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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pciehp_pci.c (3438B)

      1// SPDX-License-Identifier: GPL-2.0+
      2/*
      3 * PCI Express Hot Plug Controller Driver
      4 *
      5 * Copyright (C) 1995,2001 Compaq Computer Corporation
      6 * Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
      7 * Copyright (C) 2001 IBM Corp.
      8 * Copyright (C) 2003-2004 Intel Corporation
      9 *
     10 * All rights reserved.
     11 *
     12 * Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
     13 *
     14 */
     15
     16#define dev_fmt(fmt) "pciehp: " fmt
     17
     18#include <linux/kernel.h>
     19#include <linux/types.h>
     20#include <linux/pci.h>
     21#include "../pci.h"
     22#include "pciehp.h"
     23
     24/**
     25 * pciehp_configure_device() - enumerate PCI devices below a hotplug bridge
     26 * @ctrl: PCIe hotplug controller
     27 *
     28 * Enumerate PCI devices below a hotplug bridge and add them to the system.
     29 * Return 0 on success, %-EEXIST if the devices are already enumerated or
     30 * %-ENODEV if enumeration failed.
     31 */
     32int pciehp_configure_device(struct controller *ctrl)
     33{
     34	struct pci_dev *dev;
     35	struct pci_dev *bridge = ctrl->pcie->port;
     36	struct pci_bus *parent = bridge->subordinate;
     37	int num, ret = 0;
     38
     39	pci_lock_rescan_remove();
     40
     41	dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
     42	if (dev) {
     43		/*
     44		 * The device is already there. Either configured by the
     45		 * boot firmware or a previous hotplug event.
     46		 */
     47		ctrl_dbg(ctrl, "Device %s already exists at %04x:%02x:00, skipping hot-add\n",
     48			 pci_name(dev), pci_domain_nr(parent), parent->number);
     49		pci_dev_put(dev);
     50		ret = -EEXIST;
     51		goto out;
     52	}
     53
     54	num = pci_scan_slot(parent, PCI_DEVFN(0, 0));
     55	if (num == 0) {
     56		ctrl_err(ctrl, "No new device found\n");
     57		ret = -ENODEV;
     58		goto out;
     59	}
     60
     61	for_each_pci_bridge(dev, parent)
     62		pci_hp_add_bridge(dev);
     63
     64	pci_assign_unassigned_bridge_resources(bridge);
     65	pcie_bus_configure_settings(parent);
     66	pci_bus_add_devices(parent);
     67
     68 out:
     69	pci_unlock_rescan_remove();
     70	return ret;
     71}
     72
     73/**
     74 * pciehp_unconfigure_device() - remove PCI devices below a hotplug bridge
     75 * @ctrl: PCIe hotplug controller
     76 * @presence: whether the card is still present in the slot;
     77 *	true for safe removal via sysfs or an Attention Button press,
     78 *	false for surprise removal
     79 *
     80 * Unbind PCI devices below a hotplug bridge from their drivers and remove
     81 * them from the system.  Safely removed devices are quiesced.  Surprise
     82 * removed devices are marked as such to prevent further accesses.
     83 */
     84void pciehp_unconfigure_device(struct controller *ctrl, bool presence)
     85{
     86	struct pci_dev *dev, *temp;
     87	struct pci_bus *parent = ctrl->pcie->port->subordinate;
     88	u16 command;
     89
     90	ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n",
     91		 __func__, pci_domain_nr(parent), parent->number);
     92
     93	if (!presence)
     94		pci_walk_bus(parent, pci_dev_set_disconnected, NULL);
     95
     96	pci_lock_rescan_remove();
     97
     98	/*
     99	 * Stopping an SR-IOV PF device removes all the associated VFs,
    100	 * which will update the bus->devices list and confuse the
    101	 * iterator.  Therefore, iterate in reverse so we remove the VFs
    102	 * first, then the PF.  We do the same in pci_stop_bus_device().
    103	 */
    104	list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
    105					 bus_list) {
    106		pci_dev_get(dev);
    107		pci_stop_and_remove_bus_device(dev);
    108		/*
    109		 * Ensure that no new Requests will be generated from
    110		 * the device.
    111		 */
    112		if (presence) {
    113			pci_read_config_word(dev, PCI_COMMAND, &command);
    114			command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
    115			command |= PCI_COMMAND_INTX_DISABLE;
    116			pci_write_config_word(dev, PCI_COMMAND, command);
    117		}
    118		pci_dev_put(dev);
    119	}
    120
    121	pci_unlock_rescan_remove();
    122}