x86/cpu/AMD: Evaluate smp_num_siblings early

To support force disabling of SMT it's required to know the number of
thread siblings early. amd_get_topology() cannot be called before the APIC
driver is selected, so split out the part which initializes
smp_num_siblings and invoke it from amd_early_init().

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c
index d120e5c..b20dee9 100644 (file)
--- a/arch/x86/kernel/cpu/amd.c
+++ b/arch/x86/kernel/cpu/amd.c
@@ -315,6 +315,17 @@ static void legacy_fixup_core_id(struct cpuinfo_x86 *c)
        c->cpu_core_id %= cus_per_node;
 }
 
+
+static void amd_get_topology_early(struct cpuinfo_x86 *c)
+{
+       if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
+               u32 eax, ebx, ecx, edx;
+
+               cpuid(0x8000001e, &eax, &ebx, &ecx, &edx);
+               smp_num_siblings = ((ebx >> 8) & 0xff) + 1;
+       }
+}
+
 /*
  * Fixup core topology information for
  * (1) AMD multi-node processors
@@ -681,6 +692,8 @@ static void early_init_amd(struct cpuinfo_x86 *c)
                set_cpu_bug(c, X86_BUG_AMD_E400);
 
        early_detect_mem_encrypt(c);
+
+       amd_get_topology_early(c);
 }
 
 static void init_amd_k8(struct cpuinfo_x86 *c)