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/* uaccess.h: userspace accessor functions
*
* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#ifndef _ASM_UACCESS_H
#define _ASM_UACCESS_H
/*
* User space memory access functions
*/
#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/segment.h>
#include <asm/sections.h>
#define __ptr(x) ((unsigned long __force *)(x))
/*
* check that a range of addresses falls within the current address limit
*/
static inline int ___range_ok(unsigned long addr, unsigned long size)
{
#ifdef CONFIG_MMU
int flag = -EFAULT, tmp;
asm volatile (
" addcc %3,%2,%1,icc0 \n" /* set C-flag if addr+size>4GB */
" subcc.p %1,%4,gr0,icc1 \n" /* jump if addr+size>limit */
" bc icc0,#0,0f \n"
" bhi icc1,#0,0f \n"
" setlos #0,%0 \n" /* mark okay */
"0: \n"
: "=r"(flag), "=&r"(tmp)
: "r"(addr), "r"(size), "r"(get_addr_limit()), "0"(flag)
);
return flag;
#else
if (addr < memory_start ||
addr > memory_end ||
size > memory_end - memory_start ||
addr + size > memory_end)
return -EFAULT;
return 0;
#endif
}
#define __range_ok(addr,size) ___range_ok((unsigned long) (addr), (unsigned long) (size))
#define access_ok(type,addr,size) (__range_ok((void __user *)(addr), (size)) == 0)
#define __access_ok(addr,size) (__range_ok((addr), (size)) == 0)
/*
* 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);
/*
* These are the main single-value transfer routines. They automatically
* use the right size if we just have the right pointer type.
*/
#define __put_user(x, ptr) \
({ \
int __pu_err = 0; \
\
typeof(*(ptr)) __pu_val = (x); \
__chk_user_ptr(ptr); \
\
switch (sizeof (*(ptr))) { \
case 1: \
__put_user_asm(__pu_err, __pu_val, ptr, "b", "r"); \
break; \
case 2: \
__put_user_asm(__pu_err, __pu_val, ptr, "h", "r"); \
break; \
case 4: \
__put_user_asm(__pu_err, __pu_val, ptr, "", "r"); \
break; \
case 8: \
__put_user_asm(__pu_err, __pu_val, ptr, "d", "e"); \
break; \
default: \
__pu_err = __put_user_bad(); \
break; \
} \
__pu_err; \
})
#define put_user(x, ptr) \
({ \
typeof(*(ptr)) __user *_p = (ptr); \
int _e; \
\
_e = __range_ok(_p, sizeof(*_p)); \
if (_e == 0) \
_e = __put_user((x), _p); \
_e; \
})
extern int __put_user_bad(void);
/*
* Tell gcc we read from memory instead of writing: this is because
* we do not write to any memory gcc knows about, so there are no
* aliasing issues.
*/
#ifdef CONFIG_MMU
#define __put_user_asm(err,x,ptr,dsize,constraint) \
do { \
asm volatile("1: st"dsize"%I1 %2,%M1 \n" \
"2: \n" \
".subsection 2 \n" \
"3: setlos %3,%0 \n" \
" bra 2b \n" \
".previous \n" \
".section __ex_table,\"a\" \n" \
" .balign 8 \n" \
" .long 1b,3b \n" \
".previous" \
: "=r" (err) \
: "m" (*__ptr(ptr)), constraint (x), "i"(-EFAULT), "0"(err) \
: "memory"); \
} while (0)
#else
#define __put_user_asm(err,x,ptr,bwl,con) \
do { \
asm(" st"bwl"%I0 %1,%M0 \n" \
" membar \n" \
: \
: "m" (*__ptr(ptr)), con (x) \
: "memory"); \
} while (0)
#endif
/*****************************************************************************/
/*
*
*/
#define __get_user(x, ptr) \
({ \
int __gu_err = 0; \
__chk_user_ptr(ptr); \
\
switch (sizeof(*(ptr))) { \
case 1: { \
unsigned char __gu_val; \
__get_user_asm(__gu_err, __gu_val, ptr, "ub", "=r"); \
(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
break; \
} \
case 2: { \
unsigned short __gu_val; \
__get_user_asm(__gu_err, __gu_val, ptr, "uh", "=r"); \
(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
break; \
} \
case 4: { \
unsigned int __gu_val; \
__get_user_asm(__gu_err, __gu_val, ptr, "", "=r"); \
(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
break; \
} \
case 8: { \
unsigned long long __gu_val; \
__get_user_asm(__gu_err, __gu_val, ptr, "d", "=e"); \
(x) = *(__force __typeof__(*(ptr)) *) &__gu_val; \
break; \
} \
default: \
__gu_err = __get_user_bad(); \
break; \
} \
__gu_err; \
})
#define get_user(x, ptr) \
({ \
const typeof(*(ptr)) __user *_p = (ptr);\
int _e; \
\
_e = __range_ok(_p, sizeof(*_p)); \
if (likely(_e == 0)) \
_e = __get_user((x), _p); \
else \
(x) = (typeof(x)) 0; \
_e; \
})
extern int __get_user_bad(void);
#ifdef CONFIG_MMU
#define __get_user_asm(err,x,ptr,dtype,constraint) \
do { \
asm("1: ld"dtype"%I2 %M2,%1 \n" \
"2: \n" \
".subsection 2 \n" \
"3: setlos %3,%0 \n" \
" setlos #0,%1 \n" \
" bra 2b \n" \
".previous \n" \
".section __ex_table,\"a\" \n" \
" .balign 8 \n" \
" .long 1b,3b \n" \
".previous" \
: "=r" (err), constraint (x) \
: "m" (*__ptr(ptr)), "i"(-EFAULT), "0"(err) \
); \
} while(0)
#else
#define __get_user_asm(err,x,ptr,bwl,con) \
asm(" ld"bwl"%I1 %M1,%0 \n" \
" membar \n" \
: con(x) \
: "m" (*__ptr(ptr)))
#endif
/*****************************************************************************/
/*
*
*/
#define ____force(x) (__force void *)(void __user *)(x)
#ifdef CONFIG_MMU
extern long __memset_user(void *dst, unsigned long count);
extern long __memcpy_user(void *dst, const void *src, unsigned long count);
#define __clear_user(dst,count) __memset_user(____force(dst), (count))
#define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n))
#define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n))
#else
#define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0)
#define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0)
#define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0)
#endif
static inline unsigned long __must_check
clear_user(void __user *to, unsigned long n)
{
if (likely(__access_ok(to, n)))
n = __clear_user(to, n);
return n;
}
static inline unsigned long __must_check
__copy_to_user(void __user *to, const void *from, unsigned long n)
{
might_fault();
return __copy_to_user_inatomic(to, from, n);
}
static inline unsigned long
__copy_from_user(void *to, const void __user *from, unsigned long n)
{
might_fault();
return __copy_from_user_inatomic(to, from, n);
}
static inline long copy_from_user(void *to, const void __user *from, unsigned long n)
{
unsigned long ret = n;
if (likely(__access_ok(from, n)))
ret = __copy_from_user(to, from, n);
if (unlikely(ret != 0))
memset(to + (n - ret), 0, ret);
return ret;
}
static inline long copy_to_user(void __user *to, const void *from, unsigned long n)
{
return likely(__access_ok(to, n)) ? __copy_to_user(to, from, n) : n;
}
extern long strncpy_from_user(char *dst, const char __user *src, long count);
extern long strnlen_user(const char __user *src, long count);
#define strlen_user(str) strnlen_user(str, 32767)
extern unsigned long search_exception_table(unsigned long addr);
#endif /* _ASM_UACCESS_H */
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