[PATCH] Add smp_ops interface

[PATCH] Add smp_ops interface

[Jeremy Fitzhardinge]

Add a smp_ops interface.  This abstracts the API defined by
<linux/smp.h> for use within arch/i386.  The primary intent is that it
be used by a paravirtualizing hypervisor to implement SMP, but it
could also be used by non-APIC-using sub-architectures.

This is related to CONFIG_PARAVIRT, but is implemented unconditionally
since it is simpler that way and not a highly performance-sensitive
interface.

[ Andrew: Patch is based on 2.6.21-rc5-mm1 + the pda->percpu patch I
  posted the other day.  It will have a minor context conflict without
  that patch, but is otherwise standalone. ]

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>

---
 arch/i386/kernel/smp.c     |   21 +++++++++++++----
 arch/i386/kernel/smpboot.c |    8 +++---
 include/asm-i386/smp.h     |   53 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 9 deletions(-)

===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -483,7 +483,7 @@ void flush_tlb_all(void)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void native_smp_send_reschedule(int cpu)
 {
 	WARN_ON(cpu_is_offline(cpu));
 	send_IPI_mask(cpumask_of_cpu(cpu), RESCHEDULE_VECTOR);
@@ -576,9 +576,9 @@ static int __smp_call_function_mask(cpum
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
  */
-int smp_call_function_mask(cpumask_t mask,
-			     void (*func)(void *), void *info,
-			     int wait)
+int native_smp_call_function_mask(cpumask_t mask,
+				  void (*func)(void *), void *info,
+				  int wait)
 {
 	int ret;
 
@@ -657,7 +657,7 @@ static void stop_this_cpu (void * dummy)
  * this function calls the 'stop' function on all other CPUs in the system.
  */
 
-void smp_send_stop(void)
+void native_smp_send_stop(void)
 {
 	/* Don't deadlock on the call lock in panic */
 	int nolock = !spin_trylock(&call_lock);
@@ -733,3 +733,14 @@ int safe_smp_processor_id(void)
 
 	return cpuid >= 0 ? cpuid : 0;
 }
+
+struct smp_ops smp_ops = {
+	.smp_prepare_boot_cpu = native_smp_prepare_boot_cpu,
+	.smp_prepare_cpus = native_smp_prepare_cpus,
+	.cpu_up = native_cpu_up,
+	.smp_cpus_done = native_smp_cpus_done,
+
+	.smp_send_stop = native_smp_send_stop,
+	.smp_send_reschedule = native_smp_send_reschedule,
+	.smp_call_function_mask = native_smp_call_function_mask,
+};
===================================================================
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -1169,7 +1169,7 @@ static void __init smp_boot_cpus(unsigne
 
 /* These are wrappers to interface to the new boot process.  Someone
    who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */
-void __init smp_prepare_cpus(unsigned int max_cpus)
+void __init native_smp_prepare_cpus(unsigned int max_cpus)
 {
 	smp_commenced_mask = cpumask_of_cpu(0);
 	cpu_callin_map = cpumask_of_cpu(0);
@@ -1189,7 +1189,7 @@ static inline void switch_to_new_gdt(voi
 	asm ("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
 }
 
-void __init smp_prepare_boot_cpu(void)
+void __init native_smp_prepare_boot_cpu(void)
 {
 	unsigned int cpu = smp_processor_id();
 
@@ -1290,7 +1290,7 @@ void __cpu_die(unsigned int cpu)
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit native_cpu_up(unsigned int cpu)
 {
 	unsigned long flags;
 #ifdef CONFIG_HOTPLUG_CPU
@@ -1335,7 +1335,7 @@ int __cpuinit __cpu_up(unsigned int cpu)
 	return 0;
 }
 
-void __init smp_cpus_done(unsigned int max_cpus)
+void __init native_smp_cpus_done(unsigned int max_cpus)
 {
 #ifdef CONFIG_X86_IO_APIC
 	setup_ioapic_dest();
===================================================================
--- a/include/asm-i386/smp.h
+++ b/include/asm-i386/smp.h
@@ -47,6 +47,59 @@ extern void cpu_exit_clear(void);
 extern void cpu_exit_clear(void);
 extern void cpu_uninit(void);
 #endif
+
+struct smp_ops
+{
+	void (*smp_prepare_boot_cpu)(void);
+	void (*smp_prepare_cpus)(unsigned max_cpus);
+	int (*cpu_up)(unsigned cpu);
+	void (*smp_cpus_done)(unsigned max_cpus);
+
+	void (*smp_send_stop)(void);
+	void (*smp_send_reschedule)(int cpu);
+	int (*smp_call_function_mask)(cpumask_t mask,
+				      void (*func)(void *info), void *info,
+				      int wait);
+};
+
+extern struct smp_ops smp_ops;
+
+static inline void smp_prepare_boot_cpu(void)
+{
+	smp_ops.smp_prepare_boot_cpu();
+}
+static inline void smp_prepare_cpus(unsigned int max_cpus)
+{
+	smp_ops.smp_prepare_cpus(max_cpus);
+}
+static inline int __cpu_up(unsigned int cpu)
+{
+	return smp_ops.cpu_up(cpu);
+}
+static inline void smp_cpus_done(unsigned int max_cpus)
+{
+	smp_ops.smp_cpus_done(max_cpus);
+}
+
+static inline void smp_send_stop(void)
+{
+	smp_ops.smp_send_stop();
+}
+static inline void smp_send_reschedule(int cpu)
+{
+	smp_ops.smp_send_reschedule(cpu);
+}
+static inline int smp_call_function_mask(cpumask_t mask,
+					 void (*func) (void *info), void *info,
+					 int wait)
+{
+	return smp_ops.smp_call_function_mask(mask, func, info, wait);
+}
+
+void native_smp_prepare_boot_cpu(void);
+void native_smp_prepare_cpus(unsigned int max_cpus);
+int native_cpu_up(unsigned int cpunum);
+void native_smp_cpus_done(unsigned int max_cpus);
 
 #ifndef CONFIG_PARAVIRT
 #define startup_ipi_hook(phys_apicid, start_eip, start_esp) 		\

Re: [PATCH] Add smp_ops interface

[Jeremy Fitzhardinge]

Jeremy Fitzhardinge wrote:
> [ Andrew: Patch is based on 2.6.21-rc5-mm1 + the pda->percpu patch I
>   posted the other day.  It will have a minor context conflict without
>   that patch, but is otherwise standalone. ]
>   
Sorry, it also depends on simplify-smp_call_function.patch, which I'll
repost shortly.

    J

[PATCH] Simplify smp_call_function*() by using common implementation

[Jeremy Fitzhardinge]

smp_call_function and smp_call_function_single are almost complete
duplicates of the same logic.  This patch combines them by
implementing them in terms of the more general
smp_call_function_mask().

[ Jan, Andi: This only changes arch/i386; can x86_64 be changed in the
  same way? ]

[ Rebased onto Jan's x86_64-mm-consolidate-smp_send_stop patch ]

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Jan Beulich <jbeulich@novell.com>
Cc: Stephane Eranian <eranian@hpl.hp.com>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Andi Kleen <ak@suse.de>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Cc: Ingo Molnar <mingo@elte.hu>

---
 arch/i386/kernel/smp.c |  177 +++++++++++++++++++++++-------------------------
 1 file changed, 86 insertions(+), 91 deletions(-)

===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -515,14 +515,26 @@ void unlock_ipi_call_lock(void)
 
 static struct call_data_struct *call_data;
 
-static void __smp_call_function(void (*func) (void *info), void *info,
-				int nonatomic, int wait)
+
+static int __smp_call_function_mask(cpumask_t mask,
+				    void (*func)(void *), void *info,
+				    int wait)
 {
 	struct call_data_struct data;
-	int cpus = num_online_cpus() - 1;
+	cpumask_t allbutself;
+	int cpus;
+
+	/* Can deadlock when called with interrupts disabled */
+	WARN_ON(irqs_disabled());
+
+	allbutself = cpu_online_map;
+	cpu_clear(smp_processor_id(), allbutself);
+
+	cpus_and(mask, mask, allbutself);
+	cpus = cpus_weight(mask);
 
 	if (!cpus)
-		return;
+		return 0;
 
 	data.func = func;
 	data.info = info;
@@ -533,9 +545,12 @@ static void __smp_call_function(void (*f
 
 	call_data = &data;
 	mb();
-	
-	/* Send a message to all other CPUs and wait for them to respond */
-	send_IPI_allbutself(CALL_FUNCTION_VECTOR);
+
+	/* Send a message to other CPUs */
+	if (cpus_equal(mask, allbutself))
+		send_IPI_allbutself(CALL_FUNCTION_VECTOR);
+	else
+		send_IPI_mask(mask, CALL_FUNCTION_VECTOR);
 
 	/* Wait for response */
 	while (atomic_read(&data.started) != cpus)
@@ -544,6 +559,34 @@ static void __smp_call_function(void (*f
 	if (wait)
 		while (atomic_read(&data.finished) != cpus)
 			cpu_relax();
+
+	return 0;
+}
+
+/**
+ * smp_call_function_mask(): Run a function on a set of other CPUs.
+ * @mask: The set of cpus to run on.  Must not include the current cpu.
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait (atomically) until function has completed on other CPUs.
+ *
+ * Returns 0 on success, else a negative status code. Does not return until
+ * remote CPUs are nearly ready to execute <<func>> or are or have finished.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.
+ */
+int smp_call_function_mask(cpumask_t mask,
+			     void (*func)(void *), void *info,
+			     int wait)
+{
+	int ret;
+
+	spin_lock(&call_lock);
+	ret = __smp_call_function_mask(mask, func, info, wait);
+	spin_unlock(&call_lock);
+
+	return ret;
 }
 
 /**
@@ -559,20 +602,43 @@ static void __smp_call_function(void (*f
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
  */
-int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
-			int wait)
-{
-	/* Can deadlock when called with interrupts disabled */
-	WARN_ON(irqs_disabled());
-
-	/* Holding any lock stops cpus from going down. */
-	spin_lock(&call_lock);
-	__smp_call_function(func, info, nonatomic, wait);
-	spin_unlock(&call_lock);
-
-	return 0;
+int smp_call_function(void (*func) (void *info), void *info, int nonatomic,
+		      int wait)
+{
+	return smp_call_function_mask(cpu_online_map, func, info, wait);
 }
 EXPORT_SYMBOL(smp_call_function);
+
+/*
+ * smp_call_function_single - Run a function on another CPU
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @nonatomic: Currently unused.
+ * @wait: If true, wait until function has completed on other CPUs.
+ *
+ * Retrurns 0 on success, else a negative status code.
+ *
+ * Does not return until the remote CPU is nearly ready to execute <func>
+ * or is or has executed.
+ */
+int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+			     int nonatomic, int wait)
+{
+	/* prevent preemption and reschedule on another processor */
+	int ret;
+	int me = get_cpu();
+	if (cpu == me) {
+		WARN_ON(1);
+		put_cpu();
+		return -EBUSY;
+	}
+
+	ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, wait);
+
+	put_cpu();
+	return ret;
+}
+EXPORT_SYMBOL(smp_call_function_single);
 
 static void stop_this_cpu (void * dummy)
 {
@@ -598,7 +664,7 @@ void smp_send_stop(void)
 	unsigned long flags;
 
 	local_irq_save(flags);
-	__smp_call_function(stop_this_cpu, NULL, 0, 0);
+	__smp_call_function_mask(cpu_online_map, stop_this_cpu, NULL, 0);
 	if (!nolock)
 		spin_unlock(&call_lock);
 	disable_local_APIC();
@@ -641,77 +707,6 @@ fastcall void smp_call_function_interrup
 	}
 }
 
-/*
- * this function sends a 'generic call function' IPI to one other CPU
- * in the system.
- *
- * cpu is a standard Linux logical CPU number.
- */
-static void
-__smp_call_function_single(int cpu, void (*func) (void *info), void *info,
-				int nonatomic, int wait)
-{
-	struct call_data_struct data;
-	int cpus = 1;
-
-	data.func = func;
-	data.info = info;
-	atomic_set(&data.started, 0);
-	data.wait = wait;
-	if (wait)
-		atomic_set(&data.finished, 0);
-
-	call_data = &data;
-	wmb();
-	/* Send a message to all other CPUs and wait for them to respond */
-	send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_VECTOR);
-
-	/* Wait for response */
-	while (atomic_read(&data.started) != cpus)
-		cpu_relax();
-
-	if (!wait)
-		return;
-
-	while (atomic_read(&data.finished) != cpus)
-		cpu_relax();
-}
-
-/*
- * smp_call_function_single - Run a function on another CPU
- * @func: The function to run. This must be fast and non-blocking.
- * @info: An arbitrary pointer to pass to the function.
- * @nonatomic: Currently unused.
- * @wait: If true, wait until function has completed on other CPUs.
- *
- * Retrurns 0 on success, else a negative status code.
- *
- * Does not return until the remote CPU is nearly ready to execute <func>
- * or is or has executed.
- */
-
-int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
-			int nonatomic, int wait)
-{
-	/* prevent preemption and reschedule on another processor */
-	int me = get_cpu();
-	if (cpu == me) {
-		WARN_ON(1);
-		put_cpu();
-		return -EBUSY;
-	}
-
-	/* Can deadlock when called with interrupts disabled */
-	WARN_ON(irqs_disabled());
-
-	spin_lock_bh(&call_lock);
-	__smp_call_function_single(cpu, func, info, nonatomic, wait);
-	spin_unlock_bh(&call_lock);
-	put_cpu();
-	return 0;
-}
-EXPORT_SYMBOL(smp_call_function_single);
-
 static int convert_apicid_to_cpu(int apic_id)
 {
 	int i;

Re: [PATCH] Simplify smp_call_function*() by using common implementation

[Andi Kleen]

On Wednesday 28 March 2007 00:13, Jeremy Fitzhardinge wrote:
> smp_call_function and smp_call_function_single are almost complete
> duplicates of the same logic.  This patch combines them by
> implementing them in terms of the more general
> smp_call_function_mask().

I think I got those already.

-Andi

Re: [PATCH] Simplify smp_call_function*() by using common implementation

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> On Wednesday 28 March 2007 00:13, Jeremy Fitzhardinge wrote:
>   
>> smp_call_function and smp_call_function_single are almost complete
>> duplicates of the same logic.  This patch combines them by
>> implementing them in terms of the more general
>> smp_call_function_mask().
>>     
>
> I think I got those already.
>   

OK.  Do you have smp_ops and machine_ops?

There's a doc update patch too:

Subject: Fix smp_call_function* docs

As reported by Randy Dunlap <rdunlap@xenotime.net>

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Randy Dunlap <rdunlap@xenotime.net>

---
 arch/i386/kernel/smp.c |   27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -570,8 +570,10 @@ static int __smp_call_function_mask(cpum
  * @info: An arbitrary pointer to pass to the function.
  * @wait: If true, wait (atomically) until function has completed on other CPUs.
  *
- * Returns 0 on success, else a negative status code. Does not return until
- * remote CPUs are nearly ready to execute <<func>> or are or have finished.
+  * Returns 0 on success, else a negative status code.
+ *
+ * If @wait is true, then returns once @func has returned; otherwise
+ * it returns just before the target cpu calls @func.
  *
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
@@ -593,11 +595,13 @@ int smp_call_function_mask(cpumask_t mas
  * smp_call_function(): Run a function on all other CPUs.
  * @func: The function to run. This must be fast and non-blocking.
  * @info: An arbitrary pointer to pass to the function.
- * @nonatomic: currently unused.
+ * @nonatomic: Unused.
  * @wait: If true, wait (atomically) until function has completed on other CPUs.
  *
- * Returns 0 on success, else a negative status code. Does not return until
- * remote CPUs are nearly ready to execute <<func>> or are or have executed.
+ * Returns 0 on success, else a negative status code.
+ *
+ * If @wait is true, then returns once @func has returned; otherwise
+ * it returns just before the target cpu calls @func.
  *
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
@@ -609,17 +613,18 @@ int smp_call_function(void (*func) (void
 }
 EXPORT_SYMBOL(smp_call_function);
 
-/*
+/**
  * smp_call_function_single - Run a function on another CPU
+ * @cpu: The target CPU.  Cannot be the calling CPU.
  * @func: The function to run. This must be fast and non-blocking.
  * @info: An arbitrary pointer to pass to the function.
- * @nonatomic: Currently unused.
+ * @nonatomic: Unused.
  * @wait: If true, wait until function has completed on other CPUs.
  *
- * Retrurns 0 on success, else a negative status code.
- *
- * Does not return until the remote CPU is nearly ready to execute <func>
- * or is or has executed.
+ * Returns 0 on success, else a negative status code.
+ *
+ * If @wait is true, then returns once @func has returned; otherwise
+ * it returns just before the target cpu calls @func.
  */
 int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
 			     int nonatomic, int wait)

Re: [PATCH] Simplify smp_call_function*() by using common implementation

[Andi Kleen]

On Wednesday 28 March 2007 21:18, Jeremy Fitzhardinge wrote:
> Andi Kleen wrote:
> > On Wednesday 28 March 2007 00:13, Jeremy Fitzhardinge wrote:
> >   
> >> smp_call_function and smp_call_function_single are almost complete
> >> duplicates of the same logic.  This patch combines them by
> >> implementing them in terms of the more general
> >> smp_call_function_mask().
> >>     
> >
> > I think I got those already.
> >   
> 
> OK.  Do you have smp_ops and machine_ops?

Not yet. Can you resend the current set?

> There's a doc update patch too:

Can you send that separately after i sync out please?

Thanks

-Andi

[PATCH] Add smp_ops interface

[Jeremy Fitzhardinge]

Subject: Add smp_ops interface

Add a smp_ops interface.  This abstracts the API defined by
<linux/smp.h> for use within arch/i386.  The primary intent is that it
be used by a paravirtualizing hypervisor to implement SMP, but it
could also be used by non-APIC-using sub-architectures.

This is related to CONFIG_PARAVIRT, but is implemented unconditionally
since it is simpler that way and not a highly performance-sensitive
interface.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Andi Kleen <ak@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>

---
 arch/i386/kernel/smp.c     |   21 +++++++++++++----
 arch/i386/kernel/smpboot.c |    8 +++---
 include/asm-i386/smp.h     |   53 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 73 insertions(+), 9 deletions(-)

===================================================================
--- a/arch/i386/kernel/smp.c
+++ b/arch/i386/kernel/smp.c
@@ -483,7 +483,7 @@ void flush_tlb_all(void)
  * it goes straight through and wastes no time serializing
  * anything. Worst case is that we lose a reschedule ...
  */
-void smp_send_reschedule(int cpu)
+void native_smp_send_reschedule(int cpu)
 {
 	WARN_ON(cpu_is_offline(cpu));
 	send_IPI_mask(cpumask_of_cpu(cpu), RESCHEDULE_VECTOR);
@@ -576,9 +576,9 @@ static int __smp_call_function_mask(cpum
  * You must not call this function with disabled interrupts or from a
  * hardware interrupt handler or from a bottom half handler.
  */
-int smp_call_function_mask(cpumask_t mask,
-			     void (*func)(void *), void *info,
-			     int wait)
+int native_smp_call_function_mask(cpumask_t mask,
+				  void (*func)(void *), void *info,
+				  int wait)
 {
 	int ret;
 
@@ -657,7 +657,7 @@ static void stop_this_cpu (void * dummy)
  * this function calls the 'stop' function on all other CPUs in the system.
  */
 
-void smp_send_stop(void)
+void native_smp_send_stop(void)
 {
 	/* Don't deadlock on the call lock in panic */
 	int nolock = !spin_trylock(&call_lock);
@@ -733,3 +733,14 @@ int safe_smp_processor_id(void)
 
 	return cpuid >= 0 ? cpuid : 0;
 }
+
+struct smp_ops smp_ops = {
+	.smp_prepare_boot_cpu = native_smp_prepare_boot_cpu,
+	.smp_prepare_cpus = native_smp_prepare_cpus,
+	.cpu_up = native_cpu_up,
+	.smp_cpus_done = native_smp_cpus_done,
+
+	.smp_send_stop = native_smp_send_stop,
+	.smp_send_reschedule = native_smp_send_reschedule,
+	.smp_call_function_mask = native_smp_call_function_mask,
+};
===================================================================
--- a/arch/i386/kernel/smpboot.c
+++ b/arch/i386/kernel/smpboot.c
@@ -1169,7 +1169,7 @@ static void __init smp_boot_cpus(unsigne
 
 /* These are wrappers to interface to the new boot process.  Someone
    who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */
-void __init smp_prepare_cpus(unsigned int max_cpus)
+void __init native_smp_prepare_cpus(unsigned int max_cpus)
 {
 	smp_commenced_mask = cpumask_of_cpu(0);
 	cpu_callin_map = cpumask_of_cpu(0);
@@ -1189,7 +1189,7 @@ static inline void switch_to_new_gdt(voi
 	asm ("mov %0, %%fs" : : "r" (__KERNEL_PERCPU) : "memory");
 }
 
-void __init smp_prepare_boot_cpu(void)
+void __init native_smp_prepare_boot_cpu(void)
 {
 	unsigned int cpu = smp_processor_id();
 
@@ -1290,7 +1290,7 @@ void __cpu_die(unsigned int cpu)
 }
 #endif /* CONFIG_HOTPLUG_CPU */
 
-int __cpuinit __cpu_up(unsigned int cpu)
+int __cpuinit native_cpu_up(unsigned int cpu)
 {
 	unsigned long flags;
 #ifdef CONFIG_HOTPLUG_CPU
@@ -1335,7 +1335,7 @@ int __cpuinit __cpu_up(unsigned int cpu)
 	return 0;
 }
 
-void __init smp_cpus_done(unsigned int max_cpus)
+void __init native_smp_cpus_done(unsigned int max_cpus)
 {
 #ifdef CONFIG_X86_IO_APIC
 	setup_ioapic_dest();
===================================================================
--- a/include/asm-i386/smp.h
+++ b/include/asm-i386/smp.h
@@ -47,6 +47,59 @@ extern void cpu_exit_clear(void);
 extern void cpu_exit_clear(void);
 extern void cpu_uninit(void);
 #endif
+
+struct smp_ops
+{
+	void (*smp_prepare_boot_cpu)(void);
+	void (*smp_prepare_cpus)(unsigned max_cpus);
+	int (*cpu_up)(unsigned cpu);
+	void (*smp_cpus_done)(unsigned max_cpus);
+
+	void (*smp_send_stop)(void);
+	void (*smp_send_reschedule)(int cpu);
+	int (*smp_call_function_mask)(cpumask_t mask,
+				      void (*func)(void *info), void *info,
+				      int wait);
+};
+
+extern struct smp_ops smp_ops;
+
+static inline void smp_prepare_boot_cpu(void)
+{
+	smp_ops.smp_prepare_boot_cpu();
+}
+static inline void smp_prepare_cpus(unsigned int max_cpus)
+{
+	smp_ops.smp_prepare_cpus(max_cpus);
+}
+static inline int __cpu_up(unsigned int cpu)
+{
+	return smp_ops.cpu_up(cpu);
+}
+static inline void smp_cpus_done(unsigned int max_cpus)
+{
+	smp_ops.smp_cpus_done(max_cpus);
+}
+
+static inline void smp_send_stop(void)
+{
+	smp_ops.smp_send_stop();
+}
+static inline void smp_send_reschedule(int cpu)
+{
+	smp_ops.smp_send_reschedule(cpu);
+}
+static inline int smp_call_function_mask(cpumask_t mask,
+					 void (*func) (void *info), void *info,
+					 int wait)
+{
+	return smp_ops.smp_call_function_mask(mask, func, info, wait);
+}
+
+void native_smp_prepare_boot_cpu(void);
+void native_smp_prepare_cpus(unsigned int max_cpus);
+int native_cpu_up(unsigned int cpunum);
+void native_smp_cpus_done(unsigned int max_cpus);
 
 #ifndef CONFIG_PARAVIRT
 #define startup_ipi_hook(phys_apicid, start_eip, start_esp) 		\