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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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c4ec84c7db
Multiple race conditions are possible between PCI hotplug and the generic PCI bus rescan and device removal that can be triggered via sysfs. To avoid those race conditions make PCI hotplug use global PCI rescan-remove locking. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
138 lines
3.8 KiB
C
138 lines
3.8 KiB
C
/*
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* PCI Express Hot Plug Controller Driver
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*
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* Copyright (C) 1995,2001 Compaq Computer Corporation
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* Copyright (C) 2001 Greg Kroah-Hartman (greg@kroah.com)
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* Copyright (C) 2001 IBM Corp.
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* Copyright (C) 2003-2004 Intel Corporation
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Send feedback to <greg@kroah.com>, <kristen.c.accardi@intel.com>
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*
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/pci.h>
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#include "../pci.h"
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#include "pciehp.h"
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int pciehp_configure_device(struct slot *p_slot)
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{
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struct pci_dev *dev;
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struct pci_dev *bridge = p_slot->ctrl->pcie->port;
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struct pci_bus *parent = bridge->subordinate;
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int num, ret = 0;
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struct controller *ctrl = p_slot->ctrl;
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pci_lock_rescan_remove();
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dev = pci_get_slot(parent, PCI_DEVFN(0, 0));
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if (dev) {
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ctrl_err(ctrl, "Device %s already exists "
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"at %04x:%02x:00, cannot hot-add\n", pci_name(dev),
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pci_domain_nr(parent), parent->number);
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pci_dev_put(dev);
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ret = -EINVAL;
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goto out;
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}
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num = pci_scan_slot(parent, PCI_DEVFN(0, 0));
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if (num == 0) {
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ctrl_err(ctrl, "No new device found\n");
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ret = -ENODEV;
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goto out;
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}
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list_for_each_entry(dev, &parent->devices, bus_list)
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if ((dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) ||
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(dev->hdr_type == PCI_HEADER_TYPE_CARDBUS))
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pci_hp_add_bridge(dev);
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pci_assign_unassigned_bridge_resources(bridge);
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list_for_each_entry(dev, &parent->devices, bus_list) {
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if ((dev->class >> 16) == PCI_BASE_CLASS_DISPLAY)
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continue;
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pci_configure_slot(dev);
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}
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pci_bus_add_devices(parent);
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out:
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pci_unlock_rescan_remove();
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return ret;
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}
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int pciehp_unconfigure_device(struct slot *p_slot)
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{
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int rc = 0;
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u8 bctl = 0;
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u8 presence = 0;
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struct pci_dev *dev, *temp;
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struct pci_bus *parent = p_slot->ctrl->pcie->port->subordinate;
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u16 command;
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struct controller *ctrl = p_slot->ctrl;
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ctrl_dbg(ctrl, "%s: domain:bus:dev = %04x:%02x:00\n",
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__func__, pci_domain_nr(parent), parent->number);
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pciehp_get_adapter_status(p_slot, &presence);
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pci_lock_rescan_remove();
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/*
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* Stopping an SR-IOV PF device removes all the associated VFs,
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* which will update the bus->devices list and confuse the
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* iterator. Therefore, iterate in reverse so we remove the VFs
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* first, then the PF. We do the same in pci_stop_bus_device().
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*/
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list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
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bus_list) {
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pci_dev_get(dev);
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if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE && presence) {
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pci_read_config_byte(dev, PCI_BRIDGE_CONTROL, &bctl);
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if (bctl & PCI_BRIDGE_CTL_VGA) {
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ctrl_err(ctrl,
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"Cannot remove display device %s\n",
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pci_name(dev));
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pci_dev_put(dev);
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rc = -EINVAL;
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break;
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}
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}
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pci_stop_and_remove_bus_device(dev);
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/*
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* Ensure that no new Requests will be generated from
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* the device.
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*/
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if (presence) {
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pci_read_config_word(dev, PCI_COMMAND, &command);
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command &= ~(PCI_COMMAND_MASTER | PCI_COMMAND_SERR);
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command |= PCI_COMMAND_INTX_DISABLE;
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pci_write_config_word(dev, PCI_COMMAND, command);
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}
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pci_dev_put(dev);
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}
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pci_unlock_rescan_remove();
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return rc;
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}
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