/* SPDX-License-Identifier: GPL-2.0 */
#ifndef __SCORE_UACCESS_H
#define __SCORE_UACCESS_H
#include <linux/kernel.h>
#include <asm/extable.h>
#define get_ds() (KERNEL_DS)
#define get_fs() (current_thread_info()->addr_limit)
#define segment_eq(a, b) ((a).seg == (b).seg)
/*
* Is a address valid? This does a straighforward calculation rather
* than tests.
*
* Address valid if:
* - "addr" doesn't have any high-bits set
* - AND "size" doesn't have any high-bits set
* - AND "addr+size" doesn't have any high-bits set
* - OR we are in kernel mode.
*
* __ua_size() is a trick to avoid runtime checking of positive constant
* sizes; for those we already know at compile time that the size is ok.
*/
#define __ua_size(size) \
((__builtin_constant_p(size) && (signed long) (size) > 0) ? 0 : (size))
/*
* access_ok: - Checks if a user space pointer is valid
* @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that
* %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
* to write to a block, it is always safe to read from it.
* @addr: User space pointer to start of block to check
* @size: Size of block to check
*
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* Checks if a pointer to a block of memory in user space is valid.
*
* Returns true (nonzero) if the memory block may be valid, false (zero)
* if it is definitely invalid.
*
* Note that, depending on architecture, this function probably just
* checks that the pointer is in the user space range - after calling
* this function, memory access functions may still return -EFAULT.
*/
#define __access_ok(addr, size) \
(((long)((get_fs().seg) & \
((addr) | ((addr) + (size)) | \
__ua_size(size)))) == 0)
#define access_ok(type, addr, size) \
likely(__access_ok((unsigned long)(addr), (size)))
/*
* put_user: - Write a simple value into user space.
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
* data types like structures or arrays.
*
* @ptr must have pointer-to-simple-variable type, and @x must be assignable
* to the result of dereferencing @ptr.
*
* Returns zero on success, or -EFAULT on error.
*/
#define put_user(x, ptr) __put_user_check((x), (ptr), sizeof(*(ptr)))
/*
* get_user: - Get a simple variable from user space.
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
* data types like structures or arrays.
*
* @ptr must have pointer-to-simple-variable type, and the result of
* dereferencing @ptr must be assignable to @x without a cast.
*
* Returns zero on success, or -EFAULT on error.
* On error, the variable @x is set to zero.
*/
#define get_user(x, ptr) __get_user_check((x), (ptr), sizeof(*(ptr)))
/*
* __put_user: - Write a simple value into user space, with less checking.
* @x: Value to copy to user space.
* @ptr: Destination address, in user space.
*
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple value from kernel space to user
* space. It supports simple types like char and int, but not larger
* data types like structures or arrays.
*
* @ptr must have pointer-to-simple-variable type, and @x must be assignable
* to the result of dereferencing @ptr.
*
* Caller must check the pointer with access_ok() before calling this
* function.
*
* Returns zero on success, or -EFAULT on error.
*/
#define __put_user(x, ptr) __put_user_nocheck((x), (ptr), sizeof(*(ptr)))
/*
* __get_user: - Get a simple variable from user space, with less checking.
* @x: Variable to store result.
* @ptr: Source address, in user space.
*
* Context: User context only. This function may sleep if pagefaults are
* enabled.
*
* This macro copies a single simple variable from user space to kernel
* space. It supports simple types like char and int, but not larger
* data types like structures or arrays.
*
* @ptr must have pointer-to-simple-variable type, and the result of
* dereferencing @ptr must be assignable to @x without a cast.
*
* Caller must check the pointer with access_ok() before calling this
* function.
*
* Returns zero on success, or -EFAULT on error.
* On error, the variable @x is set to zero.
*/
#define __get_user(x, ptr) __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
struct __large_struct { unsigned long buf[100]; };
#define __m(x) (*(struct __large_struct __user *)(x))
/*
* Yuck. We need two variants, one for 64bit operation and one
* for 32 bit mode and old iron.
*/
extern void __get_user_unknown(void);
#define __get_user_common(val, size, ptr) \
do { \
switch (size) { \
case 1: \
__get_user_asm(val, "lb", ptr); \
break; \
case 2: \
__get_user_asm(val, "lh", ptr); \
break; \
case 4: \
__get_user_asm(val, "lw", ptr); \
break; \
case 8: \
if (__copy_from_user((void *)&val, ptr, 8) == 0) \
__gu_err = 0; \
else \
__gu_err = -EFAULT; \
break; \
default: \
__get_user_unknown(); \
break; \
} \
} while (0)
#define __get_user_nocheck(x, ptr, size) \
({ \
long __gu_err = 0; \
__get_user_common((x), size, ptr); \
__gu_err; \
})
#define __get_user_check(x, ptr, size) \
({ \
long __gu_err = -EFAULT; \
const __typeof__(*(ptr)) __user *__gu_ptr = (ptr); \
\
if (likely(access_ok(VERIFY_READ, __gu_ptr, size))) \
__get_user_common((x), size, __gu_ptr); \
else \
(x) = 0; \
\
__gu_err; \
})
#define __get_user_asm(val, insn, addr) \
{ \
long __gu_tmp; \
\
__asm__ __volatile__( \
"1:" insn " %1, %3\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3:li %0, %4\n" \
"li %1, 0\n" \
"j 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
".word 1b, 3b\n" \
".previous\n" \
: "=r" (__gu_err), "=r" (__gu_tmp) \
: "0" (0), "o" (__m(addr)), "i" (-EFAULT)); \
\
(val) = (__typeof__(*(addr))) __gu_tmp; \
}
/*
* Yuck. We need two variants, one for 64bit operation and one
* for 32 bit mode and old iron.
*/
#define __put_user_nocheck(val, ptr, size) \
({ \
__typeof__(*(ptr)) __pu_val; \
long __pu_err = 0; \
\
__pu_val = (val); \
switch (size) { \
case 1: \
__put_user_asm("sb", ptr); \
break; \
case 2: \
__put_user_asm("sh", ptr); \
break; \
case 4: \
__put_user_asm("sw", ptr); \
break; \
case 8: \
if ((__copy_to_user((void *)ptr, &__pu_val, 8)) == 0) \
__pu_err = 0; \
else \
__pu_err = -EFAULT; \
break; \
default: \
__put_user_unknown(); \
break; \
} \
__pu_err; \
})
#define __put_user_check(val, ptr, size) \
({ \
__typeof__(*(ptr)) __user *__pu_addr = (ptr); \
__typeof__(*(ptr)) __pu_val = (val); \
long __pu_err = -EFAULT; \
\
if (likely(access_ok(VERIFY_WRITE, __pu_addr, size))) { \
switch (size) { \
case 1: \
__put_user_asm("sb", __pu_addr); \
break; \
case 2: \
__put_user_asm("sh", __pu_addr); \
break; \
case 4: \
__put_user_asm("sw", __pu_addr); \
break; \
case 8: \
if ((__copy_to_user((void *)__pu_addr, &__pu_val, 8)) == 0)\
__pu_err = 0; \
else \
__pu_err = -EFAULT; \
break; \
default: \
__put_user_unknown(); \
break; \
} \
} \
__pu_err; \
})
#define __put_user_asm(insn, ptr) \
__asm__ __volatile__( \
"1:" insn " %2, %3\n" \
"2:\n" \
".section .fixup,\"ax\"\n" \
"3:li %0, %4\n" \
"j 2b\n" \
".previous\n" \
".section __ex_table,\"a\"\n" \
".word 1b, 3b\n" \
".previous\n" \
: "=r" (__pu_err) \
: "0" (0), "r" (__pu_val), "o" (__m(ptr)), \
"i" (-EFAULT));
extern void __put_user_unknown(void);
extern int __copy_tofrom_user(void *to, const void *from, unsigned long len);
static inline unsigned long
raw_copy_from_user(void *to, const void __user *from, unsigned long len)
{
return __copy_tofrom_user(to, (__force const void *)from, len);
}
static inline unsigned long
raw_copy_to_user(void __user *to, const void *from, unsigned long len)
{
return __copy_tofrom_user((__force void *)to, from, len);
}
#define INLINE_COPY_FROM_USER
#define INLINE_COPY_TO_USER
/*
* __clear_user: - Zero a block of memory in user space, with less checking.
* @to: Destination address, in user space.
* @n: Number of bytes to zero.
*
* Zero a block of memory in user space. Caller must check
* the specified block with access_ok() before calling this function.
*
* Returns number of bytes that could not be cleared.
* On success, this will be zero.
*/
extern unsigned long __clear_user(void __user *src, unsigned long size);
static inline unsigned long clear_user(char *src, unsigned long size)
{
if (access_ok(VERIFY_WRITE, src, size))
return __clear_user(src, size);
return -EFAULT;
}
/*
* __strncpy_from_user: - Copy a NUL terminated string from userspace, with less checking.
* @dst: Destination address, in kernel space. This buffer must be at
* least @count bytes long.
* @src: Source address, in user space.
* @count: Maximum number of bytes to copy, including the trailing NUL.
*
* Copies a NUL-terminated string from userspace to kernel space.
* Caller must check the specified block with access_ok() before calling
* this function.
*
* On success, returns the length of the string (not including the trailing
* NUL).
*
* If access to userspace fails, returns -EFAULT (some data may have been
* copied).
*
* If @count is smaller than the length of the string, copies @count bytes
* and returns @count.
*/
extern int __strncpy_from_user(char *dst, const char *src, long len);
static inline int strncpy_from_user(char *dst, const char *src, long len)
{
if (access_ok(VERIFY_READ, src, 1))
return __strncpy_from_user(dst, src, len);
return -EFAULT;
}
extern int __strnlen_user(const char *str, long len);
static inline long strnlen_user(const char __user *str, long len)
{
if (!access_ok(VERIFY_READ, str, 0))
return 0;
else
return __strnlen_user(str, len);
}
#endif /* __SCORE_UACCESS_H */