[deliverable/linux.git] / arch / arm64 / include / asm / uaccess.h

/*
 * Based on arch/arm/include/asm/uaccess.h
 *
 * Copyright (C) 2012 ARM Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
#ifndef __ASM_UACCESS_H
#define __ASM_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/string.h>
#include <linux/thread_info.h>

#include <asm/alternative.h>
#include <asm/cpufeature.h>
#include <asm/ptrace.h>
#include <asm/sysreg.h>
#include <asm/errno.h>
#include <asm/memory.h>
#include <asm/compiler.h>

#define VERIFY_READ 0
#define VERIFY_WRITE 1

/*
 * The exception table consists of pairs of relative offsets: the first
 * is the relative offset to an instruction that is allowed to fault,
 * and the second is the relative offset at which the program should
 * continue. No registers are modified, so it is entirely up to the
 * continuation code to figure out what to do.
 *
 * All the routines below use bits of fixup code that are out of line
 * with the main instruction path.  This means when everything is well,
 * we don't even have to jump over them.  Further, they do not intrude
 * on our cache or tlb entries.
 */

struct exception_table_entry
{
	int insn, fixup;
};

#define ARCH_HAS_RELATIVE_EXTABLE

extern int fixup_exception(struct pt_regs *regs);

#define KERNEL_DS	(-1UL)
#define get_ds()	(KERNEL_DS)

#define USER_DS		TASK_SIZE_64
#define get_fs()	(current_thread_info()->addr_limit)

static inline void set_fs(mm_segment_t fs)
{
	current_thread_info()->addr_limit = fs;

	/*
	 * Enable/disable UAO so that copy_to_user() etc can access
	 * kernel memory with the unprivileged instructions.
	 */
	if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS)
		asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
	else
		asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO,
				CONFIG_ARM64_UAO));
}

#define segment_eq(a, b)	((a) == (b))

/*
 * Return 1 if addr < current->addr_limit, 0 otherwise.
 */
#define __addr_ok(addr)							\
({									\
	unsigned long flag;						\
	asm("cmp %1, %0; cset %0, lo"					\
		: "=&r" (flag)						\
		: "r" (addr), "0" (current_thread_info()->addr_limit)	\
		: "cc");						\
	flag;								\
})

/*
 * Test whether a block of memory is a valid user space address.
 * Returns 1 if the range is valid, 0 otherwise.
 *
 * This is equivalent to the following test:
 * (u65)addr + (u65)size <= current->addr_limit
 *
 * This needs 65-bit arithmetic.
 */
#define __range_ok(addr, size)						\
({									\
	unsigned long flag, roksum;					\
	__chk_user_ptr(addr);						\
	asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls"		\
		: "=&r" (flag), "=&r" (roksum)				\
		: "1" (addr), "Ir" (size),				\
		  "r" (current_thread_info()->addr_limit)		\
		: "cc");						\
	flag;								\
})

#define access_ok(type, addr, size)	__range_ok(addr, size)
#define user_addr_max			get_fs

#define _ASM_EXTABLE(from, to)						\
	"	.pushsection	__ex_table, \"a\"\n"			\
	"	.align		3\n"					\
	"	.long		(" #from " - .), (" #to " - .)\n"	\
	"	.popsection\n"

/*
 * The "__xxx" versions of the user access functions do not verify the address
 * space - it must have been done previously with a separate "access_ok()"
 * call.
 *
 * The "__xxx_error" versions set the third argument to -EFAULT if an error
 * occurs, and leave it unchanged on success.
 */
#define __get_user_asm(instr, alt_instr, reg, x, addr, err, feature)	\
	asm volatile(							\
	"1:"ALTERNATIVE(instr "     " reg "1, [%2]\n",			\
			alt_instr " " reg "1, [%2]\n", feature)		\
	"2:\n"								\
	"	.section .fixup, \"ax\"\n"				\
	"	.align	2\n"						\
	"3:	mov	%w0, %3\n"					\
	"	mov	%1, #0\n"					\
	"	b	2b\n"						\
	"	.previous\n"						\
	_ASM_EXTABLE(1b, 3b)						\
	: "+r" (err), "=&r" (x)						\
	: "r" (addr), "i" (-EFAULT))

#define __get_user_err(x, ptr, err)					\
do {									\
	unsigned long __gu_val;						\
	__chk_user_ptr(ptr);						\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
			CONFIG_ARM64_PAN));				\
	switch (sizeof(*(ptr))) {					\
	case 1:								\
		__get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr),  \
			       (err), ARM64_HAS_UAO);			\
		break;							\
	case 2:								\
		__get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr),  \
			       (err), ARM64_HAS_UAO);			\
		break;							\
	case 4:								\
		__get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr),	\
			       (err), ARM64_HAS_UAO);			\
		break;							\
	case 8:								\
		__get_user_asm("ldr", "ldtr", "%",  __gu_val, (ptr),	\
			       (err), ARM64_HAS_UAO);			\
		break;							\
	default:							\
		BUILD_BUG();						\
	}								\
	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
			CONFIG_ARM64_PAN));				\
} while (0)

#define __get_user(x, ptr)						\
({									\
	int __gu_err = 0;						\
	__get_user_err((x), (ptr), __gu_err);				\
	__gu_err;							\
})

#define __get_user_error(x, ptr, err)					\
({									\
	__get_user_err((x), (ptr), (err));				\
	(void)0;							\
})

#define __get_user_unaligned __get_user

#define get_user(x, ptr)						\
({									\
	__typeof__(*(ptr)) __user *__p = (ptr);				\
	might_fault();							\
	access_ok(VERIFY_READ, __p, sizeof(*__p)) ?			\
		__get_user((x), __p) :					\
		((x) = 0, -EFAULT);					\
})

#define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature)	\
	asm volatile(							\
	"1:"ALTERNATIVE(instr "     " reg "1, [%2]\n",			\
			alt_instr " " reg "1, [%2]\n", feature)		\
	"2:\n"								\
	"	.section .fixup,\"ax\"\n"				\
	"	.align	2\n"						\
	"3:	mov	%w0, %3\n"					\
	"	b	2b\n"						\
	"	.previous\n"						\
	_ASM_EXTABLE(1b, 3b)						\
	: "+r" (err)							\
	: "r" (x), "r" (addr), "i" (-EFAULT))

#define __put_user_err(x, ptr, err)					\
do {									\
	__typeof__(*(ptr)) __pu_val = (x);				\
	__chk_user_ptr(ptr);						\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
			CONFIG_ARM64_PAN));				\
	switch (sizeof(*(ptr))) {					\
	case 1:								\
		__put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr),	\
			       (err), ARM64_HAS_UAO);			\
		break;							\
	case 2:								\
		__put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr),	\
			       (err), ARM64_HAS_UAO);			\
		break;							\
	case 4:								\
		__put_user_asm("str", "sttr", "%w", __pu_val, (ptr),	\
			       (err), ARM64_HAS_UAO);			\
		break;							\
	case 8:								\
		__put_user_asm("str", "sttr", "%", __pu_val, (ptr),	\
			       (err), ARM64_HAS_UAO);			\
		break;							\
	default:							\
		BUILD_BUG();						\
	}								\
	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
			CONFIG_ARM64_PAN));				\
} while (0)

#define __put_user(x, ptr)						\
({									\
	int __pu_err = 0;						\
	__put_user_err((x), (ptr), __pu_err);				\
	__pu_err;							\
})

#define __put_user_error(x, ptr, err)					\
({									\
	__put_user_err((x), (ptr), (err));				\
	(void)0;							\
})

#define __put_user_unaligned __put_user

#define put_user(x, ptr)						\
({									\
	__typeof__(*(ptr)) __user *__p = (ptr);				\
	might_fault();							\
	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ?			\
		__put_user((x), __p) :					\
		-EFAULT;						\
})

extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);

static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n))
		n = __copy_from_user(to, from, n);
	else /* security hole - plug it */
		memset(to, 0, n);
	return n;
}

static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
{
	if (access_ok(VERIFY_WRITE, to, n))
		n = __copy_to_user(to, from, n);
	return n;
}

static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
		n = __copy_in_user(to, from, n);
	return n;
}

#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user

static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
{
	if (access_ok(VERIFY_WRITE, to, n))
		n = __clear_user(to, n);
	return n;
}

extern long strncpy_from_user(char *dest, const char __user *src, long count);

extern __must_check long strlen_user(const char __user *str);
extern __must_check long strnlen_user(const char __user *str, long n);

#endif /* __ASM_UACCESS_H */
Commit	Line	Data
0aea86a2 CM	1	/*
	2	* Based on arch/arm/include/asm/uaccess.h
	3	*
	4	* Copyright (C) 2012 ARM Ltd.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	13	* GNU General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU General Public License
	16	* along with this program. If not, see <http://www.gnu.org/licenses/>.
	17	*/
	18	#ifndef __ASM_UACCESS_H
	19	#define __ASM_UACCESS_H
	20
	21	/*
	22	* User space memory access functions
	23	*/
	24	#include <linux/string.h>
	25	#include <linux/thread_info.h>
	26
338d4f49 JM	27	#include <asm/alternative.h>
338d4f49 JM	28	#include <asm/cpufeature.h>
0aea86a2	29	#include <asm/ptrace.h>
338d4f49	30	#include <asm/sysreg.h>
0aea86a2 CM	31	#include <asm/errno.h>
	32	#include <asm/memory.h>
	33	#include <asm/compiler.h>
	34
	35	#define VERIFY_READ 0
	36	#define VERIFY_WRITE 1
	37
	38	/*
6c94f27a AB	39	* The exception table consists of pairs of relative offsets: the first
	40	* is the relative offset to an instruction that is allowed to fault,
	41	* and the second is the relative offset at which the program should
	42	* continue. No registers are modified, so it is entirely up to the
	43	* continuation code to figure out what to do.
0aea86a2 CM	44	*
	45	* All the routines below use bits of fixup code that are out of line
	46	* with the main instruction path. This means when everything is well,
	47	* we don't even have to jump over them. Further, they do not intrude
	48	* on our cache or tlb entries.
	49	*/
	50
	51	struct exception_table_entry
	52	{
6c94f27a	53	int insn, fixup;
0aea86a2 CM	54	};
0aea86a2 CM	55
6c94f27a AB	56	#define ARCH_HAS_RELATIVE_EXTABLE
6c94f27a AB	57
0aea86a2 CM	58	extern int fixup_exception(struct pt_regs *regs);
	59
	60	#define KERNEL_DS (-1UL)
	61	#define get_ds() (KERNEL_DS)
	62
	63	#define USER_DS TASK_SIZE_64
	64	#define get_fs() (current_thread_info()->addr_limit)
	65
	66	static inline void set_fs(mm_segment_t fs)
	67	{
	68	current_thread_info()->addr_limit = fs;
57f4959b JM	69
	70	/*
	71	* Enable/disable UAO so that copy_to_user() etc can access
	72	* kernel memory with the unprivileged instructions.
	73	*/
	74	if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS)
	75	asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
	76	else
	77	asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO,
	78	CONFIG_ARM64_UAO));
0aea86a2 CM	79	}
0aea86a2 CM	80
967f0e5d	81	#define segment_eq(a, b) ((a) == (b))
0aea86a2 CM	82
	83	/*
	84	* Return 1 if addr < current->addr_limit, 0 otherwise.
	85	*/
	86	#define __addr_ok(addr) \
	87	({ \
	88	unsigned long flag; \
	89	asm("cmp %1, %0; cset %0, lo" \
	90	: "=&r" (flag) \
	91	: "r" (addr), "0" (current_thread_info()->addr_limit) \
	92	: "cc"); \
	93	flag; \
	94	})
	95
	96	/*
	97	* Test whether a block of memory is a valid user space address.
	98	* Returns 1 if the range is valid, 0 otherwise.
	99	*
	100	* This is equivalent to the following test:
31b1e940	101	* (u65)addr + (u65)size <= current->addr_limit
0aea86a2 CM	102	*
	103	* This needs 65-bit arithmetic.
	104	*/
	105	#define __range_ok(addr, size) \
	106	({ \
	107	unsigned long flag, roksum; \
	108	__chk_user_ptr(addr); \
31b1e940	109	asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls" \
0aea86a2 CM	110	: "=&r" (flag), "=&r" (roksum) \
	111	: "1" (addr), "Ir" (size), \
	112	"r" (current_thread_info()->addr_limit) \
	113	: "cc"); \
	114	flag; \
	115	})
	116
	117	#define access_ok(type, addr, size) __range_ok(addr, size)
12a0ef7b	118	#define user_addr_max get_fs
0aea86a2	119
6c94f27a AB	120	#define _ASM_EXTABLE(from, to) \
	121	" .pushsection __ex_table, \"a\"\n" \
	122	" .align 3\n" \
	123	" .long (" #from " - .), (" #to " - .)\n" \
	124	" .popsection\n"
	125
0aea86a2 CM	126	/*
	127	* The "__xxx" versions of the user access functions do not verify the address
	128	* space - it must have been done previously with a separate "access_ok()"
	129	* call.
	130	*
	131	* The "__xxx_error" versions set the third argument to -EFAULT if an error
	132	* occurs, and leave it unchanged on success.
	133	*/
57f4959b	134	#define __get_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
0aea86a2	135	asm volatile( \
57f4959b JM	136	"1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
57f4959b JM	137	alt_instr " " reg "1, [%2]\n", feature) \
0aea86a2 CM	138	"2:\n" \
	139	" .section .fixup, \"ax\"\n" \
	140	" .align 2\n" \
	141	"3: mov %w0, %3\n" \
	142	" mov %1, #0\n" \
	143	" b 2b\n" \
	144	" .previous\n" \
6c94f27a	145	_ASM_EXTABLE(1b, 3b) \
0aea86a2 CM	146	: "+r" (err), "=&r" (x) \
	147	: "r" (addr), "i" (-EFAULT))
	148
	149	#define __get_user_err(x, ptr, err) \
	150	do { \
	151	unsigned long __gu_val; \
	152	__chk_user_ptr(ptr); \
70544196	153	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	154	CONFIG_ARM64_PAN)); \
0aea86a2 CM	155	switch (sizeof(*(ptr))) { \
0aea86a2 CM	156	case 1: \
57f4959b JM	157	__get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \
57f4959b JM	158	(err), ARM64_HAS_UAO); \
0aea86a2 CM	159	break; \
0aea86a2 CM	160	case 2: \
57f4959b JM	161	__get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \
57f4959b JM	162	(err), ARM64_HAS_UAO); \
0aea86a2 CM	163	break; \
0aea86a2 CM	164	case 4: \
57f4959b JM	165	__get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \
57f4959b JM	166	(err), ARM64_HAS_UAO); \
0aea86a2 CM	167	break; \
0aea86a2 CM	168	case 8: \
57f4959b JM	169	__get_user_asm("ldr", "ldtr", "%", __gu_val, (ptr), \
57f4959b JM	170	(err), ARM64_HAS_UAO); \
0aea86a2 CM	171	break; \
	172	default: \
	173	BUILD_BUG(); \
	174	} \
58fff517	175	(x) = (__force __typeof__(*(ptr)))__gu_val; \
70544196	176	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	177	CONFIG_ARM64_PAN)); \
0aea86a2 CM	178	} while (0)
	179
	180	#define __get_user(x, ptr) \
	181	({ \
	182	int __gu_err = 0; \
	183	__get_user_err((x), (ptr), __gu_err); \
	184	__gu_err; \
	185	})
	186
	187	#define __get_user_error(x, ptr, err) \
	188	({ \
	189	__get_user_err((x), (ptr), (err)); \
	190	(void)0; \
	191	})
	192
	193	#define __get_user_unaligned __get_user
	194
	195	#define get_user(x, ptr) \
	196	({ \
1f65c13e	197	__typeof__((ptr)) __user __p = (ptr); \
56d2ef78	198	might_fault(); \
1f65c13e AT	199	access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
1f65c13e AT	200	__get_user((x), __p) : \
0aea86a2 CM	201	((x) = 0, -EFAULT); \
	202	})
	203
57f4959b	204	#define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
0aea86a2	205	asm volatile( \
57f4959b JM	206	"1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
57f4959b JM	207	alt_instr " " reg "1, [%2]\n", feature) \
0aea86a2 CM	208	"2:\n" \
	209	" .section .fixup,\"ax\"\n" \
	210	" .align 2\n" \
	211	"3: mov %w0, %3\n" \
	212	" b 2b\n" \
	213	" .previous\n" \
6c94f27a	214	_ASM_EXTABLE(1b, 3b) \
0aea86a2 CM	215	: "+r" (err) \
	216	: "r" (x), "r" (addr), "i" (-EFAULT))
	217
	218	#define __put_user_err(x, ptr, err) \
	219	do { \
	220	__typeof__(*(ptr)) __pu_val = (x); \
	221	__chk_user_ptr(ptr); \
70544196	222	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	223	CONFIG_ARM64_PAN)); \
0aea86a2 CM	224	switch (sizeof(*(ptr))) { \
0aea86a2 CM	225	case 1: \
57f4959b JM	226	__put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \
57f4959b JM	227	(err), ARM64_HAS_UAO); \
0aea86a2 CM	228	break; \
0aea86a2 CM	229	case 2: \
57f4959b JM	230	__put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \
57f4959b JM	231	(err), ARM64_HAS_UAO); \
0aea86a2 CM	232	break; \
0aea86a2 CM	233	case 4: \
57f4959b JM	234	__put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \
57f4959b JM	235	(err), ARM64_HAS_UAO); \
0aea86a2 CM	236	break; \
0aea86a2 CM	237	case 8: \
57f4959b JM	238	__put_user_asm("str", "sttr", "%", __pu_val, (ptr), \
57f4959b JM	239	(err), ARM64_HAS_UAO); \
0aea86a2 CM	240	break; \
	241	default: \
	242	BUILD_BUG(); \
	243	} \
70544196	244	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	245	CONFIG_ARM64_PAN)); \
0aea86a2 CM	246	} while (0)
	247
	248	#define __put_user(x, ptr) \
	249	({ \
	250	int __pu_err = 0; \
	251	__put_user_err((x), (ptr), __pu_err); \
	252	__pu_err; \
	253	})
	254
	255	#define __put_user_error(x, ptr, err) \
	256	({ \
	257	__put_user_err((x), (ptr), (err)); \
	258	(void)0; \
	259	})
	260
	261	#define __put_user_unaligned __put_user
	262
	263	#define put_user(x, ptr) \
	264	({ \
1f65c13e	265	__typeof__((ptr)) __user __p = (ptr); \
56d2ef78	266	might_fault(); \
1f65c13e AT	267	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \
1f65c13e AT	268	__put_user((x), __p) : \
0aea86a2 CM	269	-EFAULT; \
	270	})
	271
	272	extern unsigned long __must_check __copy_from_user(void to, const void __user from, unsigned long n);
	273	extern unsigned long __must_check __copy_to_user(void __user to, const void from, unsigned long n);
	274	extern unsigned long __must_check __copy_in_user(void __user to, const void __user from, unsigned long n);
	275	extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
	276
0aea86a2 CM	277	static inline unsigned long __must_check copy_from_user(void to, const void __user from, unsigned long n)
	278	{
	279	if (access_ok(VERIFY_READ, from, n))
	280	n = __copy_from_user(to, from, n);
	281	else /* security hole - plug it */
	282	memset(to, 0, n);
	283	return n;
	284	}
	285
	286	static inline unsigned long __must_check copy_to_user(void __user to, const void from, unsigned long n)
	287	{
	288	if (access_ok(VERIFY_WRITE, to, n))
	289	n = __copy_to_user(to, from, n);
	290	return n;
	291	}
	292
	293	static inline unsigned long __must_check copy_in_user(void __user to, const void __user from, unsigned long n)
	294	{
	295	if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
	296	n = __copy_in_user(to, from, n);
	297	return n;
	298	}
	299
	300	#define __copy_to_user_inatomic __copy_to_user
	301	#define __copy_from_user_inatomic __copy_from_user
	302
	303	static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
	304	{
	305	if (access_ok(VERIFY_WRITE, to, n))
	306	n = __clear_user(to, n);
	307	return n;
	308	}
	309
12a0ef7b	310	extern long strncpy_from_user(char dest, const char __user src, long count);
0aea86a2	311
12a0ef7b WD	312	extern __must_check long strlen_user(const char __user *str);
12a0ef7b WD	313	extern __must_check long strnlen_user(const char __user *str, long n);
0aea86a2 CM	314
0aea86a2 CM	315	#endif /* __ASM_UACCESS_H */