[coreboot-gerrit] New patch to review for coreboot: intel/skylake: add function is_secondary_thread()

[Robbie Zhang (robbie.zhang@intel.com)]

Robbie Zhang (robbie.zhang at intel.com) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/18366

-gerrit

commit 9385a66ae9a0ddc4271e2ebd5163dac2023ceaa5
Author: Robbie Zhang <robbie.zhang at intel.com>
Date:   Tue Feb 14 15:12:17 2017 -0800

    intel/skylake: add function is_secondary_thread()
    
    There are MSRs that are programmable per-core not per-thread, so add
    a function to check whether current executing CPU is a primary core
    or a "hyperthreaded"/secondary core. For instance when trying to
    program Core PRMRR MSRs(per-core) with mp_init, cpu exception is thrown
    from the secondary thread. This function was used to avoid that.
    
    Potentially this function can be put to common code or arch/x86 or cpu/x86.
    
    BUG=chrome-os-partner:62438
    BRANCH=NONE
    TEST=Tested on Eve, verified core PRMRR MSRs get programmed only on primary
    thread avoiding exeception.
    
    Change-Id: Ic9648351fadf912164a39206788859baf3e5c173
    Signed-off-by: Robbie Zhang <robbie.zhang at intel.com>
---
 src/soc/intel/skylake/cpu.c             | 8 ++++++++
 src/soc/intel/skylake/include/soc/cpu.h | 1 +
 2 files changed, 9 insertions(+)

diff --git a/src/soc/intel/skylake/cpu.c b/src/soc/intel/skylake/cpu.c
index fd726c8..6e0ad1b 100644
--- a/src/soc/intel/skylake/cpu.c
+++ b/src/soc/intel/skylake/cpu.c
@@ -431,6 +431,14 @@ static int adjust_apic_id(int index, int apic_id)
 		return index;
 }
 
+int is_secondary_thread(void)
+{
+	int apic_id;
+	apic_id = lapicid();
+
+	return (!ht_disabled) & (apic_id & 1);
+}
+
 static void per_cpu_smm_trigger(void)
 {
 	/* Relocate the SMM handler. */
diff --git a/src/soc/intel/skylake/include/soc/cpu.h b/src/soc/intel/skylake/include/soc/cpu.h
index ecb9833..bf720e6 100644
--- a/src/soc/intel/skylake/include/soc/cpu.h
+++ b/src/soc/intel/skylake/include/soc/cpu.h
@@ -63,5 +63,6 @@ int cpu_config_tdp_levels(void);
 u32 cpu_family_model(void);
 u32 cpu_stepping(void);
 int cpu_is_ult(void);
+int is_secondary_thread(void);
 
 #endif