Messages in this thread Patch in this message | | | From | Jiang Liu <> | Subject | [Bugfix v6] x86/PCI/ACPI: Fix regression caused by commit 63f1789ec716 | Date | Thu, 30 Apr 2015 12:41:28 +0800 |
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An IO port or MMIO resource assigned to a PCI host bridge may be consumed by the host bridge itself or available to its child bus/devices. The ACPI specification defines a bit (Producer/Consumer) to tell whether the resource is consumed by the host bridge itself, but firmware hasn't used that bit consistently, so we can't rely on it.
Before commit 593669c2ac0f ("x86/PCI/ACPI: Use common ACPI resource interfaces to simplify implementation"), arch/x86/pci/acpi.c ignored all IO port resources defined by acpi_resource_io and acpi_resource_fixed_io to filter out IO ports consumed by the host bridge itself.
Commit 593669c2ac0f ("x86/PCI/ACPI: Use common ACPI resource interfaces to simplify implementation") started accepting all IO port and MMIO resources, which caused a regression that IO port resources consumed by the host bridge itself became available to its child devices.
Then commit 63f1789ec716 ("x86/PCI/ACPI: Ignore resources consumed by host bridge itself") ignored resources consumed by the host bridge itself by checking the IORESOURCE_WINDOW flag, which accidently removed MMIO resources defined by acpi_resource_memory24, acpi_resource_memory32 and acpi_resource_fixed_memory32.
On x86 and IA64 platforms, all IO port and MMIO resources are assumed to be available to child bus/devices except one special case: IO port [0xCF8-0xCFF] is consumed by the host bridge itself to access PCI configuration space.
So explicitly filter out PCI CFG IO ports[0xCF8-0xCFF]. This solution will also ease the way to consolidate ACPI PCI host bridge common code from x86, ia64 and ARM64.
Related ACPI table are archived at: https://bugzilla.kernel.org/show_bug.cgi?id=94221
Related discussions at: http://patchwork.ozlabs.org/patch/461633/ https://lkml.org/lkml/2015/3/29/304
Fixes: 63f1789ec716("Ignore resources consumed by host bridge itself") Reported-by: Bernhard Thaler <bernhard.thaler@wvnet.at> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: <stable@vger.kernel.org> # 4.0 --- arch/x86/pci/acpi.c | 24 ++++++++++++++++++++++-- drivers/acpi/resource.c | 2 +- 2 files changed, 23 insertions(+), 3 deletions(-)
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index e4695985f9de..d93963340c3c 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -325,6 +325,26 @@ static void release_pci_root_info(struct pci_host_bridge *bridge) kfree(info); } +/* + * An IO port or MMIO resource assigned to a PCI host bridge may be + * consumed by the host bridge itself or available to its child + * bus/devices. The ACPI specification defines a bit (Producer/Consumer) + * to tell whether the resource is consumed by the host bridge itself, + * but firmware hasn't used that bit consistently, so we can't rely on it. + * + * On x86 and IA64 platforms, all IO port and MMIO resources are assumed + * to be available to child bus/devices except one special case: + * IO port [0xCF8-0xCFF] is consumed by the host bridge itself + * to access PCI configuration space. + * + * So explicitly filter out PCI CFG IO ports[0xCF8-0xCFF]. + */ +static bool resource_is_pcicfg_ioport(struct resource *res) +{ + return (res->flags & IORESOURCE_IO) && + res->start == 0xCF8 && res->end == 0xCFF; +} + static void probe_pci_root_info(struct pci_root_info *info, struct acpi_device *device, int busnum, int domain, @@ -346,8 +366,8 @@ static void probe_pci_root_info(struct pci_root_info *info, "no IO and memory resources present in _CRS\n"); else resource_list_for_each_entry_safe(entry, tmp, list) { - if ((entry->res->flags & IORESOURCE_WINDOW) == 0 || - (entry->res->flags & IORESOURCE_DISABLED)) + if ((entry->res->flags & IORESOURCE_DISABLED) || + resource_is_pcicfg_ioport(entry->res)) resource_list_destroy_entry(entry); else entry->res->name = info->name; diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c index 5589a6e2a023..8244f013f210 100644 --- a/drivers/acpi/resource.c +++ b/drivers/acpi/resource.c @@ -573,7 +573,7 @@ EXPORT_SYMBOL_GPL(acpi_dev_get_resources); * @ares: Input ACPI resource object. * @types: Valid resource types of IORESOURCE_XXX * - * This is a hepler function to support acpi_dev_get_resources(), which filters + * This is a helper function to support acpi_dev_get_resources(), which filters * ACPI resource objects according to resource types. */ int acpi_dev_filter_resource_type(struct acpi_resource *ares, -- 1.7.10.4
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