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/*
* include/asm-xtensa/uaccess.h
*
* User space memory access functions
*
* These routines provide basic accessing functions to the user memory
* space for the kernel. This header file provides functions such as:
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*
* Copyright (C) 2001 - 2005 Tensilica Inc.
*/
#ifndef _XTENSA_UACCESS_H
#define _XTENSA_UACCESS_H
#include <linux/prefetch.h>
#include <asm/types.h>
#include <asm/extable.h>
/*
* The fs value determines whether argument validity checking should
* be performed or not. If get_fs() == USER_DS, checking is
* performed, with get_fs() == KERNEL_DS, checking is bypassed.
*
* For historical reasons (Data Segment Register?), these macros are
* grossly misnamed.
*/
#define KERNEL_DS ((mm_segment_t) { 0 })
#define USER_DS ((mm_segment_t) { 1 })
#define get_fs() (current->thread.current_ds)
#define set_fs(val) (current->thread.current_ds = (val))
#define uaccess_kernel() (get_fs().seg == KERNEL_DS.seg)
#define __kernel_ok (uaccess_kernel())
#define __user_ok(addr, size) \
(((size) <= TASK_SIZE)&&((addr) <= TASK_SIZE-(size)))
#define __access_ok(addr, size) (__kernel_ok || __user_ok((addr), (size)))
#define access_ok(addr, size) __access_ok((unsigned long)(addr), (size))
#define user_addr_max() (uaccess_kernel() ? ~0UL : TASK_SIZE)
/*
* These are the main single-value transfer routines. They
* automatically use the right size if we just have the right pointer
* type.
*
* This gets kind of ugly. We want to return _two_ values in
* "get_user()" and yet we don't want to do any pointers, because that
* is too much of a performance impact. Thus we have a few rather ugly
* macros here, and hide all the uglyness from the user.
*
* Careful to not
* (a) re-use the arguments for side effects (sizeof is ok)
* (b) require any knowledge of processes at this stage
*/
#define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
/*
* The "__xxx" versions of the user access functions are versions that
* do not verify the address space, that must have been done previously
* with a separate "access_ok()" call (this is used when we do multiple
* accesses to the same area of user memory).
*/
#define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
extern long __put_user_bad(void);
#define __put_user_nocheck(x, ptr, size) \
({ \
long __pu_err; \
__put_user_size((x), (ptr), (size), __pu_err); \
__pu_err; \
})
#define __put_user_check(x, ptr, size) \
({ \
long __pu_err = -EFAULT; \
__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
if (access_ok(__pu_addr, size)) \
__put_user_size((x), __pu_addr, (size), __pu_err); \
__pu_err; \
})
#define __put_user_size(x, ptr, size, retval) \
do { \
int __cb; \
retval = 0; \
switch (size) { \
case 1: __put_user_asm(x, ptr, retval, 1, "s8i", __cb); break; \
case 2: __put_user_asm(x, ptr, retval, 2, "s16i", __cb); break; \
case 4: __put_user_asm(x, ptr, retval, 4, "s32i", __cb); break; \
case 8: { \
__typeof__(*ptr) __v64 = x; \
retval = __copy_to_user(ptr, &__v64, 8) ? -EFAULT : 0; \
break; \
} \
default: __put_user_bad(); \
} \
} while (0)
/*
* Consider a case of a user single load/store would cause both an
* unaligned exception and an MMU-related exception (unaligned
* exceptions happen first):
*
* User code passes a bad variable ptr to a system call.
* Kernel tries to access the variable.
* Unaligned exception occurs.
* Unaligned exception handler tries to make aligned accesses.
* Double exception occurs for MMU-related cause (e.g., page not mapped).
* do_page_fault() thinks the fault address belongs to the kernel, not the
* user, and panics.
*
* The kernel currently prohibits user unaligned accesses. We use the
* __check_align_* macros to check for unaligned addresses before
* accessing user space so we don't crash the kernel. Both
* __put_user_asm and __get_user_asm use these alignment macros, so
* macro-specific labels such as 0f, 1f, %0, %2, and %3 must stay in
* sync.
*/
#define __check_align_1 ""
#define __check_align_2 \
" _bbci.l %[mem] * 0, 1f \n" \
" movi %[err], %[efault] \n" \
" _j 2f \n"
#define __check_align_4 \
" _bbsi.l %[mem] * 0, 0f \n" \
" _bbci.l %[mem] * 0 + 1, 1f \n" \
"0: movi %[err], %[efault] \n" \
" _j 2f \n"
/*
* We don't tell gcc that we are accessing memory, but this is OK
* because we do not write to any memory gcc knows about, so there
* are no aliasing issues.
*
* WARNING: If you modify this macro at all, verify that the
* __check_align_* macros still work.
*/
#define __put_user_asm(x_, addr_, err_, align, insn, cb)\
__asm__ __volatile__( \
__check_align_##align \
"1: "insn" %[x], %[mem] \n" \
"2: \n" \
" .section .fixup,\"ax\" \n" \
" .align 4 \n" \
" .literal_position \n" \
"5: \n" \
" movi %[tmp], 2b \n" \
" movi %[err], %[efault] \n" \
" jx %[tmp] \n" \
" .previous \n" \
" .section __ex_table,\"a\" \n" \
" .long 1b, 5b \n" \
" .previous" \
:[err] "+r"(err_), [tmp] "=r"(cb), [mem] "=m"(*(addr_)) \
:[x] "r"(x_), [efault] "i"(-EFAULT))
#define __get_user_nocheck(x, ptr, size) \
({ \
long __gu_err; \
__get_user_size((x), (ptr), (size), __gu_err); \
__gu_err; \
})
#define __get_user_check(x, ptr, size) \
({ \
long __gu_err = -EFAULT; \
const __typeof__(*(ptr)) __user *__gu_addr = (ptr); \
if (access_ok(__gu_addr, size)) \
__get_user_size((x), __gu_addr, (size), __gu_err); \
else \
(x) = (__typeof__(*(ptr)))0; \
__gu_err; \
})
extern long __get_user_bad(void);
#define __get_user_size(x, ptr, size, retval) \
do { \
int __cb; \
retval = 0; \
switch (size) { \
case 1: __get_user_asm(x, ptr, retval, 1, "l8ui", __cb); break;\
case 2: __get_user_asm(x, ptr, retval, 2, "l16ui", __cb); break;\
case 4: __get_user_asm(x, ptr, retval, 4, "l32i", __cb); break;\
case 8: { \
u64 __x; \
if (unlikely(__copy_from_user(&__x, ptr, 8))) { \
retval = -EFAULT; \
(x) = (__typeof__(*(ptr)))0; \
} else { \
(x) = *(__force __typeof__(*(ptr)) *)&__x; \
} \
break; \
} \
default: \
(x) = (__typeof__(*(ptr)))0; \
__get_user_bad(); \
} \
} while (0)
/*
* WARNING: If you modify this macro at all, verify that the
* __check_align_* macros still work.
*/
#define __get_user_asm(x_, addr_, err_, align, insn, cb) \
do { \
u32 __x = 0; \
__asm__ __volatile__( \
__check_align_##align \
"1: "insn" %[x], %[mem] \n" \
"2: \n" \
" .section .fixup,\"ax\" \n" \
" .align 4 \n" \
" .literal_position \n" \
"5: \n" \
" movi %[tmp], 2b \n" \
" movi %[err], %[efault] \n" \
" jx %[tmp] \n" \
" .previous \n" \
" .section __ex_table,\"a\" \n" \
" .long 1b, 5b \n" \
" .previous" \
:[err] "+r"(err_), [tmp] "=r"(cb), [x] "+r"(__x) \
:[mem] "m"(*(addr_)), [efault] "i"(-EFAULT)); \
(x_) = (__force __typeof__(*(addr_)))__x; \
} while (0)
/*
* Copy to/from user space
*/
extern unsigned __xtensa_copy_user(void *to, const void *from, unsigned n);
static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long n)
{
prefetchw(to);
return __xtensa_copy_user(to, (__force const void *)from, n);
}
static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long n)
{
prefetch(from);
return __xtensa_copy_user((__force void *)to, from, n);
}
#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER
/*
* We need to return the number of bytes not cleared. Our memset()
* returns zero if a problem occurs while accessing user-space memory.
* In that event, return no memory cleared. Otherwise, zero for
* success.
*/
static inline unsigned long
__xtensa_clear_user(void __user *addr, unsigned long size)
{
if (!__memset((void __force *)addr, 0, size))
return size;
return 0;
}
static inline unsigned long
clear_user(void __user *addr, unsigned long size)
{
if (access_ok(addr, size))
return __xtensa_clear_user(addr, size);
return size ? -EFAULT : 0;
}
#define __clear_user __xtensa_clear_user
#ifdef CONFIG_ARCH_HAS_STRNCPY_FROM_USER
extern long __strncpy_user(char *dst, const char __user *src, long count);
static inline long
strncpy_from_user(char *dst, const char __user *src, long count)
{
if (access_ok(src, 1))
return __strncpy_user(dst, src, count);
return -EFAULT;
}
#else
long strncpy_from_user(char *dst, const char __user *src, long count);
#endif
/*
* Return the size of a string (including the ending 0!)
*/
extern long __strnlen_user(const char __user *str, long len);
static inline long strnlen_user(const char __user *str, long len)
{
if (!access_ok(str, 1))
return 0;
return __strnlen_user(str, len);
}
#endif /* _XTENSA_UACCESS_H */
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