From 4723d0f2f96e6c910f951d595067eb31e0dd2d01 Mon Sep 17 00:00:00 2001 From: Bjorn Helgaas Date: Wed, 22 Sep 2010 11:09:19 -0600 Subject: x86/PCI: coalesce overlapping host bridge windows Some BIOSes provide PCI host bridge windows that overlap, e.g., pci_root PNP0A03:00: host bridge window [mem 0xb0000000-0xffffffff] pci_root PNP0A03:00: host bridge window [mem 0xafffffff-0xdfffffff] pci_root PNP0A03:00: host bridge window [mem 0xf0000000-0xffffffff] If we simply insert these as children of iomem_resource, the second window fails because it conflicts with the first, and the third is inserted as a child of the first, i.e., b0000000-ffffffff PCI Bus 0000:00 f0000000-ffffffff PCI Bus 0000:00 When we claim PCI device resources, this can cause collisions like this if we put them in the first window: pci 0000:00:01.0: address space collision: [mem 0xff300000-0xff4fffff] conflicts with PCI Bus 0000:00 [mem 0xf0000000-0xffffffff] Host bridge windows are top-level resources by definition, so it doesn't make sense to make the third window a child of the first. This patch coalesces any host bridge windows that overlap. For the example above, the result is this single window: pci_root PNP0A03:00: host bridge window [mem 0xafffffff-0xffffffff] This fixes a 2.6.34 regression. Reference: https://bugzilla.kernel.org/show_bug.cgi?id=17011 Reported-and-tested-by: Anisse Astier Reported-and-tested-by: Pramod Dematagoda Signed-off-by: Bjorn Helgaas Signed-off-by: Jesse Barnes --- arch/x86/pci/acpi.c | 103 ++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 83 insertions(+), 20 deletions(-) (limited to 'arch/x86/pci/acpi.c') diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index 15466c096ba..0972315c386 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -138,7 +138,6 @@ setup_resource(struct acpi_resource *acpi_res, void *data) struct acpi_resource_address64 addr; acpi_status status; unsigned long flags; - struct resource *root, *conflict; u64 start, end; status = resource_to_addr(acpi_res, &addr); @@ -146,12 +145,10 @@ setup_resource(struct acpi_resource *acpi_res, void *data) return AE_OK; if (addr.resource_type == ACPI_MEMORY_RANGE) { - root = &iomem_resource; flags = IORESOURCE_MEM; if (addr.info.mem.caching == ACPI_PREFETCHABLE_MEMORY) flags |= IORESOURCE_PREFETCH; } else if (addr.resource_type == ACPI_IO_RANGE) { - root = &ioport_resource; flags = IORESOURCE_IO; } else return AE_OK; @@ -172,25 +169,90 @@ setup_resource(struct acpi_resource *acpi_res, void *data) return AE_OK; } - conflict = insert_resource_conflict(root, res); - if (conflict) { - dev_err(&info->bridge->dev, - "address space collision: host bridge window %pR " - "conflicts with %s %pR\n", - res, conflict->name, conflict); - } else { - pci_bus_add_resource(info->bus, res, 0); - info->res_num++; - if (addr.translation_offset) - dev_info(&info->bridge->dev, "host bridge window %pR " - "(PCI address [%#llx-%#llx])\n", - res, res->start - addr.translation_offset, - res->end - addr.translation_offset); + info->res_num++; + if (addr.translation_offset) + dev_info(&info->bridge->dev, "host bridge window %pR " + "(PCI address [%#llx-%#llx])\n", + res, res->start - addr.translation_offset, + res->end - addr.translation_offset); + else + dev_info(&info->bridge->dev, "host bridge window %pR\n", res); + + return AE_OK; +} + +static bool resource_contains(struct resource *res, resource_size_t point) +{ + if (res->start <= point && point <= res->end) + return true; + return false; +} + +static void coalesce_windows(struct pci_root_info *info, int type) +{ + int i, j; + struct resource *res1, *res2; + + for (i = 0; i < info->res_num; i++) { + res1 = &info->res[i]; + if (!(res1->flags & type)) + continue; + + for (j = i + 1; j < info->res_num; j++) { + res2 = &info->res[j]; + if (!(res2->flags & type)) + continue; + + /* + * I don't like throwing away windows because then + * our resources no longer match the ACPI _CRS, but + * the kernel resource tree doesn't allow overlaps. + */ + if (resource_contains(res1, res2->start) || + resource_contains(res1, res2->end) || + resource_contains(res2, res1->start) || + resource_contains(res2, res1->end)) { + res1->start = min(res1->start, res2->start); + res1->end = max(res1->end, res2->end); + dev_info(&info->bridge->dev, + "host bridge window expanded to %pR; %pR ignored\n", + res1, res2); + res2->flags = 0; + } + } + } +} + +static void add_resources(struct pci_root_info *info) +{ + int i; + struct resource *res, *root, *conflict; + + if (!pci_use_crs) + return; + + coalesce_windows(info, IORESOURCE_MEM); + coalesce_windows(info, IORESOURCE_IO); + + for (i = 0; i < info->res_num; i++) { + res = &info->res[i]; + + if (res->flags & IORESOURCE_MEM) + root = &iomem_resource; + else if (res->flags & IORESOURCE_IO) + root = &ioport_resource; else - dev_info(&info->bridge->dev, - "host bridge window %pR\n", res); + continue; + + conflict = insert_resource_conflict(root, res); + if (conflict) + dev_err(&info->bridge->dev, + "address space collision: host bridge window %pR " + "conflicts with %s %pR\n", + res, conflict->name, conflict); + else + pci_bus_add_resource(info->bus, res, 0); } - return AE_OK; } static void @@ -224,6 +286,7 @@ get_current_resources(struct acpi_device *device, int busnum, acpi_walk_resources(device->handle, METHOD_NAME__CRS, setup_resource, &info); + add_resources(&info); return; name_alloc_fail: -- cgit v1.2.3-18-g5258