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Message-ID: <20101021134900.GA6130@elte.hu>
Date: Thu, 21 Oct 2010 15:49:00 +0200
From: Ingo Molnar <mingo@...e.hu>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: linux-kernel@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
Thomas Gleixner <tglx@...utronix.de>,
Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] x86/idle for v2.6.37
Linus,
Please pull the latest x86-idle-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git x86-idle-for-linus
out-of-topic modifications in x86-idle-for-linus:
-------------------------------------------------
drivers/acpi/acpi_pad.c # bc83ccc: x86, mwait: Move mwait constants
drivers/idle/intel_idle.c # bc83ccc: x86, mwait: Move mwait constants
Thanks,
Ingo
------------------>
H. Peter Anvin (4):
x86, mwait: Move mwait constants to a common header file
x86, hotplug: Use mwait to offline a processor, fix the legacy case
x86, hotplug: Move WBINVD back outside the play_dead loop
x86, hotplug: In the MWAIT case of play_dead, CLFLUSH the cache line
arch/x86/include/asm/mwait.h | 15 +++++++
arch/x86/include/asm/processor.h | 23 -----------
arch/x86/kernel/acpi/cstate.c | 11 +-----
arch/x86/kernel/smpboot.c | 80 +++++++++++++++++++++++++++++++++++++-
drivers/acpi/acpi_pad.c | 7 +---
drivers/idle/intel_idle.c | 9 +----
6 files changed, 97 insertions(+), 48 deletions(-)
create mode 100644 arch/x86/include/asm/mwait.h
diff --git a/arch/x86/include/asm/mwait.h b/arch/x86/include/asm/mwait.h
new file mode 100644
index 0000000..bcdff99
--- /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 325b7bd..f358241 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -764,29 +764,6 @@ 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 fb7a5f0..bcc4add 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 *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 8b3bfc4..fdccfe9 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>
@@ -1383,11 +1384,88 @@ 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(¤t_cpu_data, X86_FEATURE_MWAIT))
+ return;
+ if (!cpu_has(¤t_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 = ¤t_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 b76848c..ca2694d 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 a10152b..065c804 100755
--- 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,
--
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