ARM: Kill __smp_cross_call and co

The old IPI registration interface is now unused on arm, so let's
get rid of it.
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm/include/asm/smp.h

@@ -39,12 +39,6 @@ void handle_IPI(int ipinr, struct pt_regs *regs);
  */
 extern void smp_init_cpus(void);
 
-
-/*
- * Provide a function to raise an IPI cross call on CPUs in callmap.
- */
-extern void set_smp_cross_call(void (*)(const struct cpumask *, unsigned int));
-
 /*
  * Register IPI interrupts with the arch SMP code
  */

arch/arm/kernel/smp.c

@@ -511,14 +511,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-static void (*__smp_cross_call)(const struct cpumask *, unsigned int);
-
-void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
-{
-	if (!__smp_cross_call)
-		__smp_cross_call = fn;
-}
-
 static const char *ipi_types[NR_IPI] __tracepoint_string = {
 #define S(x,s)	[x] = s
 	S(IPI_WAKEUP, "CPU wakeup interrupts"),
@@ -530,11 +522,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = {
 	S(IPI_COMPLETION, "completion interrupts"),
 };
 
-static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
-{
-	trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
-	__smp_cross_call(target, ipinr);
-}
+static void smp_cross_call(const struct cpumask *target, unsigned int ipinr);
 
 void show_ipi_list(struct seq_file *p, int prec)
 {
@@ -713,16 +701,17 @@ static irqreturn_t ipi_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
-static void ipi_send(const struct cpumask *target, unsigned int ipi)
+static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
 {
-	__ipi_send_mask(ipi_desc[ipi], target);
+	trace_ipi_raise_rcuidle(target, ipi_types[ipinr]);
+	__ipi_send_mask(ipi_desc[ipinr], target);
 }
 
 static void ipi_setup(int cpu)
 {
 	int i;
 
-	if (!ipi_irq_base)
+	if (WARN_ON_ONCE(!ipi_irq_base))
 		return;
 
 	for (i = 0; i < nr_ipi; i++)
@@ -733,7 +722,7 @@ static void ipi_teardown(int cpu)
 {
 	int i;
 
-	if (!ipi_irq_base)
+	if (WARN_ON_ONCE(!ipi_irq_base))
 		return;
 
 	for (i = 0; i < nr_ipi; i++)
@@ -759,7 +748,6 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	}
 
 	ipi_irq_base = ipi_base;
-	set_smp_cross_call(ipi_send);
 
 	/* Setup the boot CPU immediately */
 	ipi_setup(smp_processor_id());
@@ -872,7 +860,7 @@ core_initcall(register_cpufreq_notifier);
 
 static void raise_nmi(cpumask_t *mask)
 {
-	__smp_cross_call(mask, IPI_CPU_BACKTRACE);
+	__ipi_send_mask(ipi_desc[IPI_CPU_BACKTRACE], mask);
 }
 
 void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)