216 lines
6.6 KiB
C
216 lines
6.6 KiB
C
#ifndef _LINUX_FUTEX_H
|
|
#define _LINUX_FUTEX_H
|
|
|
|
#include <linux/compiler.h>
|
|
#include <linux/types.h>
|
|
|
|
/* Second argument to futex syscall */
|
|
|
|
|
|
#define FUTEX_WAIT 0
|
|
#define FUTEX_WAKE 1
|
|
#define FUTEX_FD 2
|
|
#define FUTEX_REQUEUE 3
|
|
#define FUTEX_CMP_REQUEUE 4
|
|
#define FUTEX_WAKE_OP 5
|
|
#define FUTEX_LOCK_PI 6
|
|
#define FUTEX_UNLOCK_PI 7
|
|
#define FUTEX_TRYLOCK_PI 8
|
|
#define FUTEX_WAIT_BITSET 9
|
|
#define FUTEX_WAKE_BITSET 10
|
|
#define FUTEX_WAIT_REQUEUE_PI 11
|
|
#define FUTEX_CMP_REQUEUE_PI 12
|
|
|
|
#define FUTEX_PRIVATE_FLAG 128
|
|
#define FUTEX_CLOCK_REALTIME 256
|
|
#define FUTEX_CMD_MASK ~(FUTEX_PRIVATE_FLAG | FUTEX_CLOCK_REALTIME)
|
|
|
|
#define FUTEX_WAIT_PRIVATE (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_WAKE_PRIVATE (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_REQUEUE_PRIVATE (FUTEX_REQUEUE | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_REQUEUE | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_WAKE_OP_PRIVATE (FUTEX_WAKE_OP | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \
|
|
FUTEX_PRIVATE_FLAG)
|
|
#define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \
|
|
FUTEX_PRIVATE_FLAG)
|
|
|
|
/*
|
|
* Support for robust futexes: the kernel cleans up held futexes at
|
|
* thread exit time.
|
|
*/
|
|
|
|
/*
|
|
* Per-lock list entry - embedded in user-space locks, somewhere close
|
|
* to the futex field. (Note: user-space uses a double-linked list to
|
|
* achieve O(1) list add and remove, but the kernel only needs to know
|
|
* about the forward link)
|
|
*
|
|
* NOTE: this structure is part of the syscall ABI, and must not be
|
|
* changed.
|
|
*/
|
|
struct robust_list {
|
|
struct robust_list __user *next;
|
|
};
|
|
|
|
/*
|
|
* Per-thread list head:
|
|
*
|
|
* NOTE: this structure is part of the syscall ABI, and must only be
|
|
* changed if the change is first communicated with the glibc folks.
|
|
* (When an incompatible change is done, we'll increase the structure
|
|
* size, which glibc will detect)
|
|
*/
|
|
struct robust_list_head {
|
|
/*
|
|
* The head of the list. Points back to itself if empty:
|
|
*/
|
|
struct robust_list list;
|
|
|
|
/*
|
|
* This relative offset is set by user-space, it gives the kernel
|
|
* the relative position of the futex field to examine. This way
|
|
* we keep userspace flexible, to freely shape its data-structure,
|
|
* without hardcoding any particular offset into the kernel:
|
|
*/
|
|
long futex_offset;
|
|
|
|
/*
|
|
* The death of the thread may race with userspace setting
|
|
* up a lock's links. So to handle this race, userspace first
|
|
* sets this field to the address of the to-be-taken lock,
|
|
* then does the lock acquire, and then adds itself to the
|
|
* list, and then clears this field. Hence the kernel will
|
|
* always have full knowledge of all locks that the thread
|
|
* _might_ have taken. We check the owner TID in any case,
|
|
* so only truly owned locks will be handled.
|
|
*/
|
|
struct robust_list __user *list_op_pending;
|
|
};
|
|
|
|
/*
|
|
* Are there any waiters for this robust futex:
|
|
*/
|
|
#define FUTEX_WAITERS 0x80000000
|
|
|
|
/*
|
|
* The kernel signals via this bit that a thread holding a futex
|
|
* has exited without unlocking the futex. The kernel also does
|
|
* a FUTEX_WAKE on such futexes, after setting the bit, to wake
|
|
* up any possible waiters:
|
|
*/
|
|
#define FUTEX_OWNER_DIED 0x40000000
|
|
|
|
/*
|
|
* The rest of the robust-futex field is for the TID:
|
|
*/
|
|
#define FUTEX_TID_MASK 0x3fffffff
|
|
|
|
/*
|
|
* This limit protects against a deliberately circular list.
|
|
* (Not worth introducing an rlimit for it)
|
|
*/
|
|
#define ROBUST_LIST_LIMIT 2048
|
|
|
|
/*
|
|
* bitset with all bits set for the FUTEX_xxx_BITSET OPs to request a
|
|
* match of any bit.
|
|
*/
|
|
#define FUTEX_BITSET_MATCH_ANY 0xffffffff
|
|
|
|
#ifdef __KERNEL__
|
|
struct inode;
|
|
struct mm_struct;
|
|
struct task_struct;
|
|
union ktime;
|
|
|
|
long do_futex(u32 __user *uaddr, int op, u32 val, union ktime *timeout,
|
|
u32 __user *uaddr2, u32 val2, u32 val3);
|
|
|
|
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);
|
|
extern void exit_pi_state_list(struct task_struct *curr);
|
|
extern int futex_cmpxchg_enabled;
|
|
#else
|
|
static inline void exit_robust_list(struct task_struct *curr)
|
|
{
|
|
}
|
|
static inline void exit_pi_state_list(struct task_struct *curr)
|
|
{
|
|
}
|
|
#endif
|
|
#endif /* __KERNEL__ */
|
|
|
|
#define FUTEX_OP_SET 0 /* *(int *)UADDR2 = OPARG; */
|
|
#define FUTEX_OP_ADD 1 /* *(int *)UADDR2 += OPARG; */
|
|
#define FUTEX_OP_OR 2 /* *(int *)UADDR2 |= OPARG; */
|
|
#define FUTEX_OP_ANDN 3 /* *(int *)UADDR2 &= ~OPARG; */
|
|
#define FUTEX_OP_XOR 4 /* *(int *)UADDR2 ^= OPARG; */
|
|
|
|
#define FUTEX_OP_OPARG_SHIFT 8 /* Use (1 << OPARG) instead of OPARG. */
|
|
|
|
#define FUTEX_OP_CMP_EQ 0 /* if (oldval == CMPARG) wake */
|
|
#define FUTEX_OP_CMP_NE 1 /* if (oldval != CMPARG) wake */
|
|
#define FUTEX_OP_CMP_LT 2 /* if (oldval < CMPARG) wake */
|
|
#define FUTEX_OP_CMP_LE 3 /* if (oldval <= CMPARG) wake */
|
|
#define FUTEX_OP_CMP_GT 4 /* if (oldval > CMPARG) wake */
|
|
#define FUTEX_OP_CMP_GE 5 /* if (oldval >= CMPARG) wake */
|
|
|
|
/* FUTEX_WAKE_OP will perform atomically
|
|
int oldval = *(int *)UADDR2;
|
|
*(int *)UADDR2 = oldval OP OPARG;
|
|
if (oldval CMP CMPARG)
|
|
wake UADDR2; */
|
|
|
|
#define FUTEX_OP(op, oparg, cmp, cmparg) \
|
|
(((op & 0xf) << 28) | ((cmp & 0xf) << 24) \
|
|
| ((oparg & 0xfff) << 12) | (cmparg & 0xfff))
|
|
|
|
#endif
|