[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/kasan-checks.h>
#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))

/*
 * 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 __arch_copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __arch_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)
{
	kasan_check_write(to, n);
	return  __arch_copy_from_user(to, from, n);
}

static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n)
{
	kasan_check_read(from, n);
	return  __arch_copy_to_user(to, from, n);
}

static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
	kasan_check_write(to, n);

	if (access_ok(VERIFY_READ, from, n))
		n = __arch_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)
{
	kasan_check_read(from, n);

	if (access_ok(VERIFY_WRITE, to, n))
		n = __arch_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	*/
bffe1baf	24	#include <linux/kasan-checks.h>
0aea86a2 CM	25	#include <linux/string.h>
	26	#include <linux/thread_info.h>
	27
338d4f49 JM	28	#include <asm/alternative.h>
338d4f49 JM	29	#include <asm/cpufeature.h>
0aea86a2	30	#include <asm/ptrace.h>
338d4f49	31	#include <asm/sysreg.h>
0aea86a2 CM	32	#include <asm/errno.h>
	33	#include <asm/memory.h>
	34	#include <asm/compiler.h>
	35
	36	#define VERIFY_READ 0
	37	#define VERIFY_WRITE 1
	38
	39	/*
6c94f27a AB	40	* The exception table consists of pairs of relative offsets: the first
	41	* is the relative offset to an instruction that is allowed to fault,
	42	* and the second is the relative offset at which the program should
	43	* continue. No registers are modified, so it is entirely up to the
	44	* continuation code to figure out what to do.
0aea86a2 CM	45	*
	46	* All the routines below use bits of fixup code that are out of line
	47	* with the main instruction path. This means when everything is well,
	48	* we don't even have to jump over them. Further, they do not intrude
	49	* on our cache or tlb entries.
	50	*/
	51
	52	struct exception_table_entry
	53	{
6c94f27a	54	int insn, fixup;
0aea86a2 CM	55	};
0aea86a2 CM	56
6c94f27a AB	57	#define ARCH_HAS_RELATIVE_EXTABLE
6c94f27a AB	58
0aea86a2 CM	59	extern int fixup_exception(struct pt_regs *regs);
	60
	61	#define KERNEL_DS (-1UL)
	62	#define get_ds() (KERNEL_DS)
	63
	64	#define USER_DS TASK_SIZE_64
	65	#define get_fs() (current_thread_info()->addr_limit)
	66
	67	static inline void set_fs(mm_segment_t fs)
	68	{
	69	current_thread_info()->addr_limit = fs;
57f4959b JM	70
	71	/*
	72	* Enable/disable UAO so that copy_to_user() etc can access
	73	* kernel memory with the unprivileged instructions.
	74	*/
	75	if (IS_ENABLED(CONFIG_ARM64_UAO) && fs == KERNEL_DS)
	76	asm(ALTERNATIVE("nop", SET_PSTATE_UAO(1), ARM64_HAS_UAO));
	77	else
	78	asm(ALTERNATIVE("nop", SET_PSTATE_UAO(0), ARM64_HAS_UAO,
	79	CONFIG_ARM64_UAO));
0aea86a2 CM	80	}
0aea86a2 CM	81
967f0e5d	82	#define segment_eq(a, b) ((a) == (b))
0aea86a2	83
0aea86a2 CM	84	/*
	85	* Test whether a block of memory is a valid user space address.
	86	* Returns 1 if the range is valid, 0 otherwise.
	87	*
	88	* This is equivalent to the following test:
31b1e940	89	* (u65)addr + (u65)size <= current->addr_limit
0aea86a2 CM	90	*
	91	* This needs 65-bit arithmetic.
	92	*/
	93	#define __range_ok(addr, size) \
	94	({ \
	95	unsigned long flag, roksum; \
	96	__chk_user_ptr(addr); \
31b1e940	97	asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls" \
0aea86a2 CM	98	: "=&r" (flag), "=&r" (roksum) \
	99	: "1" (addr), "Ir" (size), \
	100	"r" (current_thread_info()->addr_limit) \
	101	: "cc"); \
	102	flag; \
	103	})
	104
	105	#define access_ok(type, addr, size) __range_ok(addr, size)
12a0ef7b	106	#define user_addr_max get_fs
0aea86a2	107
6c94f27a AB	108	#define _ASM_EXTABLE(from, to) \
	109	" .pushsection __ex_table, \"a\"\n" \
	110	" .align 3\n" \
	111	" .long (" #from " - .), (" #to " - .)\n" \
	112	" .popsection\n"
	113
0aea86a2 CM	114	/*
	115	* The "__xxx" versions of the user access functions do not verify the address
	116	* space - it must have been done previously with a separate "access_ok()"
	117	* call.
	118	*
	119	* The "__xxx_error" versions set the third argument to -EFAULT if an error
	120	* occurs, and leave it unchanged on success.
	121	*/
57f4959b	122	#define __get_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
0aea86a2	123	asm volatile( \
57f4959b JM	124	"1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
57f4959b JM	125	alt_instr " " reg "1, [%2]\n", feature) \
0aea86a2 CM	126	"2:\n" \
	127	" .section .fixup, \"ax\"\n" \
	128	" .align 2\n" \
	129	"3: mov %w0, %3\n" \
	130	" mov %1, #0\n" \
	131	" b 2b\n" \
	132	" .previous\n" \
6c94f27a	133	_ASM_EXTABLE(1b, 3b) \
0aea86a2 CM	134	: "+r" (err), "=&r" (x) \
	135	: "r" (addr), "i" (-EFAULT))
	136
	137	#define __get_user_err(x, ptr, err) \
	138	do { \
	139	unsigned long __gu_val; \
	140	__chk_user_ptr(ptr); \
70544196	141	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	142	CONFIG_ARM64_PAN)); \
0aea86a2 CM	143	switch (sizeof(*(ptr))) { \
0aea86a2 CM	144	case 1: \
57f4959b JM	145	__get_user_asm("ldrb", "ldtrb", "%w", __gu_val, (ptr), \
57f4959b JM	146	(err), ARM64_HAS_UAO); \
0aea86a2 CM	147	break; \
0aea86a2 CM	148	case 2: \
57f4959b JM	149	__get_user_asm("ldrh", "ldtrh", "%w", __gu_val, (ptr), \
57f4959b JM	150	(err), ARM64_HAS_UAO); \
0aea86a2 CM	151	break; \
0aea86a2 CM	152	case 4: \
57f4959b JM	153	__get_user_asm("ldr", "ldtr", "%w", __gu_val, (ptr), \
57f4959b JM	154	(err), ARM64_HAS_UAO); \
0aea86a2 CM	155	break; \
0aea86a2 CM	156	case 8: \
57f4959b JM	157	__get_user_asm("ldr", "ldtr", "%", __gu_val, (ptr), \
57f4959b JM	158	(err), ARM64_HAS_UAO); \
0aea86a2 CM	159	break; \
	160	default: \
	161	BUILD_BUG(); \
	162	} \
58fff517	163	(x) = (__force __typeof__(*(ptr)))__gu_val; \
70544196	164	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	165	CONFIG_ARM64_PAN)); \
0aea86a2 CM	166	} while (0)
	167
	168	#define __get_user(x, ptr) \
	169	({ \
	170	int __gu_err = 0; \
	171	__get_user_err((x), (ptr), __gu_err); \
	172	__gu_err; \
	173	})
	174
	175	#define __get_user_error(x, ptr, err) \
	176	({ \
	177	__get_user_err((x), (ptr), (err)); \
	178	(void)0; \
	179	})
	180
	181	#define __get_user_unaligned __get_user
	182
	183	#define get_user(x, ptr) \
	184	({ \
1f65c13e	185	__typeof__((ptr)) __user __p = (ptr); \
56d2ef78	186	might_fault(); \
1f65c13e AT	187	access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
1f65c13e AT	188	__get_user((x), __p) : \
0aea86a2 CM	189	((x) = 0, -EFAULT); \
	190	})
	191
57f4959b	192	#define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature) \
0aea86a2	193	asm volatile( \
57f4959b JM	194	"1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \
57f4959b JM	195	alt_instr " " reg "1, [%2]\n", feature) \
0aea86a2 CM	196	"2:\n" \
	197	" .section .fixup,\"ax\"\n" \
	198	" .align 2\n" \
	199	"3: mov %w0, %3\n" \
	200	" b 2b\n" \
	201	" .previous\n" \
6c94f27a	202	_ASM_EXTABLE(1b, 3b) \
0aea86a2 CM	203	: "+r" (err) \
	204	: "r" (x), "r" (addr), "i" (-EFAULT))
	205
	206	#define __put_user_err(x, ptr, err) \
	207	do { \
	208	__typeof__(*(ptr)) __pu_val = (x); \
	209	__chk_user_ptr(ptr); \
70544196	210	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	211	CONFIG_ARM64_PAN)); \
0aea86a2 CM	212	switch (sizeof(*(ptr))) { \
0aea86a2 CM	213	case 1: \
57f4959b JM	214	__put_user_asm("strb", "sttrb", "%w", __pu_val, (ptr), \
57f4959b JM	215	(err), ARM64_HAS_UAO); \
0aea86a2 CM	216	break; \
0aea86a2 CM	217	case 2: \
57f4959b JM	218	__put_user_asm("strh", "sttrh", "%w", __pu_val, (ptr), \
57f4959b JM	219	(err), ARM64_HAS_UAO); \
0aea86a2 CM	220	break; \
0aea86a2 CM	221	case 4: \
57f4959b JM	222	__put_user_asm("str", "sttr", "%w", __pu_val, (ptr), \
57f4959b JM	223	(err), ARM64_HAS_UAO); \
0aea86a2 CM	224	break; \
0aea86a2 CM	225	case 8: \
57f4959b JM	226	__put_user_asm("str", "sttr", "%", __pu_val, (ptr), \
57f4959b JM	227	(err), ARM64_HAS_UAO); \
0aea86a2 CM	228	break; \
	229	default: \
	230	BUILD_BUG(); \
	231	} \
70544196	232	asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_ALT_PAN_NOT_UAO,\
338d4f49	233	CONFIG_ARM64_PAN)); \
0aea86a2 CM	234	} while (0)
	235
	236	#define __put_user(x, ptr) \
	237	({ \
	238	int __pu_err = 0; \
	239	__put_user_err((x), (ptr), __pu_err); \
	240	__pu_err; \
	241	})
	242
	243	#define __put_user_error(x, ptr, err) \
	244	({ \
	245	__put_user_err((x), (ptr), (err)); \
	246	(void)0; \
	247	})
	248
	249	#define __put_user_unaligned __put_user
	250
	251	#define put_user(x, ptr) \
	252	({ \
1f65c13e	253	__typeof__((ptr)) __user __p = (ptr); \
56d2ef78	254	might_fault(); \
1f65c13e AT	255	access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \
1f65c13e AT	256	__put_user((x), __p) : \
0aea86a2 CM	257	-EFAULT; \
	258	})
	259
bffe1baf YS	260	extern unsigned long __must_check __arch_copy_from_user(void to, const void __user from, unsigned long n);
bffe1baf YS	261	extern unsigned long __must_check __arch_copy_to_user(void __user to, const void from, unsigned long n);
0aea86a2 CM	262	extern unsigned long __must_check __copy_in_user(void __user to, const void __user from, unsigned long n);
	263	extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
	264
bffe1baf YS	265	static inline unsigned long __must_check __copy_from_user(void to, const void __user from, unsigned long n)
	266	{
	267	kasan_check_write(to, n);
	268	return __arch_copy_from_user(to, from, n);
	269	}
	270
	271	static inline unsigned long __must_check __copy_to_user(void __user to, const void from, unsigned long n)
	272	{
	273	kasan_check_read(from, n);
	274	return __arch_copy_to_user(to, from, n);
	275	}
	276
0aea86a2 CM	277	static inline unsigned long __must_check copy_from_user(void to, const void __user from, unsigned long n)
0aea86a2 CM	278	{
bffe1baf YS	279	kasan_check_write(to, n);
bffe1baf YS	280
0aea86a2	281	if (access_ok(VERIFY_READ, from, n))
bffe1baf	282	n = __arch_copy_from_user(to, from, n);
0aea86a2 CM	283	else /* security hole - plug it */
	284	memset(to, 0, n);
	285	return n;
	286	}
	287
	288	static inline unsigned long __must_check copy_to_user(void __user to, const void from, unsigned long n)
	289	{
bffe1baf YS	290	kasan_check_read(from, n);
bffe1baf YS	291
0aea86a2	292	if (access_ok(VERIFY_WRITE, to, n))
bffe1baf	293	n = __arch_copy_to_user(to, from, n);
0aea86a2 CM	294	return n;
	295	}
	296
	297	static inline unsigned long __must_check copy_in_user(void __user to, const void __user from, unsigned long n)
	298	{
	299	if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
	300	n = __copy_in_user(to, from, n);
	301	return n;
	302	}
	303
	304	#define __copy_to_user_inatomic __copy_to_user
	305	#define __copy_from_user_inatomic __copy_from_user
	306
	307	static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
	308	{
	309	if (access_ok(VERIFY_WRITE, to, n))
	310	n = __clear_user(to, n);
	311	return n;
	312	}
	313
12a0ef7b	314	extern long strncpy_from_user(char dest, const char __user src, long count);
0aea86a2	315
12a0ef7b WD	316	extern __must_check long strlen_user(const char __user *str);
12a0ef7b WD	317	extern __must_check long strnlen_user(const char __user *str, long n);
0aea86a2 CM	318
0aea86a2 CM	319	#endif /* __ASM_UACCESS_H */