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Diffstat (limited to 'arch/xtensa/include/asm/asm-uaccess.h')
| -rw-r--r-- | arch/xtensa/include/asm/asm-uaccess.h | 84 |
1 files changed, 84 insertions, 0 deletions
diff --git a/arch/xtensa/include/asm/asm-uaccess.h b/arch/xtensa/include/asm/asm-uaccess.h new file mode 100644 index 0000000000..7cec869136 --- /dev/null +++ b/arch/xtensa/include/asm/asm-uaccess.h @@ -0,0 +1,84 @@ +/* + * 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 */ |