Current File : //usr/src/kernels/3.10.0-957.21.3.el7.centos.plus.x86_64/include/asm-generic/uaccess.h
#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/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)
{
check_object_size(to, n, false);
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)
{
check_object_size(from, n, true);
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_fault(); \
access_ok(VERIFY_WRITE, ptr, sizeof(*ptr)) ? \
__put_user(x, ptr) : \
-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) \
({ \
might_fault(); \
access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \
__get_user(x, ptr) : \
-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 */
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