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xtensa: split uaccess.h into C and asm sides
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Al Viro
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Sep 28, 2016
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,160 @@ | ||
| /* | ||
| * 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. | ||
| */ | ||
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| #ifndef _XTENSA_ASM_UACCESS_H | ||
| #define _XTENSA_ASM_UACCESS_H | ||
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| #include <linux/errno.h> | ||
| #include <asm/types.h> | ||
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| #define VERIFY_READ 0 | ||
| #define VERIFY_WRITE 1 | ||
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| #include <asm/current.h> | ||
| #include <asm/asm-offsets.h> | ||
| #include <asm/processor.h> | ||
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| /* | ||
| * 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. | ||
| */ | ||
|
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| #define KERNEL_DS 0 | ||
| #define USER_DS 1 | ||
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| #define get_ds (KERNEL_DS) | ||
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| /* | ||
| * 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 | ||
|
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| /* | ||
| * 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 | ||
|
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| /* | ||
| * 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) | ||
| */ | ||
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| #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 | ||
|
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| /* | ||
| * 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 | ||
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| /* | ||
| * 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 | ||
|
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| #endif /* _XTENSA_ASM_UACCESS_H */ |
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