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+/*
+ * include/asm-xtensa/uaccess.h
+ *
+ * User space memory access functions
+ *
+ * These routines provide basic accessing functions to the user memory
+ * space for the kernel. This header file provides functions such as:
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2001 - 2005 Tensilica Inc.
+ */
+
+#ifndef _XTENSA_ASM_UACCESS_H
+#define _XTENSA_ASM_UACCESS_H
+
+#include <linux/errno.h>
+#include <asm/types.h>
+
+#include <asm/current.h>
+#include <asm/asm-offsets.h>
+#include <asm/processor.h>
+
+/*
+ * user_ok determines whether the access to user-space memory is allowed.
+ * See the equivalent C-macro version below for clarity.
+ *
+ * On error, user_ok branches to a label indicated by parameter
+ * <error>. This implies that the macro falls through to the next
+ * instruction on success.
+ *
+ * Note that while this macro can be used independently, we designed
+ * in for optimal use in the access_ok macro below (i.e., we fall
+ * through on success).
+ *
+ * On Entry:
+ * <aa> register containing memory address
+ * <as> register containing memory size
+ * <at> temp register
+ * <error> label to branch to on error; implies fall-through
+ * macro on success
+ * On Exit:
+ * <aa> preserved
+ * <as> preserved
+ * <at> destroyed (actually, (TASK_SIZE + 1 - size))
+ */
+ .macro user_ok aa, as, at, error
+ movi \at, __XTENSA_UL_CONST(TASK_SIZE)
+ bgeu \as, \at, \error
+ sub \at, \at, \as
+ bgeu \aa, \at, \error
+ .endm
+
+/*
+ * access_ok determines whether a memory access is allowed. See the
+ * equivalent C-macro version below for clarity.
+ *
+ * On error, access_ok branches to a label indicated by parameter
+ * <error>. This implies that the macro falls through to the next
+ * instruction on success.
+ *
+ * Note that we assume success is the common case, and we optimize the
+ * branch fall-through case on success.
+ *
+ * On Entry:
+ * <aa> register containing memory address
+ * <as> register containing memory size
+ * <at> temp register
+ * <sp>
+ * <error> label to branch to on error; implies fall-through
+ * macro on success
+ * On Exit:
+ * <aa> preserved
+ * <as> preserved
+ * <at> destroyed
+ */
+ .macro access_ok aa, as, at, sp, error
+ user_ok \aa, \as, \at, \error
+.Laccess_ok_\@:
+ .endm
+
+#endif /* _XTENSA_ASM_UACCESS_H */