generated by cgit v1.2.2 (git 2.25.0) at 2025-08-02 20:32:37 -0400
 


hl ppc">	current_thread_info()->uaccess_err = 0;				\
	stac();								\
	barrier();

#define uaccess_catch(err)						\
	clac();								\
	(err) |= (current_thread_info()->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.
 *
 * 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.
 *
 * 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
#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);				\
	switch (size) {							\
	case 1:								\
	{								\
		asm volatile("\t" ASM_STAC "\n"				\
			"1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n"		\
			"2:\t" ASM_CLAC "\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("\t" ASM_STAC "\n"				\
			"1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n"		\
			"2:\t" ASM_CLAC "\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("\t" ASM_STAC "\n"				\
			"1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"		\
			"2:\t" ASM_CLAC "\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("\t" ASM_STAC "\n"				\
			"1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n"		\
			"2:\t" ASM_CLAC "\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();					\
	}								\
	*__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);

#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
# define copy_user_diag __compiletime_error
#else
# define copy_user_diag __compiletime_warning
#endif

extern void copy_user_diag("copy_from_user() buffer size is too small")
copy_from_user_overflow(void);
extern void copy_user_diag("copy_to_user() buffer size is too small")
copy_to_user_overflow(void) __asm__("copy_from_user_overflow");

#undef copy_user_diag

#ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS

extern void
__compiletime_warning("copy_from_user() buffer size is not provably correct")
__copy_from_user_overflow(void) __asm__("copy_from_user_overflow");
#define __copy_from_user_overflow(size, count) __copy_from_user_overflow()

extern void
__compiletime_warning("copy_to_user() buffer size is not provably correct")
__copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
#define __copy_to_user_overflow(size, count) __copy_to_user_overflow()

#else

static inline void
__copy_from_user_overflow(int size, unsigned long count)
{
	WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
}

#define __copy_to_user_overflow __copy_from_user_overflow

#endif

static 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();

	/*
	 * While we would like to have the compiler do the checking for us
	 * even in the non-constant size case, any false positives there are
	 * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even
	 * without - the [hopefully] dangerous looking nature of the warning
	 * would make people go look at the respecitive call sites over and
	 * over again just to find that there's no problem).
	 *
	 * And there are cases where it's just not realistic for the compiler
	 * to prove the count to be in range. For example when multiple call
	 * sites of a helper function - perhaps in different source files -
	 * all doing proper range checking, yet the helper function not doing
	 * so again.
	 *
	 * Therefore limit the compile time checking to the constant size
	 * case, and do only runtime checking for non-constant sizes.
	 */

	if (likely(sz < 0 || sz >= n))
		n = _copy_from_user(to, from, n);
	else if(__builtin_constant_p(n))
		copy_from_user_overflow();
	else
		__copy_from_user_overflow(sz, n);

	return n;
}

static inline unsigned long __must_check
copy_to_user(void __user *to, const void *from, unsigned long n)
{
	int sz = __compiletime_object_size(from);

	might_fault();

	/* See the comment in copy_from_user() above. */
	if (likely(sz < 0 || sz >= n))
		n = _copy_to_user(to, from, n);
	else if(__builtin_constant_p(n))
		copy_to_user_overflow();
	else
		__copy_to_user_overflow(sz, n);

	return n;
}

#undef __copy_from_user_overflow
#undef __copy_to_user_overflow

#endif /* _ASM_X86_UACCESS_H */