Commit efcbd9d3 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

Merge branch 'pci/thunderbolt' 

- Detect some Thunderbolt chips that are built-in and hence 'trustworthy'
  by a heuristic since the 'ExternalFacingPort' and 'usb4-host-interface'
  ACPI properties are not quite enough (Esther Shimanovich)

* pci/thunderbolt:
  PCI: Detect and trust built-in Thunderbolt chips
parents c03d361c 3b96b895

arch/x86/pci/acpi.c

+119 −0
Original line number Diff line number Diff line
@@ -250,6 +250,125 @@ void __init pci_acpi_crs_quirks(void) 
		pr_info("Please notify linux-pci@vger.kernel.org so future kernels can do this automatically\n");

}



/*

 * Check if pdev is part of a PCIe switch that is directly below the

 * specified bridge.

 */

static bool pcie_switch_directly_under(struct pci_dev *bridge,

				       struct pci_dev *pdev)

{

	struct pci_dev *parent = pci_upstream_bridge(pdev);



	/* If the device doesn't have a parent, it's not under anything */

	if (!parent)

		return false;



	/*

	 * If the device has a PCIe type, check if it is below the

	 * corresponding PCIe switch components (if applicable). Then check

	 * if its upstream port is directly beneath the specified bridge.

	 */

	switch (pci_pcie_type(pdev)) {

	case PCI_EXP_TYPE_UPSTREAM:

		return parent == bridge;



	case PCI_EXP_TYPE_DOWNSTREAM:

		if (pci_pcie_type(parent) != PCI_EXP_TYPE_UPSTREAM)

			return false;

		parent = pci_upstream_bridge(parent);

		return parent == bridge;



	case PCI_EXP_TYPE_ENDPOINT:

		if (pci_pcie_type(parent) != PCI_EXP_TYPE_DOWNSTREAM)

			return false;

		parent = pci_upstream_bridge(parent);

		if (!parent || pci_pcie_type(parent) != PCI_EXP_TYPE_UPSTREAM)

			return false;

		parent = pci_upstream_bridge(parent);

		return parent == bridge;

	}



	return false;

}



static bool pcie_has_usb4_host_interface(struct pci_dev *pdev)

{

	struct fwnode_handle *fwnode;



	/*

	 * For USB4, the tunneled PCIe Root or Downstream Ports are marked

	 * with the "usb4-host-interface" ACPI property, so we look for

	 * that first. This should cover most cases.

	 */

	fwnode = fwnode_find_reference(dev_fwnode(&pdev->dev),

				       "usb4-host-interface", 0);

	if (!IS_ERR(fwnode)) {

		fwnode_handle_put(fwnode);

		return true;

	}



	/*

	 * Any integrated Thunderbolt 3/4 PCIe Root Ports from Intel

	 * before Alder Lake do not have the "usb4-host-interface"

	 * property so we use their PCI IDs instead. All these are

	 * tunneled. This list is not expected to grow.

	 */

	if (pdev->vendor == PCI_VENDOR_ID_INTEL) {

		switch (pdev->device) {

		/* Ice Lake Thunderbolt 3 PCIe Root Ports */

		case 0x8a1d:

		case 0x8a1f:

		case 0x8a21:

		case 0x8a23:

		/* Tiger Lake-LP Thunderbolt 4 PCIe Root Ports */

		case 0x9a23:

		case 0x9a25:

		case 0x9a27:

		case 0x9a29:

		/* Tiger Lake-H Thunderbolt 4 PCIe Root Ports */

		case 0x9a2b:

		case 0x9a2d:

		case 0x9a2f:

		case 0x9a31:

			return true;

		}

	}



	return false;

}



bool arch_pci_dev_is_removable(struct pci_dev *pdev)

{

	struct pci_dev *parent, *root;



	/* pdev without a parent or Root Port is never tunneled */

	parent = pci_upstream_bridge(pdev);

	if (!parent)

		return false;

	root = pcie_find_root_port(pdev);

	if (!root)

		return false;



	/* Internal PCIe devices are not tunneled */

	if (!root->external_facing)

		return false;



	/* Anything directly behind a "usb4-host-interface" is tunneled */

	if (pcie_has_usb4_host_interface(parent))

		return true;



	/*

	 * Check if this is a discrete Thunderbolt/USB4 controller that is

	 * directly behind the non-USB4 PCIe Root Port marked as

	 * "ExternalFacingPort". Those are not behind a PCIe tunnel.

	 */

	if (pcie_switch_directly_under(root, pdev))

		return false;



	/* PCIe devices after the discrete chip are tunneled */

	return true;

}



#ifdef	CONFIG_PCI_MMCONFIG

static int check_segment(u16 seg, struct device *dev, char *estr)

{

drivers/pci/probe.c

+23 −7
Original line number Diff line number Diff line
@@ -1635,23 +1635,33 @@ static void set_pcie_thunderbolt(struct pci_dev *dev) 


static void set_pcie_untrusted(struct pci_dev *dev)

{

	struct pci_dev *parent;

	struct pci_dev *parent = pci_upstream_bridge(dev);



	if (!parent)

		return;

	/*

	 * If the upstream bridge is untrusted we treat this device

	 * If the upstream bridge is untrusted we treat this device as

	 * untrusted as well.

	 */

	parent = pci_upstream_bridge(dev);

	if (parent && (parent->untrusted || parent->external_facing))

	if (parent->untrusted) {

		dev->untrusted = true;

		return;

	}



	if (arch_pci_dev_is_removable(dev)) {

		pci_dbg(dev, "marking as untrusted\n");

		dev->untrusted = true;

	}

}



static void pci_set_removable(struct pci_dev *dev)

{

	struct pci_dev *parent = pci_upstream_bridge(dev);



	if (!parent)

		return;

	/*

	 * We (only) consider everything downstream from an external_facing

	 * We (only) consider everything tunneled below an external_facing

	 * device to be removable by the user. We're mainly concerned with

	 * consumer platforms with user accessible thunderbolt ports that are

	 * vulnerable to DMA attacks, and we expect those ports to be marked by
@@ -1661,10 +1671,16 @@ static void pci_set_removable(struct pci_dev *dev) 
	 * accessible to user / may not be removed by end user, and thus not

	 * exposed as "removable" to userspace.

	 */

	if (parent &&

	    (parent->external_facing || dev_is_removable(&parent->dev)))

	if (dev_is_removable(&parent->dev)) {

		dev_set_removable(&dev->dev, DEVICE_REMOVABLE);

		return;

	}



	if (arch_pci_dev_is_removable(dev)) {

		pci_dbg(dev, "marking as removable\n");

		dev_set_removable(&dev->dev, DEVICE_REMOVABLE);

	}

}



/**

 * pci_ext_cfg_is_aliased - Is ext config space just an alias of std config?

include/linux/pci.h

+6 −0
Original line number Diff line number Diff line
@@ -2606,6 +2606,12 @@ pci_host_bridge_acpi_msi_domain(struct pci_bus *bus) { return NULL; } 
static inline bool pci_pr3_present(struct pci_dev *pdev) { return false; }

#endif



#if defined(CONFIG_X86) && defined(CONFIG_ACPI)

bool arch_pci_dev_is_removable(struct pci_dev *pdev);

#else

static inline bool arch_pci_dev_is_removable(struct pci_dev *pdev) { return false; }

#endif



#ifdef CONFIG_EEH

static inline struct eeh_dev *pci_dev_to_eeh_dev(struct pci_dev *pdev)

{