asm-generic: add a generic uaccess.h (eed417dd) · Commits · 戴 / test

include/asm-generic/uaccess.h

0 → 100644

+325 −0

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		#ifndef __ASM_GENERIC_UACCESS_H
		#define __ASM_GENERIC_UACCESS_H

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

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

		#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) \
		({ \
		might_sleep(); \
		__access_ok(ptr, sizeof (*ptr)) ? \
		__put_user(x, ptr) : \
		-EFAULT; \
		})

		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;
		}

		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) \
		({ \
		might_sleep(); \
		__access_ok(ptr, sizeof (*ptr)) ? \
		__get_user(x, ptr) : \
		-EFAULT; \
		})

		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;
		}

		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_sleep();
		if (__access_ok(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_sleep();
		if (__access_ok(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(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
		static inline long strnlen_user(const char __user *src, long n)
		{
		return strlen((void * __force)src) + 1;
		}
		#endif

		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_sleep();
		if (!__access_ok(to, n))
		return n;

		return __clear_user(to, n);
		}

		#endif /* __ASM_GENERIC_UACCESS_H */

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