[linux-2.6-block.git] / include / asm-generic / uaccess.h

#ifndef __ASM_GENERIC_UACCESS_H
#define __ASM_GENERIC_UACCESS_H

/*
 * User space memory access functions, these should work
 * on any machine that has kernel and user data in the same
 * address space, e.g. all NOMMU machines.
 */
#include <linux/sched.h>
#include <linux/string.h>

#include <asm/segment.h>

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

#ifndef KERNEL_DS
#define KERNEL_DS	MAKE_MM_SEG(~0UL)
#endif

#ifndef USER_DS
#define USER_DS		MAKE_MM_SEG(TASK_SIZE - 1)
#endif

#ifndef get_fs
#define get_ds()	(KERNEL_DS)
#define get_fs()	(current_thread_info()->addr_limit)

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

#ifndef segment_eq
#define segment_eq(a, b) ((a).seg == (b).seg)
#endif

#define VERIFY_READ	0
#define VERIFY_WRITE	1

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

/*
 * The architecture should really override this if possible, at least
 * doing a check on the get_fs()
 */
#ifndef __access_ok
static inline int __access_ok(unsigned long addr, unsigned long size)
{
	return 1;
}
#endif

/*
 * 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;
};

/* Returns 0 if exception not found and fixup otherwise.  */
extern unsigned long search_exception_table(unsigned long);

/*
 * architectures with an MMU should override these two
 */
#ifndef __copy_from_user
static inline __must_check long __copy_from_user(void *to,
		const void __user * from, unsigned long n)
{
	if (__builtin_constant_p(n)) {
		switch(n) {
		case 1:
			*(u8 *)to = *(u8 __force *)from;
			return 0;
		case 2:
			*(u16 *)to = *(u16 __force *)from;
			return 0;
		case 4:
			*(u32 *)to = *(u32 __force *)from;
			return 0;
#ifdef CONFIG_64BIT
		case 8:
			*(u64 *)to = *(u64 __force *)from;
			return 0;
#endif
		default:
			break;
		}
	}

	memcpy(to, (const void __force *)from, n);
	return 0;
}
#endif

#ifndef __copy_to_user
static inline __must_check long __copy_to_user(void __user *to,
		const void *from, unsigned long n)
{
	if (__builtin_constant_p(n)) {
		switch(n) {
		case 1:
			*(u8 __force *)to = *(u8 *)from;
			return 0;
		case 2:
			*(u16 __force *)to = *(u16 *)from;
			return 0;
		case 4:
			*(u32 __force *)to = *(u32 *)from;
			return 0;
#ifdef CONFIG_64BIT
		case 8:
			*(u64 __force *)to = *(u64 *)from;
			return 0;
#endif
		default:
			break;
		}
	}

	memcpy((void __force *)to, from, n);
	return 0;
}
#endif

/*
 * These are the main single-value transfer routines.  They automatically
 * use the right size if we just have the right pointer type.
 * This version just falls back to copy_{from,to}_user, which should
 * provide a fast-path for small values.
 */
#define __put_user(x, ptr) \
({								\
	__typeof__(*(ptr)) __x = (x);				\
	int __pu_err = -EFAULT;					\
        __chk_user_ptr(ptr);                                    \
	switch (sizeof (*(ptr))) {				\
	case 1:							\
	case 2:							\
	case 4:							\
	case 8:							\
		__pu_err = __put_user_fn(sizeof (*(ptr)),	\
					 ptr, &__x);		\
		break;						\
	default:						\
		__put_user_bad();				\
		break;						\
	 }							\
	__pu_err;						\
})

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

#ifndef __put_user_fn

static inline int __put_user_fn(size_t size, void __user *ptr, void *x)
{
	size = __copy_to_user(ptr, x, size);
	return size ? -EFAULT : size;
}

#define __put_user_fn(sz, u, k)	__put_user_fn(sz, u, k)

#endif

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

#define __get_user(x, ptr)					\
({								\
	int __gu_err = -EFAULT;					\
	__chk_user_ptr(ptr);					\
	switch (sizeof(*(ptr))) {				\
	case 1: {						\
		unsigned char __x;				\
		__gu_err = __get_user_fn(sizeof (*(ptr)),	\
					 ptr, &__x);		\
		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
		break;						\
	};							\
	case 2: {						\
		unsigned short __x;				\
		__gu_err = __get_user_fn(sizeof (*(ptr)),	\
					 ptr, &__x);		\
		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
		break;						\
	};							\
	case 4: {						\
		unsigned int __x;				\
		__gu_err = __get_user_fn(sizeof (*(ptr)),	\
					 ptr, &__x);		\
		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
		break;						\
	};							\
	case 8: {						\
		unsigned long long __x;				\
		__gu_err = __get_user_fn(sizeof (*(ptr)),	\
					 ptr, &__x);		\
		(x) = *(__force __typeof__(*(ptr)) *) &__x;	\
		break;						\
	};							\
	default:						\
		__get_user_bad();				\
		break;						\
	}							\
	__gu_err;						\
})

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

#ifndef __get_user_fn
static inline int __get_user_fn(size_t size, const void __user *ptr, void *x)
{
	size = __copy_from_user(x, ptr, size);
	return size ? -EFAULT : size;
}

#define __get_user_fn(sz, u, k)	__get_user_fn(sz, u, k)

#endif

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

#ifndef __copy_from_user_inatomic
#define __copy_from_user_inatomic __copy_from_user
#endif

#ifndef __copy_to_user_inatomic
#define __copy_to_user_inatomic __copy_to_user
#endif

static inline long copy_from_user(void *to,
		const void __user * from, unsigned long n)
{
	might_fault();
	if (access_ok(VERIFY_READ, from, n))
		return __copy_from_user(to, from, n);
	else
		return n;
}

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

/*
 * Copy a null terminated string from userspace.
 */
#ifndef __strncpy_from_user
static inline long
__strncpy_from_user(char *dst, const char __user *src, long count)
{
	char *tmp;
	strncpy(dst, (const char __force *)src, count);
	for (tmp = dst; *tmp && count > 0; tmp++, count--)
		;
	return (tmp - dst);
}
#endif

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

/*
 * Return the size of a string (including the ending 0)
 *
 * Return 0 on exception, a value greater than N if too long
 */
#ifndef __strnlen_user
#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
#endif

/*
 * Unlike strnlen, strnlen_user includes the nul terminator in
 * its returned count. Callers should check for a returned value
 * greater than N as an indication the string is too long.
 */
static inline long strnlen_user(const char __user *src, long n)
{
	if (!access_ok(VERIFY_READ, src, 1))
		return 0;
	return __strnlen_user(src, n);
}

static inline long strlen_user(const char __user *src)
{
	return strnlen_user(src, 32767);
}

/*
 * Zero Userspace
 */
#ifndef __clear_user
static inline __must_check unsigned long
__clear_user(void __user *to, unsigned long n)
{
	memset((void __force *)to, 0, n);
	return 0;
}
#endif

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

	return __clear_user(to, n);
}

#endif /* __ASM_GENERIC_UACCESS_H */
Commit	Line	Data
eed417dd AB	1	#ifndef __ASM_GENERIC_UACCESS_H
	2	#define __ASM_GENERIC_UACCESS_H
	3
	4	/*
	5	* User space memory access functions, these should work
0a4a6647	6	* on any machine that has kernel and user data in the same
eed417dd AB	7	* address space, e.g. all NOMMU machines.
	8	*/
	9	#include <linux/sched.h>
eed417dd AB	10	#include <linux/string.h>
	11
	12	#include <asm/segment.h>
	13
	14	#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
	15
	16	#ifndef KERNEL_DS
	17	#define KERNEL_DS MAKE_MM_SEG(~0UL)
	18	#endif
	19
	20	#ifndef USER_DS
	21	#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
	22	#endif
	23
	24	#ifndef get_fs
	25	#define get_ds() (KERNEL_DS)
	26	#define get_fs() (current_thread_info()->addr_limit)
	27
	28	static inline void set_fs(mm_segment_t fs)
	29	{
	30	current_thread_info()->addr_limit = fs;
	31	}
	32	#endif
	33
10a6007b	34	#ifndef segment_eq
eed417dd	35	#define segment_eq(a, b) ((a).seg == (b).seg)
10a6007b	36	#endif
eed417dd AB	37
	38	#define VERIFY_READ 0
	39	#define VERIFY_WRITE 1
	40
	41	#define access_ok(type, addr, size) __access_ok((unsigned long)(addr),(size))
	42
	43	/*
	44	* The architecture should really override this if possible, at least
	45	* doing a check on the get_fs()
	46	*/
	47	#ifndef __access_ok
	48	static inline int __access_ok(unsigned long addr, unsigned long size)
	49	{
	50	return 1;
	51	}
	52	#endif
	53
	54	/*
	55	* The exception table consists of pairs of addresses: the first is the
	56	* address of an instruction that is allowed to fault, and the second is
	57	* the address at which the program should continue. No registers are
	58	* modified, so it is entirely up to the continuation code to figure out
	59	* what to do.
	60	*
	61	* All the routines below use bits of fixup code that are out of line
	62	* with the main instruction path. This means when everything is well,
	63	* we don't even have to jump over them. Further, they do not intrude
	64	* on our cache or tlb entries.
	65	*/
	66
	67	struct exception_table_entry
	68	{
	69	unsigned long insn, fixup;
	70	};
	71
	72	/* Returns 0 if exception not found and fixup otherwise. */
	73	extern unsigned long search_exception_table(unsigned long);
	74
	75	/*
	76	* architectures with an MMU should override these two
	77	*/
	78	#ifndef __copy_from_user
	79	static inline __must_check long __copy_from_user(void *to,
	80	const void __user * from, unsigned long n)
	81	{
	82	if (__builtin_constant_p(n)) {
	83	switch(n) {
	84	case 1:
	85	(u8 )to = (u8 __force )from;
	86	return 0;
	87	case 2:
	88	(u16 )to = (u16 __force )from;
	89	return 0;
	90	case 4:
	91	(u32 )to = (u32 __force )from;
	92	return 0;
	93	#ifdef CONFIG_64BIT
	94	case 8:
	95	(u64 )to = (u64 __force )from;
	96	return 0;
	97	#endif
	98	default:
	99	break;
	100	}
101	}
102
103	memcpy(to, (const void __force *)from, n);
104	return 0;
105	}
106	#endif
107
108	#ifndef __copy_to_user
109	static inline __must_check long __copy_to_user(void __user *to,
110	const void *from, unsigned long n)
111	{
112	if (__builtin_constant_p(n)) {
113	switch(n) {
114	case 1:
115	(u8 __force )to = (u8 )from;
116	return 0;
117	case 2:
118	(u16 __force )to = (u16 )from;
119	return 0;
120	case 4:
121	(u32 __force )to = (u32 )from;
122	return 0;
123	#ifdef CONFIG_64BIT
124	case 8:
125	(u64 __force )to = (u64 )from;
126	return 0;
127	#endif
128	default:
129	break;
130	}
131	}
132
133	memcpy((void __force *)to, from, n);
134	return 0;
135	}
136	#endif
137
138	/*
139	* These are the main single-value transfer routines. They automatically
140	* use the right size if we just have the right pointer type.
141	* This version just falls back to copy_{from,to}_user, which should
142	* provide a fast-path for small values.
143	*/
144	#define __put_user(x, ptr) \
145	({ \
146	__typeof__(*(ptr)) __x = (x); \
147	int __pu_err = -EFAULT; \
148	__chk_user_ptr(ptr); \
149	switch (sizeof (*(ptr))) { \
150	case 1: \
151	case 2: \
152	case 4: \
153	case 8: \
154	__pu_err = __put_user_fn(sizeof (*(ptr)), \
155	ptr, &__x); \
156	break; \
157	default: \
158	__put_user_bad(); \
159	break; \
160	} \
161	__pu_err; \
162	})
163
164	#define put_user(x, ptr) \
165	({ \
a02613a4	166	void *__p = (ptr); \
e0acd0bd	167	might_fault(); \
a02613a4 YS	168	access_ok(VERIFY_WRITE, __p, sizeof(*ptr)) ? \
a02613a4 YS	169	__put_user((x), ((__typeof__((ptr)) )__p)) : \
eed417dd AB	170	-EFAULT; \
	171	})
	172
05d88a49 VG	173	#ifndef __put_user_fn
05d88a49 VG	174
eed417dd AB	175	static inline int __put_user_fn(size_t size, void __user ptr, void x)
	176	{
	177	size = __copy_to_user(ptr, x, size);
	178	return size ? -EFAULT : size;
	179	}
	180
05d88a49 VG	181	#define __put_user_fn(sz, u, k) __put_user_fn(sz, u, k)
	182
	183	#endif
	184
eed417dd AB	185	extern int __put_user_bad(void) __attribute__((noreturn));
	186
	187	#define __get_user(x, ptr) \
	188	({ \
	189	int __gu_err = -EFAULT; \
	190	__chk_user_ptr(ptr); \
	191	switch (sizeof(*(ptr))) { \
	192	case 1: { \
	193	unsigned char __x; \
	194	__gu_err = __get_user_fn(sizeof (*(ptr)), \
	195	ptr, &__x); \
	196	(x) = (__force __typeof__((ptr)) *) &__x; \
	197	break; \
	198	}; \
	199	case 2: { \
	200	unsigned short __x; \
	201	__gu_err = __get_user_fn(sizeof (*(ptr)), \
	202	ptr, &__x); \
	203	(x) = (__force __typeof__((ptr)) *) &__x; \
	204	break; \
	205	}; \
	206	case 4: { \
	207	unsigned int __x; \
	208	__gu_err = __get_user_fn(sizeof (*(ptr)), \
	209	ptr, &__x); \
	210	(x) = (__force __typeof__((ptr)) *) &__x; \
	211	break; \
	212	}; \
	213	case 8: { \
	214	unsigned long long __x; \
	215	__gu_err = __get_user_fn(sizeof (*(ptr)), \
	216	ptr, &__x); \
	217	(x) = (__force __typeof__((ptr)) *) &__x; \
	218	break; \
	219	}; \
	220	default: \
	221	__get_user_bad(); \
	222	break; \
	223	} \
	224	__gu_err; \
	225	})
	226
	227	#define get_user(x, ptr) \
	228	({ \
a02613a4	229	const void *__p = (ptr); \
e0acd0bd	230	might_fault(); \
a02613a4 YS	231	access_ok(VERIFY_READ, __p, sizeof(*ptr)) ? \
a02613a4 YS	232	__get_user((x), (__typeof__((ptr)) )__p) : \
eed417dd AB	233	-EFAULT; \
	234	})
	235
05d88a49	236	#ifndef __get_user_fn
eed417dd AB	237	static inline int __get_user_fn(size_t size, const void __user ptr, void x)
	238	{
	239	size = __copy_from_user(x, ptr, size);
	240	return size ? -EFAULT : size;
	241	}
	242
05d88a49 VG	243	#define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
	244
	245	#endif
	246
eed417dd AB	247	extern int __get_user_bad(void) __attribute__((noreturn));
	248
	249	#ifndef __copy_from_user_inatomic
	250	#define __copy_from_user_inatomic __copy_from_user
	251	#endif
	252
	253	#ifndef __copy_to_user_inatomic
	254	#define __copy_to_user_inatomic __copy_to_user
	255	#endif
	256
	257	static inline long copy_from_user(void *to,
	258	const void __user * from, unsigned long n)
	259	{
e0acd0bd	260	might_fault();
a9ede5b3	261	if (access_ok(VERIFY_READ, from, n))
eed417dd AB	262	return __copy_from_user(to, from, n);
	263	else
	264	return n;
	265	}
	266
	267	static inline long copy_to_user(void __user *to,
	268	const void *from, unsigned long n)
	269	{
e0acd0bd	270	might_fault();
a9ede5b3	271	if (access_ok(VERIFY_WRITE, to, n))
eed417dd AB	272	return __copy_to_user(to, from, n);
	273	else
	274	return n;
	275	}
	276
	277	/*
	278	* Copy a null terminated string from userspace.
	279	*/
	280	#ifndef __strncpy_from_user
	281	static inline long
	282	__strncpy_from_user(char dst, const char __user src, long count)
	283	{
	284	char *tmp;
	285	strncpy(dst, (const char __force *)src, count);
	286	for (tmp = dst; *tmp && count > 0; tmp++, count--)
	287	;
	288	return (tmp - dst);
	289	}
	290	#endif
	291
	292	static inline long
	293	strncpy_from_user(char dst, const char __user src, long count)
	294	{
a9ede5b3	295	if (!access_ok(VERIFY_READ, src, 1))
eed417dd AB	296	return -EFAULT;
	297	return __strncpy_from_user(dst, src, count);
	298	}
	299
	300	/*
	301	* Return the size of a string (including the ending 0)
	302	*
	303	* Return 0 on exception, a value greater than N if too long
	304	*/
7f509a9e	305	#ifndef __strnlen_user
830f5800	306	#define __strnlen_user(s, n) (strnlen((s), (n)) + 1)
7f509a9e G	307	#endif
7f509a9e G	308
830f5800 MS	309	/*
	310	* Unlike strnlen, strnlen_user includes the nul terminator in
	311	* its returned count. Callers should check for a returned value
	312	* greater than N as an indication the string is too long.
	313	*/
eed417dd AB	314	static inline long strnlen_user(const char __user *src, long n)
eed417dd AB	315	{
9844813f MF	316	if (!access_ok(VERIFY_READ, src, 1))
9844813f MF	317	return 0;
7f509a9e	318	return __strnlen_user(src, n);
eed417dd	319	}
eed417dd AB	320
	321	static inline long strlen_user(const char __user *src)
	322	{
	323	return strnlen_user(src, 32767);
	324	}
	325
	326	/*
	327	* Zero Userspace
	328	*/
	329	#ifndef __clear_user
	330	static inline __must_check unsigned long
	331	__clear_user(void __user *to, unsigned long n)
	332	{
	333	memset((void __force *)to, 0, n);
	334	return 0;
	335	}
	336	#endif
	337
	338	static inline __must_check unsigned long
	339	clear_user(void __user *to, unsigned long n)
	340	{
e0acd0bd	341	might_fault();
a9ede5b3	342	if (!access_ok(VERIFY_WRITE, to, n))
eed417dd AB	343	return n;
	344
	345	return __clear_user(to, n);
	346	}
	347
	348	#endif /* __ASM_GENERIC_UACCESS_H */