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46 lines
1.2 KiB
46 lines
1.2 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* This code comes from arch/arm64/kernel/crash_dump.c |
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* Created by: AKASHI Takahiro <[email protected]> |
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* Copyright (C) 2017 Linaro Limited |
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*/ |
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#include <linux/crash_dump.h> |
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#include <linux/io.h> |
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/** |
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* copy_oldmem_page() - copy one page from old kernel memory |
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* @pfn: page frame number to be copied |
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* @buf: buffer where the copied page is placed |
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* @csize: number of bytes to copy |
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* @offset: offset in bytes into the page |
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* @userbuf: if set, @buf is in a user address space |
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* |
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* This function copies one page from old kernel memory into buffer pointed by |
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* @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes |
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* copied or negative error in case of failure. |
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*/ |
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ssize_t copy_oldmem_page(unsigned long pfn, char *buf, |
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size_t csize, unsigned long offset, |
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int userbuf) |
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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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vaddr = memremap(__pfn_to_phys(pfn), PAGE_SIZE, MEMREMAP_WB); |
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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((char __user *)buf, vaddr + offset, csize)) { |
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memunmap(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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memunmap(vaddr); |
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return csize; |
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}
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