PNPACPI: truncate _CRS windows with _LEN > _MAX - _MIN + 1

The ACPI spec (sec 6.4.3.5 in v4.0) requires that for Address Space Resource
Descriptors, _LEN <= _MAX - _MIN + 1 in all cases, but there are BIOSes that
violate this.  We experimentally determined that Windows truncates the
resource so it doesn't extend past _MAX, so let's do the same thing in
Linux.

http://bugzilla.kernel.org/show_bug.cgi?id=15480

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Acked-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 30 insertions, 12 deletions

diff --git a/drivers/pnp/pnpacpi/rsparser.c b/drivers/pnp/pnpacpi/rsparser.c
index 54514aa35b09..fe5bfa998f59 100644
--- a/drivers/pnp/pnpacpi/rsparser.c
+++ b/drivers/pnp/pnpacpi/rsparser.c
@@ -273,12 +273,33 @@ static void pnpacpi_parse_allocated_busresource(struct pnp_dev *dev,
         pnp_add_bus_resource(dev, start, end);
 }
 
+static u64 addr_space_length(struct pnp_dev *dev, u64 min, u64 max, u64 len)
+{
+        u64 max_len;
+
+        max_len = max - min + 1;
+        if (len <= max_len)
+                return len;
+
+        /*
+         * Per 6.4.3.5, _LEN cannot exceed _MAX - _MIN + 1, but some BIOSes
+         * don't do this correctly, e.g.,
+         * https://bugzilla.kernel.org/show_bug.cgi?id=15480
+         */
+        dev_info(&dev->dev,
+                 "resource length %#llx doesn't fit in %#llx-%#llx, trimming\n",
+                 (unsigned long long) len, (unsigned long long) min,
+                 (unsigned long long) max);
+        return max_len;
+}
+
 static void pnpacpi_parse_allocated_address_space(struct pnp_dev *dev,
                                                   struct acpi_resource *res)
 {
         struct acpi_resource_address64 addr, *p = &addr;
         acpi_status status;
         int window;
+        u64 len;
 
         status = acpi_resource_to_address64(res, p);
         if (!ACPI_SUCCESS(status)) {
@@ -287,20 +308,18 @@ static void pnpacpi_parse_allocated_address_space(struct pnp_dev *dev,
                 return;
         }
 
+        len = addr_space_length(dev, p->minimum, p->maximum, p->address_length);
         window = (p->producer_consumer == ACPI_PRODUCER) ? 1 : 0;
 
         if (p->resource_type == ACPI_MEMORY_RANGE)
-                pnpacpi_parse_allocated_memresource(dev,
-                        p->minimum, p->address_length,
+                pnpacpi_parse_allocated_memresource(dev, p->minimum, len,
                         p->info.mem.write_protect, window);
         else if (p->resource_type == ACPI_IO_RANGE)
-                pnpacpi_parse_allocated_ioresource(dev,
-                        p->minimum, p->address_length,
+                pnpacpi_parse_allocated_ioresource(dev, p->minimum, len,
                         p->granularity == 0xfff ? ACPI_DECODE_10 :
                                 ACPI_DECODE_16, window);
         else if (p->resource_type == ACPI_BUS_NUMBER_RANGE)
-                pnpacpi_parse_allocated_busresource(dev, p->minimum,
-                                                    p->address_length);
+                pnpacpi_parse_allocated_busresource(dev, p->minimum, len);
 }
 
 static void pnpacpi_parse_allocated_ext_address_space(struct pnp_dev *dev,
@@ -308,21 +327,20 @@ static void pnpacpi_parse_allocated_ext_address_space(struct pnp_dev *dev,
 {
         struct acpi_resource_extended_address64 *p = &res->data.ext_address64;
         int window;
+        u64 len;
 
+        len = addr_space_length(dev, p->minimum, p->maximum, p->address_length);
         window = (p->producer_consumer == ACPI_PRODUCER) ? 1 : 0;
 
         if (p->resource_type == ACPI_MEMORY_RANGE)
-                pnpacpi_parse_allocated_memresource(dev,
-                        p->minimum, p->address_length,
+                pnpacpi_parse_allocated_memresource(dev, p->minimum, len,
                         p->info.mem.write_protect, window);
         else if (p->resource_type == ACPI_IO_RANGE)
-                pnpacpi_parse_allocated_ioresource(dev,
-                        p->minimum, p->address_length,
+                pnpacpi_parse_allocated_ioresource(dev, p->minimum, len,
                         p->granularity == 0xfff ? ACPI_DECODE_10 :
                                 ACPI_DECODE_16, window);
         else if (p->resource_type == ACPI_BUS_NUMBER_RANGE)
-                pnpacpi_parse_allocated_busresource(dev, p->minimum,
-                                                    p->address_length);
+                pnpacpi_parse_allocated_busresource(dev, p->minimum, len);
 }
 
 static acpi_status pnpacpi_allocated_resource(struct acpi_resource *res,