Merge branch 'x86-idle-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-idle-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, hotplug: In the MWAIT case of play_dead, CLFLUSH the cache line
  x86, hotplug: Move WBINVD back outside the play_dead loop
  x86, hotplug: Use mwait to offline a processor, fix the legacy case
  x86, mwait: Move mwait constants to a common header file

6 files changed, 97 insertions, 48 deletions

diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
new file mode 100644
index 000000000000..bcdff997668c
--- /dev/null
+++ b/arch/x86/include/asm/mwait.h
@@ -0,0 +1,15 @@
+#ifndef _ASM_X86_MWAIT_H
+#define _ASM_X86_MWAIT_H
+
+#define MWAIT_SUBSTATE_MASK             0xf
+#define MWAIT_CSTATE_MASK               0xf
+#define MWAIT_SUBSTATE_SIZE             4
+#define MWAIT_MAX_NUM_CSTATES           8
+
+#define CPUID_MWAIT_LEAF                5
+#define CPUID5_ECX_EXTENSIONS_SUPPORTED 0x1
+#define CPUID5_ECX_INTERRUPT_BREAK      0x2
+
+#define MWAIT_ECX_INTERRUPT_BREAK       0x1
+
+#endif /* _ASM_X86_MWAIT_H */
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a668d66301fe..cae9c3cb95cf 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -766,29 +766,6 @@ extern unsigned long		idle_halt;
 extern unsigned long            idle_nomwait;
 extern bool                     c1e_detected;
 
-/*
- * on systems with caches, caches must be flashed as the absolute
- * last instruction before going into a suspended halt.  Otherwise,
- * dirty data can linger in the cache and become stale on resume,
- * leading to strange errors.
- *
- * perform a variety of operations to guarantee that the compiler
- * will not reorder instructions.  wbinvd itself is serializing
- * so the processor will not reorder.
- *
- * Systems without cache can just go into halt.
- */
-static inline void wbinvd_halt(void)
-{
-        mb();
-        /* check for clflush to determine if wbinvd is legal */
-        if (cpu_has_clflush)
-                asm volatile("cli; wbinvd; 1: hlt; jmp 1b" : : : "memory");
-        else
-                while (1)
-                        halt();
-}
-
 extern void enable_sep_cpu(void);
 extern int sysenter_setup(void);
 
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
index fb16f17e59be..5812404a0d4c 100644
--- a/arch/x86/kernel/acpi/cstate.c
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -13,6 +13,7 @@
 
 #include <acpi/processor.h>
 #include <asm/acpi.h>
+#include <asm/mwait.h>
 
 /*
  * Initialize bm_flags based on the CPU cache properties
@@ -65,16 +66,6 @@ static struct cstate_entry __percpu *cpu_cstate_entry;	/* per CPU ptr */
 
 static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
 
-#define MWAIT_SUBSTATE_MASK     (0xf)
-#define MWAIT_CSTATE_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)
 
 static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index bc2cc444844a..0116552c950d 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -62,6 +62,7 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/mtrr.h>
+#include <asm/mwait.h>
 #include <asm/vmi.h>
 #include <asm/apic.h>
 #include <asm/setup.h>
@@ -1395,11 +1396,88 @@ void play_dead_common(void)
         local_irq_disable();
 }
 
+/*
+ * We need to flush the caches before going to sleep, lest we have
+ * dirty data in our caches when we come back up.
+ */
+static inline void mwait_play_dead(void)
+{
+        unsigned int eax, ebx, ecx, edx;
+        unsigned int highest_cstate = 0;
+        unsigned int highest_subcstate = 0;
+        int i;
+        void *mwait_ptr;
+
+        if (!cpu_has(&current_cpu_data, X86_FEATURE_MWAIT))
+                return;
+        if (!cpu_has(&current_cpu_data, X86_FEATURE_CLFLSH))
+                return;
+        if (current_cpu_data.cpuid_level < CPUID_MWAIT_LEAF)
+                return;
+
+        eax = CPUID_MWAIT_LEAF;
+        ecx = 0;
+        native_cpuid(&eax, &ebx, &ecx, &edx);
+
+        /*
+         * eax will be 0 if EDX enumeration is not valid.
+         * Initialized below to cstate, sub_cstate value when EDX is valid.
+         */
+        if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) {
+                eax = 0;
+        } else {
+                edx >>= MWAIT_SUBSTATE_SIZE;
+                for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
+                        if (edx & MWAIT_SUBSTATE_MASK) {
+                                highest_cstate = i;
+                                highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
+                        }
+                }
+                eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
+                        (highest_subcstate - 1);
+        }
+
+        /*
+         * This should be a memory location in a cache line which is
+         * unlikely to be touched by other processors.  The actual
+         * content is immaterial as it is not actually modified in any way.
+         */
+        mwait_ptr = &current_thread_info()->flags;
+
+        wbinvd();
+
+        while (1) {
+                /*
+                 * The CLFLUSH is a workaround for erratum AAI65 for
+                 * the Xeon 7400 series.  It's not clear it is actually
+                 * needed, but it should be harmless in either case.
+                 * The WBINVD is insufficient due to the spurious-wakeup
+                 * case where we return around the loop.
+                 */
+                clflush(mwait_ptr);
+                __monitor(mwait_ptr, 0, 0);
+                mb();
+                __mwait(eax, 0);
+        }
+}
+
+static inline void hlt_play_dead(void)
+{
+        if (current_cpu_data.x86 >= 4)
+                wbinvd();
+
+        while (1) {
+                native_halt();
+        }
+}
+
 void native_play_dead(void)
 {
         play_dead_common();
         tboot_shutdown(TB_SHUTDOWN_WFS);
-        wbinvd_halt();
+
+        mwait_play_dead();      /* Only returns on failure */
+        hlt_play_dead();
 }
 
 #else /* ... !CONFIG_HOTPLUG_CPU */
diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
index 6b115f6c4313..6afceb3d4034 100644
--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c
@@ -30,18 +30,13 @@
 #include <linux/slab.h>
 #include <acpi/acpi_bus.h>
 #include <acpi/acpi_drivers.h>
+#include <asm/mwait.h>
 
 #define ACPI_PROCESSOR_AGGREGATOR_CLASS "acpi_pad"
 #define ACPI_PROCESSOR_AGGREGATOR_DEVICE_NAME "Processor Aggregator"
 #define ACPI_PROCESSOR_AGGREGATOR_NOTIFY 0x80
 static DEFINE_MUTEX(isolated_cpus_lock);
 
-#define MWAIT_SUBSTATE_MASK     (0xf)
-#define MWAIT_CSTATE_MASK       (0xf)
-#define MWAIT_SUBSTATE_SIZE     (4)
-#define CPUID_MWAIT_LEAF (5)
-#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
-#define CPUID5_ECX_INTERRUPT_BREAK      (0x2)
 static unsigned long power_saving_mwait_eax;
 
 static unsigned char tsc_detected_unstable;
diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index c37ef64d1465..cb3ccf3ed221 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -59,18 +59,11 @@
 #include <linux/hrtimer.h>      /* ktime_get_real() */
 #include <trace/events/power.h>
 #include <linux/sched.h>
+#include <asm/mwait.h>
 
 #define INTEL_IDLE_VERSION "0.4"
 #define PREFIX "intel_idle: "
 
-#define MWAIT_SUBSTATE_MASK     (0xf)
-#define MWAIT_CSTATE_MASK       (0xf)
-#define MWAIT_SUBSTATE_SIZE     (4)
-#define MWAIT_MAX_NUM_CSTATES   8
-#define CPUID_MWAIT_LEAF (5)
-#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1)
-#define CPUID5_ECX_INTERRUPT_BREAK      (0x2)
-
 static struct cpuidle_driver intel_idle_driver = {
         .name = "intel_idle",
         .owner = THIS_MODULE,