1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Memory preserving reboot related code. 4 * 5 * Created by: Hariprasad Nellitheertha (hari@in.ibm.com) 6 * Copyright (C) IBM Corporation, 2004. All rights reserved 7 */ 8 9 #include <linux/errno.h> 10 #include <linux/crash_dump.h> 11 #include <linux/uio.h> 12 #include <linux/io.h> 13 #include <linux/cc_platform.h> 14 15 static ssize_t __copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, 16 size_t csize, unsigned long offset, 17 bool encrypted) 18 { 19 void *vaddr; 20 21 if (!csize) 22 return 0; 23 24 if (encrypted) 25 vaddr = (__force void *)ioremap_encrypted(pfn << PAGE_SHIFT, PAGE_SIZE); 26 else 27 vaddr = (__force void *)ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE); 28 29 if (!vaddr) 30 return -ENOMEM; 31 32 csize = copy_to_iter(vaddr + offset, csize, iter); 33 34 iounmap((void __iomem *)vaddr); 35 return csize; 36 } 37 38 ssize_t copy_oldmem_page(struct iov_iter *iter, unsigned long pfn, size_t csize, 39 unsigned long offset) 40 { 41 return __copy_oldmem_page(iter, pfn, csize, offset, false); 42 } 43 44 /* 45 * copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the 46 * memory with the encryption mask set to accommodate kdump on SME-enabled 47 * machines. 48 */ 49 ssize_t copy_oldmem_page_encrypted(struct iov_iter *iter, unsigned long pfn, 50 size_t csize, unsigned long offset) 51 { 52 return __copy_oldmem_page(iter, pfn, csize, offset, true); 53 } 54 55 ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos) 56 { 57 struct kvec kvec = { .iov_base = buf, .iov_len = count }; 58 struct iov_iter iter; 59 60 iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count); 61 62 return read_from_oldmem(&iter, count, ppos, 63 cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT)); 64 } 65