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Diffstat (limited to 'arch/xtensa/include/asm/asm-uaccess.h')
| -rw-r--r-- | arch/xtensa/include/asm/asm-uaccess.h | 155 |
1 files changed, 155 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 000000000..7f6cf4151 --- /dev/null +++ b/arch/xtensa/include/asm/asm-uaccess.h @@ -0,0 +1,155 @@ +/* + * 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> + +/* + * These assembly macros mirror the C macros in asm/uaccess.h. They + * should always have identical functionality. See + * arch/xtensa/kernel/sys.S for usage. + */ + +#define KERNEL_DS 0 +#define USER_DS 1 + +/* + * get_fs reads current->thread.current_ds into a register. + * On Entry: + * <ad> anything + * <sp> stack + * On Exit: + * <ad> contains current->thread.current_ds + */ + .macro get_fs ad, sp + GET_CURRENT(\ad,\sp) +#if THREAD_CURRENT_DS > 1020 + addi \ad, \ad, TASK_THREAD + l32i \ad, \ad, THREAD_CURRENT_DS - TASK_THREAD +#else + l32i \ad, \ad, THREAD_CURRENT_DS +#endif + .endm + +/* + * set_fs sets current->thread.current_ds to some value. + * On Entry: + * <at> anything (temp register) + * <av> value to write + * <sp> stack + * On Exit: + * <at> destroyed (actually, current) + * <av> preserved, value to write + */ + .macro set_fs at, av, sp + GET_CURRENT(\at,\sp) + s32i \av, \at, THREAD_CURRENT_DS + .endm + +/* + * kernel_ok determines whether we should bypass addr/size checking. + * See the equivalent C-macro version below for clarity. + * On success, kernel_ok branches to a label indicated by parameter + * <success>. This implies that the macro falls through to the next + * insruction on an error. + * + * 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 error). + * + * On Entry: + * <at> anything (temp register) + * <success> label to branch to on success; implies + * fall-through macro on error + * <sp> stack pointer + * On Exit: + * <at> destroyed (actually, current->thread.current_ds) + */ + +#if ((KERNEL_DS != 0) || (USER_DS == 0)) +# error Assembly macro kernel_ok fails +#endif + .macro kernel_ok at, sp, success + get_fs \at, \sp + beqz \at, \success + .endm + +/* + * 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 + kernel_ok \at, \sp, .Laccess_ok_\@ + user_ok \aa, \as, \at, \error +.Laccess_ok_\@: + .endm + +#endif /* _XTENSA_ASM_UACCESS_H */ |