i386: insert unclaimed MMCONFIG resources

Insert the unclaimed MMCONFIG resources into the resource tree without the
IORESOURCE_BUSY flag during late initialization.  This allows the MMCONFIG
regions to be visible in the iomem resource tree without interfering with
other system resources that were discovered during PCI initialization.

[akpm@linux-foundation.org: nanofixes]
Signed-off-by: Aaron Durbin <adurbin@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 45 insertions, 3 deletions

diff --git a/arch/i386/pci/mmconfig-shared.c b/arch/i386/pci/mmconfig-shared.c
index c7cabeed4d7b..4df637e34f81 100644
--- a/arch/i386/pci/mmconfig-shared.c
+++ b/arch/i386/pci/mmconfig-shared.c
@@ -24,6 +24,9 @@
 
 DECLARE_BITMAP(pci_mmcfg_fallback_slots, 32*PCI_MMCFG_MAX_CHECK_BUS);
 
+/* Indicate if the mmcfg resources have been placed into the resource table. */
+static int __initdata pci_mmcfg_resources_inserted;
+
 /* K8 systems have some devices (typically in the builtin northbridge)
    that are only accessible using type1
    Normally this can be expressed in the MCFG by not listing them
@@ -170,7 +173,7 @@ static int __init pci_mmcfg_check_hostbridge(void)
         return name != NULL;
 }
 
-static void __init pci_mmcfg_insert_resources(void)
+static void __init pci_mmcfg_insert_resources(unsigned long resource_flags)
 {
 #define PCI_MMCFG_RESOURCE_NAME_LEN 19
         int i;
@@ -194,10 +197,13 @@ static void __init pci_mmcfg_insert_resources(void)
                          cfg->pci_segment);
                 res->start = cfg->address;
                 res->end = res->start + (num_buses << 20) - 1;
-                res->flags = IORESOURCE_MEM | IORESOURCE_BUSY;
+                res->flags = IORESOURCE_MEM | resource_flags;
                 insert_resource(&iomem_resource, res);
                 names += PCI_MMCFG_RESOURCE_NAME_LEN;
         }
+
+        /* Mark that the resources have been inserted. */
+        pci_mmcfg_resources_inserted = 1;
 }
 
 static void __init pci_mmcfg_reject_broken(int type)
@@ -267,7 +273,43 @@ void __init pci_mmcfg_init(int type)
                 if (type == 1)
                         unreachable_devices();
                 if (known_bridge)
-                        pci_mmcfg_insert_resources();
+                        pci_mmcfg_insert_resources(IORESOURCE_BUSY);
                 pci_probe = (pci_probe & ~PCI_PROBE_MASK) | PCI_PROBE_MMCONF;
+        } else {
+                /*
+                 * Signal not to attempt to insert mmcfg resources because
+                 * the architecture mmcfg setup could not initialize.
+                 */
+                pci_mmcfg_resources_inserted = 1;
         }
 }
+
+static int __init pci_mmcfg_late_insert_resources(void)
+{
+        /*
+         * If resources are already inserted or we are not using MMCONFIG,
+         * don't insert the resources.
+         */
+        if ((pci_mmcfg_resources_inserted == 1) ||
+            (pci_probe & PCI_PROBE_MMCONF) == 0 ||
+            (pci_mmcfg_config_num == 0) ||
+            (pci_mmcfg_config == NULL) ||
+            (pci_mmcfg_config[0].address == 0))
+                return 1;
+
+        /*
+         * Attempt to insert the mmcfg resources but not with the busy flag
+         * marked so it won't cause request errors when __request_region is
+         * called.
+         */
+        pci_mmcfg_insert_resources(0);
+
+        return 0;
+}
+
+/*
+ * Perform MMCONFIG resource insertion after PCI initialization to allow for
+ * misprogrammed MCFG tables that state larger sizes but actually conflict
+ * with other system resources.
+ */
+late_initcall(pci_mmcfg_late_insert_resources);