text: #ifndef _ASM_X86_UACCESS_H
  #define _ASM_X86_UACCESS_H
  /*
   * User space memory access functions
   */
  #include <linux/errno.h>
  #include <linux/compiler.h>
  #include <linux/kasan-checks.h>
  #include <linux/thread_info.h>
  #include <linux/string.h>
  #include <linux/sched.h>
  #include <asm/asm.h>
  #include <asm/page.h>
  #include <asm/smap.h>
  #include <asm/extable.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 MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
  
  #define KERNEL_DS	MAKE_MM_SEG(-1UL)
  #define USER_DS 	MAKE_MM_SEG(TASK_SIZE_MAX)
  
  #define get_ds()	(KERNEL_DS)
  #define get_fs()	(current->thread.addr_limit)
  static inline void set_fs(mm_segment_t fs)
  {
  	current->thread.addr_limit = fs;
  	/* On user-mode return, check fs is correct */
  	set_thread_flag(TIF_FSCHECK);
  }
  
  #define segment_eq(a, b)	((a).seg == (b).seg)
  
  #define user_addr_max() (current->thread.addr_limit.seg)
  #define __addr_ok(addr) 	\
  	((unsigned long __force)(addr) < user_addr_max())
  
  /*
   * Test whether a block of memory is a valid user space address.
   * Returns 0 if the range is valid, nonzero otherwise.
   */
  static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)
  {
  	/*
  	 * If we have used "sizeof()" for the size,
  	 * we know it won't overflow the limit (but
  	 * it might overflow the 'addr', so it's
  	 * important to subtract the size from the
  	 * limit, not add it to the address).
  	 */
  	if (__builtin_constant_p(size))
  		return unlikely(addr > limit - size);
  
  	/* Arbitrary sizes? Be careful about overflow */
  	addr += size;
  	if (unlikely(addr < size))
  		return true;
  	return unlikely(addr > limit);
  }
  
  #define __range_not_ok(addr, size, limit)				\
  ({									\
  	__chk_user_ptr(addr);						\
  	__chk_range_not_ok((unsigned long __force)(addr), size, limit); \
  })
  
  #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
  # define WARN_ON_IN_IRQ()	WARN_ON_ONCE(!in_task())
  #else
  # define WARN_ON_IN_IRQ()
  #endif
  
  /**
   * 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(type, addr, size)					\
  ({									\
  	WARN_ON_IN_IRQ();						\
  	likely(!__range_not_ok(addr, size, user_addr_max()));		\
  })
  
  /*
   * 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 ugliness 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).
   */
  
  extern int __get_user_1(void);
  extern int __get_user_2(void);
  extern int __get_user_4(void);
  extern int __get_user_8(void);
  extern int __get_user_bad(void);
  
  #define __uaccess_begin() stac()
  #define __uaccess_end()   clac()
  #define __uaccess_begin_nospec()	\
  ({					\
  	stac();				\
  	barrier_nospec();		\
  })
  
  /*
   * This is a type: either unsigned long, if the argument fits into
   * that type, or otherwise unsigned long long.
   */
  #define __inttype(x) \
  __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
  
  /**
   * 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.
   */
  /*
   * Careful: we have to cast the result to the type of the pointer
   * for sign reasons.
   *
   * The use of _ASM_DX as the register specifier is a bit of a
   * simplification, as gcc only cares about it as the starting point
   * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits
   * (%ecx being the next register in gcc's x86 register sequence), and
   * %rdx on 64 bits.
   *
   * Clang/LLVM cares about the size of the register, but still wants
   * the base register for something that ends up being a pair.
   */
  #define get_user(x, ptr)						\
  ({									\
  	int __ret_gu;							\
  	register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX);		\
  	__chk_user_ptr(ptr);						\
  	might_fault();							\
  	asm volatile("call __get_user_%P4"				\
  		     : "=a" (__ret_gu), "=r" (__val_gu),		\
  			ASM_CALL_CONSTRAINT				\
  		     : "0" (ptr), "i" (sizeof(*(ptr))));		\
  	(x) = (__force __typeof__(*(ptr))) __val_gu;			\
  	__builtin_expect(__ret_gu, 0);					\
  })
  
  #define __put_user_x(size, x, ptr, __ret_pu)			\
  	asm volatile("call __put_user_" #size : "=a" (__ret_pu)	\
  		     : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
  
  
  
  #ifdef CONFIG_X86_32
  #define __put_user_asm_u64(x, addr, err, errret)			\
  	asm volatile("\n"						\
  		     "1:	movl %%eax,0(%2)\n"			\
  		     "2:	movl %%edx,4(%2)\n"			\
  		     "3:"						\
  		     ".section .fixup,\"ax\"\n"				\
  		     "4:	movl %3,%0\n"				\
  		     "	jmp 3b\n"					\
  		     ".previous\n"					\
  		     _ASM_EXTABLE(1b, 4b)				\
  		     _ASM_EXTABLE(2b, 4b)				\
  		     : "=r" (err)					\
  		     : "A" (x), "r" (addr), "i" (errret), "0" (err))
  
  #define __put_user_asm_ex_u64(x, addr)					\
  	asm volatile("\n"						\
  		     "1:	movl %%eax,0(%1)\n"			\
  		     "2:	movl %%edx,4(%1)\n"			\
  		     "3:"						\
  		     _ASM_EXTABLE_EX(1b, 2b)				\
  		     _ASM_EXTABLE_EX(2b, 3b)				\
  		     : : "A" (x), "r" (addr))
  
  #define __put_user_x8(x, ptr, __ret_pu)				\
  	asm volatile("call __put_user_8" : "=a" (__ret_pu)	\
  		     : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
  #else
  #define __put_user_asm_u64(x, ptr, retval, errret) \
  	__put_user_asm(x, ptr, retval, "q", "", "er", errret)
  #define __put_user_asm_ex_u64(x, addr)	\
  	__put_user_asm_ex(x, addr, "q", "", "er")
  #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
  #endif
  
  extern void __put_user_bad(void);
  
  /*
   * Strange magic calling convention: pointer in %ecx,
   * value in %eax(:%edx), return value in %eax. clobbers %rbx
   */
  extern void __put_user_1(void);
  extern void __put_user_2(void);
  extern void __put_user_4(void);
  extern void __put_user_8(void);
  
  /**
   * 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)					\
  ({								\
  	int __ret_pu;						\
  	__typeof__(*(ptr)) __pu_val;				\
  	__chk_user_ptr(ptr);					\
  	might_fault();						\
  	__pu_val = x;						\
  	switch (sizeof(*(ptr))) {				\
  	case 1:							\
  		__put_user_x(1, __pu_val, ptr, __ret_pu);	\
  		break;						\
  	case 2:							\
  		__put_user_x(2, __pu_val, ptr, __ret_pu);	\
  		break;						\
  	case 4:							\
  		__put_user_x(4, __pu_val, ptr, __ret_pu);	\
  		break;						\
  	case 8:							\
  		__put_user_x8(__pu_val, ptr, __ret_pu);		\
  		break;						\
  	default:						\
  		__put_user_x(X, __pu_val, ptr, __ret_pu);	\
  		break;						\
  	}							\
  	__builtin_expect(__ret_pu, 0);				\
  })
  
  #define __put_user_size(x, ptr, size, retval, errret)			\
  do {									\
  	retval = 0;							\
  	__chk_user_ptr(ptr);						\
  	switch (size) {							\
  	case 1:								\
  		__put_user_asm(x, ptr, retval, "b", "b", "iq", errret);	\
  		break;							\
  	case 2:								\
  		__put_user_asm(x, ptr, retval, "w", "w", "ir", errret);	\
  		break;							\
  	case 4:								\
  		__put_user_asm(x, ptr, retval, "l", "k", "ir", errret);	\
  		break;							\
  	case 8:								\
  		__put_user_asm_u64(x, ptr, retval, errret);		\
  		break;							\
  	default:							\
  		__put_user_bad();					\
  	}								\
  } while (0)
  
  /*
   * This doesn't do __uaccess_begin/end - the exception handling
   * around it must do that.
   */
  #define __put_user_size_ex(x, ptr, size)				\
  do {									\
  	__chk_user_ptr(ptr);						\
  	switch (size) {							\
  	case 1:								\
  		__put_user_asm_ex(x, ptr, "b", "b", "iq");		\
  		break;							\
  	case 2:								\
  		__put_user_asm_ex(x, ptr, "w", "w", "ir");		\
  		break;							\
  	case 4:								\
  		__put_user_asm_ex(x, ptr, "l", "k", "ir");		\
  		break;							\
  	case 8:								\
  		__put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr);	\
  		break;							\
  	default:							\
  		__put_user_bad();					\
  	}								\
  } while (0)
  
  #ifdef CONFIG_X86_32
  #define __get_user_asm_u64(x, ptr, retval, errret)			\
  ({									\
  	__typeof__(ptr) __ptr = (ptr);					\
  	asm volatile("\n"					\
  		     "1:	movl %2,%%eax\n"			\
  		     "2:	movl %3,%%edx\n"			\
  		     "3:\n"				\
  		     ".section .fixup,\"ax\"\n"				\
  		     "4:	mov %4,%0\n"				\
  		     "	xorl %%eax,%%eax\n"				\
  		     "	xorl %%edx,%%edx\n"				\
  		     "	jmp 3b\n"					\
  		     ".previous\n"					\
  		     _ASM_EXTABLE(1b, 4b)				\
  		     _ASM_EXTABLE(2b, 4b)				\
  		     : "=r" (retval), "=&A"(x)				\
  		     : "m" (__m(__ptr)), "m" __m(((u32 *)(__ptr)) + 1),	\
  		       "i" (errret), "0" (retval));			\
  })
  
  #define __get_user_asm_ex_u64(x, ptr)			(x) = __get_user_bad()
  #else
  #define __get_user_asm_u64(x, ptr, retval, errret) \
  	 __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
  #define __get_user_asm_ex_u64(x, ptr) \
  	 __get_user_asm_ex(x, ptr, "q", "", "=r")
  #endif
  
  #define __get_user_size(x, ptr, size, retval, errret)			\
  do {									\
  	retval = 0;							\
  	__chk_user_ptr(ptr);						\
  	switch (size) {							\
  	case 1:								\
  		__get_user_asm(x, ptr, retval, "b", "b", "=q", errret);	\
  		break;							\
  	case 2:								\
  		__get_user_asm(x, ptr, retval, "w", "w", "=r", errret);	\
  		break;							\
  	case 4:								\
  		__get_user_asm(x, ptr, retval, "l", "k", "=r", errret);	\
  		break;							\
  	case 8:								\
  		__get_user_asm_u64(x, ptr, retval, errret);		\
  		break;							\
  	default:							\
  		(x) = __get_user_bad();					\
  	}								\
  } while (0)
  
  #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)	\
  	asm volatile("\n"						\
  		     "1:	mov"itype" %2,%"rtype"1\n"		\
  		     "2:\n"						\
  		     ".section .fixup,\"ax\"\n"				\
  		     "3:	mov %3,%0\n"				\
  		     "	xor"itype" %"rtype"1,%"rtype"1\n"		\
  		     "	jmp 2b\n"					\
  		     ".previous\n"					\
  		     _ASM_EXTABLE(1b, 3b)				\
  		     : "=r" (err), ltype(x)				\
  		     : "m" (__m(addr)), "i" (errret), "0" (err))
  
  /*
   * This doesn't do __uaccess_begin/end - the exception handling
   * around it must do that.
   */
  #define __get_user_size_ex(x, ptr, size)				\
  do {									\
  	__chk_user_ptr(ptr);						\
  	switch (size) {							\
  	case 1:								\
  		__get_user_asm_ex(x, ptr, "b", "b", "=q");		\
  		break;							\
  	case 2:								\
  		__get_user_asm_ex(x, ptr, "w", "w", "=r");		\
  		break;							\
  	case 4:								\
  		__get_user_asm_ex(x, ptr, "l", "k", "=r");		\
  		break;							\
  	case 8:								\
  		__get_user_asm_ex_u64(x, ptr);				\
  		break;							\
  	default:							\
  		(x) = __get_user_bad();					\
  	}								\
  } while (0)
  
  #define __get_user_asm_ex(x, addr, itype, rtype, ltype)			\
  	asm volatile("1:	mov"itype" %1,%"rtype"0\n"		\
  		     "2:\n"						\
  		     ".section .fixup,\"ax\"\n"				\
                       "3:xor"itype" %"rtype"0,%"rtype"0\n"		\
  		     "  jmp 2b\n"					\
  		     ".previous\n"					\
  		     _ASM_EXTABLE_EX(1b, 3b)				\
  		     : ltype(x) : "m" (__m(addr)))
  
  #define __put_user_nocheck(x, ptr, size)			\
  ({								\
  	int __pu_err;						\
  	__typeof__(*(ptr)) __pu_val;				\
  	__pu_val = x;						\
  	__uaccess_begin();					\
  	__put_user_size(__pu_val, (ptr), (size), __pu_err, -EFAULT);\
  	__uaccess_end();					\
  	__builtin_expect(__pu_err, 0);				\
  })
  
  #define __get_user_nocheck(x, ptr, size)				\
  ({									\
  	int __gu_err;							\
  	__inttype(*(ptr)) __gu_val;					\
  	__typeof__(ptr) __gu_ptr = (ptr);				\
  	__typeof__(size) __gu_size = (size);				\
  	__uaccess_begin_nospec();					\
  	__get_user_size(__gu_val, __gu_ptr, __gu_size, __gu_err, -EFAULT);	\
  	__uaccess_end();						\
  	(x) = (__force __typeof__(*(ptr)))__gu_val;			\
  	__builtin_expect(__gu_err, 0);					\
  })
  
  /* FIXME: this hack is definitely wrong -AK */
  struct __large_struct { unsigned long buf[100]; };
  #define __m(x) (*(struct __large_struct __user *)(x))
  
  /*
   * 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.
   */
  #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)	\
  	asm volatile("\n"						\
  		     "1:	mov"itype" %"rtype"1,%2\n"		\
  		     "2:\n"						\
  		     ".section .fixup,\"ax\"\n"				\
  		     "3:	mov %3,%0\n"				\
  		     "	jmp 2b\n"					\
  		     ".previous\n"					\
  		     _ASM_EXTABLE(1b, 3b)				\
  		     : "=r"(err)					\
  		     : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
  
  #define __put_user_asm_ex(x, addr, itype, rtype, ltype)			\
  	asm volatile("1:	mov"itype" %"rtype"0,%1\n"		\
  		     "2:\n"						\
  		     _ASM_EXTABLE_EX(1b, 2b)				\
  		     : : ltype(x), "m" (__m(addr)))
  
  /*
   * uaccess_try and catch
   */
  #define uaccess_try	do {						\
  	current->thread.uaccess_err = 0;				\
  	__uaccess_begin();						\
  	barrier();
  
  #define uaccess_try_nospec do {						\
  	current->thread.uaccess_err = 0;				\
  	__uaccess_begin_nospec();					\
  
  #define uaccess_catch(err)						\
  	__uaccess_end();						\
  	(err) |= (current->thread.uaccess_err ? -EFAULT : 0);		\
  } while (0)
  
  /**
   * __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)))
  
  /**
   * __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((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  
  #define __get_user_unaligned __get_user
  #define __put_user_unaligned __put_user
  
  /*
   * {get|put}_user_try and catch
   *
   * get_user_try {
   *	get_user_ex(...);
   * } get_user_catch(err)
   */
  #define get_user_try		uaccess_try_nospec
  #define get_user_catch(err)	uaccess_catch(err)
  
  #define get_user_ex(x, ptr)	do {					\
  	unsigned long __gue_val;					\
  	__get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr))));	\
  	(x) = (__force __typeof__(*(ptr)))__gue_val;			\
  } while (0)
  
  #define put_user_try		uaccess_try
  #define put_user_catch(err)	uaccess_catch(err)
  
  #define put_user_ex(x, ptr)						\
  	__put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
  
  extern unsigned long
  copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
  extern __must_check long
  strncpy_from_user(char *dst, const char __user *src, long count);
  
  extern __must_check long strlen_user(const char __user *str);
  extern __must_check long strnlen_user(const char __user *str, long n);
  
  unsigned long __must_check clear_user(void __user *mem, unsigned long len);
  unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
  
  extern void __cmpxchg_wrong_size(void)
  	__compiletime_error("Bad argument size for cmpxchg");
  
  #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size)	\
  ({									\
  	int __ret = 0;							\
  	__typeof__(ptr) __uval = (uval);				\
  	__typeof__(*(ptr)) __old = (old);				\
  	__typeof__(*(ptr)) __new = (new);				\
  	__uaccess_begin_nospec();					\
  	switch (size) {							\
  	case 1:								\
  	{								\
  		asm volatile("\n"					\
  			"1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n"		\
  			"2:\n"						\
  			"\t.section .fixup, \"ax\"\n"			\
  			"3:\tmov     %3, %0\n"				\
  			"\tjmp     2b\n"				\
  			"\t.previous\n"					\
  			_ASM_EXTABLE(1b, 3b)				\
  			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
  			: "i" (-EFAULT), "q" (__new), "1" (__old)	\
  			: "memory"					\
  		);							\
  		break;							\
  	}								\
  	case 2:								\
  	{								\
  		asm volatile("\n"					\
  			"1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n"		\
  			"2:\n"						\
  			"\t.section .fixup, \"ax\"\n"			\
  			"3:\tmov     %3, %0\n"				\
  			"\tjmp     2b\n"				\
  			"\t.previous\n"					\
  			_ASM_EXTABLE(1b, 3b)				\
  			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
  			: "i" (-EFAULT), "r" (__new), "1" (__old)	\
  			: "memory"					\
  		);							\
  		break;							\
  	}								\
  	case 4:								\
  	{								\
  		asm volatile("\n"					\
  			"1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"		\
  			"2:\n"						\
  			"\t.section .fixup, \"ax\"\n"			\
  			"3:\tmov     %3, %0\n"				\
  			"\tjmp     2b\n"				\
  			"\t.previous\n"					\
  			_ASM_EXTABLE(1b, 3b)				\
  			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
  			: "i" (-EFAULT), "r" (__new), "1" (__old)	\
  			: "memory"					\
  		);							\
  		break;							\
  	}								\
  	case 8:								\
  	{								\
  		if (!IS_ENABLED(CONFIG_X86_64))				\
  			__cmpxchg_wrong_size();				\
  									\
  		asm volatile("\n"					\
  			"1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n"		\
  			"2:\n"						\
  			"\t.section .fixup, \"ax\"\n"			\
  			"3:\tmov     %3, %0\n"				\
  			"\tjmp     2b\n"				\
  			"\t.previous\n"					\
  			_ASM_EXTABLE(1b, 3b)				\
  			: "+r" (__ret), "=a" (__old), "+m" (*(ptr))	\
  			: "i" (-EFAULT), "r" (__new), "1" (__old)	\
  			: "memory"					\
  		);							\
  		break;							\
  	}								\
  	default:							\
  		__cmpxchg_wrong_size();					\
  	}								\
  	__uaccess_end();						\
  	*__uval = __old;						\
  	__ret;								\
  })
  
  #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new)		\
  ({									\
  	access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ?		\
  		__user_atomic_cmpxchg_inatomic((uval), (ptr),		\
  				(old), (new), sizeof(*(ptr))) :		\
  		-EFAULT;						\
  })
  
  /*
   * movsl can be slow when source and dest are not both 8-byte aligned
   */
  #ifdef CONFIG_X86_INTEL_USERCOPY
  extern struct movsl_mask {
  	int mask;
  } ____cacheline_aligned_in_smp movsl_mask;
  #endif
  
  #define ARCH_HAS_NOCACHE_UACCESS 1
  
  #ifdef CONFIG_X86_32
  # include <asm/uaccess_32.h>
  #else
  # include <asm/uaccess_64.h>
  #endif
  
  unsigned long __must_check _copy_from_user(void *to, const void __user *from,
  					   unsigned n);
  unsigned long __must_check _copy_to_user(void __user *to, const void *from,
  					 unsigned n);
  
  extern void __compiletime_error("usercopy buffer size is too small")
  __bad_copy_user(void);
  
  static inline void copy_user_overflow(int size, unsigned long count)
  {
  	WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
  }
  
  static __always_inline unsigned long __must_check
  copy_from_user(void *to, const void __user *from, unsigned long n)
  {
  	int sz = __compiletime_object_size(to);
  
  	might_fault();
  
  	kasan_check_write(to, n);
  
  	if (likely(sz < 0 || sz >= n)) {
  		check_object_size(to, n, false);
  		n = _copy_from_user(to, from, n);
  	} else if (!__builtin_constant_p(n))
  		copy_user_overflow(sz, n);
  	else
  		__bad_copy_user();
  
  	return n;
  }
  
  static __always_inline unsigned long __must_check
  copy_to_user(void __user *to, const void *from, unsigned long n)
  {
  	int sz = __compiletime_object_size(from);
  
  	kasan_check_read(from, n);
  
  	might_fault();
  
  	if (likely(sz < 0 || sz >= n)) {
  		check_object_size(from, n, true);
  		n = _copy_to_user(to, from, n);
  	} else if (!__builtin_constant_p(n))
  		copy_user_overflow(sz, n);
  	else
  		__bad_copy_user();
  
  	return n;
  }
  
  /*
   * We rely on the nested NMI work to allow atomic faults from the NMI path; the
   * nested NMI paths are careful to preserve CR2.
   *
   * Caller must use pagefault_enable/disable, or run in interrupt context,
   * and also do a uaccess_ok() check
   */
  #define __copy_from_user_nmi __copy_from_user_inatomic
  
  /*
   * The "unsafe" user accesses aren't really "unsafe", but the naming
   * is a big fat warning: you have to not only do the access_ok()
   * checking before using them, but you have to surround them with the
   * user_access_begin/end() pair.
   */
  #define user_access_begin()	__uaccess_begin()
  #define user_access_end()	__uaccess_end()
  
  #define unsafe_put_user(x, ptr, err_label)					\
  do {										\
  	int __pu_err;								\
  	__put_user_size((x), (ptr), sizeof(*(ptr)), __pu_err, -EFAULT);		\
  	if (unlikely(__pu_err)) goto err_label;					\
  } while (0)
  
  #define unsafe_get_user(x, ptr, err_label)					\
  do {										\
  	int __gu_err;								\
  	unsigned long __gu_val;							\
  	__get_user_size(__gu_val, (ptr), sizeof(*(ptr)), __gu_err, -EFAULT);	\
  	(x) = (__force __typeof__(*(ptr)))__gu_val;				\
  	if (unlikely(__gu_err)) goto err_label;					\
  } while (0)
  
  #endif /* _ASM_X86_UACCESS_H */
  
  