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/*
* BK Id: SCCS/s.uaccess.h 1.8 09/11/01 18:10:06 paulus
*/
#ifdef __KERNEL__
#ifndef _PPC_UACCESS_H
#define _PPC_UACCESS_H
#ifndef __ASSEMBLY__
#include <linux/sched.h>
#include <linux/errno.h>
#include <asm/processor.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
/*
* 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, 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.fs)
#define set_fs(val) (current->thread.fs = (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))
extern inline int verify_area(int type, const void * addr, unsigned long size)
{
return access_ok(type,addr,size) ? 0 : -EFAULT;
}
/*
* 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 void sort_exception_table(void);
/*
* 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.
*
* 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).
*
* As we use the same address space for kernel and user data on the
* PowerPC, we can just do these as direct assignments. (Of course, the
* exception handling means that it's no longer "just"...)
*/
#define get_user(x,ptr) \
__get_user_check((x),(ptr),sizeof(*(ptr)))
#define put_user(x,ptr) \
__put_user_check((__typeof__(*(ptr)))(x),(ptr),sizeof(*(ptr)))
#define __get_user(x,ptr) \
__get_user_nocheck((x),(ptr),sizeof(*(ptr)))
#define __put_user(x,ptr) \
__put_user_nocheck((__typeof__(*(ptr)))(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 { \
retval = 0; \
switch (size) { \
case 1: __put_user_asm(x,ptr,retval,"stb"); break; \
case 2: __put_user_asm(x,ptr,retval,"sth"); break; \
case 4: __put_user_asm(x,ptr,retval,"stw"); break; \
case 8: __put_user_asm2(x,ptr,retval); break; \
default: __put_user_bad(); \
} \
} while (0)
struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct *)(x))
/*
* 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.
*/
#define __put_user_asm(x, addr, err, op) \
__asm__ __volatile__( \
"1: "op" %1,0(%2)\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: li %0,%3\n" \
" b 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,3b\n" \
".previous" \
: "=r"(err) \
: "r"(x), "b"(addr), "i"(-EFAULT), "0"(err))
#define __put_user_asm2(x, addr, err) \
__asm__ __volatile__( \
"1: stw %1,0(%2)\n" \
"2: stw %1+1,4(%2)\n" \
"3:\n" \
".section .fixup,\"ax\"\n" \
"4: li %0,%3\n" \
" b 3b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,4b\n" \
" .long 2b,4b\n" \
".previous" \
: "=r"(err) \
: "r"(x), "b"(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) = (__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) = (__typeof__(*(ptr)))__gu_val; \
__gu_err; \
})
extern long __get_user_bad(void);
#define __get_user_size(x,ptr,size,retval) \
do { \
retval = 0; \
switch (size) { \
case 1: __get_user_asm(x,ptr,retval,"lbz"); break; \
case 2: __get_user_asm(x,ptr,retval,"lhz"); break; \
case 4: __get_user_asm(x,ptr,retval,"lwz"); break; \
case 8: __get_user_asm2(x, ptr, retval); \
default: (x) = __get_user_bad(); \
} \
} while (0)
#define __get_user_asm(x, addr, err, op) \
__asm__ __volatile__( \
"1: "op" %1,0(%2)\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: li %0,%3\n" \
" li %1,0\n" \
" b 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,3b\n" \
".previous" \
: "=r"(err), "=r"(x) \
: "b"(addr), "i"(-EFAULT), "0"(err))
#define __get_user_asm2(x, addr, err) \
__asm__ __volatile__( \
"1: lwz %1,0(%2)\n" \
"2: lwz %1+1,4(%2)\n" \
"3:\n" \
".section .fixup,\"ax\"\n" \
"4: li %0,%3\n" \
" li %1,0\n" \
" li %1+1,0\n" \
" b 3b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,4b\n" \
" .long 2b,4b\n" \
".previous" \
: "=r"(err), "=&r"(x) \
: "b"(addr), "i"(-EFAULT), "0"(err))
/* more complex routines */
extern int __copy_tofrom_user(void *to, const void *from, unsigned long size);
extern inline unsigned long
copy_from_user(void *to, const void *from, unsigned long n)
{
unsigned long over;
if (access_ok(VERIFY_READ, from, n))
return __copy_tofrom_user(to, from, n);
if ((unsigned long)from < TASK_SIZE) {
over = (unsigned long)from + n - TASK_SIZE;
return __copy_tofrom_user(to, from, n - over) + over;
}
return n;
}
extern inline unsigned long
copy_to_user(void *to, const void *from, unsigned long n)
{
unsigned long over;
if (access_ok(VERIFY_WRITE, to, n))
return __copy_tofrom_user(to, from, n);
if ((unsigned long)to < TASK_SIZE) {
over = (unsigned long)to + n - TASK_SIZE;
return __copy_tofrom_user(to, from, n - over) + over;
}
return n;
}
#define __copy_from_user(to, from, size) \
__copy_tofrom_user((to), (from), (size))
#define __copy_to_user(to, from, size) \
__copy_tofrom_user((to), (from), (size))
extern unsigned long __clear_user(void *addr, unsigned long size);
extern inline unsigned long
clear_user(void *addr, unsigned long size)
{
if (access_ok(VERIFY_WRITE, addr, size))
return __clear_user(addr, size);
return size? -EFAULT: 0;
}
extern int __strncpy_from_user(char *dst, const char *src, long count);
extern 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;
}
/*
* Return the size of a string (including the ending 0)
*
* Return 0 for error
*/
extern int __strnlen_user(const char *str, long len, unsigned long top);
/*
* Returns the length of the string at str (including the null byte),
* or 0 if we hit a page we can't access,
* or something > len if we didn't find a null byte.
*
* The `top' parameter to __strnlen_user is to make sure that
* we can never overflow from the user area into kernel space.
*/
extern __inline__ int 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, top);
}
#define strlen_user(str) strnlen_user((str), 0x7ffffffe)
#endif /* __ASSEMBLY__ */
#endif /* _PPC_UACCESS_H */
#endif /* __KERNEL__ */
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