x86: implement missing x86_64 function smp_call_function_mask()

This patch defines the missing function smp_call_function_mask() for x86_64,
this is more or less a cut&paste of i386 function. It removes also some
duplicate code.

This function is needed by KVM to execute a function on some CPUs.

AK: Fixed description
AK: Moved WARN_ON(irqs_disabled) one level up to not warn in the panic case.
[ tglx: arch/x86 adaptation ]

Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 63 insertions, 56 deletions

diff --git a/arch/x86/kernel/smp_64.c b/arch/x86/kernel/smp_64.c
index 5c2964727d19..03fa6ed559c6 100644
--- a/arch/x86/kernel/smp_64.c
+++ b/arch/x86/kernel/smp_64.c
@@ -322,17 +322,27 @@ void unlock_ipi_call_lock(void)
 }
 
 /*
- * this function sends a 'generic call function' IPI to one other CPU
- * in the system.
- *
- * cpu is a standard Linux logical CPU number.
+ * this function sends a 'generic call function' IPI to all other CPU
+ * of the system defined in the mask.
  */
-static void
-__smp_call_function_single(int cpu, 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 = 1;
+        cpumask_t allbutself;
+        int cpus;
+
+        allbutself = cpu_online_map;
+        cpu_clear(smp_processor_id(), allbutself);
+
+        cpus_and(mask, mask, allbutself);
+        cpus = cpus_weight(mask);
+
+        if (!cpus)
+                return 0;
 
         data.func = func;
         data.info = info;
@@ -343,19 +353,55 @@ __smp_call_function_single(int cpu, void (*func) (void *info), void *info,
 
         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);
+
+        /* 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)
                 cpu_relax();
 
         if (!wait)
-                return;
+                return 0;
 
         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.
+ *
+ * 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.
+ */
+int smp_call_function_mask(cpumask_t mask,
+                           void (*func)(void *), void *info,
+                           int wait)
+{
+        int ret;
+
+        /* Can deadlock when called with interrupts disabled */
+        WARN_ON(irqs_disabled());
+
+        spin_lock(&call_lock);
+        ret = __smp_call_function_mask(mask, func, info, wait);
+        spin_unlock(&call_lock);
+        return ret;
 }
+EXPORT_SYMBOL(smp_call_function_mask);
 
 /*
  * smp_call_function_single - Run a function on a specific CPU
@@ -374,6 +420,7 @@ 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();
 
         /* Can deadlock when called with interrupts disabled */
@@ -387,51 +434,14 @@ int smp_call_function_single (int cpu, void (*func) (void *info), void *info,
                 return 0;
         }
 
-        spin_lock(&call_lock);
-        __smp_call_function_single(cpu, func, info, nonatomic, wait);
-        spin_unlock(&call_lock);
+        ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, wait);
+
         put_cpu();
-        return 0;
+        return ret;
 }
 EXPORT_SYMBOL(smp_call_function_single);
 
 /*
- * this function sends a 'generic call function' IPI to all other CPUs
- * in the system.
- */
-static void __smp_call_function (void (*func) (void *info), void *info,
-                                int nonatomic, int wait)
-{
-        struct call_data_struct data;
-        int cpus = num_online_cpus()-1;
-
-        if (!cpus)
-                return;
-
-        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_allbutself(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 - 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.
@@ -449,10 +459,7 @@ static void __smp_call_function (void (*func) (void *info), void *info,
 int smp_call_function (void (*func) (void *info), void *info, int nonatomic,
                         int wait)
 {
-        spin_lock(&call_lock);
-        __smp_call_function(func,info,nonatomic,wait);
-        spin_unlock(&call_lock);
-        return 0;
+        return smp_call_function_mask(cpu_online_map, func, info, wait);
 }
 EXPORT_SYMBOL(smp_call_function);
 
@@ -479,7 +486,7 @@ void smp_send_stop(void)
         /* Don't deadlock on the call lock in panic */
         nolock = !spin_trylock(&call_lock);
         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();