1 files changed, 10 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index 728b3750a3e8..e5b27d8f1b47 100644
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -6,6 +6,7 @@
 #include <asm/processor.h>
 #include <asm/apic.h>
 #include <asm/cpu.h>
+#include <asm/pci-direct.h>
 
 #ifdef CONFIG_X86_64
 # include <asm/numa_64.h>
@@ -351,6 +352,15 @@ static void __cpuinit early_init_amd(struct cpuinfo_x86 *c)
                     (c->x86_model == 8 && c->x86_mask >= 8))
                         set_cpu_cap(c, X86_FEATURE_K6_MTRR);
 #endif
+#if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_PCI)
+        /* check CPU config space for extended APIC ID */
+        if (c->x86 >= 0xf) {
+                unsigned int val;
+                val = read_pci_config(0, 24, 0, 0x68);
+                if ((val & ((1 << 17) | (1 << 18))) == ((1 << 17) | (1 << 18)))
+                        set_cpu_cap(c, X86_FEATURE_EXTD_APICID);
+        }
+#endif
 }
 
 static void __cpuinit init_amd(struct cpuinfo_x86 *c)