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[/] [test_project/] [trunk/] [linux_sd_driver/] [include/] [linux/] [futex.h] - Blame information for rev 81

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1 62 marcus.erl 
#ifndef _LINUX_FUTEX_H
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#define _LINUX_FUTEX_H
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#include <linux/sched.h>
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union ktime;
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/* Second argument to futex syscall */
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#define FUTEX_WAIT              0
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#define FUTEX_WAKE              1
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#define FUTEX_FD                2
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#define FUTEX_REQUEUE           3
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#define FUTEX_CMP_REQUEUE       4
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#define FUTEX_WAKE_OP           5
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#define FUTEX_LOCK_PI           6
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#define FUTEX_UNLOCK_PI         7
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#define FUTEX_TRYLOCK_PI        8
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#define FUTEX_PRIVATE_FLAG      128
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#define FUTEX_CMD_MASK          ~FUTEX_PRIVATE_FLAG
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#define FUTEX_WAIT_PRIVATE      (FUTEX_WAIT | FUTEX_PRIVATE_FLAG)
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#define FUTEX_WAKE_PRIVATE      (FUTEX_WAKE | FUTEX_PRIVATE_FLAG)
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#define FUTEX_REQUEUE_PRIVATE   (FUTEX_REQUEUE | FUTEX_PRIVATE_FLAG)
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#define FUTEX_CMP_REQUEUE_PRIVATE (FUTEX_CMP_REQUEUE | FUTEX_PRIVATE_FLAG)
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#define FUTEX_WAKE_OP_PRIVATE   (FUTEX_WAKE_OP | FUTEX_PRIVATE_FLAG)
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#define FUTEX_LOCK_PI_PRIVATE   (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG)
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#define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG)
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#define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG)
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/*
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 * Support for robust futexes: the kernel cleans up held futexes at
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 * thread exit time.
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 */
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/*
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 * Per-lock list entry - embedded in user-space locks, somewhere close
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 * to the futex field. (Note: user-space uses a double-linked list to
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 * achieve O(1) list add and remove, but the kernel only needs to know
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 * about the forward link)
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 *
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 * NOTE: this structure is part of the syscall ABI, and must not be
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 * changed.
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 */
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struct robust_list {
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        struct robust_list __user *next;
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};
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/*
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 * Per-thread list head:
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 *
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 * NOTE: this structure is part of the syscall ABI, and must only be
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 * changed if the change is first communicated with the glibc folks.
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 * (When an incompatible change is done, we'll increase the structure
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 *  size, which glibc will detect)
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 */
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struct robust_list_head {
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        /*
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         * The head of the list. Points back to itself if empty:
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         */
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        struct robust_list list;
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        /*
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         * This relative offset is set by user-space, it gives the kernel
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         * the relative position of the futex field to examine. This way
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         * we keep userspace flexible, to freely shape its data-structure,
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         * without hardcoding any particular offset into the kernel:
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         */
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        long futex_offset;
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        /*
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         * The death of the thread may race with userspace setting
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         * up a lock's links. So to handle this race, userspace first
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         * sets this field to the address of the to-be-taken lock,
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         * then does the lock acquire, and then adds itself to the
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         * list, and then clears this field. Hence the kernel will
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         * always have full knowledge of all locks that the thread
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         * _might_ have taken. We check the owner TID in any case,
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         * so only truly owned locks will be handled.
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         */
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        struct robust_list __user *list_op_pending;
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};
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/*
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 * Are there any waiters for this robust futex:
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 */
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#define FUTEX_WAITERS           0x80000000
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/*
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 * The kernel signals via this bit that a thread holding a futex
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 * has exited without unlocking the futex. The kernel also does
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 * a FUTEX_WAKE on such futexes, after setting the bit, to wake
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 * up any possible waiters:
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 */
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#define FUTEX_OWNER_DIED        0x40000000
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/*
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 * The rest of the robust-futex field is for the TID:
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 */
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#define FUTEX_TID_MASK          0x3fffffff
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/*
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 * This limit protects against a deliberately circular list.
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 * (Not worth introducing an rlimit for it)
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 */
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#define ROBUST_LIST_LIMIT       2048
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#ifdef __KERNEL__
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long do_futex(u32 __user *uaddr, int op, u32 val, union ktime *timeout,
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              u32 __user *uaddr2, u32 val2, u32 val3);
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extern int
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handle_futex_death(u32 __user *uaddr, struct task_struct *curr, int pi);
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/*
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 * Futexes are matched on equal values of this key.
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 * The key type depends on whether it's a shared or private mapping.
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 * Don't rearrange members without looking at hash_futex().
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 *
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 * offset is aligned to a multiple of sizeof(u32) (== 4) by definition.
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 * We use the two low order bits of offset to tell what is the kind of key :
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 *  00 : Private process futex (PTHREAD_PROCESS_PRIVATE)
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 *       (no reference on an inode or mm)
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 *  01 : Shared futex (PTHREAD_PROCESS_SHARED)
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 *      mapped on a file (reference on the underlying inode)
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 *  10 : Shared futex (PTHREAD_PROCESS_SHARED)
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 *       (but private mapping on an mm, and reference taken on it)
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*/
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#define FUT_OFF_INODE    1 /* We set bit 0 if key has a reference on inode */
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#define FUT_OFF_MMSHARED 2 /* We set bit 1 if key has a reference on mm */
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union futex_key {
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        struct {
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                unsigned long pgoff;
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                struct inode *inode;
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                int offset;
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        } shared;
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        struct {
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                unsigned long address;
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                struct mm_struct *mm;
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                int offset;
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        } private;
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        struct {
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                unsigned long word;
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                void *ptr;
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                int offset;
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        } both;
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};
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#ifdef CONFIG_FUTEX
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extern void exit_robust_list(struct task_struct *curr);
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extern void exit_pi_state_list(struct task_struct *curr);
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#else
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static inline void exit_robust_list(struct task_struct *curr)
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{
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}
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static inline void exit_pi_state_list(struct task_struct *curr)
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{
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}
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#endif
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#endif /* __KERNEL__ */
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#define FUTEX_OP_SET            0        /* *(int *)UADDR2 = OPARG; */
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#define FUTEX_OP_ADD            1       /* *(int *)UADDR2 += OPARG; */
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#define FUTEX_OP_OR             2       /* *(int *)UADDR2 |= OPARG; */
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#define FUTEX_OP_ANDN           3       /* *(int *)UADDR2 &= ~OPARG; */
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#define FUTEX_OP_XOR            4       /* *(int *)UADDR2 ^= OPARG; */
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#define FUTEX_OP_OPARG_SHIFT    8       /* Use (1 << OPARG) instead of OPARG.  */
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#define FUTEX_OP_CMP_EQ         0        /* if (oldval == CMPARG) wake */
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#define FUTEX_OP_CMP_NE         1       /* if (oldval != CMPARG) wake */
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#define FUTEX_OP_CMP_LT         2       /* if (oldval < CMPARG) wake */
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#define FUTEX_OP_CMP_LE         3       /* if (oldval <= CMPARG) wake */
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#define FUTEX_OP_CMP_GT         4       /* if (oldval > CMPARG) wake */
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#define FUTEX_OP_CMP_GE         5       /* if (oldval >= CMPARG) wake */
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/* FUTEX_WAKE_OP will perform atomically
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   int oldval = *(int *)UADDR2;
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   *(int *)UADDR2 = oldval OP OPARG;
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   if (oldval CMP CMPARG)
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     wake UADDR2;  */
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#define FUTEX_OP(op, oparg, cmp, cmparg) \
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  (((op & 0xf) << 28) | ((cmp & 0xf) << 24)             \
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   | ((oparg & 0xfff) << 12) | (cmparg & 0xfff))
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#endif

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