x86: convert to generic helpers for IPI function calls

This converts x86, x86-64, and xen to use the new helpers for
smp_call_function() and friends, and adds support for
smp_call_function_single().

Acked-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

6 files changed, 33 insertions, 196 deletions

diff --git a/arch/x86/kernel/apic_32.c b/arch/x86/kernel/apic_32.c
index 4b99b1bdeb6c..71017f71f4bc 100644
--- a/arch/x86/kernel/apic_32.c
+++ b/arch/x86/kernel/apic_32.c
@@ -1358,6 +1358,10 @@ void __init smp_intr_init(void)
 
         /* IPI for generic function call */
         set_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
+
+        /* IPI for single call function */
+        set_intr_gate(CALL_FUNCTION_SINGLE_VECTOR,
+                                call_function_single_interrupt);
 }
 #endif
 
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S
index 556a8df522a7..6d1fe270a96d 100644
--- a/arch/x86/kernel/entry_64.S
+++ b/arch/x86/kernel/entry_64.S
@@ -711,6 +711,9 @@ END(invalidate_interrupt\num)
 ENTRY(call_function_interrupt)
         apicinterrupt CALL_FUNCTION_VECTOR,smp_call_function_interrupt
 END(call_function_interrupt)
+ENTRY(call_function_single_interrupt)
+        apicinterrupt CALL_FUNCTION_SINGLE_VECTOR,smp_call_function_single_interrupt
+END(call_function_single_interrupt)
 ENTRY(irq_move_cleanup_interrupt)
         apicinterrupt IRQ_MOVE_CLEANUP_VECTOR,smp_irq_move_cleanup_interrupt
 END(irq_move_cleanup_interrupt)
diff --git a/arch/x86/kernel/i8259_64.c b/arch/x86/kernel/i8259_64.c
index fa57a1568508..00d2ccdc69f8 100644
--- a/arch/x86/kernel/i8259_64.c
+++ b/arch/x86/kernel/i8259_64.c
@@ -494,6 +494,10 @@ void __init native_init_IRQ(void)
         /* IPI for generic function call */
         set_intr_gate(CALL_FUNCTION_VECTOR, call_function_interrupt);
 
+        /* IPI for generic single function call */
+        set_intr_gate(CALL_FUNCTION_SINGLE_VECTOR,
+                                call_function_single_interrupt);
+
         /* Low priority IPI to cleanup after moving an irq */
         set_intr_gate(IRQ_MOVE_CLEANUP_VECTOR, irq_move_cleanup_interrupt);
 #endif
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 0cb7aadc87cd..575aa3d7248a 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -121,132 +121,23 @@ static void native_smp_send_reschedule(int cpu)
         send_IPI_mask(cpumask_of_cpu(cpu), RESCHEDULE_VECTOR);
 }
 
-/*
- * Structure and data for smp_call_function(). This is designed to minimise
- * static memory requirements. It also looks cleaner.
- */
-static DEFINE_SPINLOCK(call_lock);
-
-struct call_data_struct {
-        void (*func) (void *info);
-        void *info;
-        atomic_t started;
-        atomic_t finished;
-        int wait;
-};
-
-void lock_ipi_call_lock(void)
+void native_send_call_func_single_ipi(int cpu)
 {
-        spin_lock_irq(&call_lock);
-}
-
-void unlock_ipi_call_lock(void)
-{
-        spin_unlock_irq(&call_lock);
-}
-
-static struct call_data_struct *call_data;
-
-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;
-        mb();
-
-        /* 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)
-                while (atomic_read(&data.finished) != cpus)
-                        cpu_relax();
+        send_IPI_mask(cpumask_of_cpu(cpu), CALL_FUNCTION_SINGLE_VECTOR);
 }
 
-
-/**
- * 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.
- */
-static int
-native_smp_call_function_mask(cpumask_t mask,
-                              void (*func)(void *), void *info,
-                              int wait)
+void native_send_call_func_ipi(cpumask_t mask)
 {
-        struct call_data_struct data;
         cpumask_t allbutself;
-        int cpus;
-
-        /* Can deadlock when called with interrupts disabled */
-        WARN_ON(irqs_disabled());
-
-        /* Holding any lock stops cpus from going down. */
-        spin_lock(&call_lock);
 
         allbutself = cpu_online_map;
         cpu_clear(smp_processor_id(), allbutself);
 
-        cpus_and(mask, mask, allbutself);
-        cpus = cpus_weight(mask);
-
-        if (!cpus) {
-                spin_unlock(&call_lock);
-                return 0;
-        }
-
-        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 other CPUs */
         if (cpus_equal(mask, allbutself) &&
             cpus_equal(cpu_online_map, cpu_callout_map))
                 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)
-                while (atomic_read(&data.finished) != cpus)
-                        cpu_relax();
-        spin_unlock(&call_lock);
-
-        return 0;
 }
 
 static void stop_this_cpu(void *dummy)
@@ -268,18 +159,13 @@ static void stop_this_cpu(void *dummy)
 
 static void native_smp_send_stop(void)
 {
-        int nolock;
         unsigned long flags;
 
         if (reboot_force)
                 return;
 
-        /* Don't deadlock on the call lock in panic */
-        nolock = !spin_trylock(&call_lock);
+        smp_call_function(stop_this_cpu, NULL, 0, 0);
         local_irq_save(flags);
-        __smp_call_function(stop_this_cpu, NULL, 0, 0);
-        if (!nolock)
-                spin_unlock(&call_lock);
         disable_local_APIC();
         local_irq_restore(flags);
 }
@@ -301,33 +187,28 @@ void smp_reschedule_interrupt(struct pt_regs *regs)
 
 void smp_call_function_interrupt(struct pt_regs *regs)
 {
-        void (*func) (void *info) = call_data->func;
-        void *info = call_data->info;
-        int wait = call_data->wait;
-
         ack_APIC_irq();
-        /*
-         * Notify initiating CPU that I've grabbed the data and am
-         * about to execute the function
-         */
-        mb();
-        atomic_inc(&call_data->started);
-        /*
-         * At this point the info structure may be out of scope unless wait==1
-         */
         irq_enter();
-        (*func)(info);
+        generic_smp_call_function_interrupt();
 #ifdef CONFIG_X86_32
         __get_cpu_var(irq_stat).irq_call_count++;
 #else
         add_pda(irq_call_count, 1);
 #endif
         irq_exit();
+}
 
-        if (wait) {
-                mb();
-                atomic_inc(&call_data->finished);
-        }
+void smp_call_function_single_interrupt(void)
+{
+        ack_APIC_irq();
+        irq_enter();
+        generic_smp_call_function_single_interrupt();
+#ifdef CONFIG_X86_32
+        __get_cpu_var(irq_stat).irq_call_count++;
+#else
+        add_pda(irq_call_count, 1);
+#endif
+        irq_exit();
 }
 
 struct smp_ops smp_ops = {
@@ -338,7 +219,8 @@ struct smp_ops smp_ops = {
 
         .smp_send_stop = native_smp_send_stop,
         .smp_send_reschedule = native_smp_send_reschedule,
-        .smp_call_function_mask = native_smp_call_function_mask,
+
+        .send_call_func_ipi = native_send_call_func_ipi,
+        .send_call_func_single_ipi = native_send_call_func_single_ipi,
 };
 EXPORT_SYMBOL_GPL(smp_ops);
-
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index 56078d61c793..89647898f546 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -345,7 +345,7 @@ static void __cpuinit start_secondary(void *unused)
          * lock helps us to not include this cpu in a currently in progress
          * smp_call_function().
          */
-        lock_ipi_call_lock();
+        ipi_call_lock_irq();
 #ifdef CONFIG_X86_64
         spin_lock(&vector_lock);
 
@@ -357,7 +357,7 @@ static void __cpuinit start_secondary(void *unused)
         spin_unlock(&vector_lock);
 #endif
         cpu_set(smp_processor_id(), cpu_online_map);
-        unlock_ipi_call_lock();
+        ipi_call_unlock_irq();
         per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
 
         setup_secondary_clock();
diff --git a/arch/x86/kernel/smpcommon.c b/arch/x86/kernel/smpcommon.c
index 3449064d141a..99941b37eca0 100644
--- a/arch/x86/kernel/smpcommon.c
+++ b/arch/x86/kernel/smpcommon.c
@@ -25,59 +25,3 @@ __cpuinit void init_gdt(int cpu)
         per_cpu(cpu_number, cpu) = cpu;
 }
 #endif
-
-/**
- * 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: Unused.
- * @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(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 a specific 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: Unused.
- * @wait: If true, wait 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.
- */
-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) {
-                local_irq_disable();
-                func(info);
-                local_irq_enable();
-                put_cpu();
-                return 0;
-        }
-
-        ret = smp_call_function_mask(cpumask_of_cpu(cpu), func, info, wait);
-
-        put_cpu();
-        return ret;
-}
-EXPORT_SYMBOL(smp_call_function_single);