1 files changed, 163 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/futex.h b/arch/xtensa/include/asm/futex.h
new file mode 100644
index 000000000..a1a27b2ea
--- /dev/null
+++ b/arch/xtensa/include/asm/futex.h
@@ -0,0 +1,163 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Atomic futex routines
+ *
+ * Based on the PowerPC implementataion
+ *
+ * Copyright (C) 2013 TangoTec Ltd.
+ *
+ * Baruch Siach <baruch@tkos.co.il>
+ */
+
+#ifndef _ASM_XTENSA_FUTEX_H
+#define _ASM_XTENSA_FUTEX_H
+
+#include <linux/futex.h>
+#include <linux/uaccess.h>
+#include <linux/errno.h>
+
+#if XCHAL_HAVE_EXCLUSIVE
+#define __futex_atomic_op(insn, ret, old, uaddr, arg)	\
+	__asm__ __volatile(				\
+	"1:	l32ex	%[oldval], %[addr]\n"		\
+		insn "\n"				\
+	"2:	s32ex	%[newval], %[addr]\n"		\
+	"	getex	%[newval]\n"			\
+	"	beqz	%[newval], 1b\n"		\
+	"	movi	%[newval], 0\n"			\
+	"3:\n"						\
+	"	.section .fixup,\"ax\"\n"		\
+	"	.align 4\n"				\
+	"	.literal_position\n"			\
+	"5:	movi	%[oldval], 3b\n"		\
+	"	movi	%[newval], %[fault]\n"		\
+	"	jx	%[oldval]\n"			\
+	"	.previous\n"				\
+	"	.section __ex_table,\"a\"\n"		\
+	"	.long 1b, 5b, 2b, 5b\n"			\
+	"	.previous\n"				\
+	: [oldval] "=&r" (old), [newval] "=&r" (ret)	\
+	: [addr] "r" (uaddr), [oparg] "r" (arg),	\
+	  [fault] "I" (-EFAULT)				\
+	: "memory")
+#elif XCHAL_HAVE_S32C1I
+#define __futex_atomic_op(insn, ret, old, uaddr, arg)	\
+	__asm__ __volatile(				\
+	"1:	l32i	%[oldval], %[mem]\n"		\
+		insn "\n"				\
+	"	wsr	%[oldval], scompare1\n"		\
+	"2:	s32c1i	%[newval], %[mem]\n"		\
+	"	bne	%[newval], %[oldval], 1b\n"	\
+	"	movi	%[newval], 0\n"			\
+	"3:\n"						\
+	"	.section .fixup,\"ax\"\n"		\
+	"	.align 4\n"				\
+	"	.literal_position\n"			\
+	"5:	movi	%[oldval], 3b\n"		\
+	"	movi	%[newval], %[fault]\n"		\
+	"	jx	%[oldval]\n"			\
+	"	.previous\n"				\
+	"	.section __ex_table,\"a\"\n"		\
+	"	.long 1b, 5b, 2b, 5b\n"			\
+	"	.previous\n"				\
+	: [oldval] "=&r" (old), [newval] "=&r" (ret),	\
+	  [mem] "+m" (*(uaddr))				\
+	: [oparg] "r" (arg), [fault] "I" (-EFAULT)	\
+	: "memory")
+#endif
+
+static inline int arch_futex_atomic_op_inuser(int op, int oparg, int *oval,
+		u32 __user *uaddr)
+{
+#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
+	int oldval = 0, ret;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	switch (op) {
+	case FUTEX_OP_SET:
+		__futex_atomic_op("mov %[newval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ADD:
+		__futex_atomic_op("add %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_OR:
+		__futex_atomic_op("or %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	case FUTEX_OP_ANDN:
+		__futex_atomic_op("and %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, ~oparg);
+		break;
+	case FUTEX_OP_XOR:
+		__futex_atomic_op("xor %[newval], %[oldval], %[oparg]",
+				  ret, oldval, uaddr, oparg);
+		break;
+	default:
+		ret = -ENOSYS;
+	}
+
+	if (!ret)
+		*oval = oldval;
+
+	return ret;
+#else
+	return -ENOSYS;
+#endif
+}
+
+static inline int
+futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
+			      u32 oldval, u32 newval)
+{
+#if XCHAL_HAVE_S32C1I || XCHAL_HAVE_EXCLUSIVE
+	unsigned long tmp;
+	int ret = 0;
+
+	if (!access_ok(uaddr, sizeof(u32)))
+		return -EFAULT;
+
+	__asm__ __volatile__ (
+	"	# futex_atomic_cmpxchg_inatomic\n"
+#if XCHAL_HAVE_EXCLUSIVE
+	"1:	l32ex	%[tmp], %[addr]\n"
+	"	s32i	%[tmp], %[uval], 0\n"
+	"	bne	%[tmp], %[oldval], 2f\n"
+	"	mov	%[tmp], %[newval]\n"
+	"3:	s32ex	%[tmp], %[addr]\n"
+	"	getex	%[tmp]\n"
+	"	beqz	%[tmp], 1b\n"
+#elif XCHAL_HAVE_S32C1I
+	"	wsr	%[oldval], scompare1\n"
+	"1:	s32c1i	%[newval], %[addr], 0\n"
+	"	s32i	%[newval], %[uval], 0\n"
+#endif
+	"2:\n"
+	"	.section .fixup,\"ax\"\n"
+	"	.align 4\n"
+	"	.literal_position\n"
+	"4:	movi	%[tmp], 2b\n"
+	"	movi	%[ret], %[fault]\n"
+	"	jx	%[tmp]\n"
+	"	.previous\n"
+	"	.section __ex_table,\"a\"\n"
+	"	.long 1b, 4b\n"
+#if XCHAL_HAVE_EXCLUSIVE
+	"	.long 3b, 4b\n"
+#endif
+	"	.previous\n"
+	: [ret] "+r" (ret), [newval] "+r" (newval), [tmp] "=&r" (tmp)
+	: [addr] "r" (uaddr), [oldval] "r" (oldval), [uval] "r" (uval),
+	  [fault] "I" (-EFAULT)
+	: "memory");
+
+	return ret;
+#else
+	return -ENOSYS;
+#endif
+}
+
+#endif /* _ASM_XTENSA_FUTEX_H */