#ifndef _LINUX_FUTEX_H
#define _LINUX_FUTEX_H
+#include <linux/sched.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_WAIT 0
+#define FUTEX_WAKE 1
+#define FUTEX_FD 2
+#define FUTEX_REQUEUE 3
+#define FUTEX_CMP_REQUEUE 4
+#define FUTEX_WAKE_OP 5
+
+/*
+ * 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
long do_futex(unsigned long uaddr, int op, int val,
unsigned long timeout, unsigned long uaddr2, int val2,
int val3);
+extern int handle_futex_death(u32 __user *uaddr, struct task_struct *curr);
+
+#ifdef CONFIG_FUTEX
+extern void exit_robust_list(struct task_struct *curr);
+#else
+static inline void exit_robust_list(struct task_struct *curr)
+{
+}
+#endif
+
+#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