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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mmap.c (2676B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Generic PCI resource mmap helper
      4 *
      5 * Copyright © 2017 Amazon.com, Inc. or its affiliates.
      6 *
      7 * Author: David Woodhouse <dwmw2@infradead.org>
      8 */
      9
     10#include <linux/kernel.h>
     11#include <linux/mm.h>
     12#include <linux/pci.h>
     13
     14#ifdef ARCH_GENERIC_PCI_MMAP_RESOURCE
     15
     16/*
     17 * Modern setup: generic pci_mmap_resource_range(), and implement the legacy
     18 * pci_mmap_page_range() (if needed) as a wrapper round it.
     19 */
     20
     21#ifdef HAVE_PCI_MMAP
     22int pci_mmap_page_range(struct pci_dev *pdev, int bar,
     23			struct vm_area_struct *vma,
     24			enum pci_mmap_state mmap_state, int write_combine)
     25{
     26	resource_size_t start, end;
     27
     28	pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
     29
     30	/* Adjust vm_pgoff to be the offset within the resource */
     31	vma->vm_pgoff -= start >> PAGE_SHIFT;
     32	return pci_mmap_resource_range(pdev, bar, vma, mmap_state,
     33				       write_combine);
     34}
     35#endif
     36
     37static const struct vm_operations_struct pci_phys_vm_ops = {
     38#ifdef CONFIG_HAVE_IOREMAP_PROT
     39	.access = generic_access_phys,
     40#endif
     41};
     42
     43int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
     44			    struct vm_area_struct *vma,
     45			    enum pci_mmap_state mmap_state, int write_combine)
     46{
     47	unsigned long size;
     48	int ret;
     49
     50	size = ((pci_resource_len(pdev, bar) - 1) >> PAGE_SHIFT) + 1;
     51	if (vma->vm_pgoff + vma_pages(vma) > size)
     52		return -EINVAL;
     53
     54	if (write_combine)
     55		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);
     56	else
     57		vma->vm_page_prot = pgprot_device(vma->vm_page_prot);
     58
     59	if (mmap_state == pci_mmap_io) {
     60		ret = pci_iobar_pfn(pdev, bar, vma);
     61		if (ret)
     62			return ret;
     63	} else
     64		vma->vm_pgoff += (pci_resource_start(pdev, bar) >> PAGE_SHIFT);
     65
     66	vma->vm_ops = &pci_phys_vm_ops;
     67
     68	return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
     69				  vma->vm_end - vma->vm_start,
     70				  vma->vm_page_prot);
     71}
     72
     73#elif defined(HAVE_PCI_MMAP) /* && !ARCH_GENERIC_PCI_MMAP_RESOURCE */
     74
     75/*
     76 * Legacy setup: Implement pci_mmap_resource_range() as a wrapper around
     77 * the architecture's pci_mmap_page_range(), converting to "user visible"
     78 * addresses as necessary.
     79 */
     80
     81int pci_mmap_resource_range(struct pci_dev *pdev, int bar,
     82			    struct vm_area_struct *vma,
     83			    enum pci_mmap_state mmap_state, int write_combine)
     84{
     85	resource_size_t start, end;
     86
     87	/*
     88	 * pci_mmap_page_range() expects the same kind of entry as coming
     89	 * from /proc/bus/pci/ which is a "user visible" value. If this is
     90	 * different from the resource itself, arch will do necessary fixup.
     91	 */
     92	pci_resource_to_user(pdev, bar, &pdev->resource[bar], &start, &end);
     93	vma->vm_pgoff += start >> PAGE_SHIFT;
     94	return pci_mmap_page_range(pdev, bar, vma, mmap_state, write_combine);
     95}
     96#endif