Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3)  * Copyright (c) 2010-2011, The Linux Foundation. All rights reserved.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)  * Support for user memory access from kernel.  This will
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8)  * probably be inlined for performance at some point, but
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9)  * for ease of debug, and to a lesser degree for code size,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10)  * we implement here as subroutines.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) #include <linux/types.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) #include <linux/pgtable.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)  * For clear_user(), exploit previously defined copy_to_user function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)  * and the fact that we've got a handy zero page defined in kernel/head.S
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)  * dczero here would be even faster.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) __kernel_size_t __clear_user_hexagon(void __user *dest, unsigned long count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24) 	long uncleared;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) 	while (count > PAGE_SIZE) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) 		uncleared = raw_copy_to_user(dest, &empty_zero_page, PAGE_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) 		if (uncleared)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 			return count - (PAGE_SIZE - uncleared);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 		count -= PAGE_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 		dest += PAGE_SIZE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 	if (count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 		count = raw_copy_to_user(dest, &empty_zero_page, count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	return count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) unsigned long clear_user_hexagon(void __user *dest, unsigned long count)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 	if (!access_ok(dest, count))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 		return count;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 	else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 		return __clear_user_hexagon(dest, count);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) }