[mirror_ubuntu-bionic-kernel.git] / include / asm-s390 / uaccess.h

/*
 *  include/asm-s390/uaccess.h
 *
 *  S390 version
 *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
 *    Author(s): Hartmut Penner (hp@de.ibm.com),
 *               Martin Schwidefsky (schwidefsky@de.ibm.com)
 *
 *  Derived from "include/asm-i386/uaccess.h"
 */
#ifndef __S390_UACCESS_H
#define __S390_UACCESS_H

/*
 * User space memory access functions
 */
#include <linux/sched.h>
#include <linux/errno.h>

#define VERIFY_READ     0
#define VERIFY_WRITE    1


/*
 * 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.
 */

#define MAKE_MM_SEG(a)  ((mm_segment_t) { (a) })


#define KERNEL_DS       MAKE_MM_SEG(0)
#define USER_DS         MAKE_MM_SEG(1)

#define get_ds()        (KERNEL_DS)
#define get_fs()        (current->thread.mm_segment)

#ifdef __s390x__
#define set_fs(x) \
({									\
	unsigned long __pto;						\
	current->thread.mm_segment = (x);				\
	__pto = current->thread.mm_segment.ar4 ?			\
		S390_lowcore.user_asce : S390_lowcore.kernel_asce;	\
	asm volatile ("lctlg 7,7,%0" : : "m" (__pto) );			\
})
#else
#define set_fs(x) \
({									\
	unsigned long __pto;						\
	current->thread.mm_segment = (x);				\
	__pto = current->thread.mm_segment.ar4 ?			\
		S390_lowcore.user_asce : S390_lowcore.kernel_asce;	\
	asm volatile ("lctl  7,7,%0" : : "m" (__pto) );			\
})
#endif

#define segment_eq(a,b) ((a).ar4 == (b).ar4)


#define __access_ok(addr,size) (1)

#define access_ok(type,addr,size) __access_ok(addr,size)

/* this function will go away soon - use access_ok() instead */
extern inline int __deprecated verify_area(int type, const void __user *addr,
						unsigned long size)
{
	return access_ok(type, addr, size) ? 0 : -EFAULT;
}

/*
 * The exception table consists of pairs of addresses: the first is the
 * address of an instruction that is allowed to fault, and the second is
 * the address 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
{
        unsigned long insn, fixup;
};

#ifndef __s390x__
#define __uaccess_fixup \
	".section .fixup,\"ax\"\n"	\
	"2: lhi    %0,%4\n"		\
	"   bras   1,3f\n"		\
	"   .long  1b\n"		\
	"3: l      1,0(1)\n"		\
	"   br     1\n"			\
	".previous\n"			\
	".section __ex_table,\"a\"\n"	\
	"   .align 4\n"			\
	"   .long  0b,2b\n"		\
	".previous"
#define __uaccess_clobber "cc", "1"
#else /* __s390x__ */
#define __uaccess_fixup \
	".section .fixup,\"ax\"\n"	\
	"2: lghi   %0,%4\n"		\
	"   jg     1b\n"		\
	".previous\n"			\
	".section __ex_table,\"a\"\n"	\
	"   .align 8\n"			\
	"   .quad  0b,2b\n"		\
	".previous"
#define __uaccess_clobber "cc"
#endif /* __s390x__ */

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 */
#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
#define __put_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile(						\
		"0: mvcs  0(%1,%2),%3,%0\n"			\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err)					\
		: "d" (sizeof(*(ptr))), "a" (ptr), "Q" (x),	\
		  "K" (-EFAULT)					\
		: __uaccess_clobber );				\
})
#else
#define __put_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile(						\
		"0: mvcs  0(%1,%2),0(%3),%0\n"			\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err)					\
		: "d" (sizeof(*(ptr))), "a" (ptr), "a" (&(x)),	\
		  "K" (-EFAULT), "m" (x)			\
		: __uaccess_clobber );				\
})
#endif

#define __put_user(x, ptr) \
({								\
	__typeof__(*(ptr)) __x = (x);				\
	int __pu_err;						\
        __chk_user_ptr(ptr);                                    \
	switch (sizeof (*(ptr))) {				\
	case 1:							\
	case 2:							\
	case 4:							\
	case 8:							\
		__put_user_asm(__x, ptr, __pu_err);		\
		break;						\
	default:						\
		__put_user_bad();				\
		break;						\
	 }							\
	__pu_err;						\
})

#define put_user(x, ptr)					\
({								\
	might_sleep();						\
	__put_user(x, ptr);					\
})


extern int __put_user_bad(void) __attribute__((noreturn));

#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
#define __get_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile (						\
		"0: mvcp  %O1(%2,%R1),0(%3),%0\n"		\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err), "=Q" (x)				\
		: "d" (sizeof(*(ptr))), "a" (ptr),		\
		  "K" (-EFAULT)					\
		: __uaccess_clobber );				\
})
#else
#define __get_user_asm(x, ptr, err) \
({								\
	err = 0;						\
	asm volatile (						\
		"0: mvcp  0(%2,%5),0(%3),%0\n"			\
		"1:\n"						\
		__uaccess_fixup					\
		: "+&d" (err), "=m" (x)				\
		: "d" (sizeof(*(ptr))), "a" (ptr),		\
		  "K" (-EFAULT), "a" (&(x))			\
		: __uaccess_clobber );				\
})
#endif

#define __get_user(x, ptr)					\
({								\
	__typeof__(*(ptr)) __x;					\
	int __gu_err;						\
        __chk_user_ptr(ptr);                                    \
	switch (sizeof(*(ptr))) {				\
	case 1:							\
	case 2:							\
	case 4:							\
	case 8:							\
		__get_user_asm(__x, ptr, __gu_err);		\
		break;						\
	default:						\
		__get_user_bad();				\
		break;						\
	}							\
	(x) = __x;						\
	__gu_err;						\
})

#define get_user(x, ptr)					\
({								\
	might_sleep();						\
	__get_user(x, ptr);					\
})

extern int __get_user_bad(void) __attribute__((noreturn));

#define __put_user_unaligned __put_user
#define __get_user_unaligned __get_user

extern long __copy_to_user_asm(const void *from, long n, void __user *to);

/**
 * __copy_to_user: - Copy a block of data into user space, with less checking.
 * @to:   Destination address, in user space.
 * @from: Source address, in kernel space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from kernel space to user space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 */
static inline unsigned long
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
	return __copy_to_user_asm(from, n, to);
}

#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user

/**
 * copy_to_user: - Copy a block of data into user space.
 * @to:   Destination address, in user space.
 * @from: Source address, in kernel space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from kernel space to user space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 */
static inline unsigned long
copy_to_user(void __user *to, const void *from, unsigned long n)
{
	might_sleep();
	if (access_ok(VERIFY_WRITE, to, n))
		n = __copy_to_user(to, from, n);
	return n;
}

extern long __copy_from_user_asm(void *to, long n, const void __user *from);

/**
 * __copy_from_user: - Copy a block of data from user space, with less checking.
 * @to:   Destination address, in kernel space.
 * @from: Source address, in user space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from user space to kernel space.  Caller must check
 * the specified block with access_ok() before calling this function.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 *
 * If some data could not be copied, this function will pad the copied
 * data to the requested size using zero bytes.
 */
static inline unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
	return __copy_from_user_asm(to, n, from);
}

/**
 * copy_from_user: - Copy a block of data from user space.
 * @to:   Destination address, in kernel space.
 * @from: Source address, in user space.
 * @n:    Number of bytes to copy.
 *
 * Context: User context only.  This function may sleep.
 *
 * Copy data from user space to kernel space.
 *
 * Returns number of bytes that could not be copied.
 * On success, this will be zero.
 *
 * If some data could not be copied, this function will pad the copied
 * data to the requested size using zero bytes.
 */
static inline unsigned long
copy_from_user(void *to, const void __user *from, unsigned long n)
{
	might_sleep();
	if (access_ok(VERIFY_READ, from, n))
		n = __copy_from_user(to, from, n);
	else
		memset(to, 0, n);
	return n;
}

extern unsigned long __copy_in_user_asm(const void __user *from, long n,
							void __user *to);

static inline unsigned long
__copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
	return __copy_in_user_asm(from, n, to);
}

static inline unsigned long
copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
	might_sleep();
	if (__access_ok(from,n) && __access_ok(to,n))
		n = __copy_in_user_asm(from, n, to);
	return n;
}

/*
 * Copy a null terminated string from userspace.
 */
extern long __strncpy_from_user_asm(long count, char *dst,
					const char __user *src);

static inline long
strncpy_from_user(char *dst, const char __user *src, long count)
{
        long res = -EFAULT;
        might_sleep();
        if (access_ok(VERIFY_READ, src, 1))
                res = __strncpy_from_user_asm(count, dst, src);
        return res;
}


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

static inline unsigned long
strnlen_user(const char __user * src, unsigned long n)
{
	might_sleep();
	return __strnlen_user_asm(n, src);
}

/**
 * strlen_user: - Get the size of a string in user space.
 * @str: The string to measure.
 *
 * Context: User context only.  This function may sleep.
 *
 * Get the size of a NUL-terminated string in user space.
 *
 * Returns the size of the string INCLUDING the terminating NUL.
 * On exception, returns 0.
 *
 * If there is a limit on the length of a valid string, you may wish to
 * consider using strnlen_user() instead.
 */
#define strlen_user(str) strnlen_user(str, ~0UL)

/*
 * Zero Userspace
 */

extern long __clear_user_asm(void __user *to, long n);

static inline unsigned long
__clear_user(void __user *to, unsigned long n)
{
	return __clear_user_asm(to, n);
}

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

#endif /* __S390_UACCESS_H */
Commit	Line	Data
1da177e4 LT	1	/*
	2	* include/asm-s390/uaccess.h
	3	*
	4	* S390 version
	5	* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
	6	* Author(s): Hartmut Penner (hp@de.ibm.com),
	7	* Martin Schwidefsky (schwidefsky@de.ibm.com)
	8	*
	9	* Derived from "include/asm-i386/uaccess.h"
	10	*/
	11	#ifndef __S390_UACCESS_H
	12	#define __S390_UACCESS_H
	13
	14	/*
	15	* User space memory access functions
	16	*/
	17	#include <linux/sched.h>
	18	#include <linux/errno.h>
	19
	20	#define VERIFY_READ 0
	21	#define VERIFY_WRITE 1
	22
	23
	24	/*
	25	* The fs value determines whether argument validity checking should be
	26	* performed or not. If get_fs() == USER_DS, checking is performed, with
	27	* get_fs() == KERNEL_DS, checking is bypassed.
	28	*
	29	* For historical reasons, these macros are grossly misnamed.
	30	*/
	31
	32	#define MAKE_MM_SEG(a) ((mm_segment_t) { (a) })
	33
	34
	35	#define KERNEL_DS MAKE_MM_SEG(0)
	36	#define USER_DS MAKE_MM_SEG(1)
	37
	38	#define get_ds() (KERNEL_DS)
	39	#define get_fs() (current->thread.mm_segment)
	40
	41	#ifdef __s390x__
	42	#define set_fs(x) \
	43	({ \
	44	unsigned long __pto; \
	45	current->thread.mm_segment = (x); \
	46	__pto = current->thread.mm_segment.ar4 ? \
	47	S390_lowcore.user_asce : S390_lowcore.kernel_asce; \
	48	asm volatile ("lctlg 7,7,%0" : : "m" (__pto) ); \
	49	})
	50	#else
	51	#define set_fs(x) \
	52	({ \
	53	unsigned long __pto; \
	54	current->thread.mm_segment = (x); \
	55	__pto = current->thread.mm_segment.ar4 ? \
	56	S390_lowcore.user_asce : S390_lowcore.kernel_asce; \
	57	asm volatile ("lctl 7,7,%0" : : "m" (__pto) ); \
	58	})
	59	#endif
	60
	61	#define segment_eq(a,b) ((a).ar4 == (b).ar4)
	62
	63
	64	#define __access_ok(addr,size) (1)
65
66	#define access_ok(type,addr,size) __access_ok(addr,size)
67
68	/* this function will go away soon - use access_ok() instead */
69	extern inline int __deprecated verify_area(int type, const void __user *addr,
70	unsigned long size)
71	{
72	return access_ok(type, addr, size) ? 0 : -EFAULT;
73	}
74
75	/*
76	* The exception table consists of pairs of addresses: the first is the
77	* address of an instruction that is allowed to fault, and the second is
78	* the address at which the program should continue. No registers are
79	* modified, so it is entirely up to the continuation code to figure out
80	* what to do.
81	*
82	* All the routines below use bits of fixup code that are out of line
83	* with the main instruction path. This means when everything is well,
84	* we don't even have to jump over them. Further, they do not intrude
85	* on our cache or tlb entries.
86	*/
87
88	struct exception_table_entry
89	{
90	unsigned long insn, fixup;
91	};
92
93	#ifndef __s390x__
94	#define __uaccess_fixup \
95	".section .fixup,\"ax\"\n" \
96	"2: lhi %0,%4\n" \
97	" bras 1,3f\n" \
98	" .long 1b\n" \
99	"3: l 1,0(1)\n" \
100	" br 1\n" \
101	".previous\n" \
102	".section __ex_table,\"a\"\n" \
103	" .align 4\n" \
104	" .long 0b,2b\n" \
105	".previous"
106	#define __uaccess_clobber "cc", "1"
107	#else /* __s390x__ */
108	#define __uaccess_fixup \
109	".section .fixup,\"ax\"\n" \
110	"2: lghi %0,%4\n" \
111	" jg 1b\n" \
112	".previous\n" \
113	".section __ex_table,\"a\"\n" \
114	" .align 8\n" \
115	" .quad 0b,2b\n" \
116	".previous"
117	#define __uaccess_clobber "cc"
118	#endif /* __s390x__ */
119
120	/*
121	* These are the main single-value transfer routines. They automatically
122	* use the right size if we just have the right pointer type.
123	*/
124	#if __GNUC__ > 3 \|\| (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
125	#define __put_user_asm(x, ptr, err) \
126	({ \
127	err = 0; \
128	asm volatile( \
129	"0: mvcs 0(%1,%2),%3,%0\n" \
130	"1:\n" \
131	__uaccess_fixup \
132	: "+&d" (err) \
133	: "d" (sizeof(*(ptr))), "a" (ptr), "Q" (x), \
134	"K" (-EFAULT) \
135	: __uaccess_clobber ); \
136	})
137	#else
138	#define __put_user_asm(x, ptr, err) \
139	({ \
140	err = 0; \
141	asm volatile( \
142	"0: mvcs 0(%1,%2),0(%3),%0\n" \
143	"1:\n" \
144	__uaccess_fixup \
145	: "+&d" (err) \
146	: "d" (sizeof(*(ptr))), "a" (ptr), "a" (&(x)), \
147	"K" (-EFAULT), "m" (x) \
148	: __uaccess_clobber ); \
149	})
150	#endif
151
1da177e4 LT	152	#define __put_user(x, ptr) \
	153	({ \
	154	__typeof__(*(ptr)) __x = (x); \
	155	int __pu_err; \
17566c3c	156	__chk_user_ptr(ptr); \
1da177e4 LT	157	switch (sizeof (*(ptr))) { \
	158	case 1: \
	159	case 2: \
	160	case 4: \
	161	case 8: \
	162	__put_user_asm(__x, ptr, __pu_err); \
	163	break; \
	164	default: \
	165	__put_user_bad(); \
	166	break; \
	167	} \
	168	__pu_err; \
	169	})
1da177e4 LT	170
	171	#define put_user(x, ptr) \
	172	({ \
	173	might_sleep(); \
	174	__put_user(x, ptr); \
	175	})
	176
	177
	178	extern int __put_user_bad(void) __attribute__((noreturn));
	179
	180	#if __GNUC__ > 3 \|\| (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
	181	#define __get_user_asm(x, ptr, err) \
	182	({ \
	183	err = 0; \
	184	asm volatile ( \
	185	"0: mvcp %O1(%2,%R1),0(%3),%0\n" \
	186	"1:\n" \
	187	__uaccess_fixup \
	188	: "+&d" (err), "=Q" (x) \
	189	: "d" (sizeof(*(ptr))), "a" (ptr), \
	190	"K" (-EFAULT) \
	191	: __uaccess_clobber ); \
	192	})
	193	#else
	194	#define __get_user_asm(x, ptr, err) \
	195	({ \
	196	err = 0; \
	197	asm volatile ( \
	198	"0: mvcp 0(%2,%5),0(%3),%0\n" \
	199	"1:\n" \
	200	__uaccess_fixup \
	201	: "+&d" (err), "=m" (x) \
	202	: "d" (sizeof(*(ptr))), "a" (ptr), \
	203	"K" (-EFAULT), "a" (&(x)) \
	204	: __uaccess_clobber ); \
	205	})
	206	#endif
	207
1da177e4 LT	208	#define __get_user(x, ptr) \
	209	({ \
	210	__typeof__(*(ptr)) __x; \
	211	int __gu_err; \
17566c3c	212	__chk_user_ptr(ptr); \
1da177e4 LT	213	switch (sizeof(*(ptr))) { \
	214	case 1: \
	215	case 2: \
	216	case 4: \
	217	case 8: \
	218	__get_user_asm(__x, ptr, __gu_err); \
	219	break; \
	220	default: \
	221	__get_user_bad(); \
	222	break; \
	223	} \
	224	(x) = __x; \
	225	__gu_err; \
	226	})
1da177e4 LT	227
	228	#define get_user(x, ptr) \
	229	({ \
	230	might_sleep(); \
	231	__get_user(x, ptr); \
	232	})
	233
	234	extern int __get_user_bad(void) __attribute__((noreturn));
	235
	236	#define __put_user_unaligned __put_user
	237	#define __get_user_unaligned __get_user
	238
	239	extern long __copy_to_user_asm(const void from, long n, void __user to);
	240
	241	/**
	242	* __copy_to_user: - Copy a block of data into user space, with less checking.
	243	* @to: Destination address, in user space.
	244	* @from: Source address, in kernel space.
	245	* @n: Number of bytes to copy.
	246	*
	247	* Context: User context only. This function may sleep.
	248	*
	249	* Copy data from kernel space to user space. Caller must check
	250	* the specified block with access_ok() before calling this function.
	251	*
	252	* Returns number of bytes that could not be copied.
	253	* On success, this will be zero.
	254	*/
	255	static inline unsigned long
	256	__copy_to_user(void __user to, const void from, unsigned long n)
	257	{
	258	return __copy_to_user_asm(from, n, to);
	259	}
	260
	261	#define __copy_to_user_inatomic __copy_to_user
	262	#define __copy_from_user_inatomic __copy_from_user
	263
	264	/**
	265	* copy_to_user: - Copy a block of data into user space.
	266	* @to: Destination address, in user space.
	267	* @from: Source address, in kernel space.
	268	* @n: Number of bytes to copy.
	269	*
	270	* Context: User context only. This function may sleep.
	271	*
	272	* Copy data from kernel space to user space.
	273	*
	274	* Returns number of bytes that could not be copied.
	275	* On success, this will be zero.
	276	*/
	277	static inline unsigned long
	278	copy_to_user(void __user to, const void from, unsigned long n)
	279	{
	280	might_sleep();
	281	if (access_ok(VERIFY_WRITE, to, n))
	282	n = __copy_to_user(to, from, n);
	283	return n;
	284	}
	285
	286	extern long __copy_from_user_asm(void to, long n, const void __user from);
	287
	288	/**
	289	* __copy_from_user: - Copy a block of data from user space, with less checking.
	290	* @to: Destination address, in kernel space.
291	* @from: Source address, in user space.
292	* @n: Number of bytes to copy.
293	*
294	* Context: User context only. This function may sleep.
295	*
296	* Copy data from user space to kernel space. Caller must check
297	* the specified block with access_ok() before calling this function.
298	*
299	* Returns number of bytes that could not be copied.
300	* On success, this will be zero.
301	*
302	* If some data could not be copied, this function will pad the copied
303	* data to the requested size using zero bytes.
304	*/
305	static inline unsigned long
306	__copy_from_user(void to, const void __user from, unsigned long n)
307	{
308	return __copy_from_user_asm(to, n, from);
309	}
310
311	/**
312	* copy_from_user: - Copy a block of data from user space.
313	* @to: Destination address, in kernel space.
314	* @from: Source address, in user space.
315	* @n: Number of bytes to copy.
316	*
317	* Context: User context only. This function may sleep.
318	*
319	* Copy data from user space to kernel space.
320	*
321	* Returns number of bytes that could not be copied.
322	* On success, this will be zero.
323	*
324	* If some data could not be copied, this function will pad the copied
325	* data to the requested size using zero bytes.
326	*/
327	static inline unsigned long
328	copy_from_user(void to, const void __user from, unsigned long n)
329	{
330	might_sleep();
331	if (access_ok(VERIFY_READ, from, n))
332	n = __copy_from_user(to, from, n);
333	else
334	memset(to, 0, n);
335	return n;
336	}
337
338	extern unsigned long __copy_in_user_asm(const void __user *from, long n,
339	void __user *to);
340
341	static inline unsigned long
342	__copy_in_user(void __user to, const void __user from, unsigned long n)
343	{
344	return __copy_in_user_asm(from, n, to);
345	}
346
347	static inline unsigned long
348	copy_in_user(void __user to, const void __user from, unsigned long n)
349	{
350	might_sleep();
351	if (__access_ok(from,n) && __access_ok(to,n))
352	n = __copy_in_user_asm(from, n, to);
353	return n;
354	}
355
356	/*
357	* Copy a null terminated string from userspace.
358	*/
359	extern long __strncpy_from_user_asm(long count, char *dst,
360	const char __user *src);
361
362	static inline long
363	strncpy_from_user(char dst, const char __user src, long count)
364	{
365	long res = -EFAULT;
366	might_sleep();
367	if (access_ok(VERIFY_READ, src, 1))
368	res = __strncpy_from_user_asm(count, dst, src);
369	return res;
370	}
371
372
373	extern long __strnlen_user_asm(long count, const char __user *src);
374
375	static inline unsigned long
376	strnlen_user(const char __user * src, unsigned long n)
377	{
378	might_sleep();
379	return __strnlen_user_asm(n, src);
380	}
381
382	/**
383	* strlen_user: - Get the size of a string in user space.
384	* @str: The string to measure.
385	*
386	* Context: User context only. This function may sleep.
387	*
388	* Get the size of a NUL-terminated string in user space.
389	*
390	* Returns the size of the string INCLUDING the terminating NUL.
391	* On exception, returns 0.
392	*
393	* If there is a limit on the length of a valid string, you may wish to
394	* consider using strnlen_user() instead.
395	*/
396	#define strlen_user(str) strnlen_user(str, ~0UL)
397
398	/*
399	* Zero Userspace
400	*/
401
402	extern long __clear_user_asm(void __user *to, long n);
403
404	static inline unsigned long
405	__clear_user(void __user *to, unsigned long n)
406	{
407	return __clear_user_asm(to, n);
408	}
409
410	static inline unsigned long
411	clear_user(void __user *to, unsigned long n)
412	{
413	might_sleep();
414	if (access_ok(VERIFY_WRITE, to, n))
415	n = __clear_user_asm(to, n);
416	return n;
417	}
418
419	#endif /* __S390_UACCESS_H */