78 lines
2.2 KiB
C
78 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Memory preserving reboot related code.
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*
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* Created by: Hariprasad Nellitheertha (hari@in.ibm.com)
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* Copyright (C) IBM Corporation, 2004. All rights reserved
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*/
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#include <linux/errno.h>
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#include <linux/crash_dump.h>
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#include <linux/uaccess.h>
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#include <linux/io.h>
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static ssize_t __copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
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unsigned long offset, int userbuf,
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bool encrypted)
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{
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void *vaddr;
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if (!csize)
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return 0;
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if (encrypted)
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vaddr = (__force void *)ioremap_encrypted(pfn << PAGE_SHIFT, PAGE_SIZE);
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else
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vaddr = (__force void *)ioremap_cache(pfn << PAGE_SHIFT, PAGE_SIZE);
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if (!vaddr)
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return -ENOMEM;
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if (userbuf) {
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if (copy_to_user((void __user *)buf, vaddr + offset, csize)) {
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iounmap((void __iomem *)vaddr);
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return -EFAULT;
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}
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} else
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memcpy(buf, vaddr + offset, csize);
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set_iounmap_nonlazy();
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iounmap((void __iomem *)vaddr);
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return csize;
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}
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/**
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* copy_oldmem_page - copy one page of memory
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* @pfn: page frame number to be copied
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* @buf: target memory address for the copy; this can be in kernel address
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* space or user address space (see @userbuf)
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* @csize: number of bytes to copy
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* @offset: offset in bytes into the page (based on pfn) to begin the copy
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* @userbuf: if set, @buf is in user address space, use copy_to_user(),
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* otherwise @buf is in kernel address space, use memcpy().
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*
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* Copy a page from the old kernel's memory. For this page, there is no pte
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* mapped in the current kernel. We stitch up a pte, similar to kmap_atomic.
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*/
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ssize_t copy_oldmem_page(unsigned long pfn, char *buf, size_t csize,
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unsigned long offset, int userbuf)
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{
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return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, false);
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}
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/**
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* copy_oldmem_page_encrypted - same as copy_oldmem_page() above but ioremap the
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* memory with the encryption mask set to accommodate kdump on SME-enabled
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* machines.
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*/
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ssize_t copy_oldmem_page_encrypted(unsigned long pfn, char *buf, size_t csize,
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unsigned long offset, int userbuf)
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{
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return __copy_oldmem_page(pfn, buf, csize, offset, userbuf, true);
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}
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ssize_t elfcorehdr_read(char *buf, size_t count, u64 *ppos)
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{
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return read_from_oldmem(buf, count, ppos, 0, sev_active());
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}
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