X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=include%2Flinux%2Ffutex.h;h=966a5b3da439b40232c269f44026733db5a76244;hb=43bc926fffd92024b46cafaf7350d669ba9ca884;hp=65d6cfdb6d39c11098008268c6e97df7a3b5b462;hpb=cee37fe97739d85991964371c1f3a745c00dd236;p=linux-2.6.git

diff --git a/include/linux/futex.h b/include/linux/futex.h
index 65d6cfdb6..966a5b3da 100644
--- a/include/linux/futex.h
+++ b/include/linux/futex.h
@@ -1,17 +1,132 @@
 #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