// SPDX-License-Identifier: GPL-2.0#include <linux/compiler.h>#include <linux/errno.h>#include <linux/export.h>#include <linux/fault-inject-usercopy.h>#include <linux/instrumented.h>#include <linux/kernel.h>#include <linux/nospec.h>#include <linux/string.h>#include <linux/uaccess.h>#include <linux/wordpart.h> /* out-of-line parts */ #if !defined(INLINE_COPY_USER)unsigned long _copy_from_user(void *to, const void __user *from, unsigned long n){	return _inline_copy_from_user(to, from, n);}EXPORT_SYMBOL(_copy_from_user); unsigned long _copy_to_user(void __user *to, const void *from, unsigned long n){	return _inline_copy_to_user(to, from, n);}EXPORT_SYMBOL(_copy_to_user);#endif /** * check_zeroed_user: check if a userspace buffer only contains zero bytes * @from: Source address, in userspace. * @size: Size of buffer. * * This is effectively shorthand for "memchr_inv(from, 0, size) == NULL" for * userspace addresses (and is more efficient because we don't care where the * first non-zero byte is). * * Returns: *  * 0: There were non-zero bytes present in the buffer. *  * 1: The buffer was full of zero bytes. *  * -EFAULT: access to userspace failed. */int check_zeroed_user(const void __user *from, size_t size){	unsigned long val;	uintptr_t align = (uintptr_t) from % sizeof(unsigned long); 	if (unlikely(size == 0))		return 1; 	from -= align;	size += align; 	if (!user_read_access_begin(from, size))		return -EFAULT; 	unsafe_get_user(val, (unsigned long __user *) from, err_fault);	if (align)		val &= ~aligned_byte_mask(align); 	while (size > sizeof(unsigned long)) {		if (unlikely(val))			goto done; 		from += sizeof(unsigned long);		size -= sizeof(unsigned long); 		unsafe_get_user(val, (unsigned long __user *) from, err_fault);	} 	if (size < sizeof(unsigned long))		val &= aligned_byte_mask(size); done:	user_read_access_end();	return (val == 0);err_fault:	user_read_access_end();	return -EFAULT;}EXPORT_SYMBOL(check_zeroed_user);