4 files changed, 156 insertions, 20 deletions

diff --git a/arch/i386/kernel/acpi/boot.c b/arch/i386/kernel/acpi/boot.c
index 92f79cd..ab974ff 100644
--- a/arch/i386/kernel/acpi/boot.c
+++ b/arch/i386/kernel/acpi/boot.c
@@ -332,7 +332,7 @@ acpi_parse_ioapic(acpi_table_entry_header * header, const unsigned long end)
 /*
  * Parse Interrupt Source Override for the ACPI SCI
  */
-static void acpi_sci_ioapic_setup(u32 gsi, u16 polarity, u16 trigger)
+static void acpi_sci_ioapic_setup(u32 bus_irq, u32 gsi, u16 polarity, u16 trigger)
 {
 	if (trigger == 0)	/* compatible SCI trigger is level */
 		trigger = 3;
@@ -352,13 +352,13 @@ static void acpi_sci_ioapic_setup(u32 gsi, u16 polarity, u16 trigger)
 	 * If GSI is < 16, this will update its flags,
 	 * else it will create a new mp_irqs[] entry.
 	 */
-	mp_override_legacy_irq(gsi, polarity, trigger, gsi);
+	mp_override_legacy_irq(bus_irq, polarity, trigger, gsi);
 
 	/*
 	 * stash over-ride to indicate we've been here
 	 * and for later update of acpi_fadt
 	 */
-	acpi_sci_override_gsi = gsi;
+	acpi_sci_override_gsi = bus_irq;
 	return;
 }
 
@@ -376,7 +376,7 @@ acpi_parse_int_src_ovr(acpi_table_entry_header * header,
 	acpi_table_print_madt_entry(header);
 
 	if (intsrc->bus_irq == acpi_fadt.sci_int) {
-		acpi_sci_ioapic_setup(intsrc->global_irq,
+		acpi_sci_ioapic_setup(intsrc->bus_irq, intsrc->global_irq,
 				      intsrc->flags.polarity,
 				      intsrc->flags.trigger);
 		return 0;
@@ -879,7 +879,7 @@ static int __init acpi_parse_madt_ioapic_entries(void)
 	 * pretend we got one so we can set the SCI flags.
 	 */
 	if (!acpi_sci_override_gsi)
-		acpi_sci_ioapic_setup(acpi_fadt.sci_int, 0, 0);
+		acpi_sci_ioapic_setup(acpi_fadt.sci_int, acpi_fadt.sci_int, 0, 0);
 
 	/* Fill in identity legacy mapings where no override */
 	mp_config_acpi_legacy_irqs();
diff --git a/arch/i386/kernel/acpi/cstate.c b/arch/i386/kernel/acpi/cstate.c
index 25db49e..20563e5 100644
--- a/arch/i386/kernel/acpi/cstate.c
+++ b/arch/i386/kernel/acpi/cstate.c
@@ -10,6 +10,7 @@
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/acpi.h>
+#include <linux/cpu.h>
 
 #include <acpi/processor.h>
 #include <asm/acpi.h>
@@ -41,5 +42,124 @@ void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
 		flags->bm_check = 1;
 	}
 }
-
 EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
+
+/* The code below handles cstate entry with monitor-mwait pair on Intel*/
+
+struct cstate_entry_s {
+	struct {
+		unsigned int eax;
+		unsigned int ecx;
+	} states[ACPI_PROCESSOR_MAX_POWER];
+};
+static struct cstate_entry_s *cpu_cstate_entry;	/* per CPU ptr */
+
+static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
+
+#define MWAIT_SUBSTATE_MASK	(0xf)
+#define MWAIT_SUBSTATE_SIZE	(4)
+
+#define CPUID_MWAIT_LEAF (5)
+#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
+#define CPUID5_ECX_INTERRUPT_BREAK	(0x2)
+
+#define MWAIT_ECX_INTERRUPT_BREAK	(0x1)
+
+#define NATIVE_CSTATE_BEYOND_HALT	(2)
+
+int acpi_processor_ffh_cstate_probe(unsigned int cpu,
+		struct acpi_processor_cx *cx, struct acpi_power_register *reg)
+{
+	struct cstate_entry_s *percpu_entry;
+	struct cpuinfo_x86 *c = cpu_data + cpu;
+
+	cpumask_t saved_mask;
+	int retval;
+	unsigned int eax, ebx, ecx, edx;
+	unsigned int edx_part;
+	unsigned int cstate_type; /* C-state type and not ACPI C-state type */
+	unsigned int num_cstate_subtype;
+
+	if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF )
+		return -1;
+
+	if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
+		return -1;
+
+	percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
+	percpu_entry->states[cx->index].eax = 0;
+	percpu_entry->states[cx->index].ecx = 0;
+
+	/* Make sure we are running on right CPU */
+	saved_mask = current->cpus_allowed;
+	retval = set_cpus_allowed(current, cpumask_of_cpu(cpu));
+	if (retval)
+		return -1;
+
+	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
+
+	/* Check whether this particular cx_type (in CST) is supported or not */
+	cstate_type = (cx->address >> MWAIT_SUBSTATE_SIZE) + 1;
+	edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
+	num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
+
+	retval = 0;
+	if (num_cstate_subtype < (cx->address & MWAIT_SUBSTATE_MASK)) {
+		retval = -1;
+		goto out;
+	}
+
+	/* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
+	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
+		retval = -1;
+		goto out;
+	}
+	percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
+
+	/* Use the hint in CST */
+	percpu_entry->states[cx->index].eax = cx->address;
+
+	if (!mwait_supported[cstate_type]) {
+		mwait_supported[cstate_type] = 1;
+		printk(KERN_DEBUG "Monitor-Mwait will be used to enter C-%d "
+		       "state\n", cx->type);
+	}
+
+out:
+	set_cpus_allowed(current, saved_mask);
+	return retval;
+}
+EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
+
+void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
+{
+	unsigned int cpu = smp_processor_id();
+	struct cstate_entry_s *percpu_entry;
+
+	percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
+	mwait_idle_with_hints(percpu_entry->states[cx->index].eax,
+	                      percpu_entry->states[cx->index].ecx);
+}
+EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter);
+
+static int __init ffh_cstate_init(void)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+	if (c->x86_vendor != X86_VENDOR_INTEL)
+		return -1;
+
+	cpu_cstate_entry = alloc_percpu(struct cstate_entry_s);
+	return 0;
+}
+
+static void __exit ffh_cstate_exit(void)
+{
+	if (cpu_cstate_entry) {
+		free_percpu(cpu_cstate_entry);
+		cpu_cstate_entry = NULL;
+	}
+}
+
+arch_initcall(ffh_cstate_init);
+__exitcall(ffh_cstate_exit);
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index b0a0780..57d3759 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -236,20 +236,28 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait);
  * We execute MONITOR against need_resched and enter optimized wait state
  * through MWAIT. Whenever someone changes need_resched, we would be woken
  * up from MWAIT (without an IPI).
+ *
+ * New with Core Duo processors, MWAIT can take some hints based on CPU
+ * capability.
  */
-static void mwait_idle(void)
+void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
 {
-	local_irq_enable();
-
-	while (!need_resched()) {
+	if (!need_resched()) {
 		__monitor((void *)&current_thread_info()->flags, 0, 0);
 		smp_mb();
-		if (need_resched())
-			break;
-		__mwait(0, 0);
+		if (!need_resched())
+			__mwait(eax, ecx);
 	}
 }
 
+/* Default MONITOR/MWAIT with no hints, used for default C1 state */
+static void mwait_idle(void)
+{
+	local_irq_enable();
+	while (!need_resched())
+		mwait_idle_with_hints(0, 0);
+}
+
 void __devinit select_idle_routine(const struct cpuinfo_x86 *c)
 {
 	if (cpu_has(c, X86_FEATURE_MWAIT)) {
diff --git a/arch/x86_64/kernel/process.c b/arch/x86_64/kernel/process.c
index 5e95b25..49f7fac 100644
--- a/arch/x86_64/kernel/process.c
+++ b/arch/x86_64/kernel/process.c
@@ -238,20 +238,28 @@ void cpu_idle (void)
  * We execute MONITOR against need_resched and enter optimized wait state
  * through MWAIT. Whenever someone changes need_resched, we would be woken
  * up from MWAIT (without an IPI).
+ *
+ * New with Core Duo processors, MWAIT can take some hints based on CPU
+ * capability.
  */
-static void mwait_idle(void)
+void mwait_idle_with_hints(unsigned long eax, unsigned long ecx)
 {
-	local_irq_enable();
-
-	while (!need_resched()) {
+	if (!need_resched()) {
 		__monitor((void *)&current_thread_info()->flags, 0, 0);
 		smp_mb();
-		if (need_resched())
-			break;
-		__mwait(0, 0);
+		if (!need_resched())
+			__mwait(eax, ecx);
 	}
 }
 
+/* Default MONITOR/MWAIT with no hints, used for default C1 state */
+static void mwait_idle(void)
+{
+	local_irq_enable();
+	while (!need_resched())
+		mwait_idle_with_hints(0,0);
+}
+
 void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
 {
 	static int printed;