[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

[Randy Dunlap]

On Tue, 27 Mar 2007 15:13:29 -0700 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().
> 
> [ 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

> @@ -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.

                                              func() or <what>??
      and what does "nearly ready" mean?

> + *
> + * 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.

      Returns

> + *
> + * Does not return until the remote CPU is nearly ready to execute <func>

Same comments:  what is "nearly ready"?  and s/<func>/func()/

> + * or is or has executed.

      Huh?  or what??

> + */
> +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)
>  {

> @@ -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;


---
~Randy
*** Remember to use Documentation/SubmitChecklist when testing your code ***

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

[Jeremy Fitzhardinge]

Randy Dunlap wrote:
>                                               func() or <what>??
>       and what does "nearly ready" mean?
>   

Sorry, I forgot to include your doc updates from last time.

"nearly ready" means that its just about to call the function, but
hasn't necessarily done so.

    J

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) 		\

[PATCH] Add machine_ops interface to abstract halting and rebooting

[Jeremy Fitzhardinge]

machine_ops is an interface for the machine_* functions defined in
<linux/reboot.h>.  This is intended to allow hypervisors to intercept
the reboot process, but it could be used to implement other x86
subarchtecture reboots.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>

---
 arch/i386/kernel/apm.c    |    3 --
 arch/i386/kernel/reboot.c |   49 +++++++++++++++++++++++++++++++++++++--------
 include/asm-i386/reboot.h |   20 ++++++++++++++++++
 3 files changed, 62 insertions(+), 10 deletions(-)

===================================================================
--- a/arch/i386/kernel/apm.c
+++ b/arch/i386/kernel/apm.c
@@ -233,10 +233,9 @@
 #include <asm/desc.h>
 #include <asm/i8253.h>
 #include <asm/paravirt.h>
+#include <asm/reboot.h>
 
 #include "io_ports.h"
-
-extern void machine_real_restart(unsigned char *, int);
 
 #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT)
 extern int (*console_blank_hook)(int);
===================================================================
--- a/arch/i386/kernel/reboot.c
+++ b/arch/i386/kernel/reboot.c
@@ -18,6 +18,7 @@
 #include <asm/desc.h>
 #include "mach_reboot.h"
 #include <asm/reboot_fixups.h>
+#include <asm/reboot.h>
 
 /*
  * Power off function, if any
@@ -280,7 +281,7 @@ EXPORT_SYMBOL(machine_real_restart);
 EXPORT_SYMBOL(machine_real_restart);
 #endif
 
-void machine_shutdown(void)
+static void native_machine_shutdown(void)
 {
 #ifdef CONFIG_SMP
 	int reboot_cpu_id;
@@ -320,7 +321,7 @@ void __attribute__((weak)) mach_reboot_f
 {
 }
 
-void machine_emergency_restart(void)
+static void native_machine_emergency_restart(void)
 {
 	if (!reboot_thru_bios) {
 		if (efi_enabled) {
@@ -344,17 +345,17 @@ void machine_emergency_restart(void)
 	machine_real_restart(jump_to_bios, sizeof(jump_to_bios));
 }
 
-void machine_restart(char * __unused)
+static void native_machine_restart(char * __unused)
 {
 	machine_shutdown();
 	machine_emergency_restart();
 }
 
-void machine_halt(void)
-{
-}
-
-void machine_power_off(void)
+static void native_machine_halt(void)
+{
+}
+
+static void native_machine_power_off(void)
 {
 	if (pm_power_off) {
 		machine_shutdown();
@@ -363,3 +364,35 @@ void machine_power_off(void)
 }
 
 
+struct machine_ops machine_ops = {
+	.power_off = native_machine_power_off,
+	.shutdown = native_machine_shutdown,
+	.emergency_restart = native_machine_emergency_restart,
+	.restart = native_machine_restart,
+	.halt = native_machine_halt,
+};
+
+void machine_power_off(void)
+{
+	machine_ops.power_off();
+}
+
+void machine_shutdown(void)
+{
+	machine_ops.shutdown();
+}
+
+void machine_emergency_restart(void)
+{
+	machine_ops.emergency_restart();
+}
+
+void machine_restart(char *cmd)
+{
+	machine_ops.restart(cmd);
+}
+
+void machine_halt(void)
+{
+	machine_ops.halt();
+}
===================================================================
--- /dev/null
+++ b/include/asm-i386/reboot.h
@@ -0,0 +1,20 @@
+#ifndef _ASM_REBOOT_H
+#define _ASM_REBOOT_H
+
+struct pt_regs;
+
+struct machine_ops
+{
+	void (*restart)(char *cmd);
+	void (*halt)(void);
+	void (*power_off)(void);
+	void (*shutdown)(void);
+	void (*crash_shutdown)(struct pt_regs *);
+	void (*emergency_restart)(void);
+};
+
+extern struct machine_ops machine_ops;
+
+void machine_real_restart(unsigned char *code, int length);
+
+#endif	/* _ASM_REBOOT_H */

Re: [PATCH] Add machine_ops interface to abstract halting and rebooting

[Andi Kleen]

On Wednesday 28 March 2007 21:32, Jeremy Fitzhardinge wrote:
> machine_ops is an interface for the machine_* functions defined in
> <linux/reboot.h>.  This is intended to allow hypervisors to intercept
> the reboot process, but it could be used to implement other x86
> subarchtecture reboots.

Both patches added thanks
-Andi

Re: [PATCH] Add machine_ops interface to abstract halting and rebooting

[Jeremy Fitzhardinge]

Andi Kleen wrote:
> On Wednesday 28 March 2007 21:32, Jeremy Fitzhardinge wrote:
>   
>> machine_ops is an interface for the machine_* functions defined in
>> <linux/reboot.h>.  This is intended to allow hypervisors to intercept
>> the reboot process, but it could be used to implement other x86
>> subarchtecture reboots.
>>     
>
> Both patches added thanks
>   

I presume you've also got the reboot-fixups cleanup patch?

    J

Re: [PATCH] Add machine_ops interface to abstract halting and rebooting

[Andi Kleen]

On Wednesday 28 March 2007 21:47, Jeremy Fitzhardinge wrote:
> Andi Kleen wrote:
> > On Wednesday 28 March 2007 21:32, Jeremy Fitzhardinge wrote:
> >   
> >> machine_ops is an interface for the machine_* functions defined in
> >> <linux/reboot.h>.  This is intended to allow hypervisors to intercept
> >> the reboot process, but it could be used to implement other x86
> >> subarchtecture reboots.
> >>     
> >
> > Both patches added thanks
> >   
> 
> I presume you've also got the reboot-fixups cleanup patch?

No, please resend too

-Andi

[PATCH] Clean up mach_reboot_fixups

[Jeremy Fitzhardinge]

Two cleanups:
 - reboot_fixups.h is entirely i386-dependent, so put it in asm-i386
 - use a weak version rather than ifdeffery

[ Andi - the machine_ops probably depends on this, but only in a minor
  context-clash way. ]

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: Jaya Kumar <jayalk@intworks.biz>

---
 arch/i386/kernel/reboot.c        |    6 +++++-
 arch/i386/kernel/reboot_fixups.c |    2 +-
 include/asm-i386/reboot_fixups.h |    6 ++++++
 include/linux/reboot_fixups.h    |   10 ----------
 4 files changed, 12 insertions(+), 12 deletions(-)

===================================================================
--- a/arch/i386/kernel/reboot.c
+++ b/arch/i386/kernel/reboot.c
@@ -17,7 +17,7 @@
 #include <asm/apic.h>
 #include <asm/desc.h>
 #include "mach_reboot.h"
-#include <linux/reboot_fixups.h>
+#include <asm/reboot_fixups.h>
 
 /*
  * Power off function, if any
@@ -314,6 +314,10 @@ void machine_shutdown(void)
 #ifdef CONFIG_X86_IO_APIC
 	disable_IO_APIC();
 #endif
+}
+
+void __attribute__((weak)) mach_reboot_fixups(void)
+{
 }
 
 void machine_emergency_restart(void)
===================================================================
--- a/arch/i386/kernel/reboot_fixups.c
+++ b/arch/i386/kernel/reboot_fixups.c
@@ -10,7 +10,7 @@
 
 #include <asm/delay.h>
 #include <linux/pci.h>
-#include <linux/reboot_fixups.h>
+#include <asm/reboot_fixups.h>
 
 static void cs5530a_warm_reset(struct pci_dev *dev)
 {
===================================================================
--- /dev/null
+++ b/include/asm-i386/reboot_fixups.h
@@ -0,0 +1,6 @@
+#ifndef _LINUX_REBOOT_FIXUPS_H
+#define _LINUX_REBOOT_FIXUPS_H
+
+extern void mach_reboot_fixups(void);
+
+#endif /* _LINUX_REBOOT_FIXUPS_H */
===================================================================
--- a/include/linux/reboot_fixups.h
+++ /dev/null
@@ -1,10 +0,0 @@
-#ifndef _LINUX_REBOOT_FIXUPS_H
-#define _LINUX_REBOOT_FIXUPS_H
-
-#ifdef CONFIG_X86_REBOOTFIXUPS
-extern void mach_reboot_fixups(void);
-#else
-#define mach_reboot_fixups() ((void)(0))
-#endif
-
-#endif /* _LINUX_REBOOT_FIXUPS_H */

Re: [PATCH] Clean up mach_reboot_fixups

[Andi Kleen]

On Wednesday 28 March 2007 22:11, Jeremy Fitzhardinge wrote:
> Two cleanups:
>  - reboot_fixups.h is entirely i386-dependent, so put it in asm-i386
>  - use a weak version rather than ifdeffery
> 
> [ Andi - the machine_ops probably depends on this, but only in a minor
>   context-clash way. ]

Sorry I actually had it already, but forgot about it

-Andi