Kyösti Mälkki ([email protected]) just uploaded a new patch set to 
gerrit, which you can find at http://review.coreboot.org/1142

-gerrit

commit 18165693d04195d9fb80c13e1e420cb9be8991b6
Author: Kyösti Mälkki <[email protected]>
Date:   Wed Jun 27 16:14:49 2012 +0300

    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 <[email protected]>
---
 src/cpu/intel/hyperthreading/intel_sibling.c |   21 +++++++++++++++++++++
 src/cpu/intel/model_f2x/model_f2x_init.c     |   12 ++++++++----
 src/cpu/intel/model_f3x/model_f3x_init.c     |   12 ++++++++----
 src/cpu/intel/model_f4x/model_f4x_init.c     |   12 ++++++++----
 src/include/cpu/intel/hyperthreading.h       |    1 +
 5 files changed, 46 insertions(+), 12 deletions(-)

diff --git a/src/cpu/intel/hyperthreading/intel_sibling.c 
b/src/cpu/intel/hyperthreading/intel_sibling.c
index 2d2e105..b9a9ae7 100644
--- a/src/cpu/intel/hyperthreading/intel_sibling.c
+++ b/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;
diff --git a/src/cpu/intel/model_f2x/model_f2x_init.c 
b/src/cpu/intel/model_f2x/model_f2x_init.c
index ec78672..8fd8abc 100644
--- a/src/cpu/intel/model_f2x/model_f2x_init.c
+++ b/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();
diff --git a/src/cpu/intel/model_f3x/model_f3x_init.c 
b/src/cpu/intel/model_f3x/model_f3x_init.c
index 580c98b..2504ba9 100644
--- a/src/cpu/intel/model_f3x/model_f3x_init.c
+++ b/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();
diff --git a/src/cpu/intel/model_f4x/model_f4x_init.c 
b/src/cpu/intel/model_f4x/model_f4x_init.c
index 54edf2e..f3f0b2a 100644
--- a/src/cpu/intel/model_f4x/model_f4x_init.c
+++ b/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();
diff --git a/src/include/cpu/intel/hyperthreading.h 
b/src/include/cpu/intel/hyperthreading.h
index 0a1461c..c84a6a7 100644
--- a/src/include/cpu/intel/hyperthreading.h
+++ b/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 */

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