[IA64] Implement futex primitives

Implement futex_atomic_op_inuser() and futex_atomic_cmpxchg_inatomic()
on IA64 in order to fully support all futex functionality.

Signed-off-by: Jakub Jelinek <jakub@redhat.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>

include/asm-ia64/futex.h

@@ -1,6 +1,124 @@
 #ifndef _ASM_FUTEX_H
 #define _ASM_FUTEX_H
 
-#include <asm-generic/futex.h>
+#include <linux/futex.h>
+#include <asm/errno.h>
+#include <asm/system.h>
+#include <asm/uaccess.h>
 
-#endif
+#define __futex_atomic_op1(insn, ret, oldval, uaddr, oparg) \
+do {									\
+	register unsigned long r8 __asm ("r8") = 0;			\
+	__asm__ __volatile__(						\
+		"	mf;;					\n"	\
+		"[1:] "	insn ";;				\n"	\
+		"	.xdata4 \"__ex_table\", 1b-., 2f-.	\n"	\
+		"[2:]"							\
+		: "+r" (r8), "=r" (oldval)				\
+		: "r" (uaddr), "r" (oparg)				\
+		: "memory");						\
+	ret = r8;							\
+} while (0)
+
+#define __futex_atomic_op2(insn, ret, oldval, uaddr, oparg) \
+do {									\
+	register unsigned long r8 __asm ("r8") = 0;			\
+	int val, newval;						\
+	do {								\
+		__asm__ __volatile__(					\
+			"	mf;;				  \n"	\
+			"[1:]	ld4 %3=[%4];;			  \n"	\
+			"	mov %2=%3			  \n"	\
+				insn	";;			  \n"	\
+			"	mov ar.ccv=%2;;			  \n"	\
+			"[2:]	cmpxchg4.acq %1=[%4],%3,ar.ccv;;  \n"	\
+			"	.xdata4 \"__ex_table\", 1b-., 3f-.\n"	\
+			"	.xdata4 \"__ex_table\", 2b-., 3f-.\n"	\
+			"[3:]"						\
+			: "+r" (r8), "=r" (val), "=&r" (oldval),	\
+			   "=&r" (newval)				\
+			: "r" (uaddr), "r" (oparg)			\
+			: "memory");					\
+		if (unlikely (r8))					\
+			break;						\
+	} while (unlikely (val != oldval));				\
+	ret = r8;							\
+} while (0)
+
+static inline int
+futex_atomic_op_inuser (int encoded_op, int __user *uaddr)
+{
+	int op = (encoded_op >> 28) & 7;
+	int cmp = (encoded_op >> 24) & 15;
+	int oparg = (encoded_op << 8) >> 20;
+	int cmparg = (encoded_op << 20) >> 20;
+	int oldval = 0, ret;
+	if (encoded_op & (FUTEX_OP_OPARG_SHIFT << 28))
+		oparg = 1 << oparg;
+
+	if (! access_ok (VERIFY_WRITE, uaddr, sizeof(int)))
+		return -EFAULT;
+
+	inc_preempt_count();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op1("xchg4 %1=[%2],%3", ret, oldval, uaddr,
+				   oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op2("add %3=%3,%5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op2("or %3=%3,%5", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op2("and %3=%3,%5", ret, oldval, uaddr,
+				   ~oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op2("xor %3=%3,%5", ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	dec_preempt_count();
+
+	if (!ret) {
+		switch (cmp) {
+		case FUTEX_OP_CMP_EQ: ret = (oldval == cmparg); break;
+		case FUTEX_OP_CMP_NE: ret = (oldval != cmparg); break;
+		case FUTEX_OP_CMP_LT: ret = (oldval < cmparg); break;
+		case FUTEX_OP_CMP_GE: ret = (oldval >= cmparg); break;
+		case FUTEX_OP_CMP_LE: ret = (oldval <= cmparg); break;
+		case FUTEX_OP_CMP_GT: ret = (oldval > cmparg); break;
+		default: ret = -ENOSYS;
+		}
+	}
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(int __user *uaddr, int oldval, int newval)
+{
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(int)))
+		return -EFAULT;
+
+	{
+		register unsigned long r8 __asm ("r8");
+		__asm__ __volatile__(
+			"	mf;;					\n"
+			"	mov ar.ccv=%3;;				\n"
+			"[1:]	cmpxchg4.acq %0=[%1],%2,ar.ccv		\n"
+			"	.xdata4 \"__ex_table\", 1b-., 2f-.	\n"
+			"[2:]"
+			: "=r" (r8)
+			: "r" (uaddr), "r" (newval),
+			  "rO" ((long) (unsigned) oldval)
+			: "memory");
+		return r8;
+	}
+}
+
+#endif /* _ASM_FUTEX_H */