7 files changed, 122 insertions, 153 deletions

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 696387ffe49..2c7121d9bff 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -27,8 +27,8 @@ config PM_DEBUG
 	like suspend support.
 
 config SOFTWARE_SUSPEND
-	bool "Software Suspend (EXPERIMENTAL)"
-	depends on EXPERIMENTAL && PM && SWAP
+	bool "Software Suspend"
+	depends on EXPERIMENTAL && PM && SWAP && ((X86 && SMP) || ((FVR || PPC32 || X86) && !SMP))
 	---help---
 	  Enable the possibility of suspending the machine.
 	  It doesn't need APM.
@@ -72,3 +72,7 @@ config PM_STD_PARTITION
 	  suspended image to. It will simply pick the first available swap 
 	  device.
 
+config SUSPEND_SMP
+	bool
+	depends on HOTPLUG_CPU && X86 && PM
+	default y
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index fbdc634135a..2f438d0eaa1 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -3,9 +3,9 @@ ifeq ($(CONFIG_PM_DEBUG),y)
 EXTRA_CFLAGS	+=	-DDEBUG
 endif
 
-swsusp-smp-$(CONFIG_SMP)	+= smp.o
-
 obj-y				:= main.o process.o console.o pm.o
-obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o $(swsusp-smp-y) disk.o
+obj-$(CONFIG_SOFTWARE_SUSPEND)	+= swsusp.o disk.o
+
+obj-$(CONFIG_SUSPEND_SMP)	+= smp.o
 
 obj-$(CONFIG_MAGIC_SYSRQ)	+= poweroff.o
diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index 02b6764034d..fb8de63c291 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -117,8 +117,8 @@ static void finish(void)
 {
 	device_resume();
 	platform_finish();
-	enable_nonboot_cpus();
 	thaw_processes();
+	enable_nonboot_cpus();
 	pm_restore_console();
 }
 
@@ -131,28 +131,35 @@ static int prepare_processes(void)
 
 	sys_sync();
 
+	disable_nonboot_cpus();
+
 	if (freeze_processes()) {
 		error = -EBUSY;
-		return error;
+		goto thaw;
 	}
 
 	if (pm_disk_mode == PM_DISK_PLATFORM) {
 		if (pm_ops && pm_ops->prepare) {
 			if ((error = pm_ops->prepare(PM_SUSPEND_DISK)))
-				return error;
+				goto thaw;
 		}
 	}
 
 	/* Free memory before shutting down devices. */
 	free_some_memory();
-
 	return 0;
+thaw:
+	thaw_processes();
+	enable_nonboot_cpus();
+	pm_restore_console();
+	return error;
 }
 
 static void unprepare_processes(void)
 {
-	enable_nonboot_cpus();
+	platform_finish();
 	thaw_processes();
+	enable_nonboot_cpus();
 	pm_restore_console();
 }
 
@@ -160,15 +167,9 @@ static int prepare_devices(void)
 {
 	int error;
 
-	disable_nonboot_cpus();
-	if ((error = device_suspend(PMSG_FREEZE))) {
+	if ((error = device_suspend(PMSG_FREEZE)))
 		printk("Some devices failed to suspend\n");
-		platform_finish();
-		enable_nonboot_cpus();
-		return error;
-	}
-
-	return 0;
+	return error;
 }
 
 /**
@@ -185,9 +186,9 @@ int pm_suspend_disk(void)
 	int error;
 
 	error = prepare_processes();
-	if (!error) {
-		error = prepare_devices();
-	}
+	if (error)
+		return error;
+	error = prepare_devices();
 
 	if (error) {
 		unprepare_processes();
@@ -250,7 +251,7 @@ static int software_resume(void)
 
 	if ((error = prepare_processes())) {
 		swsusp_close();
-		goto Cleanup;
+		goto Done;
 	}
 
 	pr_debug("PM: Reading swsusp image.\n");
diff --git a/kernel/power/main.c b/kernel/power/main.c
index 4cdebc972ff..c94cb9e9509 100644
--- a/kernel/power/main.c
+++ b/kernel/power/main.c
@@ -55,6 +55,13 @@ static int suspend_prepare(suspend_state_t state)
 
 	pm_prepare_console();
 
+	disable_nonboot_cpus();
+
+	if (num_online_cpus() != 1) {
+		error = -EPERM;
+		goto Enable_cpu;
+	}
+
 	if (freeze_processes()) {
 		error = -EAGAIN;
 		goto Thaw;
@@ -75,6 +82,8 @@ static int suspend_prepare(suspend_state_t state)
 		pm_ops->finish(state);
  Thaw:
 	thaw_processes();
+ Enable_cpu:
+	enable_nonboot_cpus();
 	pm_restore_console();
 	return error;
 }
@@ -113,6 +122,7 @@ static void suspend_finish(suspend_state_t state)
 	if (pm_ops && pm_ops->finish)
 		pm_ops->finish(state);
 	thaw_processes();
+	enable_nonboot_cpus();
 	pm_restore_console();
 }
 
@@ -150,12 +160,6 @@ static int enter_state(suspend_state_t state)
 		goto Unlock;
 	}
 
-	/* Suspend is hard to get right on SMP. */
-	if (num_online_cpus() != 1) {
-		error = -EPERM;
-		goto Unlock;
-	}
-
 	pr_debug("PM: Preparing system for %s sleep\n", pm_states[state]);
 	if ((error = suspend_prepare(state)))
 		goto Unlock;
diff --git a/kernel/power/process.c b/kernel/power/process.c
index 78d92dc6a1e..0a086640bcf 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -32,7 +32,7 @@ static inline int freezeable(struct task_struct * p)
 }
 
 /* Refrigerator is place where frozen processes are stored :-). */
-void refrigerator(unsigned long flag)
+void refrigerator(void)
 {
 	/* Hmm, should we be allowed to suspend when there are realtime
 	   processes around? */
@@ -41,14 +41,13 @@ void refrigerator(unsigned long flag)
 	current->state = TASK_UNINTERRUPTIBLE;
 	pr_debug("%s entered refrigerator\n", current->comm);
 	printk("=");
-	current->flags &= ~PF_FREEZE;
 
+	frozen_process(current);
 	spin_lock_irq(&current->sighand->siglock);
 	recalc_sigpending(); /* We sent fake signal, clean it up */
 	spin_unlock_irq(&current->sighand->siglock);
 
-	current->flags |= PF_FROZEN;
-	while (current->flags & PF_FROZEN)
+	while (frozen(current))
 		schedule();
 	pr_debug("%s left refrigerator\n", current->comm);
 	current->state = save;
@@ -57,10 +56,10 @@ void refrigerator(unsigned long flag)
 /* 0 = success, else # of processes that we failed to stop */
 int freeze_processes(void)
 {
-       int todo;
-       unsigned long start_time;
+	int todo;
+	unsigned long start_time;
 	struct task_struct *g, *p;
-	
+
 	printk( "Stopping tasks: " );
 	start_time = jiffies;
 	do {
@@ -70,14 +69,12 @@ int freeze_processes(void)
 			unsigned long flags;
 			if (!freezeable(p))
 				continue;
-			if ((p->flags & PF_FROZEN) ||
+			if ((frozen(p)) ||
 			    (p->state == TASK_TRACED) ||
 			    (p->state == TASK_STOPPED))
 				continue;
 
-			/* FIXME: smp problem here: we may not access other process' flags
-			   without locking */
-			p->flags |= PF_FREEZE;
+			freeze(p);
 			spin_lock_irqsave(&p->sighand->siglock, flags);
 			signal_wake_up(p, 0);
 			spin_unlock_irqrestore(&p->sighand->siglock, flags);
@@ -91,7 +88,7 @@ int freeze_processes(void)
 			return todo;
 		}
 	} while(todo);
-	
+
 	printk( "|\n" );
 	BUG_ON(in_atomic());
 	return 0;
@@ -106,10 +103,7 @@ void thaw_processes(void)
 	do_each_thread(g, p) {
 		if (!freezeable(p))
 			continue;
-		if (p->flags & PF_FROZEN) {
-			p->flags &= ~PF_FROZEN;
-			wake_up_process(p);
-		} else
+		if (!thaw_process(p))
 			printk(KERN_INFO " Strange, %s not stopped\n", p->comm );
 	} while_each_thread(g, p);
 
diff --git a/kernel/power/smp.c b/kernel/power/smp.c
index cba3584b80f..bbe23079c62 100644
--- a/kernel/power/smp.c
+++ b/kernel/power/smp.c
@@ -13,73 +13,52 @@
 #include <linux/interrupt.h>
 #include <linux/suspend.h>
 #include <linux/module.h>
+#include <linux/cpu.h>
 #include <asm/atomic.h>
 #include <asm/tlbflush.h>
 
-static atomic_t cpu_counter, freeze;
-
-
-static void smp_pause(void * data)
-{
-	struct saved_context ctxt;
-	__save_processor_state(&ctxt);
-	printk("Sleeping in:\n");
-	dump_stack();
-	atomic_inc(&cpu_counter);
-	while (atomic_read(&freeze)) {
-		/* FIXME: restore takes place at random piece inside this.
-		   This should probably be written in assembly, and
-		   preserve general-purpose registers, too
-
-		   What about stack? We may need to move to new stack here.
-
-		   This should better be ran with interrupts disabled.
-		 */
-		cpu_relax();
-		barrier();
-	}
-	atomic_dec(&cpu_counter);
-	__restore_processor_state(&ctxt);
-}
-
-static cpumask_t oldmask;
+/* This is protected by pm_sem semaphore */
+static cpumask_t frozen_cpus;
 
 void disable_nonboot_cpus(void)
 {
-	oldmask = current->cpus_allowed;
-	set_cpus_allowed(current, cpumask_of_cpu(0));
-	printk("Freezing CPUs (at %d)", _smp_processor_id());
-	current->state = TASK_INTERRUPTIBLE;
-	schedule_timeout(HZ);
-	printk("...");
-	BUG_ON(_smp_processor_id() != 0);
-
-	/* FIXME: for this to work, all the CPUs must be running
-	 * "idle" thread (or we deadlock). Is that guaranteed? */
+	int cpu, error;
 
-	atomic_set(&cpu_counter, 0);
-	atomic_set(&freeze, 1);
-	smp_call_function(smp_pause, NULL, 0, 0);
-	while (atomic_read(&cpu_counter) < (num_online_cpus() - 1)) {
-		cpu_relax();
-		barrier();
+	error = 0;
+	cpus_clear(frozen_cpus);
+	printk("Freezing cpus ...\n");
+	for_each_online_cpu(cpu) {
+		if (cpu == 0)
+			continue;
+		error = cpu_down(cpu);
+		if (!error) {
+			cpu_set(cpu, frozen_cpus);
+			printk("CPU%d is down\n", cpu);
+			continue;
+		}
+		printk("Error taking cpu %d down: %d\n", cpu, error);
 	}
-	printk("ok\n");
+	BUG_ON(smp_processor_id() != 0);
+	if (error)
+		panic("cpus not sleeping");
 }
 
 void enable_nonboot_cpus(void)
 {
-	printk("Restarting CPUs");
-	atomic_set(&freeze, 0);
-	while (atomic_read(&cpu_counter)) {
-		cpu_relax();
-		barrier();
-	}
-	printk("...");
-	set_cpus_allowed(current, oldmask);
-	schedule();
-	printk("ok\n");
+	int cpu, error;
 
+	printk("Thawing cpus ...\n");
+	for_each_cpu_mask(cpu, frozen_cpus) {
+		error = smp_prepare_cpu(cpu);
+		if (!error)
+			error = cpu_up(cpu);
+		if (!error) {
+			printk("CPU%d is up\n", cpu);
+			continue;
+		}
+		printk("Error taking cpu %d up: %d\n", cpu, error);
+		panic("Not enough cpus");
+	}
+	cpus_clear(frozen_cpus);
 }
 
-
diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 90b3b68dee3..c285fc5a232 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -10,12 +10,12 @@
  * This file is released under the GPLv2.
  *
  * I'd like to thank the following people for their work:
- * 
+ *
  * Pavel Machek <pavel@ucw.cz>:
  * Modifications, defectiveness pointing, being with me at the very beginning,
  * suspend to swap space, stop all tasks. Port to 2.4.18-ac and 2.5.17.
  *
- * Steve Doddi <dirk@loth.demon.co.uk>: 
+ * Steve Doddi <dirk@loth.demon.co.uk>:
  * Support the possibility of hardware state restoring.
  *
  * Raph <grey.havens@earthling.net>:
@@ -81,14 +81,14 @@ static int nr_copy_pages_check;
 extern char resume_file[];
 
 /* Local variables that should not be affected by save */
-unsigned int nr_copy_pages __nosavedata = 0;
+static unsigned int nr_copy_pages __nosavedata = 0;
 
 /* Suspend pagedir is allocated before final copy, therefore it
-   must be freed after resume 
+   must be freed after resume
 
    Warning: this is evil. There are actually two pagedirs at time of
    resume. One is "pagedir_save", which is empty frame allocated at
-   time of suspend, that must be freed. Second is "pagedir_nosave", 
+   time of suspend, that must be freed. Second is "pagedir_nosave",
    allocated at time of resume, that travels through memory not to
    collide with anything.
 
@@ -132,7 +132,7 @@ static int mark_swapfiles(swp_entry_t prev)
 {
 	int error;
 
-	rw_swap_page_sync(READ, 
+	rw_swap_page_sync(READ,
 			  swp_entry(root_swap, 0),
 			  virt_to_page((unsigned long)&swsusp_header));
 	if (!memcmp("SWAP-SPACE",swsusp_header.sig, 10) ||
@@ -140,7 +140,7 @@ static int mark_swapfiles(swp_entry_t prev)
 		memcpy(swsusp_header.orig_sig,swsusp_header.sig, 10);
 		memcpy(swsusp_header.sig,SWSUSP_SIG, 10);
 		swsusp_header.swsusp_info = prev;
-		error = rw_swap_page_sync(WRITE, 
+		error = rw_swap_page_sync(WRITE,
 					  swp_entry(root_swap, 0),
 					  virt_to_page((unsigned long)
 						       &swsusp_header));
@@ -174,22 +174,22 @@ static int is_resume_device(const struct swap_info_struct *swap_info)
 static int swsusp_swap_check(void) /* This is called before saving image */
 {
 	int i, len;
-	
+
 	len=strlen(resume_file);
 	root_swap = 0xFFFF;
-	
+
 	swap_list_lock();
-	for(i=0; i<MAX_SWAPFILES; i++) {
+	for (i=0; i<MAX_SWAPFILES; i++) {
 		if (swap_info[i].flags == 0) {
 			swapfile_used[i]=SWAPFILE_UNUSED;
 		} else {
-			if(!len) {
+			if (!len) {
 	    			printk(KERN_WARNING "resume= option should be used to set suspend device" );
-				if(root_swap == 0xFFFF) {
+				if (root_swap == 0xFFFF) {
 					swapfile_used[i] = SWAPFILE_SUSPEND;
 					root_swap = i;
 				} else
-					swapfile_used[i] = SWAPFILE_IGNORED;				  
+					swapfile_used[i] = SWAPFILE_IGNORED;
 			} else {
 	  			/* we ignore all swap devices that are not the resume_file */
 				if (is_resume_device(&swap_info[i])) {
@@ -209,15 +209,15 @@ static int swsusp_swap_check(void) /* This is called before saving image */
  * This is called after saving image so modification
  * will be lost after resume... and that's what we want.
  * we make the device unusable. A new call to
- * lock_swapdevices can unlock the devices. 
+ * lock_swapdevices can unlock the devices.
  */
 static void lock_swapdevices(void)
 {
 	int i;
 
 	swap_list_lock();
-	for(i = 0; i< MAX_SWAPFILES; i++)
-		if(swapfile_used[i] == SWAPFILE_IGNORED) {
+	for (i = 0; i< MAX_SWAPFILES; i++)
+		if (swapfile_used[i] == SWAPFILE_IGNORED) {
 			swap_info[i].flags ^= 0xFF;
 		}
 	swap_list_unlock();
@@ -229,7 +229,7 @@ static void lock_swapdevices(void)
  *	@loc:	Place to store the entry we used.
  *
  *	Allocate a new swap entry and 'sync' it. Note we discard -EIO
- *	errors. That is an artifact left over from swsusp. It did not 
+ *	errors. That is an artifact left over from swsusp. It did not
  *	check the return of rw_swap_page_sync() at all, since most pages
  *	written back to swap would return -EIO.
  *	This is a partial improvement, since we will at least return other
@@ -241,7 +241,7 @@ static int write_page(unsigned long addr, swp_entry_t * loc)
 	int error = 0;
 
 	entry = get_swap_page();
-	if (swp_offset(entry) && 
+	if (swp_offset(entry) &&
 	    swapfile_used[swp_type(entry)] == SWAPFILE_SUSPEND) {
 		error = rw_swap_page_sync(WRITE, entry,
 					  virt_to_page(addr));
@@ -257,7 +257,7 @@ static int write_page(unsigned long addr, swp_entry_t * loc)
 /**
  *	data_free - Free the swap entries used by the saved image.
  *
- *	Walk the list of used swap entries and free each one. 
+ *	Walk the list of used swap entries and free each one.
  *	This is only used for cleanup when suspend fails.
  */
 static void data_free(void)
@@ -290,7 +290,7 @@ static int data_write(void)
 		mod = 1;
 
 	printk( "Writing data to swap (%d pages)...     ", nr_copy_pages );
-	for_each_pbe(p, pagedir_nosave) {
+	for_each_pbe (p, pagedir_nosave) {
 		if (!(i%mod))
 			printk( "\b\b\b\b%3d%%", i / mod );
 		if ((error = write_page(p->address, &(p->swap_address))))
@@ -335,7 +335,7 @@ static int close_swap(void)
 
 	dump_info();
 	error = write_page((unsigned long)&swsusp_info, &entry);
-	if (!error) { 
+	if (!error) {
 		printk( "S" );
 		error = mark_swapfiles(entry);
 		printk( "|\n" );
@@ -370,7 +370,7 @@ static int write_pagedir(void)
 	struct pbe * pbe;
 
 	printk( "Writing pagedir...");
-	for_each_pb_page(pbe, pagedir_nosave) {
+	for_each_pb_page (pbe, pagedir_nosave) {
 		if ((error = write_page((unsigned long)pbe, &swsusp_info.pagedir[n++])))
 			return error;
 	}
@@ -472,7 +472,7 @@ static int save_highmem(void)
 	int res = 0;
 
 	pr_debug("swsusp: Saving Highmem\n");
-	for_each_zone(zone) {
+	for_each_zone (zone) {
 		if (is_highmem(zone))
 			res = save_highmem_zone(zone);
 		if (res)
@@ -547,7 +547,7 @@ static void count_data_pages(void)
 
 	nr_copy_pages = 0;
 
-	for_each_zone(zone) {
+	for_each_zone (zone) {
 		if (is_highmem(zone))
 			continue;
 		mark_free_pages(zone);
@@ -562,9 +562,9 @@ static void copy_data_pages(void)
 	struct zone *zone;
 	unsigned long zone_pfn;
 	struct pbe * pbe = pagedir_nosave;
-	
+
 	pr_debug("copy_data_pages(): pages to copy: %d\n", nr_copy_pages);
-	for_each_zone(zone) {
+	for_each_zone (zone) {
 		if (is_highmem(zone))
 			continue;
 		mark_free_pages(zone);
@@ -702,7 +702,7 @@ static void free_image_pages(void)
 {
 	struct pbe * p;
 
-	for_each_pbe(p, pagedir_save) {
+	for_each_pbe (p, pagedir_save) {
 		if (p->address) {
 			ClearPageNosave(virt_to_page(p->address));
 			free_page(p->address);
@@ -719,7 +719,7 @@ static int alloc_image_pages(void)
 {
 	struct pbe * p;
 
-	for_each_pbe(p, pagedir_save) {
+	for_each_pbe (p, pagedir_save) {
 		p->address = get_zeroed_page(GFP_ATOMIC | __GFP_COLD);
 		if (!p->address)
 			return -ENOMEM;
@@ -740,7 +740,7 @@ void swsusp_free(void)
 /**
  *	enough_free_mem - Make sure we enough free memory to snapshot.
  *
- *	Returns TRUE or FALSE after checking the number of available 
+ *	Returns TRUE or FALSE after checking the number of available
  *	free pages.
  */
 
@@ -758,11 +758,11 @@ static int enough_free_mem(void)
 /**
  *	enough_swap - Make sure we have enough swap to save the image.
  *
- *	Returns TRUE or FALSE after checking the total amount of swap 
+ *	Returns TRUE or FALSE after checking the total amount of swap
  *	space avaiable.
  *
  *	FIXME: si_swapinfo(&i) returns all swap devices information.
- *	We should only consider resume_device. 
+ *	We should only consider resume_device.
  */
 
 static int enough_swap(void)
@@ -781,18 +781,18 @@ static int swsusp_alloc(void)
 {
 	int error;
 
+	pagedir_nosave = NULL;
+	nr_copy_pages = calc_nr(nr_copy_pages);
+
 	pr_debug("suspend: (pages needed: %d + %d free: %d)\n",
 		 nr_copy_pages, PAGES_FOR_IO, nr_free_pages());
 
-	pagedir_nosave = NULL;
 	if (!enough_free_mem())
 		return -ENOMEM;
 
 	if (!enough_swap())
 		return -ENOSPC;
 
-	nr_copy_pages = calc_nr(nr_copy_pages);
-
 	if (!(pagedir_save = alloc_pagedir(nr_copy_pages))) {
 		printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
 		return -ENOMEM;
@@ -827,8 +827,8 @@ static int suspend_prepare_image(void)
 	error = swsusp_alloc();
 	if (error)
 		return error;
-	
-	/* During allocating of suspend pagedir, new cold pages may appear. 
+
+	/* During allocating of suspend pagedir, new cold pages may appear.
 	 * Kill them.
 	 */
 	drain_local_pages();
@@ -929,21 +929,6 @@ int swsusp_resume(void)
 	return error;
 }
 
-/* More restore stuff */
-
-/*
- * Returns true if given address/order collides with any orig_address 
- */
-static int does_collide_order(unsigned long addr, int order)
-{
-	int i;
-	
-	for (i=0; i < (1<<order); i++)
-		if (!PageNosaveFree(virt_to_page(addr + i * PAGE_SIZE)))
-			return 1;
-	return 0;
-}
-
 /**
  *	On resume, for storing the PBE list and the image,
  *	we can only use memory pages that do not conflict with the pages
@@ -973,7 +958,7 @@ static unsigned long get_usable_page(unsigned gfp_mask)
 	unsigned long m;
 
 	m = get_zeroed_page(gfp_mask);
-	while (does_collide_order(m, 0)) {
+	while (!PageNosaveFree(virt_to_page(m))) {
 		eat_page((void *)m);
 		m = get_zeroed_page(gfp_mask);
 		if (!m)
@@ -1045,7 +1030,7 @@ static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
 
 	/* Set page flags */
 
-	for_each_zone(zone) {
+	for_each_zone (zone) {
         	for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
                 	SetPageNosaveFree(pfn_to_page(zone_pfn +
 					zone->zone_start_pfn));
@@ -1061,7 +1046,7 @@ static struct pbe * swsusp_pagedir_relocate(struct pbe *pblist)
 	/* Relocate colliding pages */
 
 	for_each_pb_page (pbpage, pblist) {
-		if (does_collide_order((unsigned long)pbpage, 0)) {
+		if (!PageNosaveFree(virt_to_page((unsigned long)pbpage))) {
 			m = (void *)get_usable_page(GFP_ATOMIC | __GFP_COLD);
 			if (!m) {
 				error = -ENOMEM;
@@ -1193,8 +1178,10 @@ static const char * sanity_check(void)
 		return "version";
 	if (strcmp(swsusp_info.uts.machine,system_utsname.machine))
 		return "machine";
+#if 0
 	if(swsusp_info.cpus != num_online_cpus())
 		return "number of cpus";
+#endif
 	return NULL;
 }