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/*
* Based on arch/arm/include/asm/uaccess.h
*
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#ifndef __ASM_UACCESS_H
#define __ASM_UACCESS_H
/*
* User space memory access functions
*/
#include <linux/string.h>
#include <linux/thread_info.h>
#include <asm/ptrace.h>
#include <asm/errno.h>
#include <asm/memory.h>
#include <asm/compiler.h>
#define VERIFY_READ 0
#define VERIFY_WRITE 1
/*
* 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;
};
extern int fixup_exception(struct pt_regs *regs);
#define KERNEL_DS (-1UL)
#define get_ds() (KERNEL_DS)
#define USER_DS TASK_SIZE_64
#define get_fs() (current_thread_info()->addr_limit)
static inline void set_fs(mm_segment_t fs)
{
current_thread_info()->addr_limit = fs;
}
#define segment_eq(a,b) ((a) == (b))
/*
* Return 1 if addr < current->addr_limit, 0 otherwise.
*/
#define __addr_ok(addr) \
({ \
unsigned long flag; \
asm("cmp %1, %0; cset %0, lo" \
: "=&r" (flag) \
: "r" (addr), "0" (current_thread_info()->addr_limit) \
: "cc"); \
flag; \
})
/*
* Test whether a block of memory is a valid user space address.
* Returns 1 if the range is valid, 0 otherwise.
*
* This is equivalent to the following test:
* (u65)addr + (u65)size < (u65)current->addr_limit
*
* This needs 65-bit arithmetic.
*/
#define __range_ok(addr, size) \
({ \
unsigned long flag, roksum; \
__chk_user_ptr(addr); \
asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, cc" \
: "=&r" (flag), "=&r" (roksum) \
: "1" (addr), "Ir" (size), \
"r" (current_thread_info()->addr_limit) \
: "cc"); \
flag; \
})
#define access_ok(type, addr, size) __range_ok(addr, size)
/*
* The "__xxx" versions of the user access functions do not verify the address
* space - it must have been done previously with a separate "access_ok()"
* call.
*
* The "__xxx_error" versions set the third argument to -EFAULT if an error
* occurs, and leave it unchanged on success.
*/
#define __get_user_asm(instr, reg, x, addr, err) \
asm volatile( \
"1: " instr " " reg "1, [%2]\n" \
"2:\n" \
" .section .fixup, \"ax\"\n" \
" .align 2\n" \
"3: mov %w0, %3\n" \
" mov %1, #0\n" \
" b 2b\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .align 3\n" \
" .quad 1b, 3b\n" \
" .previous" \
: "+r" (err), "=&r" (x) \
: "r" (addr), "i" (-EFAULT))
#define __get_user_err(x, ptr, err) \
do { \
unsigned long __gu_val; \
__chk_user_ptr(ptr); \
switch (sizeof(*(ptr))) { \
case 1: \
__get_user_asm("ldrb", "%w", __gu_val, (ptr), (err)); \
break; \
case 2: \
__get_user_asm("ldrh", "%w", __gu_val, (ptr), (err)); \
break; \
case 4: \
__get_user_asm("ldr", "%w", __gu_val, (ptr), (err)); \
break; \
case 8: \
__get_user_asm("ldr", "%", __gu_val, (ptr), (err)); \
break; \
default: \
BUILD_BUG(); \
} \
(x) = (__typeof__(*(ptr)))__gu_val; \
} while (0)
#define __get_user(x, ptr) \
({ \
int __gu_err = 0; \
__get_user_err((x), (ptr), __gu_err); \
__gu_err; \
})
#define __get_user_error(x, ptr, err) \
({ \
__get_user_err((x), (ptr), (err)); \
(void)0; \
})
#define __get_user_unaligned __get_user
#define get_user(x, ptr) \
({ \
__typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \
access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \
__get_user((x), __p) : \
((x) = 0, -EFAULT); \
})
#define __put_user_asm(instr, reg, x, addr, err) \
asm volatile( \
"1: " instr " " reg "1, [%2]\n" \
"2:\n" \
" .section .fixup,\"ax\"\n" \
" .align 2\n" \
"3: mov %w0, %3\n" \
" b 2b\n" \
" .previous\n" \
" .section __ex_table,\"a\"\n" \
" .align 3\n" \
" .quad 1b, 3b\n" \
" .previous" \
: "+r" (err) \
: "r" (x), "r" (addr), "i" (-EFAULT))
#define __put_user_err(x, ptr, err) \
do { \
__typeof__(*(ptr)) __pu_val = (x); \
__chk_user_ptr(ptr); \
switch (sizeof(*(ptr))) { \
case 1: \
__put_user_asm("strb", "%w", __pu_val, (ptr), (err)); \
break; \
case 2: \
__put_user_asm("strh", "%w", __pu_val, (ptr), (err)); \
break; \
case 4: \
__put_user_asm("str", "%w", __pu_val, (ptr), (err)); \
break; \
case 8: \
__put_user_asm("str", "%", __pu_val, (ptr), (err)); \
break; \
default: \
BUILD_BUG(); \
} \
} while (0)
#define __put_user(x, ptr) \
({ \
int __pu_err = 0; \
__put_user_err((x), (ptr), __pu_err); \
__pu_err; \
})
#define __put_user_error(x, ptr, err) \
({ \
__put_user_err((x), (ptr), (err)); \
(void)0; \
})
#define __put_user_unaligned __put_user
#define put_user(x, ptr) \
({ \
__typeof__(*(ptr)) __user *__p = (ptr); \
might_fault(); \
access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \
__put_user((x), __p) : \
-EFAULT; \
})
extern unsigned long __must_check __copy_from_user(void *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n);
extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n);
extern unsigned long __must_check __clear_user(void __user *addr, unsigned long n);
extern unsigned long __must_check __strncpy_from_user(char *to, const char __user *from, unsigned long count);
extern unsigned long __must_check __strnlen_user(const char __user *s, long n);
static inline unsigned long __must_check copy_from_user(void *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n))
n = __copy_from_user(to, from, n);
else /* security hole - plug it */
memset(to, 0, n);
return n;
}
static inline unsigned long __must_check copy_to_user(void __user *to, const void *from, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
n = __copy_to_user(to, from, n);
return n;
}
static inline unsigned long __must_check copy_in_user(void __user *to, const void __user *from, unsigned long n)
{
if (access_ok(VERIFY_READ, from, n) && access_ok(VERIFY_WRITE, to, n))
n = __copy_in_user(to, from, n);
return n;
}
#define __copy_to_user_inatomic __copy_to_user
#define __copy_from_user_inatomic __copy_from_user
static inline unsigned long __must_check clear_user(void __user *to, unsigned long n)
{
if (access_ok(VERIFY_WRITE, to, n))
n = __clear_user(to, n);
return n;
}
static inline long __must_check strncpy_from_user(char *dst, const char __user *src, long count)
{
long res = -EFAULT;
if (access_ok(VERIFY_READ, src, 1))
res = __strncpy_from_user(dst, src, count);
return res;
}
#define strlen_user(s) strnlen_user(s, ~0UL >> 1)
static inline long __must_check strnlen_user(const char __user *s, long n)
{
unsigned long res = 0;
if (__addr_ok(s))
res = __strnlen_user(s, n);
return res;
}
#endif /* __ASM_UACCESS_H */
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