linux/include/asm-arm26/uaccess.h

#ifndef _ASMARM_UACCESS_H
#define _ASMARM_UACCESS_H

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

#define VERIFY_READ 0
#define VERIFY_WRITE 1

/*
 * 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);
extern int fixup_exception(struct pt_regs *regs);

#define get_ds()	(KERNEL_DS)
#define get_fs()	(current_thread_info()->addr_limit)
#define segment_eq(a,b)	((a) == (b))

#include <asm/uaccess-asm.h>

#define access_ok(type,addr,size)	(__range_ok(addr,size) == 0)

/*
 * Single-value transfer routines.  They automatically use the right
 * size if we just have the right pointer type.  Note that the functions
 * which read from user space (*get_*) need to take care not to leak
 * kernel data even if the calling code is buggy and fails to check
 * the return value.  This means zeroing out the destination variable
 * or buffer on error.  Normally this is done out of line by the
 * fixup code, but there are a few places where it intrudes on the
 * main code path.  When we only write to user space, there is no
 * problem.
 *
 * 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.  Note that these
 * versions are void (ie, don't return a value as such).
 */

extern int __get_user_1(void *);
extern int __get_user_2(void *);
extern int __get_user_4(void *);
extern int __get_user_8(void *);
extern int __get_user_bad(void);

#define __get_user_x(__r1,__p,__e,__s,__i...)				\
	   __asm__ __volatile__ ("bl	__get_user_" #__s		\
		: "=&r" (__e), "=r" (__r1)				\
		: "0" (__p)						\
		: __i)

#define get_user(x,p)							\
	({								\
		register const typeof(*(p)) *__p asm("r0") = (p);	\
		register typeof(*(p)) __r1 asm("r1");			\
		register int __e asm("r0");				\
		switch (sizeof(*(p))) {					\
		case 1:							\
			__get_user_x(__r1, __p, __e, 1, "lr");		\
	       		break;						\
		case 2:							\
			__get_user_x(__r1, __p, __e, 2, "r2", "lr");	\
			break;						\
		case 4:							\
	       		__get_user_x(__r1, __p, __e, 4, "lr");		\
			break;						\
		case 8:							\
			__get_user_x(__r1, __p, __e, 8, "lr");		\
	       		break;						\
		default: __e = __get_user_bad(); break;			\
		}							\
		x = __r1;						\
		__e;							\
	})


#define __get_user(x,ptr)                                               \
({                                                                      \
        long __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_err(x,ptr,err)                                       \
do {                                                                    \
        unsigned long __gu_addr = (unsigned long)(ptr);                 \
        unsigned long __gu_val;                                         \
        switch (sizeof(*(ptr))) {                                       \
        case 1: __get_user_asm_byte(__gu_val,__gu_addr,err);    break;  \
        case 2: __get_user_asm_half(__gu_val,__gu_addr,err);    break;  \
        case 4: __get_user_asm_word(__gu_val,__gu_addr,err);    break;  \
        default: (__gu_val) = __get_user_bad();                         \
        }                                                               \
        (x) = (__typeof__(*(ptr)))__gu_val;                             \
} while (0)

extern int __put_user_1(void *, unsigned int);
extern int __put_user_2(void *, unsigned int);
extern int __put_user_4(void *, unsigned int);
extern int __put_user_8(void *, unsigned long long);
extern int __put_user_bad(void);

#define __put_user_x(__r1,__p,__e,__s)                                  \
           __asm__ __volatile__ (                                       \
                __asmeq("%0", "r0") __asmeq("%2", "r1")                 \
                "bl     __put_user_" #__s                               \
                : "=&r" (__e)                                           \
                : "0" (__p), "r" (__r1)                                 \
                : "ip", "lr", "cc")

#define put_user(x,p)                                                   \
        ({                                                              \
                register const typeof(*(p)) __r1 asm("r1") = (x);       \
                register const typeof(*(p)) *__p asm("r0") = (p);       \
                register int __e asm("r0");                             \
                switch (sizeof(*(__p))) {                               \
                case 1:                                                 \
                        __put_user_x(__r1, __p, __e, 1);                \
                        break;                                          \
                case 2:                                                 \
                        __put_user_x(__r1, __p, __e, 2);                \
                        break;                                          \
                case 4:                                                 \
                        __put_user_x(__r1, __p, __e, 4);                \
                        break;                                          \
                case 8:                                                 \
                        __put_user_x(__r1, __p, __e, 8);                \
                        break;                                          \
                default: __e = __put_user_bad(); break;                 \
                }                                                       \
                __e;                                                    \
        })

#if 0
/*********************   OLD METHOD *******************/
#define __put_user_x(__r1,__p,__e,__s,__i...)				\
	   __asm__ __volatile__ ("bl	__put_user_" #__s		\
		: "=&r" (__e)						\
		: "0" (__p), "r" (__r1)					\
		: __i)

#define put_user(x,p)							\
	({								\
		register const typeof(*(p)) __r1 asm("r1") = (x);	\
		register const typeof(*(p)) *__p asm("r0") = (p);	\
		register int __e asm("r0");				\
		switch (sizeof(*(p))) {					\
		case 1:							\
			__put_user_x(__r1, __p, __e, 1, "r2", "lr");	\
			break;						\
		case 2:							\
			__put_user_x(__r1, __p, __e, 2, "r2", "lr");	\
			break;						\
		case 4:							\
			__put_user_x(__r1, __p, __e, 4, "r2", "lr");	\
			break;						\
		case 8:							\
			__put_user_x(__r1, __p, __e, 8, "r2", "ip", "lr");	\
			break;						\
		default: __e = __put_user_bad(); break;			\
		}							\
		__e;							\
	})
/*************************************************/
#endif

#define __put_user(x,ptr)                                               \
({                                                                      \
        long __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_err(x,ptr,err)                                       \
do {                                                                    \
        unsigned long __pu_addr = (unsigned long)(ptr);                 \
        __typeof__(*(ptr)) __pu_val = (x);                              \
        switch (sizeof(*(ptr))) {                                       \
        case 1: __put_user_asm_byte(__pu_val,__pu_addr,err);    break;  \
        case 2: __put_user_asm_half(__pu_val,__pu_addr,err);    break;  \
        case 4: __put_user_asm_word(__pu_val,__pu_addr,err);    break;  \
        case 8: __put_user_asm_dword(__pu_val,__pu_addr,err);   break;  \
        default: __put_user_bad();                                      \
        }                                                               \
} while (0)

static __inline__ unsigned long copy_from_user(void *to, const void *from, unsigned long n)
{
	if (access_ok(VERIFY_READ, from, n))
		__do_copy_from_user(to, from, n);
	else /* security hole - plug it */
		memzero(to, n);
	return n;
}

static __inline__ unsigned long __copy_from_user(void *to, const void *from, unsigned long n)
{
	__do_copy_from_user(to, from, n);
	return n;
}

static __inline__ unsigned long copy_to_user(void *to, const void *from, unsigned long n)
{
	if (access_ok(VERIFY_WRITE, to, n))
		__do_copy_to_user(to, from, n);
	return n;
}

static __inline__ unsigned long __copy_to_user(void *to, const void *from, unsigned long n)
{
	__do_copy_to_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 clear_user (void *to, unsigned long n)
{
	if (access_ok(VERIFY_WRITE, to, n))
		__do_clear_user(to, n);
	return n;
}

static __inline__ unsigned long __clear_user (void *to, unsigned long n)
{
	__do_clear_user(to, n);
	return n;
}

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

static __inline__ long __strncpy_from_user (char *dst, const char *src, long count)
{
	long res;
	__do_strncpy_from_user(dst, src, count, res);
	return res;
}

#define strlen_user(s)	strnlen_user(s, ~0UL >> 1)

static inline long strnlen_user(const char *s, long n)
{
	unsigned long res = 0;

	if (__addr_ok(s))
		__do_strnlen_user(s, n, res);

	return res;
}

#endif /* _ASMARM_UACCESS_H */