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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uio_pci_generic.c (4168B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* uio_pci_generic - generic UIO driver for PCI 2.3 devices
      3 *
      4 * Copyright (C) 2009 Red Hat, Inc.
      5 * Author: Michael S. Tsirkin <mst@redhat.com>
      6 *
      7 * Since the driver does not declare any device ids, you must allocate
      8 * id and bind the device to the driver yourself.  For example:
      9 *
     10 * # echo "8086 10f5" > /sys/bus/pci/drivers/uio_pci_generic/new_id
     11 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/e1000e/unbind
     12 * # echo -n 0000:00:19.0 > /sys/bus/pci/drivers/uio_pci_generic/bind
     13 * # ls -l /sys/bus/pci/devices/0000:00:19.0/driver
     14 * .../0000:00:19.0/driver -> ../../../bus/pci/drivers/uio_pci_generic
     15 *
     16 * Driver won't bind to devices which do not support the Interrupt Disable Bit
     17 * in the command register. All devices compliant to PCI 2.3 (circa 2002) and
     18 * all compliant PCI Express devices should support this bit.
     19 */
     20
     21#include <linux/device.h>
     22#include <linux/module.h>
     23#include <linux/pci.h>
     24#include <linux/slab.h>
     25#include <linux/uio_driver.h>
     26
     27#define DRIVER_VERSION	"0.01.0"
     28#define DRIVER_AUTHOR	"Michael S. Tsirkin <mst@redhat.com>"
     29#define DRIVER_DESC	"Generic UIO driver for PCI 2.3 devices"
     30
     31struct uio_pci_generic_dev {
     32	struct uio_info info;
     33	struct pci_dev *pdev;
     34};
     35
     36static inline struct uio_pci_generic_dev *
     37to_uio_pci_generic_dev(struct uio_info *info)
     38{
     39	return container_of(info, struct uio_pci_generic_dev, info);
     40}
     41
     42static int release(struct uio_info *info, struct inode *inode)
     43{
     44	struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
     45
     46	/*
     47	 * This driver is insecure when used with devices doing DMA, but some
     48	 * people (mis)use it with such devices.
     49	 * Let's at least make sure DMA isn't left enabled after the userspace
     50	 * driver closes the fd.
     51	 * Note that there's a non-zero chance doing this will wedge the device
     52	 * at least until reset.
     53	 */
     54	pci_clear_master(gdev->pdev);
     55	return 0;
     56}
     57
     58/* Interrupt handler. Read/modify/write the command register to disable
     59 * the interrupt. */
     60static irqreturn_t irqhandler(int irq, struct uio_info *info)
     61{
     62	struct uio_pci_generic_dev *gdev = to_uio_pci_generic_dev(info);
     63
     64	if (!pci_check_and_mask_intx(gdev->pdev))
     65		return IRQ_NONE;
     66
     67	/* UIO core will signal the user process. */
     68	return IRQ_HANDLED;
     69}
     70
     71static int probe(struct pci_dev *pdev,
     72			   const struct pci_device_id *id)
     73{
     74	struct uio_pci_generic_dev *gdev;
     75	struct uio_mem *uiomem;
     76	int err;
     77	int i;
     78
     79	err = pcim_enable_device(pdev);
     80	if (err) {
     81		dev_err(&pdev->dev, "%s: pci_enable_device failed: %d\n",
     82			__func__, err);
     83		return err;
     84	}
     85
     86	if (pdev->irq && !pci_intx_mask_supported(pdev))
     87		return -ENODEV;
     88
     89	gdev = devm_kzalloc(&pdev->dev, sizeof(struct uio_pci_generic_dev), GFP_KERNEL);
     90	if (!gdev)
     91		return -ENOMEM;
     92
     93	gdev->info.name = "uio_pci_generic";
     94	gdev->info.version = DRIVER_VERSION;
     95	gdev->info.release = release;
     96	gdev->pdev = pdev;
     97	if (pdev->irq && (pdev->irq != IRQ_NOTCONNECTED)) {
     98		gdev->info.irq = pdev->irq;
     99		gdev->info.irq_flags = IRQF_SHARED;
    100		gdev->info.handler = irqhandler;
    101	} else {
    102		dev_warn(&pdev->dev, "No IRQ assigned to device: "
    103			 "no support for interrupts?\n");
    104	}
    105
    106	uiomem = &gdev->info.mem[0];
    107	for (i = 0; i < MAX_UIO_MAPS; ++i) {
    108		struct resource *r = &pdev->resource[i];
    109
    110		if (r->flags != (IORESOURCE_SIZEALIGN | IORESOURCE_MEM))
    111			continue;
    112
    113		if (uiomem >= &gdev->info.mem[MAX_UIO_MAPS]) {
    114			dev_warn(
    115				&pdev->dev,
    116				"device has more than " __stringify(
    117					MAX_UIO_MAPS) " I/O memory resources.\n");
    118			break;
    119		}
    120
    121		uiomem->memtype = UIO_MEM_PHYS;
    122		uiomem->addr = r->start & PAGE_MASK;
    123		uiomem->offs = r->start & ~PAGE_MASK;
    124		uiomem->size =
    125			(uiomem->offs + resource_size(r) + PAGE_SIZE - 1) &
    126			PAGE_MASK;
    127		uiomem->name = r->name;
    128		++uiomem;
    129	}
    130
    131	while (uiomem < &gdev->info.mem[MAX_UIO_MAPS]) {
    132		uiomem->size = 0;
    133		++uiomem;
    134	}
    135
    136	return devm_uio_register_device(&pdev->dev, &gdev->info);
    137}
    138
    139static struct pci_driver uio_pci_driver = {
    140	.name = "uio_pci_generic",
    141	.id_table = NULL, /* only dynamic id's */
    142	.probe = probe,
    143};
    144
    145module_pci_driver(uio_pci_driver);
    146MODULE_VERSION(DRIVER_VERSION);
    147MODULE_LICENSE("GPL v2");
    148MODULE_AUTHOR(DRIVER_AUTHOR);
    149MODULE_DESCRIPTION(DRIVER_DESC);