uaccess.h

《嵌入式系统设计与实例开发实验教材二源码》Linux内核移植与编译实验

/* We let the __ versions of copy_from/to_user inline, because they're often
 * used in fast paths and have only a small space overhead.
 */
static inline unsigned long
__generic_copy_from_user_nocheck(void *to, const void *from, unsigned long n)
{
	__copy_user_zeroing(to,from,n);
	return n;
}

static inline unsigned long
__generic_copy_to_user_nocheck(void *to, const void *from, unsigned long n)
{
	__copy_user(to,from,n);
	return n;
}


/* Optimize just a little bit when we know the size of the move. */
#define __constant_copy_user(to, from, size)			\
do {								\
	int __d0, __d1;						\
	switch (size & 3) {					\
	default:						\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:\n"					\
			".section .fixup,\"ax\"\n"		\
			"2:	shl $2,%0\n"			\
			"	jmp 1b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,2b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	case 1:							\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:	movsb\n"			\
			"2:\n"					\
			".section .fixup,\"ax\"\n"		\
			"3:	shl $2,%0\n"			\
			"4:	incl %0\n"			\
			"	jmp 2b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,3b\n"			\
			"	.long 1b,4b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	case 2:							\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:	movsw\n"			\
			"2:\n"					\
			".section .fixup,\"ax\"\n"		\
			"3:	shl $2,%0\n"			\
			"4:	addl $2,%0\n"			\
			"	jmp 2b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,3b\n"			\
			"	.long 1b,4b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	case 3:							\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:	movsw\n"			\
			"2:	movsb\n"			\
			"3:\n"					\
			".section .fixup,\"ax\"\n"		\
			"4:	shl $2,%0\n"			\
			"5:	addl $2,%0\n"			\
			"6:	incl %0\n"			\
			"	jmp 3b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,4b\n"			\
			"	.long 1b,5b\n"			\
			"	.long 2b,6b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	}							\
} while (0)

/* Optimize just a little bit when we know the size of the move. */
#define __constant_copy_user_zeroing(to, from, size)		\
do {								\
	int __d0, __d1;						\
	switch (size & 3) {					\
	default:						\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:\n"					\
			".section .fixup,\"ax\"\n"		\
			"2:	pushl %0\n"			\
			"	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	rep; stosl\n"			\
			"	popl %%eax\n"			\
			"	popl %0\n"			\
			"	shl $2,%0\n"			\
			"	jmp 1b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,2b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	case 1:							\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:	movsb\n"			\
			"2:\n"					\
			".section .fixup,\"ax\"\n"		\
			"3:	pushl %0\n"			\
			"	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	rep; stosl\n"			\
			"	stosb\n"			\
			"	popl %%eax\n"			\
			"	popl %0\n"			\
			"	shl $2,%0\n"			\
			"	incl %0\n"			\
			"	jmp 2b\n"			\
			"4:	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	stosb\n"			\
			"	popl %%eax\n"			\
			"	incl %0\n"			\
			"	jmp 2b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,3b\n"			\
			"	.long 1b,4b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	case 2:							\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:	movsw\n"			\
			"2:\n"					\
			".section .fixup,\"ax\"\n"		\
			"3:	pushl %0\n"			\
			"	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	rep; stosl\n"			\
			"	stosw\n"			\
			"	popl %%eax\n"			\
			"	popl %0\n"			\
			"	shl $2,%0\n"			\
			"	addl $2,%0\n"			\
			"	jmp 2b\n"			\
			"4:	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	stosw\n"			\
			"	popl %%eax\n"			\
			"	addl $2,%0\n"			\
			"	jmp 2b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,3b\n"			\
			"	.long 1b,4b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	case 3:							\
		__asm__ __volatile__(				\
			"0:	rep; movsl\n"			\
			"1:	movsw\n"			\
			"2:	movsb\n"			\
			"3:\n"					\
			".section .fixup,\"ax\"\n"		\
			"4:	pushl %0\n"			\
			"	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	rep; stosl\n"			\
			"	stosw\n"			\
			"	stosb\n"			\
			"	popl %%eax\n"			\
			"	popl %0\n"			\
			"	shl $2,%0\n"			\
			"	addl $3,%0\n"			\
			"	jmp 2b\n"			\
			"5:	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	stosw\n"			\
			"	stosb\n"			\
			"	popl %%eax\n"			\
			"	addl $3,%0\n"			\
			"	jmp 2b\n"			\
			"6:	pushl %%eax\n"			\
			"	xorl %%eax,%%eax\n"		\
			"	stosb\n"			\
			"	popl %%eax\n"			\
			"	incl %0\n"			\
			"	jmp 3b\n"			\
			".previous\n"				\
			".section __ex_table,\"a\"\n"		\
			"	.align 4\n"			\
			"	.long 0b,4b\n"			\
			"	.long 1b,5b\n"			\
			"	.long 2b,6b\n"			\
			".previous"				\
			: "=c"(size), "=&S" (__d0), "=&D" (__d1)\
			: "1"(from), "2"(to), "0"(size/4)	\
			: "memory");				\
		break;						\
	}							\
} while (0)

unsigned long __generic_copy_to_user(void *, const void *, unsigned long);
unsigned long __generic_copy_from_user(void *, const void *, unsigned long);

static inline unsigned long
__constant_copy_to_user(void *to, const void *from, unsigned long n)
{
	prefetch(from);
	if (access_ok(VERIFY_WRITE, to, n))
		__constant_copy_user(to,from,n);
	return n;
}

static inline unsigned long
__constant_copy_from_user(void *to, const void *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n))
		__constant_copy_user_zeroing(to,from,n);
	else
		memset(to, 0, n);
	return n;
}

static inline unsigned long
__constant_copy_to_user_nocheck(void *to, const void *from, unsigned long n)
{
	__constant_copy_user(to,from,n);
	return n;
}

static inline unsigned long
__constant_copy_from_user_nocheck(void *to, const void *from, unsigned long n)
{
	__constant_copy_user_zeroing(to,from,n);
	return n;
}

#define copy_to_user(to,from,n)				\
	(__builtin_constant_p(n) ?			\
	 __constant_copy_to_user((to),(from),(n)) :	\
	 __generic_copy_to_user((to),(from),(n)))

#define copy_from_user(to,from,n)			\
	(__builtin_constant_p(n) ?			\
	 __constant_copy_from_user((to),(from),(n)) :	\
	 __generic_copy_from_user((to),(from),(n)))

#define __copy_to_user(to,from,n)			\
	(__builtin_constant_p(n) ?			\
	 __constant_copy_to_user_nocheck((to),(from),(n)) :	\
	 __generic_copy_to_user_nocheck((to),(from),(n)))

#define __copy_from_user(to,from,n)			\
	(__builtin_constant_p(n) ?			\
	 __constant_copy_from_user_nocheck((to),(from),(n)) :	\
	 __generic_copy_from_user_nocheck((to),(from),(n)))

long strncpy_from_user(char *dst, const char *src, long count);
long __strncpy_from_user(char *dst, const char *src, long count);
#define strlen_user(str) strnlen_user(str, ~0UL >> 1)
long strnlen_user(const char *str, long n);
unsigned long clear_user(void *mem, unsigned long len);
unsigned long __clear_user(void *mem, unsigned long len);

#endif /* __i386_UACCESS_H */