CONFIG_COMPAT_32BIT_TIME
	450	SYSCALL_DEFINE6(futex_time32, u32 __user *, uaddr, int, op, u32, val,
	451	const struct old_timespec32 __user , utime, u32 __user , uaddr2,
	452	u32, val3)
	453	{
	454	int ret, cmd = op & FUTEX_CMD_MASK;
	455	ktime_t t, *tp = NULL;
	456	struct timespec64 ts;
	457
	458	if (utime && futex_cmd_has_timeout(cmd)) {
	459	if (get_old_timespec32(&ts, utime))
	460	return -EFAULT;
	461	ret = futex_init_timeout(cmd, op, &ts, &t);
	462	if (ret)
	463	return ret;
	464	tp = &t;
	465	}
	466
	467	return do_futex(uaddr, op, val, tp, uaddr2, (unsigned long)utime, val3);
	468	}
	469	#endif /* CONFIG_COMPAT_32BIT_TIME */
	470