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authorVenkatesh Pallipadi <venkatesh.pallipadi@intel.com>2006-01-11 22:44:24 +0100
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-11 19:04:54 -0800
commitd25bf7e5fe73b5b6d2246ab0be08ae35d718456b (patch)
tree472749fef9b017e9a4d94f9e07a29dc44c3294cb /arch/x86_64/kernel
parent6eb0a0fd059598ee0d49c6283ce25cccd743e9fc (diff)
[PATCH] x86_64: Handle missing local APIC timer interrupts on C3 state
Whenever we see that a CPU is capable of C3 (during ACPI cstate init), we disable local APIC timer and switch to using a broadcast from external timer interrupt (IRQ 0). Patch below adds the code for x86_64. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/x86_64/kernel')
-rw-r--r--arch/x86_64/kernel/apic.c55
-rw-r--r--arch/x86_64/kernel/time.c5
2 files changed, 58 insertions, 2 deletions
diff --git a/arch/x86_64/kernel/apic.c b/arch/x86_64/kernel/apic.c
index fa47ae73157..40cbd60e2d0 100644
--- a/arch/x86_64/kernel/apic.c
+++ b/arch/x86_64/kernel/apic.c
@@ -25,6 +25,7 @@
#include <linux/mc146818rtc.h>
#include <linux/kernel_stat.h>
#include <linux/sysdev.h>
+#include <linux/module.h>
#include <asm/atomic.h>
#include <asm/smp.h>
@@ -38,6 +39,12 @@ int apic_verbosity;
int disable_apic_timer __initdata;
+/*
+ * cpu_mask that denotes the CPUs that needs timer interrupt coming in as
+ * IPIs in place of local APIC timers
+ */
+static cpumask_t timer_interrupt_broadcast_ipi_mask;
+
/* Using APIC to generate smp_local_timer_interrupt? */
int using_apic_timer = 0;
@@ -656,9 +663,14 @@ void __init init_apic_mappings(void)
static void __setup_APIC_LVTT(unsigned int clocks)
{
unsigned int lvtt_value, tmp_value, ver;
+ int cpu = smp_processor_id();
ver = GET_APIC_VERSION(apic_read(APIC_LVR));
lvtt_value = APIC_LVT_TIMER_PERIODIC | LOCAL_TIMER_VECTOR;
+
+ if (cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask))
+ lvtt_value |= APIC_LVT_MASKED;
+
apic_write_around(APIC_LVTT, lvtt_value);
/*
@@ -781,7 +793,7 @@ void __cpuinit setup_secondary_APIC_clock(void)
local_irq_enable();
}
-void __cpuinit disable_APIC_timer(void)
+void disable_APIC_timer(void)
{
if (using_apic_timer) {
unsigned long v;
@@ -793,7 +805,10 @@ void __cpuinit disable_APIC_timer(void)
void enable_APIC_timer(void)
{
- if (using_apic_timer) {
+ int cpu = smp_processor_id();
+
+ if (using_apic_timer &&
+ !cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) {
unsigned long v;
v = apic_read(APIC_LVTT);
@@ -801,6 +816,42 @@ void enable_APIC_timer(void)
}
}
+void switch_APIC_timer_to_ipi(void *cpumask)
+{
+ cpumask_t mask = *(cpumask_t *)cpumask;
+ int cpu = smp_processor_id();
+
+ if (cpu_isset(cpu, mask) &&
+ !cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) {
+ disable_APIC_timer();
+ cpu_set(cpu, timer_interrupt_broadcast_ipi_mask);
+ }
+}
+EXPORT_SYMBOL(switch_APIC_timer_to_ipi);
+
+void smp_send_timer_broadcast_ipi(void)
+{
+ cpumask_t mask;
+
+ cpus_and(mask, cpu_online_map, timer_interrupt_broadcast_ipi_mask);
+ if (!cpus_empty(mask)) {
+ send_IPI_mask(mask, LOCAL_TIMER_VECTOR);
+ }
+}
+
+void switch_ipi_to_APIC_timer(void *cpumask)
+{
+ cpumask_t mask = *(cpumask_t *)cpumask;
+ int cpu = smp_processor_id();
+
+ if (cpu_isset(cpu, mask) &&
+ cpu_isset(cpu, timer_interrupt_broadcast_ipi_mask)) {
+ cpu_clear(cpu, timer_interrupt_broadcast_ipi_mask);
+ enable_APIC_timer();
+ }
+}
+EXPORT_SYMBOL(switch_ipi_to_APIC_timer);
+
int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 43c9fa0f8d5..211bf0e51d9 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -471,6 +471,11 @@ static irqreturn_t timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
write_sequnlock(&xtime_lock);
+#ifdef CONFIG_X86_LOCAL_APIC
+ if (using_apic_timer)
+ smp_send_timer_broadcast_ipi();
+#endif
+
return IRQ_HANDLED;
}