/*
* OpenRISC Linux
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* OpenRISC implementation:
* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
* et al.
*
* 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_OPENRISC_UACCESS_H
#define __ASM_OPENRISC_UACCESS_H
/*
* User space memory access functions
*/
#include <linux/errno.h>
#include <linux/thread_info.h>
#include <linux/prefetch.h>
#include <linux/string.h>
#include <asm/page.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.
*/
/* addr_limit is the maximum accessible address for the task. we misuse
* the KERNEL_DS and USER_DS values to both assign and compare the
* addr_limit values through the equally misnamed get/set_fs macros.
* (see above)
*/
#define KERNEL_DS (~0UL)
#define get_ds() (KERNEL_DS)
#define USER_DS (TASK_SIZE)
#define get_fs() (current_thread_info()->addr_limit)
#define set_fs(x) (current_thread_info()->addr_limit = (x))
#define segment_eq(a, b) ((a) == (b))
/* Ensure that the range from addr to addr+size is all within the process'
* address space
*/
#define __range_ok(addr, size) (size <= get_fs() && addr <= (get_fs()-size))
/* Ensure that addr is below task's addr_limit */
#define __addr_ok(addr) ((unsigned long) addr < get_fs())
#define access_ok(type, addr, size) \
__range_ok((unsigned long)addr, (unsigned long)size)
/*
* 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, "l.sb"); break; \
case 2: __put_user_asm(x, ptr, retval, "l.sh"); break; \
case 4: __put_user_asm(x, ptr, retval, "l.sw"); 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" 0(%2),%1\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3: l.addi %0,r0,%3\n" \
" l.j 2b\n" \
" l.nop\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,3b\n" \
".previous" \
: "=r"(err) \
: "r"(x), "r"(addr), "i"(-EFAULT), "0"(err))
#define __put_user_asm2(x, addr, err) \
__asm__ __volatile__( \
"1: l.sw 0(%2),%1\n" \
"2: l.sw 4(%2),%H1\n" \
"3:\n" \
".section .fixup,\"ax\"\n" \
"4: l.addi %0,r0,%3\n" \
" l.j 3b\n" \
" l.nop\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,4b\n" \
" .long 2b,4b\n" \
".previous" \
: "=r"(err) \
: "r"(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) = (__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, "l.lbz"); break; \
case 2: __get_user_asm(x, ptr, retval, "l.lhz"); break; \
case 4: __get_user_asm(x, ptr, retval, "l.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: l.addi %0,r0,%3\n" \
" l.addi %1,r0,0\n" \
" l.j 2b\n" \
" l.nop\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,3b\n" \
".previous" \
: "=r"(err), "=r"(x) \
: "r"(addr), "i"(-EFAULT), "0"(err))
#define __get_user_asm2(x, addr, err) \
__asm__ __volatile__( \
"1: l.lwz %1,0(%2)\n" \
"2: l.lwz %H1,4(%2)\n" \
"3:\n" \
".section .fixup,\"ax\"\n" \
"4: l.addi %0,r0,%3\n" \
" l.addi %1,r0,0\n" \
" l.addi %H1,r0,0\n" \
" l.j 3b\n" \
" l.nop\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
" .align 2\n" \
" .long 1b,4b\n" \
" .long 2b,4b\n" \
".previous" \
: "=r"(err), "=&r"(x) \
: "r"(addr), "i"(-EFAULT), "0"(err))
/* more complex routines */
extern unsigned long __must_check
__copy_tofrom_user(void *to, const void *from, unsigned long size);
#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)
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user
static 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;
}
static 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;
}
extern unsigned long __clear_user(void *addr, unsigned long size);
static inline __must_check unsigned long
clear_user(void *addr, unsigned long size)
{
if (access_ok(VERIFY_WRITE, addr, size))
return __clear_user(addr, size);
if ((unsigned long)addr < TASK_SIZE) {
unsigned long over = (unsigned long)addr + size - TASK_SIZE;
return __clear_user(addr, size - over) + over;
}
return size;
}
extern int __strncpy_from_user(char *dst, const char *src, long count);
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;
}
/*
* 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.
*/
static inline long strnlen_user(const char __user *str, long len)
{
unsigned long top = (unsigned long)get_fs();
unsigned long res = 0;
if (__addr_ok(str))
res = __strnlen_user(str, len, top);
return res;
}
#define strlen_user(str) strnlen_user(str, TASK_SIZE-1)
#endif /* __ASM_OPENRISC_UACCESS_H */