Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  1) // SPDX-License-Identifier: GPL-2.0
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  3)  *	crash_dump.c - Memory preserving reboot related code.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  4)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  5)  *	Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  6)  *	Copyright (C) IBM Corporation, 2004. All rights reserved
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  7)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  8) #include <linux/errno.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  9) #include <linux/crash_dump.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) #include <linux/io.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) #include <linux/uaccess.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) /**
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14)  * copy_oldmem_page - copy one page from "oldmem"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15)  * @pfn: page frame number to be copied
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16)  * @buf: target memory address for the copy; this can be in kernel address
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17)  *	space or user address space (see @userbuf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18)  * @csize: number of bytes to copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19)  * @offset: offset in bytes into the page (based on pfn) to begin the copy
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20)  * @userbuf: if set, @buf is in user address space, use copy_to_user(),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21)  *	otherwise @buf is in kernel address space, use memcpy().
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23)  * Copy a page from "oldmem". For this page, there is no pte mapped
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)  * in the current kernel. We stitch up a pte, similar to kmap_atomic.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) ssize_t copy_oldmem_page(unsigned long pfn, char *buf,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27)                                size_t csize, unsigned long offset, int userbuf)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) 	void  *vaddr;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) 	if (!csize)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) 		return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) 	vaddr = ioremap(pfn << PAGE_SHIFT, PAGE_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) 	if (userbuf) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) 		if (copy_to_user(buf, (vaddr + offset), csize)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) 			iounmap(vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) 			return -EFAULT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) 	} else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) 	memcpy(buf, (vaddr + offset), csize);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) 	iounmap(vaddr);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45) 	return csize;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) }