cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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remap.c (1614B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Copyright (c) 2014 The Linux Foundation
      4 */
      5#include <linux/dma-map-ops.h>
      6#include <linux/slab.h>
      7#include <linux/vmalloc.h>
      8
      9struct page **dma_common_find_pages(void *cpu_addr)
     10{
     11	struct vm_struct *area = find_vm_area(cpu_addr);
     12
     13	if (!area || area->flags != VM_DMA_COHERENT)
     14		return NULL;
     15	return area->pages;
     16}
     17
     18/*
     19 * Remaps an array of PAGE_SIZE pages into another vm_area.
     20 * Cannot be used in non-sleeping contexts
     21 */
     22void *dma_common_pages_remap(struct page **pages, size_t size,
     23			 pgprot_t prot, const void *caller)
     24{
     25	void *vaddr;
     26
     27	vaddr = vmap(pages, PAGE_ALIGN(size) >> PAGE_SHIFT,
     28		     VM_DMA_COHERENT, prot);
     29	if (vaddr)
     30		find_vm_area(vaddr)->pages = pages;
     31	return vaddr;
     32}
     33
     34/*
     35 * Remaps an allocated contiguous region into another vm_area.
     36 * Cannot be used in non-sleeping contexts
     37 */
     38void *dma_common_contiguous_remap(struct page *page, size_t size,
     39			pgprot_t prot, const void *caller)
     40{
     41	int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
     42	struct page **pages;
     43	void *vaddr;
     44	int i;
     45
     46	pages = kmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
     47	if (!pages)
     48		return NULL;
     49	for (i = 0; i < count; i++)
     50		pages[i] = nth_page(page, i);
     51	vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
     52	kfree(pages);
     53
     54	return vaddr;
     55}
     56
     57/*
     58 * Unmaps a range previously mapped by dma_common_*_remap
     59 */
     60void dma_common_free_remap(void *cpu_addr, size_t size)
     61{
     62	struct vm_struct *area = find_vm_area(cpu_addr);
     63
     64	if (!area || area->flags != VM_DMA_COHERENT) {
     65		WARN(1, "trying to free invalid coherent area: %p\n", cpu_addr);
     66		return;
     67	}
     68
     69	vunmap(cpu_addr);
     70}