| #ifndef _LINUX_FUTEX_H |
| #define _LINUX_FUTEX_H |
| |
| |
| #include <linux/types.h> |
| |
| struct inode; |
| struct mm_struct; |
| struct task_struct; |
| union ktime; |
| |
| /* 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_BITS | FUTEX_PRIVATE_FLAG) |
| #define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITS | 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 *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 *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 |
| |
| |
| #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 |