[137/151] x86: Under BIOS control, restore APs APIC_LVTTHMR to the BSP value

From: Greg KH
Date: Wed Dec 16 2009 - 23:09:55 EST

2.6.32-stable review patch. If anyone has any objections, please let us know.


From: Yong Wang <yong.y.wang@xxxxxxxxxxxxxxx>

Upstream commit a2202aa29289db64ca7988b12343158b67b27f10.

On platforms where bios handles the thermal monitor interrupt,
APIC_LVTTHMR on each logical CPU is programmed to generate a SMI and OS
can't touch it.

Unfortunately AP bringup sequence using INIT-SIPI-SIPI clear all
the LVT entries except the mask bit. Essentially this results in
all LVT entries including the thermal monitoring interrupt set to masked
(clearing the bios programmed value for APIC_LVTTHMR).

And this leads to kernel take over the thermal monitoring interrupt
on AP's but not on BSP (leaving the bios programmed value only on BSP).

As a result of this, we have seen system hangs when the thermal
monitoring interrupt is generated.

Fix this by reading the initial value of thermal LVT entry on BSP
and if bios has taken over the control, then program the same value
on all AP's and leave the thermal monitoring interrupt control
on all the logical cpu's to the bios.

Signed-off-by: Yong Wang <yong.y.wang@xxxxxxxxx>
Reviewed-by: Suresh Siddha <suresh.b.siddha@xxxxxxxxx>
Cc: Borislav Petkov <borislav.petkov@xxxxxxx>
Cc: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
LKML-Reference: <20091110013824.GA24940@xxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

arch/x86/include/asm/mce.h | 6 ++++++
arch/x86/kernel/cpu/mcheck/therm_throt.c | 29 ++++++++++++++++++++++++++++-
arch/x86/kernel/setup.c | 3 +++
3 files changed, 37 insertions(+), 1 deletion(-)

--- a/arch/x86/include/asm/mce.h
+++ b/arch/x86/include/asm/mce.h
@@ -214,5 +214,11 @@ void intel_init_thermal(struct cpuinfo_x

void mce_log_therm_throt_event(__u64 status);

+extern void mcheck_intel_therm_init(void);
+static inline void mcheck_intel_therm_init(void) { }
#endif /* __KERNEL__ */
#endif /* _ASM_X86_MCE_H */
--- 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_sta

static atomic_t therm_throt_en = ATOMIC_INIT(0);

+static u32 lvtthmr_init __read_mostly;
#define define_therm_throt_sysdev_one_ro(_name) \
static SYSDEV_ATTR(_name, 0444, therm_throt_sysdev_show_##_name, NULL)
@@ -254,6 +256,18 @@ asmlinkage void smp_thermal_interrupt(st

+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 (cpu_has(&boot_cpu_data, X86_FEATURE_ACPI) &&
+ cpu_has(&boot_cpu_data, X86_FEATURE_ACC))
+ lvtthmr_init = apic_read(APIC_LVTTHMR);
void intel_init_thermal(struct cpuinfo_x86 *c)
unsigned int cpu = smp_processor_id();
@@ -270,7 +284,20 @@ void intel_init_thermal(struct cpuinfo_x
* 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)) {
"CPU%d: Thermal monitoring handled by SMI\n", cpu);
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -109,6 +109,7 @@
#ifdef CONFIG_X86_64
#include <asm/numa_64.h>
+#include <asm/mce.h>

* end_pfn only includes RAM, while max_pfn_mapped includes all e820 entries.
@@ -1031,6 +1032,8 @@ void __init setup_arch(char **cmdline_p)
+ mcheck_intel_therm_init();

#ifdef CONFIG_X86_32

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/