Merge remote-tracking branch 'linus/master' into staging/for_v3.8

* linus/master: (1428 commits)
  futex: avoid wake_futex() for a PI futex_q
  watchdog: using u64 in get_sample_period()
  writeback: put unused inodes to LRU after writeback completion
  mm: vmscan: check for fatal signals iff the process was throttled
  Revert "mm: remove __GFP_NO_KSWAPD"
  proc: check vma->vm_file before dereferencing
  UAPI: strip the _UAPI prefix from header guards during header installation
  include/linux/bug.h: fix sparse warning related to BUILD_BUG_ON_INVALID
  Linux 3.7-rc7
  powerpc/eeh: Do not invalidate PE properly
  ALSA: hda - Fix build without CONFIG_PM
  of/address: sparc: Declare of_iomap as an extern function for sparc again
  PM / QoS: fix wrong error-checking condition
  bnx2x: remove redundant warning log
  vxlan: fix command usage in its doc
  8139cp: revert "set ring address before enabling receiver"
  MPI: Fix compilation on MIPS with GCC 4.4 and newer
  MIPS: Fix crash that occurs when function tracing is enabled
  MIPS: Merge overlapping bootmem ranges
  jbd: Fix lock ordering bug in journal_unmap_buffer()
  ...

1 files changed, 32 insertions, 7 deletions

diff --git a/drivers/iommu/amd_iommu_init.c b/drivers/iommu/amd_iommu_init.c
index 18b0d99bd4d6..81837b0710a9 100644
--- a/drivers/iommu/amd_iommu_init.c
+++ b/drivers/iommu/amd_iommu_init.c
@@ -1599,21 +1599,46 @@ static void __init free_on_init_error(void)
 #endif
 }
 
+/* SB IOAPIC is always on this device in AMD systems */
+#define IOAPIC_SB_DEVID		((0x00 << 8) | PCI_DEVFN(0x14, 0))
+
 static bool __init check_ioapic_information(void)
 {
+	bool ret, has_sb_ioapic;
 	int idx;
 
-	for (idx = 0; idx < nr_ioapics; idx++) {
-		int id = mpc_ioapic_id(idx);
+	has_sb_ioapic = false;
+	ret           = false;
 
-		if (get_ioapic_devid(id) < 0) {
-			pr_err(FW_BUG "AMD-Vi: IO-APIC[%d] not in IVRS table\n", id);
-			pr_err("AMD-Vi: Disabling interrupt remapping due to BIOS Bug\n");
-			return false;
+	for (idx = 0; idx < nr_ioapics; idx++) {
+		int devid, id = mpc_ioapic_id(idx);
+
+		devid = get_ioapic_devid(id);
+		if (devid < 0) {
+			pr_err(FW_BUG "AMD-Vi: IOAPIC[%d] not in IVRS table\n", id);
+			ret = false;
+		} else if (devid == IOAPIC_SB_DEVID) {
+			has_sb_ioapic = true;
+			ret           = true;
 		}
 	}
 
-	return true;
+	if (!has_sb_ioapic) {
+		/*
+		 * We expect the SB IOAPIC to be listed in the IVRS
+		 * table. The system timer is connected to the SB IOAPIC
+		 * and if we don't have it in the list the system will
+		 * panic at boot time.  This situation usually happens
+		 * when the BIOS is buggy and provides us the wrong
+		 * device id for the IOAPIC in the system.
+		 */
+		pr_err(FW_BUG "AMD-Vi: No southbridge IOAPIC found in IVRS table\n");
+	}
+
+	if (!ret)
+		pr_err("AMD-Vi: Disabling interrupt remapping due to BIOS Bug(s)\n");
+
+	return ret;
 }
 
 static void __init free_dma_resources(void)