// SPDX-License-Identifier: GPL-2.0-only /* * arch/arm/kernel/crash_dump.c * * Copyright (C) 2010 Nokia Corporation. * Author: Mika Westerberg * * This code is taken from arch/x86/kernel/crash_dump_64.c * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) * Copyright (C) IBM Corporation, 2004. All rights reserved */ #include <linux/errno.h> #include <linux/crash_dump.h> #include <linux/uaccess.h> #include <linux/io.h> /** * copy_oldmem_page() - copy one page from old kernel memory * @pfn: page frame number to be copied * @buf: buffer where the copied page is placed * @csize: number of bytes to copy * @offset: offset in bytes into the page * @userbuf: if set, @buf is int he user address space * * This function copies one page from old kernel memory into buffer pointed by * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes * copied or negative error in case of failure. */ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize, unsigned long offset, int userbuf) { void *vaddr; if (!csize) return 0; vaddr = ioremap(__pfn_to_phys(pfn), PAGE_SIZE); if (!vaddr) return -ENOMEM; if (userbuf) { if (copy_to_user(buf, vaddr + offset, csize)) { iounmap(vaddr); return -EFAULT; } } else { memcpy(buf, vaddr + offset, csize); } iounmap(vaddr); return csize; }