Commit 162b83bd authored by Rui Wang's avatar Rui Wang Committed by Ingo Molnar
Browse files

x86/ioapic: Fix lost IOAPIC resource after hot-removal and hotadd 



IOAPIC resource at 0xfecxxxxx gets lost from /proc/iomem after
hot-removing and then hot-adding the IOAPIC device.

After system boot, in /proc/iomem:

 fec00000-fecfffff : PNP0003:00
   fec00000-fec003ff : IOAPIC 0
   fec01000-fec013ff : IOAPIC 1
   fec40000-fec403ff : IOAPIC 2
   fec80000-fec803ff : IOAPIC 3
   fecc0000-fecc03ff : IOAPIC 4

Then hot-remove IOAPIC 2 and hot-add it again:

 fec00000-fecfffff : PNP0003:00
   fec00000-fec003ff : IOAPIC 0
   fec01000-fec013ff : IOAPIC 1
   fec80000-fec803ff : IOAPIC 3
   fecc0000-fecc03ff : IOAPIC 4

The range at 0xfec40000 is lost from /proc/iomem - which is a bug.

This bug happens because handle_ioapic_add() requests resources from
either PCI config BAR or ACPI "_CRS", not both. But Intel platforms
map the IOxAPIC registers both at the PCI config BAR (called MBAR, dynamic),
and at the ACPI "_CRS" (called ABAR, static). The 0xfecX_YZ00 to 0xfecX_YZFF
range appears in "_CRS" of each IOAPIC device.

Both ranges should be claimed from /proc/iomem for exclusive use.

Signed-off-by: default avatarRui Wang <rui.y.wang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bhelgaas@google.com
Cc: helgaas@kernel.org
Cc: linux-acpi@vger.kernel.org
Cc: linux-pci@vger.kernel.org
Cc: rjw@rjwysocki.net
Cc: tony.luck@intel.com
Link: http://lkml.kernel.org/r/1471420837-31003-5-git-send-email-rui.y.wang@intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 6ab7eba5

drivers/acpi/ioapic.c

+20 −16
Original line number Diff line number Diff line
@@ -97,7 +97,7 @@ static acpi_status handle_ioapic_add(acpi_handle handle, u32 lvl, 
	unsigned long long gsi_base;

	struct acpi_pci_ioapic *ioapic;

	struct pci_dev *dev = NULL;

	struct resource *res = NULL;

	struct resource *res = NULL, *pci_res = NULL, *crs_res;

	char *type = NULL;



	if (!acpi_is_ioapic(handle, &type))
@@ -137,23 +137,28 @@ static acpi_status handle_ioapic_add(acpi_handle handle, u32 lvl, 
		pci_set_master(dev);

		if (pci_request_region(dev, 0, type))

			goto exit_disable;

		res = &dev->resource[0];

		pci_res = &dev->resource[0];

		ioapic->pdev = dev;

	} else {

		pci_dev_put(dev);

		dev = NULL;

	}



		res = &ioapic->res;

		acpi_walk_resources(handle, METHOD_NAME__CRS, setup_res, res);

		if (res->flags == 0) {

	crs_res = &ioapic->res;

	acpi_walk_resources(handle, METHOD_NAME__CRS, setup_res, crs_res);

	if (crs_res->flags == 0) {

		acpi_handle_warn(handle, "failed to get resource\n");

			goto exit_free;

		} else if (request_resource(&iomem_resource, res)) {

		goto exit_release;

	} else if (request_resource(&iomem_resource, crs_res)) {

		acpi_handle_warn(handle, "failed to insert resource\n");

			goto exit_free;

		}

		goto exit_release;

	}



	/* try pci resource first, then "_CRS" resource */

	res = pci_res;

	if (!res || !res->flags)

		res = crs_res;



	if (acpi_register_ioapic(handle, res->start, (u32)gsi_base)) {

		acpi_handle_warn(handle, "failed to register IOAPIC\n");

		goto exit_release;
@@ -174,14 +179,13 @@ done: 
exit_release:

	if (dev)

		pci_release_region(dev, 0);

	else

		release_resource(res);

	if (ioapic->res.flags && ioapic->res.parent)

		release_resource(&ioapic->res);

exit_disable:

	if (dev)

		pci_disable_device(dev);

exit_put:

	pci_dev_put(dev);

exit_free:

	kfree(ioapic);

exit:

	mutex_unlock(&ioapic_list_lock);
@@ -217,9 +221,9 @@ int acpi_ioapic_remove(struct acpi_pci_root *root) 
			pci_release_region(ioapic->pdev, 0);

			pci_disable_device(ioapic->pdev);

			pci_dev_put(ioapic->pdev);

		} else if (ioapic->res.flags && ioapic->res.parent) {

			release_resource(&ioapic->res);

		}

		if (ioapic->res.flags && ioapic->res.parent)

			release_resource(&ioapic->res);

		list_del(&ioapic->list);

		kfree(ioapic);

	}

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