[mirror_ubuntu-eoan-kernel.git] / include / linux / futex.h

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_FUTEX_H
#define _LINUX_FUTEX_H

#include <linux/ktime.h>
#include <uapi/linux/futex.h>

struct inode;
struct mm_struct;
struct task_struct;

extern int
handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);

/*
 * Futexes are matched on equal values of this key.
 * The key type depends on whether it's a shared or private mapping.
 * Don't rearrange members without looking at hash_futex().
 *
 * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
 * We use the two low order bits of offset to tell what is the kind of key :
 *  00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
 *       (no reference on an inode or mm)
 *  01 : Shared futex (PTHREAD_PROCESS_SHARED)
 *	mapped on a file (reference on the underlying inode)
 *  10 : Shared futex (PTHREAD_PROCESS_SHARED)
 *       (but private mapping on an mm, and reference taken on it)
*/

#define FUT_OFF_INODE    1 /* We set bit 0 if key has a reference on inode */
#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */

union futex_key {
	struct {
		unsigned long pgoff;
		struct inode *inode;
		int offset;
	} shared;
	struct {
		unsigned long address;
		struct mm_struct *mm;
		int offset;
	} private;
	struct {
		unsigned long word;
		void *ptr;
		int offset;
	} both;
};

#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }

#ifdef CONFIG_FUTEX
extern void exit_robust_list(struct task_struct *curr);

long do_futex(u32 __user *uaddr, int op, u32 val, ktime_t *timeout,
	      u32 __user *uaddr2, u32 val2, u32 val3);
#ifdef CONFIG_HAVE_FUTEX_CMPXCHG
#define futex_cmpxchg_enabled 1
#else
extern int futex_cmpxchg_enabled;
#endif
#else
static inline void exit_robust_list(struct task_struct *curr)
{
}

static inline long do_futex(u32 __user *uaddr, int op, u32 val,
			    ktime_t *timeout, u32 __user *uaddr2,
			    u32 val2, u32 val3)
{
	return -EINVAL;
}
#endif

#ifdef CONFIG_FUTEX_PI
extern void exit_pi_state_list(struct task_struct *curr);
#else
static inline void exit_pi_state_list(struct task_struct *curr)
{
}
#endif

#endif
Commit	Line	Data
b2441318	1	/* SPDX-License-Identifier: GPL-2.0 */
1da177e4 LT	2	#ifndef _LINUX_FUTEX_H
	3	#define _LINUX_FUTEX_H
	4
2456e855	5	#include <linux/ktime.h>
607ca46e	6	#include <uapi/linux/futex.h>
0771dfef	7
9064a678 MF	8	struct inode;
	9	struct mm_struct;
	10	struct task_struct;
9064a678	11
e3f2ddea IM	12	extern int
e3f2ddea IM	13	handle_futex_death(u32 __user uaddr, struct task_struct curr, int pi);
0771dfef	14
9adef58b RR	15	/*
	16	* Futexes are matched on equal values of this key.
	17	* The key type depends on whether it's a shared or private mapping.
	18	* Don't rearrange members without looking at hash_futex().
	19	*
	20	* offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
34f01cc1 ED	21	* We use the two low order bits of offset to tell what is the kind of key :
	22	* 00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
	23	* (no reference on an inode or mm)
	24	* 01 : Shared futex (PTHREAD_PROCESS_SHARED)
	25	* mapped on a file (reference on the underlying inode)
	26	* 10 : Shared futex (PTHREAD_PROCESS_SHARED)
	27	* (but private mapping on an mm, and reference taken on it)
	28	*/
	29
	30	#define FUT_OFF_INODE 1 /* We set bit 0 if key has a reference on inode */
	31	#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */
	32
9adef58b RR	33	union futex_key {
	34	struct {
	35	unsigned long pgoff;
	36	struct inode *inode;
	37	int offset;
	38	} shared;
	39	struct {
	40	unsigned long address;
	41	struct mm_struct *mm;
	42	int offset;
	43	} private;
	44	struct {
	45	unsigned long word;
	46	void *ptr;
	47	int offset;
	48	} both;
	49	};
9adef58b	50
38d47c1b PZ	51	#define FUTEX_KEY_INIT (union futex_key) { .both = { .ptr = NULL } }
38d47c1b PZ	52
0771dfef IM	53	#ifdef CONFIG_FUTEX
0771dfef IM	54	extern void exit_robust_list(struct task_struct *curr);
2de0db99 DB	55
	56	long do_futex(u32 __user uaddr, int op, u32 val, ktime_t timeout,
	57	u32 __user *uaddr2, u32 val2, u32 val3);
03b8c7b6 HC	58	#ifdef CONFIG_HAVE_FUTEX_CMPXCHG
	59	#define futex_cmpxchg_enabled 1
	60	#else
a0c1e907	61	extern int futex_cmpxchg_enabled;
03b8c7b6	62	#endif
0771dfef IM	63	#else
	64	static inline void exit_robust_list(struct task_struct *curr)
	65	{
	66	}
2de0db99 DB	67
	68	static inline long do_futex(u32 __user *uaddr, int op, u32 val,
	69	ktime_t timeout, u32 __user uaddr2,
	70	u32 val2, u32 val3)
	71	{
	72	return -EINVAL;
	73	}
bc2eecd7 NP	74	#endif
	75
	76	#ifdef CONFIG_FUTEX_PI
	77	extern void exit_pi_state_list(struct task_struct *curr);
	78	#else
c87e2837 IM	79	static inline void exit_pi_state_list(struct task_struct *curr)
	80	{
	81	}
0771dfef	82	#endif
bc2eecd7	83
1da177e4	84	#endif