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 <anisse@xxxxxxxxx>
Reported-and-tested-by: Pramod Dematagoda <pmd.lotr.gandalf@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bjorn.helgaas@xxxxxx>
---
arch/x86/pci/acpi.c | 103 +++++++++++++++++++++++++++++++++++++++++----------
1 files changed, 83 insertions(+), 20 deletions(-)
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
index 15466c0..0972315 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:
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