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- /*
- * 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) 1996, 1997, 1998, 1999, 2000, 03, 04 by Ralf Baechle
- * Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- * Copyright (C) 2007 Maciej W. Rozycki
- */
- #ifndef _ASM_UACCESS_H
- #define _ASM_UACCESS_H
- #include <linux/kernel.h>
- #include <linux/errno.h>
- #include <linux/thread_info.h>
- /*
- * The fs value determines whether argument validity checking should be
- * performed or not. If get_fs() == USER_DS, checking is performed, with
- * get_fs() == KERNEL_DS, checking is bypassed.
- *
- * For historical reasons, these macros are grossly misnamed.
- */
- #ifdef CONFIG_32BIT
- #define __UA_LIMIT 0x80000000UL
- #define __UA_ADDR ".word"
- #define __UA_LA "la"
- #define __UA_ADDU "addu"
- #define __UA_t0 "$8"
- #define __UA_t1 "$9"
- #endif /* CONFIG_32BIT */
- #ifdef CONFIG_64BIT
- extern u64 __ua_limit;
- #define __UA_LIMIT __ua_limit
- #define __UA_ADDR ".dword"
- #define __UA_LA "dla"
- #define __UA_ADDU "daddu"
- #define __UA_t0 "$12"
- #define __UA_t1 "$13"
- #endif /* CONFIG_64BIT */
- /*
- * USER_DS is a bitmask that has the bits set that may not be set in a valid
- * userspace address. Note that we limit 32-bit userspace to 0x7fff8000 but
- * the arithmetic we're doing only works if the limit is a power of two, so
- * we use 0x80000000 here on 32-bit kernels. If a process passes an invalid
- * address in this range it's the process's problem, not ours :-)
- */
- #define KERNEL_DS ((mm_segment_t) { 0UL })
- #define USER_DS ((mm_segment_t) { __UA_LIMIT })
- #define VERIFY_READ 0
- #define VERIFY_WRITE 1
- #define get_ds() (KERNEL_DS)
- #define get_fs() (current_thread_info()->addr_limit)
- #define set_fs(x) (current_thread_info()->addr_limit = (x))
- #define segment_eq(a, b) ((a).seg == (b).seg)
- /*
- * Is a address valid? This does a straighforward calculation rather
- * than tests.
- *
- * Address valid if:
- * - "addr" doesn't have any high-bits set
- * - AND "size" doesn't have any high-bits set
- * - AND "addr+size" doesn't have any high-bits set
- * - OR we are in kernel mode.
- *
- * __ua_size() is a trick to avoid runtime checking of positive constant
- * sizes; for those we already know at compile time that the size is ok.
- */
- #define __ua_size(size) \
- ((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
- /*
- * access_ok: - Checks if a user space pointer is valid
- * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
- * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
- * to write to a block, it is always safe to read from it.
- * @addr: User space pointer to start of block to check
- * @size: Size of block to check
- *
- * Context: User context only. This function may sleep.
- *
- * Checks if a pointer to a block of memory in user space is valid.
- *
- * Returns true (nonzero) if the memory block may be valid, false (zero)
- * if it is definitely invalid.
- *
- * Note that, depending on architecture, this function probably just
- * checks that the pointer is in the user space range - after calling
- * this function, memory access functions may still return -EFAULT.
- */
- #define __access_mask get_fs().seg
- #define __access_ok(addr, size, mask) \
- ({ \
- unsigned long __addr = (unsigned long) (addr); \
- unsigned long __size = size; \
- unsigned long __mask = mask; \
- unsigned long __ok; \
- \
- __chk_user_ptr(addr); \
- __ok = (signed long)(__mask & (__addr | (__addr + __size) | \
- __ua_size(__size))); \
- __ok == 0; \
- })
- #define access_ok(type, addr, size) \
- likely(__access_ok((addr), (size), __access_mask))
- /*
- * put_user: - Write a simple value into user space.
- * @x: Value to copy to user space.
- * @ptr: Destination address, in user space.
- *
- * Context: User context only. This function may sleep.
- *
- * This macro copies a single simple value from kernel space to user
- * space. It supports simple types like char and int, but not larger
- * data types like structures or arrays.
- *
- * @ptr must have pointer-to-simple-variable type, and @x must be assignable
- * to the result of dereferencing @ptr.
- *
- * Returns zero on success, or -EFAULT on error.
- */
- #define put_user(x,ptr) \
- __put_user_check((x), (ptr), sizeof(*(ptr)))
- /*
- * get_user: - Get a simple variable from user space.
- * @x: Variable to store result.
- * @ptr: Source address, in user space.
- *
- * Context: User context only. This function may sleep.
- *
- * This macro copies a single simple variable from user space to kernel
- * space. It supports simple types like char and int, but not larger
- * data types like structures or arrays.
- *
- * @ptr must have pointer-to-simple-variable type, and the result of
- * dereferencing @ptr must be assignable to @x without a cast.
- *
- * Returns zero on success, or -EFAULT on error.
- * On error, the variable @x is set to zero.
- */
- #define get_user(x,ptr) \
- __get_user_check((x), (ptr), sizeof(*(ptr)))
- /*
- * __put_user: - Write a simple value into user space, with less checking.
- * @x: Value to copy to user space.
- * @ptr: Destination address, in user space.
- *
- * Context: User context only. This function may sleep.
- *
- * This macro copies a single simple value from kernel space to user
- * space. It supports simple types like char and int, but not larger
- * data types like structures or arrays.
- *
- * @ptr must have pointer-to-simple-variable type, and @x must be assignable
- * to the result of dereferencing @ptr.
- *
- * Caller must check the pointer with access_ok() before calling this
- * function.
- *
- * Returns zero on success, or -EFAULT on error.
- */
- #define __put_user(x,ptr) \
- __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
- /*
- * __get_user: - Get a simple variable from user space, with less checking.
- * @x: Variable to store result.
- * @ptr: Source address, in user space.
- *
- * Context: User context only. This function may sleep.
- *
- * This macro copies a single simple variable from user space to kernel
- * space. It supports simple types like char and int, but not larger
- * data types like structures or arrays.
- *
- * @ptr must have pointer-to-simple-variable type, and the result of
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