[PATCH] x86: fix the irqbalance quirk for E7320/E7520/E7525

Move the irqbalance quirks for E7320/E7520/E7525(Errata 23 in
http://download.intel.com/design/chipsets/specupdt/30304203.pdf) to early
quirks.

And add a PCI quirk for these platforms to check(which happens very late
during the boot) if the APIC routing is indeed set to default flat mode.

This fixes the breakage(in x86_64) of this quirk due to cpu hotplug which
selects physical mode instead of the logical flat(as needed for this errata
workaround).

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Andi Kleen <ak@suse.de>
Cc: "Li, Shaohua" <shaohua.li@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>

2 files changed, 21 insertions, 0 deletions

diff --git a/arch/x86_64/kernel/early-quirks.c b/arch/x86_64/kernel/early-quirks.c
index fb0c6da41b7e..829698f6d049 100644
--- a/arch/x86_64/kernel/early-quirks.c
+++ b/arch/x86_64/kernel/early-quirks.c
@@ -71,6 +71,18 @@ static void ati_bugs(void)
 {
 }
 
+static void intel_bugs(void)
+{
+        u16 device = read_pci_config_16(0, 0, 0, PCI_DEVICE_ID);
+
+#ifdef CONFIG_SMP
+        if (device == PCI_DEVICE_ID_INTEL_E7320_MCH ||
+            device == PCI_DEVICE_ID_INTEL_E7520_MCH ||
+            device == PCI_DEVICE_ID_INTEL_E7525_MCH)
+                quirk_intel_irqbalance();
+#endif
+}
+
 struct chipset {
         u16 vendor;
         void (*f)(void);
@@ -80,6 +92,7 @@ static struct chipset early_qrk[] = {
         { PCI_VENDOR_ID_NVIDIA, nvidia_bugs },
         { PCI_VENDOR_ID_VIA, via_bugs },
         { PCI_VENDOR_ID_ATI, ati_bugs },
+        { PCI_VENDOR_ID_INTEL, intel_bugs},
         {}
 };
 
diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c
index 62c2e747af58..4c161c208d5b 100644
--- a/arch/x86_64/kernel/smpboot.c
+++ b/arch/x86_64/kernel/smpboot.c
@@ -60,6 +60,7 @@
 #include <asm/irq.h>
 #include <asm/hw_irq.h>
 #include <asm/numa.h>
+#include <asm/genapic.h>
 
 /* Number of siblings per CPU package */
 int smp_num_siblings = 1;
@@ -1167,6 +1168,13 @@ int __cpuinit __cpu_up(unsigned int cpu)
 
         while (!cpu_isset(cpu, cpu_online_map))
                 cpu_relax();
+
+        if (num_online_cpus() > 8 && genapic == &apic_flat) {
+                printk(KERN_WARNING
+                       "flat APIC routing can't be used with > 8 cpus\n");
+                BUG();
+        }
+
         err = 0;
 
         return err;