Intel CPUs: execute microcode update only once per core

Early HT-enabled CPUs do not serialize microcode updates within a core.
Solve this by running microcode updates on the thread with the smallest
lapic ID of a core only.

Also set MTRRs once per core only.

Change-Id: I6a3cc9ecec2d8e0caed29605a9b19ec35a817620
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: http://review.coreboot.org/1142
Tested-by: build bot (Jenkins)
Reviewed-by: Sven Schnelle <svens@stackframe.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/cpu/intel/hyperthreading/intel_sibling.c

@@ -14,6 +14,27 @@
 static int first_time = 1;
 static int disable_siblings = !CONFIG_LOGICAL_CPUS;
 
+/* Return true if running thread does not have the smallest lapic ID
+ * within a CPU core.
+ */
+int intel_ht_sibling(void)
+{
+	unsigned int core_ids, apic_ids, threads;
+
+	apic_ids = 1;
+	if (cpuid_eax(0) >= 1)
+		apic_ids = (cpuid_ebx(1) >> 16) & 0xff;
+	if (apic_ids < 1)
+		apic_ids = 1;
+
+	core_ids = 1;
+	if (cpuid_eax(0) >= 4)
+		core_ids += (cpuid_eax(4) >> 26) & 0x3f;
+
+	threads = (apic_ids / core_ids);
+	return !!(lapicid() & (threads-1));
+}
+
 void intel_sibling_init(device_t cpu)
 {
 	unsigned i, siblings;

src/cpu/intel/model_f2x/model_f2x_init.c

@@ -48,11 +48,15 @@ static void model_f2x_init(device_t cpu)
 {
 	/* Turn on caching if we haven't already */
 	x86_enable_cache();
-	x86_setup_mtrrs();
-	x86_mtrr_check();
 
-	/* Update the microcode */
-	intel_update_microcode(microcode_updates);
+	if (!intel_ht_sibling()) {
+		/* MTRRs are shared between threads */
+		x86_setup_mtrrs();
+		x86_mtrr_check();
+
+		/* Update the microcode */
+		intel_update_microcode(microcode_updates);
+	}
 
 	/* Enable the local cpu apics */
 	setup_lapic();

src/cpu/intel/model_f3x/model_f3x_init.c

@@ -31,11 +31,15 @@ static void model_f3x_init(device_t cpu)
 {
 	/* Turn on caching if we haven't already */
 	x86_enable_cache();
-	x86_setup_mtrrs();
-	x86_mtrr_check();
 
-	/* Update the microcode */
-	intel_update_microcode(microcode_updates);
+	if (!intel_ht_sibling()) {
+		/* MTRRs are shared between threads */
+		x86_setup_mtrrs();
+		x86_mtrr_check();
+
+		/* Update the microcode */
+		intel_update_microcode(microcode_updates);
+	}
 
 	/* Enable the local cpu apics */
 	setup_lapic();

src/cpu/intel/model_f4x/model_f4x_init.c

@@ -39,11 +39,15 @@ static void model_f4x_init(device_t cpu)
 {
 	/* Turn on caching if we haven't already */
 	x86_enable_cache();
-	x86_setup_mtrrs();
-	x86_mtrr_check();
 
-	/* Update the microcode */
-	intel_update_microcode(microcode_updates);
+	if (!intel_ht_sibling()) {
+		/* MTRRs are shared between threads */
+		x86_setup_mtrrs();
+		x86_mtrr_check();
+
+		/* Update the microcode */
+		intel_update_microcode(microcode_updates);
+	}
 
 	/* Enable the local cpu apics */
 	setup_lapic();

src/include/cpu/intel/hyperthreading.h

@@ -3,5 +3,6 @@
 
 struct device;
 void intel_sibling_init(struct device *cpu);
+int intel_ht_sibling(void);
 
 #endif /* CPU_INTEL_HYPERTHREADING_H */