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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qib_user_pages.c (4412B)

      1/*
      2 * Copyright (c) 2006, 2007, 2008, 2009 QLogic Corporation. All rights reserved.
      3 * Copyright (c) 2003, 2004, 2005, 2006 PathScale, Inc. All rights reserved.
      4 *
      5 * This software is available to you under a choice of one of two
      6 * licenses.  You may choose to be licensed under the terms of the GNU
      7 * General Public License (GPL) Version 2, available from the file
      8 * COPYING in the main directory of this source tree, or the
      9 * OpenIB.org BSD license below:
     10 *
     11 *     Redistribution and use in source and binary forms, with or
     12 *     without modification, are permitted provided that the following
     13 *     conditions are met:
     14 *
     15 *      - Redistributions of source code must retain the above
     16 *        copyright notice, this list of conditions and the following
     17 *        disclaimer.
     18 *
     19 *      - Redistributions in binary form must reproduce the above
     20 *        copyright notice, this list of conditions and the following
     21 *        disclaimer in the documentation and/or other materials
     22 *        provided with the distribution.
     23 *
     24 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
     25 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     26 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
     27 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
     28 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
     29 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
     30 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
     31 * SOFTWARE.
     32 */
     33
     34#include <linux/mm.h>
     35#include <linux/sched/signal.h>
     36#include <linux/device.h>
     37
     38#include "qib.h"
     39
     40static void __qib_release_user_pages(struct page **p, size_t num_pages,
     41				     int dirty)
     42{
     43	unpin_user_pages_dirty_lock(p, num_pages, dirty);
     44}
     45
     46/*
     47 * qib_map_page - a safety wrapper around pci_map_page()
     48 *
     49 * A dma_addr of all 0's is interpreted by the chip as "disabled".
     50 * Unfortunately, it can also be a valid dma_addr returned on some
     51 * architectures.
     52 *
     53 * The powerpc iommu assigns dma_addrs in ascending order, so we don't
     54 * have to bother with retries or mapping a dummy page to insure we
     55 * don't just get the same mapping again.
     56 *
     57 * I'm sure we won't be so lucky with other iommu's, so FIXME.
     58 */
     59int qib_map_page(struct pci_dev *hwdev, struct page *page, dma_addr_t *daddr)
     60{
     61	dma_addr_t phys;
     62
     63	phys = dma_map_page(&hwdev->dev, page, 0, PAGE_SIZE, DMA_FROM_DEVICE);
     64	if (dma_mapping_error(&hwdev->dev, phys))
     65		return -ENOMEM;
     66
     67	if (!phys) {
     68		dma_unmap_page(&hwdev->dev, phys, PAGE_SIZE, DMA_FROM_DEVICE);
     69		phys = dma_map_page(&hwdev->dev, page, 0, PAGE_SIZE,
     70				    DMA_FROM_DEVICE);
     71		if (dma_mapping_error(&hwdev->dev, phys))
     72			return -ENOMEM;
     73		/*
     74		 * FIXME: If we get 0 again, we should keep this page,
     75		 * map another, then free the 0 page.
     76		 */
     77	}
     78	*daddr = phys;
     79	return 0;
     80}
     81
     82/**
     83 * qib_get_user_pages - lock user pages into memory
     84 * @start_page: the start page
     85 * @num_pages: the number of pages
     86 * @p: the output page structures
     87 *
     88 * This function takes a given start page (page aligned user virtual
     89 * address) and pins it and the following specified number of pages.  For
     90 * now, num_pages is always 1, but that will probably change at some point
     91 * (because caller is doing expected sends on a single virtually contiguous
     92 * buffer, so we can do all pages at once).
     93 */
     94int qib_get_user_pages(unsigned long start_page, size_t num_pages,
     95		       struct page **p)
     96{
     97	unsigned long locked, lock_limit;
     98	size_t got;
     99	int ret;
    100
    101	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
    102	locked = atomic64_add_return(num_pages, &current->mm->pinned_vm);
    103
    104	if (locked > lock_limit && !capable(CAP_IPC_LOCK)) {
    105		ret = -ENOMEM;
    106		goto bail;
    107	}
    108
    109	mmap_read_lock(current->mm);
    110	for (got = 0; got < num_pages; got += ret) {
    111		ret = pin_user_pages(start_page + got * PAGE_SIZE,
    112				     num_pages - got,
    113				     FOLL_LONGTERM | FOLL_WRITE | FOLL_FORCE,
    114				     p + got, NULL);
    115		if (ret < 0) {
    116			mmap_read_unlock(current->mm);
    117			goto bail_release;
    118		}
    119	}
    120	mmap_read_unlock(current->mm);
    121
    122	return 0;
    123bail_release:
    124	__qib_release_user_pages(p, got, 0);
    125bail:
    126	atomic64_sub(num_pages, &current->mm->pinned_vm);
    127	return ret;
    128}
    129
    130void qib_release_user_pages(struct page **p, size_t num_pages)
    131{
    132	__qib_release_user_pages(p, num_pages, 1);
    133
    134	/* during close after signal, mm can be NULL */
    135	if (current->mm)
    136		atomic64_sub(num_pages, &current->mm->pinned_vm);
    137}