| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197 | /* * 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_64BITextern 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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