From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 arch/parisc/include/asm/futex.h | 154 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 154 insertions(+)
 create mode 100644 arch/parisc/include/asm/futex.h

(limited to 'arch/parisc/include/asm/futex.h')

diff --git a/arch/parisc/include/asm/futex.h b/arch/parisc/include/asm/futex.h
new file mode 100644
index 000000000..49df14805
--- /dev/null
+++ b/arch/parisc/include/asm/futex.h
@@ -0,0 +1,154 @@
+#ifndef _ASM_PARISC_FUTEX_H
+#define _ASM_PARISC_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/atomic.h>
+#include <asm/errno.h>
+
+/* The following has to match the LWS code in syscall.S.  We have
+   sixteen four-word locks. */
+
+static inline void
+_futex_spin_lock_irqsave(u32 __user *uaddr, unsigned long int *flags)
+{
+	extern u32 lws_lock_start[];
+	long index = ((long)uaddr & 0xf0) >> 2;
+	arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
+	local_irq_save(*flags);
+	arch_spin_lock(s);
+}
+
+static inline void
+_futex_spin_unlock_irqrestore(u32 __user *uaddr, unsigned long int *flags)
+{
+	extern u32 lws_lock_start[];
+	long index = ((long)uaddr & 0xf0) >> 2;
+	arch_spinlock_t *s = (arch_spinlock_t *)&lws_lock_start[index];
+	arch_spin_unlock(s);
+	local_irq_restore(*flags);
+}
+
+static inline int
+futex_atomic_op_inuser (int encoded_op, u32 __user *uaddr)
+{
+	unsigned long int flags;
+	u32 val;
+	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(*uaddr)))
+		return -EFAULT;
+
+	pagefault_disable();
+
+	_futex_spin_lock_irqsave(uaddr, &flags);
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		/* *(int *)UADDR2 = OPARG; */
+		ret = get_user(oldval, uaddr);
+		if (!ret)
+			ret = put_user(oparg, uaddr);
+		break;
+	case FUTEX_OP_ADD:
+		/* *(int *)UADDR2 += OPARG; */
+		ret = get_user(oldval, uaddr);
+		if (!ret) {
+			val = oldval + oparg;
+			ret = put_user(val, uaddr);
+		}
+		break;
+	case FUTEX_OP_OR:
+		/* *(int *)UADDR2 |= OPARG; */
+		ret = get_user(oldval, uaddr);
+		if (!ret) {
+			val = oldval | oparg;
+			ret = put_user(val, uaddr);
+		}
+		break;
+	case FUTEX_OP_ANDN:
+		/* *(int *)UADDR2 &= ~OPARG; */
+		ret = get_user(oldval, uaddr);
+		if (!ret) {
+			val = oldval & ~oparg;
+			ret = put_user(val, uaddr);
+		}
+		break;
+	case FUTEX_OP_XOR:
+		/* *(int *)UADDR2 ^= OPARG; */
+		ret = get_user(oldval, uaddr);
+		if (!ret) {
+			val = oldval ^ oparg;
+			ret = put_user(val, uaddr);
+		}
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	_futex_spin_unlock_irqrestore(uaddr, &flags);
+
+	pagefault_enable();
+
+	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;
+}
+
+/* Non-atomic version */
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+			      u32 oldval, u32 newval)
+{
+	int ret;
+	u32 val;
+	unsigned long flags;
+
+	/* futex.c wants to do a cmpxchg_inatomic on kernel NULL, which is
+	 * our gateway page, and causes no end of trouble...
+	 */
+	if (segment_eq(KERNEL_DS, get_fs()) && !uaddr)
+		return -EFAULT;
+
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	/* HPPA has no cmpxchg in hardware and therefore the
+	 * best we can do here is use an array of locks. The
+	 * lock selected is based on a hash of the userspace
+	 * address. This should scale to a couple of CPUs.
+	 */
+
+	_futex_spin_lock_irqsave(uaddr, &flags);
+
+	ret = get_user(val, uaddr);
+
+	if (!ret && val == oldval)
+		ret = put_user(newval, uaddr);
+
+	*uval = val;
+
+	_futex_spin_unlock_irqrestore(uaddr, &flags);
+
+	return ret;
+}
+
+#endif /*__KERNEL__*/
+#endif /*_ASM_PARISC_FUTEX_H*/
-- 
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