/* * 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 */