Add SMP helper functions for clockevents support

This patch adds the smp_call_function_single and smp_timer_broadcast
functions and modifies ipi_timer to call the platform-specific function
local_timer_interrupt.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

arch/arm/kernel/smp.c

@@ -454,6 +454,27 @@ int smp_call_function(void (*func)(void *info), void *info, int retry,
 }
 EXPORT_SYMBOL_GPL(smp_call_function);
 
+int smp_call_function_single(int cpu, void (*func)(void *info), void *info,
+			     int retry, int wait)
+{
+	/* prevent preemption and reschedule on another processor */
+	int current_cpu = get_cpu();
+	int ret = 0;
+
+	if (cpu == current_cpu) {
+		local_irq_disable();
+		func(info);
+		local_irq_enable();
+	} else
+		ret = smp_call_function_on_cpu(func, info, retry, wait,
+					       cpumask_of_cpu(cpu));
+
+	put_cpu();
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_function_single);
+
 void show_ipi_list(struct seq_file *p)
 {
 	unsigned int cpu;
@@ -481,8 +502,7 @@ void show_local_irqs(struct seq_file *p)
 static void ipi_timer(void)
 {
 	irq_enter();
-	profile_tick(CPU_PROFILING);
-	update_process_times(user_mode(get_irq_regs()));
+	local_timer_interrupt();
 	irq_exit();
 }
 
@@ -621,6 +641,11 @@ void smp_send_timer(void)
 	send_ipi_message(mask, IPI_TIMER);
 }
 
+void smp_timer_broadcast(cpumask_t mask)
+{
+	send_ipi_message(mask, IPI_TIMER);
+}
+
 void smp_send_stop(void)
 {
 	cpumask_t mask = cpu_online_map;

include/asm-arm/smp.h

@@ -60,6 +60,11 @@ extern void smp_cross_call(cpumask_t callmap);
  */
 extern void smp_send_timer(void);
 
+/*
+ * Broadcast a clock event to other CPUs.
+ */
+extern void smp_timer_broadcast(cpumask_t mask);
+
 /*
  * Boot a secondary CPU, and assign it the specified idle task.
  * This also gives us the initial stack to use for this CPU.
@@ -96,6 +101,11 @@ extern void platform_cpu_die(unsigned int cpu);
 extern int platform_cpu_kill(unsigned int cpu);
 extern void platform_cpu_enable(unsigned int cpu);
 
+/*
+ * Local timer interrupt handling function (can be IPI'ed).
+ */
+extern void local_timer_interrupt(void);
+
 #ifdef CONFIG_LOCAL_TIMERS
 /*
  * Setup a local timer interrupt for a CPU.