1 files changed, 40 insertions, 5 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/therm_throt.c b/arch/x86/kernel/cpu/mcheck/therm_throt.c
index b3a1dba75330..81c499eceb21 100644
--- a/arch/x86/kernel/cpu/mcheck/therm_throt.c
+++ b/arch/x86/kernel/cpu/mcheck/therm_throt.c
@@ -49,6 +49,8 @@ static DEFINE_PER_CPU(struct thermal_state, thermal_state);
 
 static atomic_t therm_throt_en  = ATOMIC_INIT(0);
 
+static u32 lvtthmr_init __read_mostly;
+
 #ifdef CONFIG_SYSFS
 #define define_therm_throt_sysdev_one_ro(_name)                         \
         static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
@@ -254,14 +256,34 @@ asmlinkage void smp_thermal_interrupt(struct pt_regs *regs)
         ack_APIC_irq();
 }
 
+/* Thermal monitoring depends on APIC, ACPI and clock modulation */
+static int intel_thermal_supported(struct cpuinfo_x86 *c)
+{
+        if (!cpu_has_apic)
+                return 0;
+        if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
+                return 0;
+        return 1;
+}
+
+void __init mcheck_intel_therm_init(void)
+{
+        /*
+         * This function is only called on boot CPU. Save the init thermal
+         * LVT value on BSP and use that value to restore APs' thermal LVT
+         * entry BIOS programmed later
+         */
+        if (intel_thermal_supported(&boot_cpu_data))
+                lvtthmr_init = apic_read(APIC_LVTTHMR);
+}
+
 void intel_init_thermal(struct cpuinfo_x86 *c)
 {
         unsigned int cpu = smp_processor_id();
         int tm2 = 0;
         u32 l, h;
 
-        /* Thermal monitoring depends on ACPI and clock modulation*/
-        if (!cpu_has(c, X86_FEATURE_ACPI) || !cpu_has(c, X86_FEATURE_ACC))
+        if (!intel_thermal_supported(c))
                 return;
 
         /*
@@ -270,7 +292,20 @@ void intel_init_thermal(struct cpuinfo_x86 *c)
          * since it might be delivered via SMI already:
          */
         rdmsr(MSR_IA32_MISC_ENABLE, l, h);
-        h = apic_read(APIC_LVTTHMR);
+
+        /*
+         * The initial value of thermal LVT entries on all APs always reads
+         * 0x10000 because APs are woken up by BSP issuing INIT-SIPI-SIPI
+         * sequence to them and LVT registers are reset to 0s except for
+         * the mask bits which are set to 1s when APs receive INIT IPI.
+         * Always restore the value that BIOS has programmed on AP based on
+         * BSP's info we saved since BIOS is always setting the same value
+         * for all threads/cores
+         */
+        apic_write(APIC_LVTTHMR, lvtthmr_init);
+
+        h = lvtthmr_init;
+
         if ((l & MSR_IA32_MISC_ENABLE_TM1) && (h & APIC_DM_SMI)) {
                 printk(KERN_DEBUG
                        "CPU%d: Thermal monitoring handled by SMI\n", cpu);
@@ -312,8 +347,8 @@ void intel_init_thermal(struct cpuinfo_x86 *c)
         l = apic_read(APIC_LVTTHMR);
         apic_write(APIC_LVTTHMR, l & ~APIC_LVT_MASKED);
 
-        printk(KERN_INFO "CPU%d: Thermal monitoring enabled (%s)\n",
-               cpu, tm2 ? "TM2" : "TM1");
+        printk_once(KERN_INFO "CPU0: Thermal monitoring enabled (%s)\n",
+                       tm2 ? "TM2" : "TM1");
 
         /* enable thermal throttle processing */
         atomic_set(&therm_throt_en, 1);