1 files changed, 105 insertions, 0 deletions
diff --git a/arch/powerpc/include/asm/futex.h b/arch/powerpc/include/asm/futex.h
new file mode 100644
index 000000000..1eabc20dd
--- /dev/null
+++ b/arch/powerpc/include/asm/futex.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_FUTEX_H
+#define _ASM_POWERPC_FUTEX_H
+
+#ifdef __KERNEL__
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <asm/errno.h>
+#include <asm/synch.h>
+#include <asm/asm-405.h>
+
+#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
+  __asm__ __volatile ( \
+	PPC_ATOMIC_ENTRY_BARRIER \
+"1:	lwarx	%0,0,%2\n" \
+	insn \
+	PPC405_ERR77(0, %2) \
+"2:	stwcx.	%1,0,%2\n" \
+	"bne-	1b\n" \
+	PPC_ATOMIC_EXIT_BARRIER \
+	"li	%1,0\n" \
+"3:	.section .fixup,\"ax\"\n" \
+"4:	li	%1,%3\n" \
+	"b	3b\n" \
+	".previous\n" \
+	EX_TABLE(1b, 4b) \
+	EX_TABLE(2b, 4b) \
+	: "=&r" (oldval), "=&r" (ret) \
+	: "b" (uaddr), "i" (-EFAULT), "r" (oparg) \
+	: "cr0", "memory")
+
+static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
+		u32 __user *uaddr)
+{
+	int oldval = 0, ret;
+
+	allow_write_to_user(uaddr, sizeof(*uaddr));
+	pagefault_disable();
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("mr %1,%4\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("add %1,%0,%4\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("or %1,%0,%4\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("andc %1,%0,%4\n", ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("xor %1,%0,%4\n", ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	pagefault_enable();
+
+	*oval = oldval;
+
+	prevent_write_to_user(uaddr, sizeof(*uaddr));
+	return ret;
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+			      u32 oldval, u32 newval)
+{
+	int ret = 0;
+	u32 prev;
+
+	if (!access_ok(VERIFY_WRITE, uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	allow_write_to_user(uaddr, sizeof(*uaddr));
+        __asm__ __volatile__ (
+        PPC_ATOMIC_ENTRY_BARRIER
+"1:     lwarx   %1,0,%3         # futex_atomic_cmpxchg_inatomic\n\
+        cmpw    0,%1,%4\n\
+        bne-    3f\n"
+        PPC405_ERR77(0,%3)
+"2:     stwcx.  %5,0,%3\n\
+        bne-    1b\n"
+        PPC_ATOMIC_EXIT_BARRIER
+"3:	.section .fixup,\"ax\"\n\
+4:	li	%0,%6\n\
+	b	3b\n\
+	.previous\n"
+	EX_TABLE(1b, 4b)
+	EX_TABLE(2b, 4b)
+        : "+r" (ret), "=&r" (prev), "+m" (*uaddr)
+        : "r" (uaddr), "r" (oldval), "r" (newval), "i" (-EFAULT)
+        : "cc", "memory");
+
+	*uval = prev;
+	prevent_write_to_user(uaddr, sizeof(*uaddr));
+        return ret;
+}
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_FUTEX_H */