358 lines
10 KiB
C
358 lines
10 KiB
C
/*
|
|
* 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/errno.h>
|
|
#include <linux/prefetch.h>
|
|
#include <asm/types.h>
|
|
|
|
#define VERIFY_READ 0
|
|
#define VERIFY_WRITE 1
|
|
|
|
#include <linux/sched.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_ds() (KERNEL_DS)
|
|
#define get_fs() (current->thread.current_ds)
|
|
#define set_fs(val) (current->thread.current_ds = (val))
|
|
|
|
#define segment_eq(a, b) ((a).seg == (b).seg)
|
|
|
|
#define __kernel_ok (segment_eq(get_fs(), KERNEL_DS))
|
|
#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(type, addr, size) __access_ok((unsigned long)(addr), (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)) *__pu_addr = (ptr); \
|
|
if (access_ok(VERIFY_WRITE, __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); \
|
|
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 %3, 0, 1f \n" \
|
|
" movi %0, %4 \n" \
|
|
" _j 2f \n"
|
|
|
|
#define __check_align_4 \
|
|
" _bbsi.l %3, 0, 0f \n" \
|
|
" _bbci.l %3, 1, 1f \n" \
|
|
"0: movi %0, %4 \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" %2, %3, 0 \n" \
|
|
"2: \n" \
|
|
" .section .fixup,\"ax\" \n" \
|
|
" .align 4 \n" \
|
|
"4: \n" \
|
|
" .long 2b \n" \
|
|
"5: \n" \
|
|
" l32r %1, 4b \n" \
|
|
" movi %0, %4 \n" \
|
|
" jx %1 \n" \
|
|
" .previous \n" \
|
|
" .section __ex_table,\"a\" \n" \
|
|
" .long 1b, 5b \n" \
|
|
" .previous" \
|
|
:"=r" (err), "=r" (cb) \
|
|
:"r" ((int)(x)), "r" (addr), "i" (-EFAULT), "0" (err))
|
|
|
|
#define __get_user_nocheck(x, ptr, size) \
|
|
({ \
|
|
long __gu_err, __gu_val; \
|
|
__get_user_size(__gu_val, (ptr), (size), __gu_err); \
|
|
(x) = (__force __typeof__(*(ptr)))__gu_val; \
|
|
__gu_err; \
|
|
})
|
|
|
|
#define __get_user_check(x, ptr, size) \
|
|
({ \
|
|
long __gu_err = -EFAULT, __gu_val = 0; \
|
|
const __typeof__(*(ptr)) *__gu_addr = (ptr); \
|
|
if (access_ok(VERIFY_READ, __gu_addr, size)) \
|
|
__get_user_size(__gu_val, __gu_addr, (size), __gu_err); \
|
|
(x) = (__force __typeof__(*(ptr)))__gu_val; \
|
|
__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: retval = __copy_from_user(&x, ptr, 8); break; \
|
|
default: (x) = __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) \
|
|
__asm__ __volatile__( \
|
|
__check_align_##align \
|
|
"1: "insn" %2, %3, 0 \n" \
|
|
"2: \n" \
|
|
" .section .fixup,\"ax\" \n" \
|
|
" .align 4 \n" \
|
|
"4: \n" \
|
|
" .long 2b \n" \
|
|
"5: \n" \
|
|
" l32r %1, 4b \n" \
|
|
" movi %2, 0 \n" \
|
|
" movi %0, %4 \n" \
|
|
" jx %1 \n" \
|
|
" .previous \n" \
|
|
" .section __ex_table,\"a\" \n" \
|
|
" .long 1b, 5b \n" \
|
|
" .previous" \
|
|
:"=r" (err), "=r" (cb), "=r" (x) \
|
|
:"r" (addr), "i" (-EFAULT), "0" (err))
|
|
|
|
|
|
/*
|
|
* Copy to/from user space
|
|
*/
|
|
|
|
/*
|
|
* We use a generic, arbitrary-sized copy subroutine. The Xtensa
|
|
* architecture would cause heavy code bloat if we tried to inline
|
|
* these functions and provide __constant_copy_* equivalents like the
|
|
* i386 versions. __xtensa_copy_user is quite efficient. See the
|
|
* .fixup section of __xtensa_copy_user for a discussion on the
|
|
* X_zeroing equivalents for Xtensa.
|
|
*/
|
|
|
|
extern unsigned __xtensa_copy_user(void *to, const void *from, unsigned n);
|
|
#define __copy_user(to, from, size) __xtensa_copy_user(to, from, size)
|
|
|
|
|
|
static inline unsigned long
|
|
__generic_copy_from_user_nocheck(void *to, const void *from, unsigned long n)
|
|
{
|
|
return __copy_user(to, from, n);
|
|
}
|
|
|
|
static inline unsigned long
|
|
__generic_copy_to_user_nocheck(void *to, const void *from, unsigned long n)
|
|
{
|
|
return __copy_user(to, from, n);
|
|
}
|
|
|
|
static inline unsigned long
|
|
__generic_copy_to_user(void *to, const void *from, unsigned long n)
|
|
{
|
|
prefetch(from);
|
|
if (access_ok(VERIFY_WRITE, to, n))
|
|
return __copy_user(to, from, n);
|
|
return n;
|
|
}
|
|
|
|
static inline unsigned long
|
|
__generic_copy_from_user(void *to, const void *from, unsigned long n)
|
|
{
|
|
prefetchw(to);
|
|
if (access_ok(VERIFY_READ, from, n))
|
|
return __copy_user(to, from, n);
|
|
else
|
|
memset(to, 0, n);
|
|
return n;
|
|
}
|
|
|
|
#define copy_to_user(to, from, n) __generic_copy_to_user((to), (from), (n))
|
|
#define copy_from_user(to, from, n) __generic_copy_from_user((to), (from), (n))
|
|
#define __copy_to_user(to, from, n) \
|
|
__generic_copy_to_user_nocheck((to), (from), (n))
|
|
#define __copy_from_user(to, from, n) \
|
|
__generic_copy_from_user_nocheck((to), (from), (n))
|
|
#define __copy_to_user_inatomic __copy_to_user
|
|
#define __copy_from_user_inatomic __copy_from_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 *addr, unsigned long size)
|
|
{
|
|
if ( ! memset(addr, 0, size) )
|
|
return size;
|
|
return 0;
|
|
}
|
|
|
|
static inline unsigned long
|
|
clear_user(void *addr, unsigned long size)
|
|
{
|
|
if (access_ok(VERIFY_WRITE, addr, size))
|
|
return __xtensa_clear_user(addr, size);
|
|
return size ? -EFAULT : 0;
|
|
}
|
|
|
|
#define __clear_user __xtensa_clear_user
|
|
|
|
|
|
extern long __strncpy_user(char *, const char *, long);
|
|
#define __strncpy_from_user __strncpy_user
|
|
|
|
static inline long
|
|
strncpy_from_user(char *dst, const char *src, long count)
|
|
{
|
|
if (access_ok(VERIFY_READ, src, 1))
|
|
return __strncpy_from_user(dst, src, count);
|
|
return -EFAULT;
|
|
}
|
|
|
|
|
|
#define strlen_user(str) strnlen_user((str), TASK_SIZE - 1)
|
|
|
|
/*
|
|
* Return the size of a string (including the ending 0!)
|
|
*/
|
|
extern long __strnlen_user(const char *, long);
|
|
|
|
static inline long strnlen_user(const char *str, long len)
|
|
{
|
|
unsigned long top = __kernel_ok ? ~0UL : TASK_SIZE - 1;
|
|
|
|
if ((unsigned long)str > top)
|
|
return 0;
|
|
return __strnlen_user(str, len);
|
|
}
|
|
|
|
|
|
struct exception_table_entry
|
|
{
|
|
unsigned long insn, fixup;
|
|
};
|
|
|
|
#endif /* _XTENSA_UACCESS_H */
|