[PATCH 0/6] Do not use sysdevs for implementing "core" PM operations on x86

[PATCH 0/6] Do not use sysdevs for implementing "core" PM operations on x86

[Rafael J. Wysocki]

Hi,

On Saturday, March 12, 2011, Rafael J. Wysocki wrote:
> On Thursday, March 10, 2011, Rafael J. Wysocki wrote:
> > There are multiple problems with sysdevs, or struct sys_device objects to
> > be precise, that are so annoying that some people have started to think
> > of removind them entirely from the kernel.  To me, personally, the most
> > obvious issue is the way sysdevs are used for defining suspend/resume
> > callbacks to be executed with one CPU on-line and interrupts disabled.
> > Greg and Kay may tell you more about the other problems with sysdevs. :-)
> > 
> > Some subsystems need to carry out certain operations during suspend after
> > we've disabled non-boot CPUs and interrupts have been switched off on the
> > only on-line one.  Currently, the only way to achieve that is to define
> > sysdev suspend/resume callbacks, but this is cumbersome and inefficient.
> > Namely, to do that, one has to define a sysdev class providing the callbacks
> > and a sysdev actually using them, which is excessively complicated.  Moreover,
> > the sysdev suspend/resume callbacks take arguments that are not really used
> > by the majority of subsystems defining sysdev suspend/resume callbacks
> > (or even if they are used, they don't really _need_ to be used, so they
> > are simply unnecessary).  Of course, if a sysdev is only defined to provide
> > suspend/resume (and maybe shutdown) callbacks, there's no real reason why
> > it should show up in sysfs.
> > 
> > For this reason, I thought it would be a good idea to provide a simpler
> > interface for subsystems to define "very late" suspend callbacks and
> > "very early" resume callbacks (and "very late" shutdown callbacks as well)
> > without the entire bloat related to sysdevs.  The interface is introduced
> > by the first of the following patches, while the second patch converts some
> > sysdev users related to the x86 architecture to using the new interface.
> > 
> > I believe that call sysdev users who need to define suspend/resume/shutdown
> > callbacks may be converted to using the interface provided by the first patch,
> > which in turn should allow us to convert the remaining sysdev functionality
> > into "normal" struct device interfaces.  Still, even if that turns out to be
> > too complicated, the bloat reduction resulting from the second patch kind of
> > shows that moving at least some sysdev users to a simpler interface (like in
> > the first patch) is a good idea anyway.
> > 
> > This is a proof of concept, so the patches have not been tested.  Please be
> > extrememly careful, because they touch sensitive code, so to speak.  In the
> > majority of cases the changes are rather straightforward, but there are some
> > more interesting cases as well (io_apic.c most importantly).
> 
> Since Greg likes the idea and there haven't been any objections so far, here's
> the official submission.  The patches have been tested on HP nx6325 and
> Toshiba Portege R500.
> 
> Patch [1/8] is regareded as 2.6.38 material, following Greg's advice.  The
> other patches in the set are regarded as 2.6.39 material.  The last one
> obviously depends on all of the previous ones.
> 
> [1/8] - Introduce struct syscore_ops for registering operations to be run on
>         one CPU during suspend/resume/shutdown.
> 
> [2/8] - Convert sysdev users in arch/x86 to using struct syscore_ops.
> 
> [3/8] - Make ACPI use struct syscore_ops for irqrouter_resume().
> 
> [4/8] - Make timekeeping use struct syscore_ops for suspend/resume.
> 
> [5/8] - Make Intel IOMMU use struct syscore_ops for suspend/resume.
> 
> [6/8] - Make KVM use struct syscore_ops for suspend/resume.
> 
> [7/8] - Make cpufreq use struct syscore_ops for boot CPU suspend/resume.
> 
> [8/8] - Introduce config switch allowing architectures to skip sysdev
>         suspend/resume/shutdown code.
> 
> If there are no objectsions, I'd like to push these patches through the suspend
> tree.

[1/8] has been merged in the meantime and [3/8] has been included into the
ACPI tree.  if there are no objections, I'm going to push the following
patches to Linus this week through the suspend-2.6 tree:

[1/6] - Convert sysdev users in arch/x86 to using struct syscore_ops.

[2/6] - Make timekeeping use struct syscore_ops for suspend/resume.
 
[3/6] - Make Intel IOMMU use struct syscore_ops for suspend/resume.

[4/6] - Make KVM use struct syscore_ops for suspend/resume.

[5/6] - Make cpufreq use struct syscore_ops for boot CPU suspend/resume.

[6/6] - Introduce config switch allowing architectures to skip sysdev
        suspend/resume/shutdown code.

Thanks,
Rafael

[PATCH 1/6] x86: Use syscore_ops instead of sysdev classes and sysdevs

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

Some subsystems in the x86 tree need to carry out suspend/resume and
shutdown operations with one CPU on-line and interrupts disabled and
they define sysdev classes and sysdevs or sysdev drivers for this
purpose.  This leads to unnecessarily complicated code and excessive
memory usage, so switch them to using struct syscore_ops objects for
this purpose instead.

Generally, there are three categories of subsystems that use
sysdevs for implementing PM operations: (1) subsystems whose
suspend/resume callbacks ignore their arguments entirely (the
majority), (2) subsystems whose suspend/resume callbacks use their
struct sys_device argument, but don't really need to do that,
because they can be implemented differently in an arguably simpler
way (io_apic.c), and (3) subsystems whose suspend/resume callbacks
use their struct sys_device argument, but the value of that argument
is always the same and could be ignored (microcode_core.c).  In all
of these cases the subsystems in question may be readily converted to
using struct syscore_ops objects for power management and shutdown.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/x86/kernel/amd_iommu_init.c |   26 ++--------
 arch/x86/kernel/apic/apic.c      |   33 +++----------
 arch/x86/kernel/apic/io_apic.c   |   97 ++++++++++++++++++---------------------
 arch/x86/kernel/cpu/mcheck/mce.c |   21 ++++----
 arch/x86/kernel/cpu/mtrr/main.c  |   10 ++--
 arch/x86/kernel/i8237.c          |   30 ++----------
 arch/x86/kernel/i8259.c          |   33 ++++---------
 arch/x86/kernel/microcode_core.c |   34 +++++--------
 arch/x86/kernel/pci-gart_64.c    |   32 ++----------
 arch/x86/oprofile/nmi_int.c      |   44 ++++-------------
 10 files changed, 128 insertions(+), 232 deletions(-)

Index: linux-2.6/arch/x86/kernel/amd_iommu_init.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/amd_iommu_init.c
+++ linux-2.6/arch/x86/kernel/amd_iommu_init.c
@@ -21,7 +21,7 @@
 #include <linux/acpi.h>
 #include <linux/list.h>
 #include <linux/slab.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/interrupt.h>
 #include <linux/msi.h>
 #include <asm/pci-direct.h>
@@ -1260,7 +1260,7 @@ static void disable_iommus(void)
  * disable suspend until real resume implemented
  */
 
-static int amd_iommu_resume(struct sys_device *dev)
+static void amd_iommu_resume(void)
 {
 	struct amd_iommu *iommu;
 
@@ -1276,11 +1276,9 @@ static int amd_iommu_resume(struct sys_d
 	 */
 	amd_iommu_flush_all_devices();
 	amd_iommu_flush_all_domains();
-
-	return 0;
 }
 
-static int amd_iommu_suspend(struct sys_device *dev, pm_message_t state)
+static int amd_iommu_suspend(void)
 {
 	/* disable IOMMUs to go out of the way for BIOS */
 	disable_iommus();
@@ -1288,17 +1286,11 @@ static int amd_iommu_suspend(struct sys_
 	return 0;
 }
 
-static struct sysdev_class amd_iommu_sysdev_class = {
-	.name = "amd_iommu",
+static struct syscore_ops amd_iommu_syscore_ops = {
 	.suspend = amd_iommu_suspend,
 	.resume = amd_iommu_resume,
 };
 
-static struct sys_device device_amd_iommu = {
-	.id = 0,
-	.cls = &amd_iommu_sysdev_class,
-};
-
 /*
  * This is the core init function for AMD IOMMU hardware in the system.
  * This function is called from the generic x86 DMA layer initialization
@@ -1415,14 +1407,6 @@ static int __init amd_iommu_init(void)
 		goto free;
 	}
 
-	ret = sysdev_class_register(&amd_iommu_sysdev_class);
-	if (ret)
-		goto free;
-
-	ret = sysdev_register(&device_amd_iommu);
-	if (ret)
-		goto free;
-
 	ret = amd_iommu_init_devices();
 	if (ret)
 		goto free;
@@ -1441,6 +1425,8 @@ static int __init amd_iommu_init(void)
 
 	amd_iommu_init_notifier();
 
+	register_syscore_ops(&amd_iommu_syscore_ops);
+
 	if (iommu_pass_through)
 		goto out;
 
Index: linux-2.6/arch/x86/kernel/apic/apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/apic.c
+++ linux-2.6/arch/x86/kernel/apic/apic.c
@@ -24,7 +24,7 @@
 #include <linux/ftrace.h>
 #include <linux/ioport.h>
 #include <linux/module.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/delay.h>
 #include <linux/timex.h>
 #include <linux/dmar.h>
@@ -2046,7 +2046,7 @@ static struct {
 	unsigned int apic_thmr;
 } apic_pm_state;
 
-static int lapic_suspend(struct sys_device *dev, pm_message_t state)
+static int lapic_suspend(void)
 {
 	unsigned long flags;
 	int maxlvt;
@@ -2084,23 +2084,21 @@ static int lapic_suspend(struct sys_devi
 	return 0;
 }
 
-static int lapic_resume(struct sys_device *dev)
+static void lapic_resume(void)
 {
 	unsigned int l, h;
 	unsigned long flags;
-	int maxlvt;
-	int ret = 0;
+	int maxlvt, ret;
 	struct IO_APIC_route_entry **ioapic_entries = NULL;
 
 	if (!apic_pm_state.active)
-		return 0;
+		return;
 
 	local_irq_save(flags);
 	if (intr_remapping_enabled) {
 		ioapic_entries = alloc_ioapic_entries();
 		if (!ioapic_entries) {
 			WARN(1, "Alloc ioapic_entries in lapic resume failed.");
-			ret = -ENOMEM;
 			goto restore;
 		}
 
@@ -2162,8 +2160,6 @@ static int lapic_resume(struct sys_devic
 	}
 restore:
 	local_irq_restore(flags);
-
-	return ret;
 }
 
 /*
@@ -2171,17 +2167,11 @@ restore:
  * are needed on every CPU up until machine_halt/restart/poweroff.
  */
 
-static struct sysdev_class lapic_sysclass = {
-	.name		= "lapic",
+static struct syscore_ops lapic_syscore_ops = {
 	.resume		= lapic_resume,
 	.suspend	= lapic_suspend,
 };
 
-static struct sys_device device_lapic = {
-	.id	= 0,
-	.cls	= &lapic_sysclass,
-};
-
 static void __cpuinit apic_pm_activate(void)
 {
 	apic_pm_state.active = 1;
@@ -2189,16 +2179,11 @@ static void __cpuinit apic_pm_activate(v
 
 static int __init init_lapic_sysfs(void)
 {
-	int error;
-
-	if (!cpu_has_apic)
-		return 0;
 	/* XXX: remove suspend/resume procs if !apic_pm_state.active? */
+	if (cpu_has_apic)
+		register_syscore_ops(&lapic_syscore_ops);
 
-	error = sysdev_class_register(&lapic_sysclass);
-	if (!error)
-		error = sysdev_register(&device_lapic);
-	return error;
+	return 0;
 }
 
 /* local apic needs to resume before other devices access its registers. */
Index: linux-2.6/arch/x86/kernel/apic/io_apic.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/apic/io_apic.c
+++ linux-2.6/arch/x86/kernel/apic/io_apic.c
@@ -30,7 +30,7 @@
 #include <linux/compiler.h>
 #include <linux/acpi.h>
 #include <linux/module.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/msi.h>
 #include <linux/htirq.h>
 #include <linux/freezer.h>
@@ -2918,89 +2918,84 @@ static int __init io_apic_bug_finalize(v
 
 late_initcall(io_apic_bug_finalize);
 
-struct sysfs_ioapic_data {
-	struct sys_device dev;
-	struct IO_APIC_route_entry entry[0];
-};
-static struct sysfs_ioapic_data * mp_ioapic_data[MAX_IO_APICS];
+static struct IO_APIC_route_entry *ioapic_saved_data[MAX_IO_APICS];
 
-static int ioapic_suspend(struct sys_device *dev, pm_message_t state)
+static void suspend_ioapic(int ioapic_id)
 {
-	struct IO_APIC_route_entry *entry;
-	struct sysfs_ioapic_data *data;
+	struct IO_APIC_route_entry *saved_data = ioapic_saved_data[ioapic_id];
 	int i;
 
-	data = container_of(dev, struct sysfs_ioapic_data, dev);
-	entry = data->entry;
-	for (i = 0; i < nr_ioapic_registers[dev->id]; i ++, entry ++ )
-		*entry = ioapic_read_entry(dev->id, i);
+	if (!saved_data)
+		return;
+
+	for (i = 0; i < nr_ioapic_registers[ioapic_id]; i++)
+		saved_data[i] = ioapic_read_entry(ioapic_id, i);
+}
+
+static int ioapic_suspend(void)
+{
+	int ioapic_id;
+
+	for (ioapic_id = 0; ioapic_id < nr_ioapics; ioapic_id++)
+		suspend_ioapic(ioapic_id);
 
 	return 0;
 }
 
-static int ioapic_resume(struct sys_device *dev)
+static void resume_ioapic(int ioapic_id)
 {
-	struct IO_APIC_route_entry *entry;
-	struct sysfs_ioapic_data *data;
+	struct IO_APIC_route_entry *saved_data = ioapic_saved_data[ioapic_id];
 	unsigned long flags;
 	union IO_APIC_reg_00 reg_00;
 	int i;
 
-	data = container_of(dev, struct sysfs_ioapic_data, dev);
-	entry = data->entry;
+	if (!saved_data)
+		return;
 
 	raw_spin_lock_irqsave(&ioapic_lock, flags);
-	reg_00.raw = io_apic_read(dev->id, 0);
-	if (reg_00.bits.ID != mp_ioapics[dev->id].apicid) {
-		reg_00.bits.ID = mp_ioapics[dev->id].apicid;
-		io_apic_write(dev->id, 0, reg_00.raw);
+	reg_00.raw = io_apic_read(ioapic_id, 0);
+	if (reg_00.bits.ID != mp_ioapics[ioapic_id].apicid) {
+		reg_00.bits.ID = mp_ioapics[ioapic_id].apicid;
+		io_apic_write(ioapic_id, 0, reg_00.raw);
 	}
 	raw_spin_unlock_irqrestore(&ioapic_lock, flags);
-	for (i = 0; i < nr_ioapic_registers[dev->id]; i++)
-		ioapic_write_entry(dev->id, i, entry[i]);
+	for (i = 0; i < nr_ioapic_registers[ioapic_id]; i++)
+		ioapic_write_entry(ioapic_id, i, saved_data[i]);
+}
 
-	return 0;
+static void ioapic_resume(void)
+{
+	int ioapic_id;
+
+	for (ioapic_id = nr_ioapics - 1; ioapic_id >= 0; ioapic_id--)
+		resume_ioapic(ioapic_id);
 }
 
-static struct sysdev_class ioapic_sysdev_class = {
-	.name = "ioapic",
+static struct syscore_ops ioapic_syscore_ops = {
 	.suspend = ioapic_suspend,
 	.resume = ioapic_resume,
 };
 
-static int __init ioapic_init_sysfs(void)
+static int __init ioapic_init_ops(void)
 {
-	struct sys_device * dev;
-	int i, size, error;
+	int i;
 
-	error = sysdev_class_register(&ioapic_sysdev_class);
-	if (error)
-		return error;
+	for (i = 0; i < nr_ioapics; i++) {
+		unsigned int size;
 
-	for (i = 0; i < nr_ioapics; i++ ) {
-		size = sizeof(struct sys_device) + nr_ioapic_registers[i]
+		size = nr_ioapic_registers[i]
 			* sizeof(struct IO_APIC_route_entry);
-		mp_ioapic_data[i] = kzalloc(size, GFP_KERNEL);
-		if (!mp_ioapic_data[i]) {
-			printk(KERN_ERR "Can't suspend/resume IOAPIC %d\n", i);
-			continue;
-		}
-		dev = &mp_ioapic_data[i]->dev;
-		dev->id = i;
-		dev->cls = &ioapic_sysdev_class;
-		error = sysdev_register(dev);
-		if (error) {
-			kfree(mp_ioapic_data[i]);
-			mp_ioapic_data[i] = NULL;
-			printk(KERN_ERR "Can't suspend/resume IOAPIC %d\n", i);
-			continue;
-		}
+		ioapic_saved_data[i] = kzalloc(size, GFP_KERNEL);
+		if (!ioapic_saved_data[i])
+			pr_err("IOAPIC %d: suspend/resume impossible!\n", i);
 	}
 
+	register_syscore_ops(&ioapic_syscore_ops);
+
 	return 0;
 }
 
-device_initcall(ioapic_init_sysfs);
+device_initcall(ioapic_init_ops);
 
 /*
  * Dynamic irq allocate and deallocation
Index: linux-2.6/arch/x86/kernel/i8237.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/i8237.c
+++ linux-2.6/arch/x86/kernel/i8237.c
@@ -10,7 +10,7 @@
  */
 
 #include <linux/init.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/dma.h>
 
@@ -21,7 +21,7 @@
  * in asm/dma.h.
  */
 
-static int i8237A_resume(struct sys_device *dev)
+static void i8237A_resume(void)
 {
 	unsigned long flags;
 	int i;
@@ -41,31 +41,15 @@ static int i8237A_resume(struct sys_devi
 	enable_dma(4);
 
 	release_dma_lock(flags);
-
-	return 0;
 }
 
-static int i8237A_suspend(struct sys_device *dev, pm_message_t state)
-{
-	return 0;
-}
-
-static struct sysdev_class i8237_sysdev_class = {
-	.name		= "i8237",
-	.suspend	= i8237A_suspend,
+static struct syscore_ops i8237_syscore_ops = {
 	.resume		= i8237A_resume,
 };
 
-static struct sys_device device_i8237A = {
-	.id		= 0,
-	.cls		= &i8237_sysdev_class,
-};
-
-static int __init i8237A_init_sysfs(void)
+static int __init i8237A_init_ops(void)
 {
-	int error = sysdev_class_register(&i8237_sysdev_class);
-	if (!error)
-		error = sysdev_register(&device_i8237A);
-	return error;
+	register_syscore_ops(&i8237_syscore_ops);
+	return 0;
 }
-device_initcall(i8237A_init_sysfs);
+device_initcall(i8237A_init_ops);
Index: linux-2.6/arch/x86/kernel/i8259.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/i8259.c
+++ linux-2.6/arch/x86/kernel/i8259.c
@@ -8,7 +8,7 @@
 #include <linux/random.h>
 #include <linux/init.h>
 #include <linux/kernel_stat.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/bitops.h>
 #include <linux/acpi.h>
 #include <linux/io.h>
@@ -245,20 +245,19 @@ static void save_ELCR(char *trigger)
 	trigger[1] = inb(0x4d1) & 0xDE;
 }
 
-static int i8259A_resume(struct sys_device *dev)
+static void i8259A_resume(void)
 {
 	init_8259A(i8259A_auto_eoi);
 	restore_ELCR(irq_trigger);
-	return 0;
 }
 
-static int i8259A_suspend(struct sys_device *dev, pm_message_t state)
+static int i8259A_suspend(void)
 {
 	save_ELCR(irq_trigger);
 	return 0;
 }
 
-static int i8259A_shutdown(struct sys_device *dev)
+static void i8259A_shutdown(void)
 {
 	/* Put the i8259A into a quiescent state that
 	 * the kernel initialization code can get it
@@ -266,21 +265,14 @@ static int i8259A_shutdown(struct sys_de
 	 */
 	outb(0xff, PIC_MASTER_IMR);	/* mask all of 8259A-1 */
 	outb(0xff, PIC_SLAVE_IMR);	/* mask all of 8259A-1 */
-	return 0;
 }
 
-static struct sysdev_class i8259_sysdev_class = {
-	.name = "i8259",
+static struct syscore_ops i8259_syscore_ops = {
 	.suspend = i8259A_suspend,
 	.resume = i8259A_resume,
 	.shutdown = i8259A_shutdown,
 };
 
-static struct sys_device device_i8259A = {
-	.id	= 0,
-	.cls	= &i8259_sysdev_class,
-};
-
 static void mask_8259A(void)
 {
 	unsigned long flags;
@@ -399,17 +391,12 @@ struct legacy_pic default_legacy_pic = {
 
 struct legacy_pic *legacy_pic = &default_legacy_pic;
 
-static int __init i8259A_init_sysfs(void)
+static int __init i8259A_init_ops(void)
 {
-	int error;
-
-	if (legacy_pic != &default_legacy_pic)
-		return 0;
+	if (legacy_pic == &default_legacy_pic)
+		register_syscore_ops(&i8259_syscore_ops);
 
-	error = sysdev_class_register(&i8259_sysdev_class);
-	if (!error)
-		error = sysdev_register(&device_i8259A);
-	return error;
+	return 0;
 }
 
-device_initcall(i8259A_init_sysfs);
+device_initcall(i8259A_init_ops);
Index: linux-2.6/arch/x86/kernel/pci-gart_64.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/pci-gart_64.c
+++ linux-2.6/arch/x86/kernel/pci-gart_64.c
@@ -27,7 +27,7 @@
 #include <linux/kdebug.h>
 #include <linux/scatterlist.h>
 #include <linux/iommu-helper.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/io.h>
 #include <linux/gfp.h>
 #include <asm/atomic.h>
@@ -589,7 +589,7 @@ void set_up_gart_resume(u32 aper_order,
 	aperture_alloc = aper_alloc;
 }
 
-static void gart_fixup_northbridges(struct sys_device *dev)
+static void gart_fixup_northbridges(void)
 {
 	int i;
 
@@ -613,33 +613,20 @@ static void gart_fixup_northbridges(stru
 	}
 }
 
-static int gart_resume(struct sys_device *dev)
+static void gart_resume(void)
 {
 	pr_info("PCI-DMA: Resuming GART IOMMU\n");
 
-	gart_fixup_northbridges(dev);
+	gart_fixup_northbridges();
 
 	enable_gart_translations();
-
-	return 0;
 }
 
-static int gart_suspend(struct sys_device *dev, pm_message_t state)
-{
-	return 0;
-}
-
-static struct sysdev_class gart_sysdev_class = {
-	.name		= "gart",
-	.suspend	= gart_suspend,
+static struct syscore_ops gart_syscore_ops = {
 	.resume		= gart_resume,
 
 };
 
-static struct sys_device device_gart = {
-	.cls		= &gart_sysdev_class,
-};
-
 /*
  * Private Northbridge GATT initialization in case we cannot use the
  * AGP driver for some reason.
@@ -650,7 +637,7 @@ static __init int init_amd_gatt(struct a
 	unsigned aper_base, new_aper_base;
 	struct pci_dev *dev;
 	void *gatt;
-	int i, error;
+	int i;
 
 	pr_info("PCI-DMA: Disabling AGP.\n");
 
@@ -685,12 +672,7 @@ static __init int init_amd_gatt(struct a
 
 	agp_gatt_table = gatt;
 
-	error = sysdev_class_register(&gart_sysdev_class);
-	if (!error)
-		error = sysdev_register(&device_gart);
-	if (error)
-		panic("Could not register gart_sysdev -- "
-		      "would corrupt data on next suspend");
+	register_syscore_ops(&gart_syscore_ops);
 
 	flush_gart();
 
Index: linux-2.6/arch/x86/oprofile/nmi_int.c
===================================================================
--- linux-2.6.orig/arch/x86/oprofile/nmi_int.c
+++ linux-2.6/arch/x86/oprofile/nmi_int.c
@@ -15,7 +15,7 @@
 #include <linux/notifier.h>
 #include <linux/smp.h>
 #include <linux/oprofile.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/slab.h>
 #include <linux/moduleparam.h>
 #include <linux/kdebug.h>
@@ -536,7 +536,7 @@ static void nmi_shutdown(void)
 
 #ifdef CONFIG_PM
 
-static int nmi_suspend(struct sys_device *dev, pm_message_t state)
+static int nmi_suspend(void)
 {
 	/* Only one CPU left, just stop that one */
 	if (nmi_enabled == 1)
@@ -544,49 +544,31 @@ static int nmi_suspend(struct sys_device
 	return 0;
 }
 
-static int nmi_resume(struct sys_device *dev)
+static void nmi_resume(void)
 {
 	if (nmi_enabled == 1)
 		nmi_cpu_start(NULL);
-	return 0;
 }
 
-static struct sysdev_class oprofile_sysclass = {
-	.name		= "oprofile",
+static struct syscore_ops oprofile_syscore_ops = {
 	.resume		= nmi_resume,
 	.suspend	= nmi_suspend,
 };
 
-static struct sys_device device_oprofile = {
-	.id	= 0,
-	.cls	= &oprofile_sysclass,
-};
-
-static int __init init_sysfs(void)
+static void __init init_suspend_resume(void)
 {
-	int error;
-
-	error = sysdev_class_register(&oprofile_sysclass);
-	if (error)
-		return error;
-
-	error = sysdev_register(&device_oprofile);
-	if (error)
-		sysdev_class_unregister(&oprofile_sysclass);
-
-	return error;
+	register_syscore_ops(&oprofile_syscore_ops);
 }
 
-static void exit_sysfs(void)
+static void exit_suspend_resume(void)
 {
-	sysdev_unregister(&device_oprofile);
-	sysdev_class_unregister(&oprofile_sysclass);
+	unregister_syscore_ops(&oprofile_syscore_ops);
 }
 
 #else
 
-static inline int  init_sysfs(void) { return 0; }
-static inline void exit_sysfs(void) { }
+static inline void init_suspend_resume(void) { }
+static inline void exit_suspend_resume(void) { }
 
 #endif /* CONFIG_PM */
 
@@ -789,9 +771,7 @@ int __init op_nmi_init(struct oprofile_o
 
 	mux_init(ops);
 
-	ret = init_sysfs();
-	if (ret)
-		return ret;
+	init_suspend_resume();
 
 	printk(KERN_INFO "oprofile: using NMI interrupt.\n");
 	return 0;
@@ -799,5 +779,5 @@ int __init op_nmi_init(struct oprofile_o
 
 void op_nmi_exit(void)
 {
-	exit_sysfs();
+	exit_suspend_resume();
 }
Index: linux-2.6/arch/x86/kernel/cpu/mcheck/mce.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/mcheck/mce.c
+++ linux-2.6/arch/x86/kernel/cpu/mcheck/mce.c
@@ -21,6 +21,7 @@
 #include <linux/percpu.h>
 #include <linux/string.h>
 #include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/delay.h>
 #include <linux/ctype.h>
 #include <linux/sched.h>
@@ -1749,14 +1750,14 @@ static int mce_disable_error_reporting(v
 	return 0;
 }
 
-static int mce_suspend(struct sys_device *dev, pm_message_t state)
+static int mce_suspend(void)
 {
 	return mce_disable_error_reporting();
 }
 
-static int mce_shutdown(struct sys_device *dev)
+static void mce_shutdown(void)
 {
-	return mce_disable_error_reporting();
+	mce_disable_error_reporting();
 }
 
 /*
@@ -1764,14 +1765,18 @@ static int mce_shutdown(struct sys_devic
  * Only one CPU is active at this time, the others get re-added later using
  * CPU hotplug:
  */
-static int mce_resume(struct sys_device *dev)
+static void mce_resume(void)
 {
 	__mcheck_cpu_init_generic();
 	__mcheck_cpu_init_vendor(__this_cpu_ptr(&cpu_info));
-
-	return 0;
 }
 
+static struct syscore_ops mce_syscore_ops = {
+	.suspend	= mce_suspend,
+	.shutdown	= mce_shutdown,
+	.resume		= mce_resume,
+};
+
 static void mce_cpu_restart(void *data)
 {
 	del_timer_sync(&__get_cpu_var(mce_timer));
@@ -1808,9 +1813,6 @@ static void mce_enable_ce(void *all)
 }
 
 static struct sysdev_class mce_sysclass = {
-	.suspend	= mce_suspend,
-	.shutdown	= mce_shutdown,
-	.resume		= mce_resume,
 	.name		= "machinecheck",
 };
 
@@ -2139,6 +2141,7 @@ static __init int mcheck_init_device(voi
 			return err;
 	}
 
+	register_syscore_ops(&mce_syscore_ops);
 	register_hotcpu_notifier(&mce_cpu_notifier);
 	misc_register(&mce_log_device);
 
Index: linux-2.6/arch/x86/kernel/cpu/mtrr/main.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/mtrr/main.c
+++ linux-2.6/arch/x86/kernel/cpu/mtrr/main.c
@@ -45,6 +45,7 @@
 #include <linux/cpu.h>
 #include <linux/pci.h>
 #include <linux/smp.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/processor.h>
 #include <asm/e820.h>
@@ -630,7 +631,7 @@ struct mtrr_value {
 
 static struct mtrr_value mtrr_value[MTRR_MAX_VAR_RANGES];
 
-static int mtrr_save(struct sys_device *sysdev, pm_message_t state)
+static int mtrr_save(void)
 {
 	int i;
 
@@ -642,7 +643,7 @@ static int mtrr_save(struct sys_device *
 	return 0;
 }
 
-static int mtrr_restore(struct sys_device *sysdev)
+static void mtrr_restore(void)
 {
 	int i;
 
@@ -653,12 +654,11 @@ static int mtrr_restore(struct sys_devic
 				    mtrr_value[i].ltype);
 		}
 	}
-	return 0;
 }
 
 
 
-static struct sysdev_driver mtrr_sysdev_driver = {
+static struct syscore_ops mtrr_syscore_ops = {
 	.suspend	= mtrr_save,
 	.resume		= mtrr_restore,
 };
@@ -839,7 +839,7 @@ static int __init mtrr_init_finialize(vo
 	 * TBD: is there any system with such CPU which supports
 	 * suspend/resume? If no, we should remove the code.
 	 */
-	sysdev_driver_register(&cpu_sysdev_class, &mtrr_sysdev_driver);
+	register_syscore_ops(&mtrr_syscore_ops);
 
 	return 0;
 }
Index: linux-2.6/arch/x86/kernel/microcode_core.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/microcode_core.c
+++ linux-2.6/arch/x86/kernel/microcode_core.c
@@ -82,6 +82,7 @@
 #include <linux/cpu.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
+#include <linux/syscore_ops.h>
 
 #include <asm/microcode.h>
 #include <asm/processor.h>
@@ -438,33 +439,25 @@ static int mc_sysdev_remove(struct sys_d
 	return 0;
 }
 
-static int mc_sysdev_resume(struct sys_device *dev)
+static struct sysdev_driver mc_sysdev_driver = {
+	.add			= mc_sysdev_add,
+	.remove			= mc_sysdev_remove,
+};
+
+/**
+ * mc_bp_resume - Update boot CPU microcode during resume.
+ */
+static void mc_bp_resume(void)
 {
-	int cpu = dev->id;
+	int cpu = smp_processor_id();
 	struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
 
-	if (!cpu_online(cpu))
-		return 0;
-
-	/*
-	 * All non-bootup cpus are still disabled,
-	 * so only CPU 0 will apply ucode here.
-	 *
-	 * Moreover, there can be no concurrent
-	 * updates from any other places at this point.
-	 */
-	WARN_ON(cpu != 0);
-
 	if (uci->valid && uci->mc)
 		microcode_ops->apply_microcode(cpu);
-
-	return 0;
 }
 
-static struct sysdev_driver mc_sysdev_driver = {
-	.add			= mc_sysdev_add,
-	.remove			= mc_sysdev_remove,
-	.resume			= mc_sysdev_resume,
+static struct syscore_ops mc_syscore_ops = {
+	.resume			= mc_bp_resume,
 };
 
 static __cpuinit int
@@ -542,6 +535,7 @@ static int __init microcode_init(void)
 	if (error)
 		return error;
 
+	register_syscore_ops(&mc_syscore_ops);
 	register_hotcpu_notifier(&mc_cpu_notifier);
 
 	pr_info("Microcode Update Driver: v" MICROCODE_VERSION

[PATCH 2/6] timekeeping: Use syscore_ops instead of sysdev class and sysdev

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

The timekeeping subsystem uses a sysdev class and a sysdev for
executing timekeeping_suspend() after interrupts have been turned off
on the boot CPU (during system suspend) and for executing
timekeeping_resume() before turning on interrupts on the boot CPU
(during system resume).  However, since both of these functions
ignore their arguments, the entire mechanism may be replaced with a
struct syscore_ops object which is simpler.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
---
 kernel/time/timekeeping.c |   27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

Index: linux-2.6/kernel/time/timekeeping.c
===================================================================
--- linux-2.6.orig/kernel/time/timekeeping.c
+++ linux-2.6/kernel/time/timekeeping.c
@@ -14,7 +14,7 @@
 #include <linux/init.h>
 #include <linux/mm.h>
 #include <linux/sched.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/clocksource.h>
 #include <linux/jiffies.h>
 #include <linux/time.h>
@@ -597,13 +597,12 @@ static struct timespec timekeeping_suspe
 
 /**
  * timekeeping_resume - Resumes the generic timekeeping subsystem.
- * @dev:	unused
  *
  * This is for the generic clocksource timekeeping.
  * xtime/wall_to_monotonic/jiffies/etc are
  * still managed by arch specific suspend/resume code.
  */
-static int timekeeping_resume(struct sys_device *dev)
+static void timekeeping_resume(void)
 {
 	unsigned long flags;
 	struct timespec ts;
@@ -632,11 +631,9 @@ static int timekeeping_resume(struct sys
 
 	/* Resume hrtimers */
 	hres_timers_resume();
-
-	return 0;
 }
 
-static int timekeeping_suspend(struct sys_device *dev, pm_message_t state)
+static int timekeeping_suspend(void)
 {
 	unsigned long flags;
 
@@ -654,26 +651,18 @@ static int timekeeping_suspend(struct sy
 }
 
 /* sysfs resume/suspend bits for timekeeping */
-static struct sysdev_class timekeeping_sysclass = {
-	.name		= "timekeeping",
+static struct syscore_ops timekeeping_syscore_ops = {
 	.resume		= timekeeping_resume,
 	.suspend	= timekeeping_suspend,
 };
 
-static struct sys_device device_timer = {
-	.id		= 0,
-	.cls		= &timekeeping_sysclass,
-};
-
-static int __init timekeeping_init_device(void)
+static int __init timekeeping_init_ops(void)
 {
-	int error = sysdev_class_register(&timekeeping_sysclass);
-	if (!error)
-		error = sysdev_register(&device_timer);
-	return error;
+	register_syscore_ops(&timekeeping_syscore_ops);
+	return 0;
 }
 
-device_initcall(timekeeping_init_device);
+device_initcall(timekeeping_init_ops);
 
 /*
  * If the error is already larger, we look ahead even further

[PATCH 3/6] PCI / Intel IOMMU: Use syscore_ops instead of sysdev class and sysdev

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

The Intel IOMMU subsystem uses a sysdev class and a sysdev for
executing iommu_suspend() after interrupts have been turned off
on the boot CPU (during system suspend) and for executing
iommu_resume() before turning on interrupts on the boot CPU
(during system resume).  However, since both of these functions
ignore their arguments, the entire mechanism may be replaced with a
struct syscore_ops object which is simpler.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/pci/intel-iommu.c |   38 +++++++++-----------------------------
 1 file changed, 9 insertions(+), 29 deletions(-)

Index: linux-2.6/drivers/pci/intel-iommu.c
===================================================================
--- linux-2.6.orig/drivers/pci/intel-iommu.c
+++ linux-2.6/drivers/pci/intel-iommu.c
@@ -36,7 +36,7 @@
 #include <linux/iova.h>
 #include <linux/iommu.h>
 #include <linux/intel-iommu.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/tboot.h>
 #include <linux/dmi.h>
 #include <asm/cacheflush.h>
@@ -3135,7 +3135,7 @@ static void iommu_flush_all(void)
 	}
 }
 
-static int iommu_suspend(struct sys_device *dev, pm_message_t state)
+static int iommu_suspend(void)
 {
 	struct dmar_drhd_unit *drhd;
 	struct intel_iommu *iommu = NULL;
@@ -3175,7 +3175,7 @@ nomem:
 	return -ENOMEM;
 }
 
-static int iommu_resume(struct sys_device *dev)
+static void iommu_resume(void)
 {
 	struct dmar_drhd_unit *drhd;
 	struct intel_iommu *iommu = NULL;
@@ -3183,7 +3183,7 @@ static int iommu_resume(struct sys_devic
 
 	if (init_iommu_hw()) {
 		WARN(1, "IOMMU setup failed, DMAR can not resume!\n");
-		return -EIO;
+		return;
 	}
 
 	for_each_active_iommu(iommu, drhd) {
@@ -3204,40 +3204,20 @@ static int iommu_resume(struct sys_devic
 
 	for_each_active_iommu(iommu, drhd)
 		kfree(iommu->iommu_state);
-
-	return 0;
 }
 
-static struct sysdev_class iommu_sysclass = {
-	.name		= "iommu",
+static struct syscore_ops iommu_syscore_ops = {
 	.resume		= iommu_resume,
 	.suspend	= iommu_suspend,
 };
 
-static struct sys_device device_iommu = {
-	.cls	= &iommu_sysclass,
-};
-
-static int __init init_iommu_sysfs(void)
+static void __init init_iommu_pm_ops(void)
 {
-	int error;
-
-	error = sysdev_class_register(&iommu_sysclass);
-	if (error)
-		return error;
-
-	error = sysdev_register(&device_iommu);
-	if (error)
-		sysdev_class_unregister(&iommu_sysclass);
-
-	return error;
+	register_syscore_ops(&iommu_syscore_ops);
 }
 
 #else
-static int __init init_iommu_sysfs(void)
-{
-	return 0;
-}
+static inline int init_iommu_pm_ops(void) { }
 #endif	/* CONFIG_PM */
 
 /*
@@ -3320,7 +3300,7 @@ int __init intel_iommu_init(void)
 #endif
 	dma_ops = &intel_dma_ops;
 
-	init_iommu_sysfs();
+	init_iommu_pm_ops();
 
 	register_iommu(&intel_iommu_ops);
 

[PATCH 4/6] KVM: Use syscore_ops instead of sysdev class and sysdev

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

KVM uses a sysdev class and a sysdev for executing kvm_suspend()
after interrupts have been turned off on the boot CPU (during system
suspend) and for executing kvm_resume() before turning on interrupts
on the boot CPU (during system resume).  However, since both of these
functions ignore their arguments, the entire mechanism may be
replaced with a struct syscore_ops object which is simpler.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 virt/kvm/kvm_main.c |   34 ++++++++--------------------------
 1 file changed, 8 insertions(+), 26 deletions(-)

Index: linux-2.6/virt/kvm/kvm_main.c
===================================================================
--- linux-2.6.orig/virt/kvm/kvm_main.c
+++ linux-2.6/virt/kvm/kvm_main.c
@@ -30,7 +30,7 @@
 #include <linux/debugfs.h>
 #include <linux/highmem.h>
 #include <linux/file.h>
-#include <linux/sysdev.h>
+#include <linux/syscore_ops.h>
 #include <linux/cpu.h>
 #include <linux/sched.h>
 #include <linux/cpumask.h>
@@ -2447,33 +2447,26 @@ static void kvm_exit_debug(void)
 	debugfs_remove(kvm_debugfs_dir);
 }
 
-static int kvm_suspend(struct sys_device *dev, pm_message_t state)
+static int kvm_suspend(void)
 {
 	if (kvm_usage_count)
 		hardware_disable_nolock(NULL);
 	return 0;
 }
 
-static int kvm_resume(struct sys_device *dev)
+static void kvm_resume(void)
 {
 	if (kvm_usage_count) {
 		WARN_ON(raw_spin_is_locked(&kvm_lock));
 		hardware_enable_nolock(NULL);
 	}
-	return 0;
 }
 
-static struct sysdev_class kvm_sysdev_class = {
-	.name = "kvm",
+static struct syscore_ops kvm_syscore_ops = {
 	.suspend = kvm_suspend,
 	.resume = kvm_resume,
 };
 
-static struct sys_device kvm_sysdev = {
-	.id = 0,
-	.cls = &kvm_sysdev_class,
-};
-
 struct page *bad_page;
 pfn_t bad_pfn;
 
@@ -2557,14 +2550,6 @@ int kvm_init(void *opaque, unsigned vcpu
 		goto out_free_2;
 	register_reboot_notifier(&kvm_reboot_notifier);
 
-	r = sysdev_class_register(&kvm_sysdev_class);
-	if (r)
-		goto out_free_3;
-
-	r = sysdev_register(&kvm_sysdev);
-	if (r)
-		goto out_free_4;
-
 	/* A kmem cache lets us meet the alignment requirements of fx_save. */
 	if (!vcpu_align)
 		vcpu_align = __alignof__(struct kvm_vcpu);
@@ -2572,7 +2557,7 @@ int kvm_init(void *opaque, unsigned vcpu
 					   0, NULL);
 	if (!kvm_vcpu_cache) {
 		r = -ENOMEM;
-		goto out_free_5;
+		goto out_free_3;
 	}
 
 	r = kvm_async_pf_init();
@@ -2589,6 +2574,8 @@ int kvm_init(void *opaque, unsigned vcpu
 		goto out_unreg;
 	}
 
+	register_syscore_ops(&kvm_syscore_ops);
+
 	kvm_preempt_ops.sched_in = kvm_sched_in;
 	kvm_preempt_ops.sched_out = kvm_sched_out;
 
@@ -2600,10 +2587,6 @@ out_unreg:
 	kvm_async_pf_deinit();
 out_free:
 	kmem_cache_destroy(kvm_vcpu_cache);
-out_free_5:
-	sysdev_unregister(&kvm_sysdev);
-out_free_4:
-	sysdev_class_unregister(&kvm_sysdev_class);
 out_free_3:
 	unregister_reboot_notifier(&kvm_reboot_notifier);
 	unregister_cpu_notifier(&kvm_cpu_notifier);
@@ -2631,8 +2614,7 @@ void kvm_exit(void)
 	misc_deregister(&kvm_dev);
 	kmem_cache_destroy(kvm_vcpu_cache);
 	kvm_async_pf_deinit();
-	sysdev_unregister(&kvm_sysdev);
-	sysdev_class_unregister(&kvm_sysdev_class);
+	unregister_syscore_ops(&kvm_syscore_ops);
 	unregister_reboot_notifier(&kvm_reboot_notifier);
 	unregister_cpu_notifier(&kvm_cpu_notifier);
 	on_each_cpu(hardware_disable_nolock, NULL, 1);

[PATCH 5/6] cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

The cpufreq subsystem uses sysdev suspend and resume for
executing cpufreq_suspend() and cpufreq_resume(), respectively,
during system suspend, after interrupts have been switched off on the
boot CPU, and during system resume, while interrupts are still off on
the boot CPU.  In both cases the other CPUs are off-line at the
relevant point (either they have been switched off via CPU hotplug
during suspend, or they haven't been switched on yet during resume).
For this reason, although it may seem that cpufreq_suspend() and
cpufreq_resume() are executed for all CPUs in the system, they are
only called for the boot CPU in fact, which is quite confusing.

To remove the confusion and to prepare for elimiating sysdev
suspend and resume operations from the kernel enirely, convernt
cpufreq to using a struct syscore_ops object for the boot CPU
suspend and resume and rename the callbacks so that their names
reflect their purpose.  In addition, put some explanatory remarks
into their kerneldoc comments.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 drivers/cpufreq/cpufreq.c |   66 ++++++++++++++++++----------------------------
 1 file changed, 26 insertions(+), 40 deletions(-)

Index: linux-2.6/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-2.6.orig/drivers/cpufreq/cpufreq.c
+++ linux-2.6/drivers/cpufreq/cpufreq.c
@@ -28,6 +28,7 @@
 #include <linux/cpu.h>
 #include <linux/completion.h>
 #include <linux/mutex.h>
+#include <linux/syscore_ops.h>
 
 #include <trace/events/power.h>
 
@@ -1340,35 +1341,31 @@ out:
 }
 EXPORT_SYMBOL(cpufreq_get);
 
+static struct sysdev_driver cpufreq_sysdev_driver = {
+	.add		= cpufreq_add_dev,
+	.remove		= cpufreq_remove_dev,
+};
+
 
 /**
- *	cpufreq_suspend - let the low level driver prepare for suspend
+ * cpufreq_bp_suspend - Prepare the boot CPU for system suspend.
+ *
+ * This function is only executed for the boot processor.  The other CPUs
+ * have been put offline by means of CPU hotplug.
  */
-
-static int cpufreq_suspend(struct sys_device *sysdev, pm_message_t pmsg)
+static int cpufreq_bp_suspend(void)
 {
 	int ret = 0;
 
-	int cpu = sysdev->id;
+	int cpu = smp_processor_id();
 	struct cpufreq_policy *cpu_policy;
 
 	dprintk("suspending cpu %u\n", cpu);
 
-	if (!cpu_online(cpu))
-		return 0;
-
-	/* we may be lax here as interrupts are off. Nonetheless
-	 * we need to grab the correct cpu policy, as to check
-	 * whether we really run on this CPU.
-	 */
-
+	/* If there's no policy for the boot CPU, we have nothing to do. */
 	cpu_policy = cpufreq_cpu_get(cpu);
 	if (!cpu_policy)
-		return -EINVAL;
-
-	/* only handle each CPU group once */
-	if (unlikely(cpu_policy->cpu != cpu))
-		goto out;
+		return 0;
 
 	if (cpufreq_driver->suspend) {
 		ret = cpufreq_driver->suspend(cpu_policy);
@@ -1377,13 +1374,12 @@ static int cpufreq_suspend(struct sys_de
 					"step on CPU %u\n", cpu_policy->cpu);
 	}
 
-out:
 	cpufreq_cpu_put(cpu_policy);
 	return ret;
 }
 
 /**
- *	cpufreq_resume -  restore proper CPU frequency handling after resume
+ * cpufreq_bp_resume - Restore proper frequency handling of the boot CPU.
  *
  *	1.) resume CPUfreq hardware support (cpufreq_driver->resume())
  *	2.) schedule call cpufreq_update_policy() ASAP as interrupts are
@@ -1391,31 +1387,23 @@ out:
  *	    what we believe it to be. This is a bit later than when it
  *	    should be, but nonethteless it's better than calling
  *	    cpufreq_driver->get() here which might re-enable interrupts...
+ *
+ * This function is only executed for the boot CPU.  The other CPUs have not
+ * been turned on yet.
  */
-static int cpufreq_resume(struct sys_device *sysdev)
+static void cpufreq_bp_resume(void)
 {
 	int ret = 0;
 
-	int cpu = sysdev->id;
+	int cpu = smp_processor_id();
 	struct cpufreq_policy *cpu_policy;
 
 	dprintk("resuming cpu %u\n", cpu);
 
-	if (!cpu_online(cpu))
-		return 0;
-
-	/* we may be lax here as interrupts are off. Nonetheless
-	 * we need to grab the correct cpu policy, as to check
-	 * whether we really run on this CPU.
-	 */
-
+	/* If there's no policy for the boot CPU, we have nothing to do. */
 	cpu_policy = cpufreq_cpu_get(cpu);
 	if (!cpu_policy)
-		return -EINVAL;
-
-	/* only handle each CPU group once */
-	if (unlikely(cpu_policy->cpu != cpu))
-		goto fail;
+		return;
 
 	if (cpufreq_driver->resume) {
 		ret = cpufreq_driver->resume(cpu_policy);
@@ -1430,14 +1418,11 @@ static int cpufreq_resume(struct sys_dev
 
 fail:
 	cpufreq_cpu_put(cpu_policy);
-	return ret;
 }
 
-static struct sysdev_driver cpufreq_sysdev_driver = {
-	.add		= cpufreq_add_dev,
-	.remove		= cpufreq_remove_dev,
-	.suspend	= cpufreq_suspend,
-	.resume		= cpufreq_resume,
+static struct syscore_ops cpufreq_syscore_ops = {
+	.suspend	= cpufreq_bp_suspend,
+	.resume		= cpufreq_bp_resume,
 };
 
 
@@ -2002,6 +1987,7 @@ static int __init cpufreq_core_init(void
 	cpufreq_global_kobject = kobject_create_and_add("cpufreq",
 						&cpu_sysdev_class.kset.kobj);
 	BUG_ON(!cpufreq_global_kobject);
+	register_syscore_ops(&cpufreq_syscore_ops);
 
 	return 0;
 }

[PATCH 6/6] Introduce ARCH_NO_SYSDEV_OPS config option (v2)

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rjw@sisk.pl>

Introduce Kconfig option allowing architectures where sysdev
operations used during system suspend, resume and shutdown have been
completely replaced with struct sycore_ops operations to avoid
building sysdev code that will never be used.

Make callbacks in struct sys_device and struct sysdev_driver depend
on ARCH_NO_SYSDEV_OPS to allows us to verify if all of the references
have been actually removed from the code the given architecture
depends on.

Make x86 select ARCH_NO_SYSDEV_OPS.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 arch/x86/Kconfig       |    1 +
 drivers/base/Kconfig   |    7 +++++++
 drivers/base/sys.c     |    3 ++-
 include/linux/device.h |    4 ++++
 include/linux/pm.h     |   10 ++++++++--
 include/linux/sysdev.h |    7 +++++--
 6 files changed, 27 insertions(+), 5 deletions(-)

Index: linux-2.6/include/linux/pm.h
===================================================================
--- linux-2.6.orig/include/linux/pm.h
+++ linux-2.6/include/linux/pm.h
@@ -529,13 +529,19 @@ struct dev_power_domain {
  */
 
 #ifdef CONFIG_PM_SLEEP
-extern void device_pm_lock(void);
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
+extern int sysdev_suspend(pm_message_t state);
 extern int sysdev_resume(void);
+#else
+static inline int sysdev_suspend(pm_message_t state) { return 0; }
+static inline int sysdev_resume(void) { return 0; }
+#endif
+
+extern void device_pm_lock(void);
 extern void dpm_resume_noirq(pm_message_t state);
 extern void dpm_resume_end(pm_message_t state);
 
 extern void device_pm_unlock(void);
-extern int sysdev_suspend(pm_message_t state);
 extern int dpm_suspend_noirq(pm_message_t state);
 extern int dpm_suspend_start(pm_message_t state);
 
Index: linux-2.6/include/linux/sysdev.h
===================================================================
--- linux-2.6.orig/include/linux/sysdev.h
+++ linux-2.6/include/linux/sysdev.h
@@ -33,12 +33,13 @@ struct sysdev_class {
 	const char *name;
 	struct list_head	drivers;
 	struct sysdev_class_attribute **attrs;
-
+	struct kset		kset;
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
 	/* Default operations for these types of devices */
 	int	(*shutdown)(struct sys_device *);
 	int	(*suspend)(struct sys_device *, pm_message_t state);
 	int	(*resume)(struct sys_device *);
-	struct kset		kset;
+#endif
 };
 
 struct sysdev_class_attribute {
@@ -76,9 +77,11 @@ struct sysdev_driver {
 	struct list_head	entry;
 	int	(*add)(struct sys_device *);
 	int	(*remove)(struct sys_device *);
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
 	int	(*shutdown)(struct sys_device *);
 	int	(*suspend)(struct sys_device *, pm_message_t state);
 	int	(*resume)(struct sys_device *);
+#endif
 };
 
 
Index: linux-2.6/include/linux/device.h
===================================================================
--- linux-2.6.orig/include/linux/device.h
+++ linux-2.6/include/linux/device.h
@@ -633,8 +633,12 @@ static inline int devtmpfs_mount(const c
 /* drivers/base/power/shutdown.c */
 extern void device_shutdown(void);
 
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
 /* drivers/base/sys.c */
 extern void sysdev_shutdown(void);
+#else
+static inline void sysdev_shutdown(void) { }
+#endif
 
 /* debugging and troubleshooting/diagnostic helpers. */
 extern const char *dev_driver_string(const struct device *dev);
Index: linux-2.6/arch/x86/Kconfig
===================================================================
--- linux-2.6.orig/arch/x86/Kconfig
+++ linux-2.6/arch/x86/Kconfig
@@ -71,6 +71,7 @@ config X86
 	select GENERIC_IRQ_SHOW
 	select IRQ_FORCED_THREADING
 	select USE_GENERIC_SMP_HELPERS if SMP
+	select ARCH_NO_SYSDEV_OPS
 
 config INSTRUCTION_DECODER
 	def_bool (KPROBES || PERF_EVENTS)
Index: linux-2.6/drivers/base/sys.c
===================================================================
--- linux-2.6.orig/drivers/base/sys.c
+++ linux-2.6/drivers/base/sys.c
@@ -329,7 +329,7 @@ void sysdev_unregister(struct sys_device
 }
 
 
-
+#ifndef CONFIG_ARCH_NO_SYSDEV_OPS
 /**
  *	sysdev_shutdown - Shut down all system devices.
  *
@@ -524,6 +524,7 @@ int sysdev_resume(void)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(sysdev_resume);
+#endif /* CONFIG_ARCH_NO_SYSDEV_OPS */
 
 int __init system_bus_init(void)
 {
Index: linux-2.6/drivers/base/Kconfig
===================================================================
--- linux-2.6.orig/drivers/base/Kconfig
+++ linux-2.6/drivers/base/Kconfig
@@ -168,4 +168,11 @@ config SYS_HYPERVISOR
 	bool
 	default n
 
+config ARCH_NO_SYSDEV_OPS
+	bool
+	---help---
+	  To be selected by architectures that don't use sysdev class or
+	  sysdev driver power management (suspend/resume) and shutdown
+	  operations.
+
 endmenu

Re: [PATCH 4/6] KVM: Use syscore_ops instead of sysdev class and sysdev

[Avi Kivity]

On 03/22/2011 01:37 AM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki<rjw@sisk.pl>
>
> KVM uses a sysdev class and a sysdev for executing kvm_suspend()
> after interrupts have been turned off on the boot CPU (during system
> suspend) and for executing kvm_resume() before turning on interrupts
> on the boot CPU (during system resume).  However, since both of these
> functions ignore their arguments, the entire mechanism may be
> replaced with a struct syscore_ops object which is simpler.
>

Acked-by: Avi Kivity <avi@redhat.com>

-- 
error compiling committee.c: too many arguments to function

Re: [PATCH 0/6] Do not use sysdevs for implementing "core" PM operations on x86

[Ingo Molnar]

* Rafael J. Wysocki <rjw@sisk.pl> wrote:

> > If there are no objectsions, I'd like to push these patches through the suspend
> > tree.
> 
> [1/8] has been merged in the meantime and [3/8] has been included into the
> ACPI tree.  if there are no objections, I'm going to push the following
> patches to Linus this week through the suspend-2.6 tree:
> 
> [1/6] - Convert sysdev users in arch/x86 to using struct syscore_ops.
> 
> [2/6] - Make timekeeping use struct syscore_ops for suspend/resume.
>  
> [3/6] - Make Intel IOMMU use struct syscore_ops for suspend/resume.
> 
> [4/6] - Make KVM use struct syscore_ops for suspend/resume.
> 
> [5/6] - Make cpufreq use struct syscore_ops for boot CPU suspend/resume.
> 
> [6/6] - Introduce config switch allowing architectures to skip sysdev
>         suspend/resume/shutdown code.

The x86 bits look fine.

Acked-by: Ingo Molnar <mingo@elte.hu>

The patches affect a lot of hardware so please make sure they are tested well 
before pushing them to Linus :-)

	Ingo

Re: [PATCH 3/6] PCI / Intel IOMMU: Use syscore_ops instead of sysdev class and sysdev

[Joerg Roedel]

On Mon, Mar 21, 2011 at 07:36:17PM -0400, Rafael J. Wysocki wrote:
>  drivers/pci/intel-iommu.c |   38 +++++++++-----------------------------
>  1 file changed, 9 insertions(+), 29 deletions(-)

Looks good. I prepare a patch to convert AMD IOMMU to syscore_ops too.

	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632

Re: [PATCH 0/6] Do not use sysdevs for implementing "core" PM operations on x86

[Rafael J. Wysocki]

On Tuesday, March 22, 2011, Ingo Molnar wrote:
> 
> * Rafael J. Wysocki <rjw@sisk.pl> wrote:
> 
> > > If there are no objectsions, I'd like to push these patches through the suspend
> > > tree.
> > 
> > [1/8] has been merged in the meantime and [3/8] has been included into the
> > ACPI tree.  if there are no objections, I'm going to push the following
> > patches to Linus this week through the suspend-2.6 tree:
> > 
> > [1/6] - Convert sysdev users in arch/x86 to using struct syscore_ops.
> > 
> > [2/6] - Make timekeeping use struct syscore_ops for suspend/resume.
> >  
> > [3/6] - Make Intel IOMMU use struct syscore_ops for suspend/resume.
> > 
> > [4/6] - Make KVM use struct syscore_ops for suspend/resume.
> > 
> > [5/6] - Make cpufreq use struct syscore_ops for boot CPU suspend/resume.
> > 
> > [6/6] - Introduce config switch allowing architectures to skip sysdev
> >         suspend/resume/shutdown code.
> 
> The x86 bits look fine.
> 
> Acked-by: Ingo Molnar <mingo@elte.hu>

Thanks!

> The patches affect a lot of hardware so please make sure they are tested well 
> before pushing them to Linus :-)

I have tested the majority, but unfortunately I have no hardware to test
the Intel IOMMU patch on it.

Thanks,
Rafael

Re: [PATCH 3/6] PCI / Intel IOMMU: Use syscore_ops instead of sysdev class and sysdev

[Rafael J. Wysocki]

On Tuesday, March 22, 2011, Joerg Roedel wrote:
> On Mon, Mar 21, 2011 at 07:36:17PM -0400, Rafael J. Wysocki wrote:
> >  drivers/pci/intel-iommu.c |   38 +++++++++-----------------------------
> >  1 file changed, 9 insertions(+), 29 deletions(-)
> 
> Looks good.

May I take that as an ACK?

> I prepare a patch to convert AMD IOMMU to syscore_ops too.

Already done.  :-)

It's a part of patch [1/6].

Thanks,
Rafael

Re: [PATCH 3/6] PCI / Intel IOMMU: Use syscore_ops instead of sysdev class and sysdev

[Roedel, Joerg]

On Tue, Mar 22, 2011 at 06:07:21PM -0400, Rafael J. Wysocki wrote:
> On Tuesday, March 22, 2011, Joerg Roedel wrote:
> > On Mon, Mar 21, 2011 at 07:36:17PM -0400, Rafael J. Wysocki wrote:
> > >  drivers/pci/intel-iommu.c |   38 +++++++++-----------------------------
> > >  1 file changed, 9 insertions(+), 29 deletions(-)
> > 
> > Looks good.
> 
> May I take that as an ACK?

Sure :-)
 
> > I prepare a patch to convert AMD IOMMU to syscore_ops too.
> 
> Already done.  :-)
> 
> It's a part of patch [1/6].

I see, saves me work, thanks :-)

	Joerg

-- 
AMD Operating System Research Center

Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach
General Managers: Alberto Bozzo, Andrew Bowd
Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632

[GIT PULL] More power management updates for 2.6.39

[Rafael J. Wysocki]

Hi Linus,

Please pull additional power management updates for 2.6.39 from:

git://git.kernel.org/pub/scm/linux/kernel/git/rafael/suspend-2.6.git syscore

They make subsystems that x86 depends on use struct syscore_ops objects instead
of sysdevs for "core" power management, which reduces the code size and kernel
memory footprint a bit and sipmlifies the "core" suspend/resume and shutdown
code paths.


 arch/x86/Kconfig                 |    1 +
 arch/x86/kernel/amd_iommu_init.c |   26 ++--------
 arch/x86/kernel/apic/apic.c      |   33 ++++---------
 arch/x86/kernel/apic/io_apic.c   |   97 ++++++++++++++++++--------------------
 arch/x86/kernel/cpu/mcheck/mce.c |   21 +++++----
 arch/x86/kernel/cpu/mtrr/main.c  |   10 ++--
 arch/x86/kernel/i8237.c          |   30 +++---------
 arch/x86/kernel/i8259.c          |   33 ++++---------
 arch/x86/kernel/microcode_core.c |   34 ++++++--------
 arch/x86/kernel/pci-gart_64.c    |   32 +++----------
 arch/x86/oprofile/nmi_int.c      |   44 +++++------------
 drivers/base/Kconfig             |    7 +++
 drivers/base/sys.c               |    3 +-
 drivers/cpufreq/cpufreq.c        |   66 ++++++++++----------------
 drivers/pci/intel-iommu.c        |   38 ++++-----------
 include/linux/device.h           |    4 ++
 include/linux/pm.h               |   10 +++-
 include/linux/sysdev.h           |    7 ++-
 kernel/time/timekeeping.c        |   27 +++-------
 virt/kvm/kvm_main.c              |   34 +++----------
 20 files changed, 206 insertions(+), 351 deletions(-)

---------------

Rafael J. Wysocki (6):
      x86: Use syscore_ops instead of sysdev classes and sysdevs
      timekeeping: Use syscore_ops instead of sysdev class and sysdev
      PCI / Intel IOMMU: Use syscore_ops instead of sysdev class and sysdev
      KVM: Use syscore_ops instead of sysdev class and sysdev
      cpufreq: Use syscore_ops for boot CPU suspend/resume (v2)
      Introduce ARCH_NO_SYSDEV_OPS config option (v2)