arm64: Kill __smp_cross_call and co

The old IPI registration interface is now unused on arm64, so let's
get rid of it.
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/irq_work.h

@@ -2,11 +2,9 @@
 #ifndef __ASM_IRQ_WORK_H
 #define __ASM_IRQ_WORK_H
 
-#include <asm/smp.h>
-
 static inline bool arch_irq_work_has_interrupt(void)
 {
-	return !!__smp_cross_call;
+	return true;
 }
 
 #endif /* __ASM_IRQ_WORK_H */

arch/arm64/include/asm/smp.h

@@ -60,24 +60,12 @@ struct seq_file;
  */
 extern void show_ipi_list(struct seq_file *p, int prec);
 
-/*
- * Called from C code, this handles an IPI.
- */
-extern void handle_IPI(int ipinr, struct pt_regs *regs);
-
 /*
  * Discover the set of possible CPUs and determine their
  * SMP operations.
  */
 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));
-
-extern void (*__smp_cross_call)(const struct cpumask *, unsigned int);
-
 /*
  * Register IPI interrupts with the arch SMP code
  */

arch/arm64/kernel/smp.c

@@ -782,13 +782,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	}
 }
 
-void (*__smp_cross_call)(const struct cpumask *, unsigned int);
-
-void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
-{
-	__smp_cross_call = fn;
-}
-
 static const char *ipi_types[NR_IPI] __tracepoint_string = {
 #define S(x,s)	[x] = s
 	S(IPI_RESCHEDULE, "Rescheduling interrupts"),
@@ -800,11 +793,7 @@ static const char *ipi_types[NR_IPI] __tracepoint_string = {
 	S(IPI_WAKEUP, "CPU wake-up interrupts"),
 };
 
-static void smp_cross_call(const struct cpumask *target, unsigned int ipinr)
-{
-	trace_ipi_raise(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)
 {
@@ -851,7 +840,6 @@ void arch_send_wakeup_ipi_mask(const struct cpumask *mask)
 #ifdef CONFIG_IRQ_WORK
 void arch_irq_work_raise(void)
 {
-	if (__smp_cross_call)
 	smp_cross_call(cpumask_of(smp_processor_id()), IPI_IRQ_WORK);
 }
 #endif
@@ -959,34 +947,23 @@ static void do_handle_IPI(int ipinr)
 		trace_ipi_exit_rcuidle(ipi_types[ipinr]);
 }
 
-/* Legacy version, should go away once all irqchips have been converted */
-void handle_IPI(int ipinr, struct pt_regs *regs)
-{
-	struct pt_regs *old_regs = set_irq_regs(regs);
-
-	irq_enter();
-	do_handle_IPI(ipinr);
-	irq_exit();
-
-	set_irq_regs(old_regs);
-}
-
 static irqreturn_t ipi_handler(int irq, void *data)
 {
 	do_handle_IPI(irq - ipi_irq_base);
 	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(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++)
@@ -997,7 +974,7 @@ 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++)
@@ -1023,7 +1000,6 @@ void __init set_smp_ipi_range(int ipi_base, int n)
 	}
 
 	ipi_irq_base = ipi_base;
-	__smp_cross_call = ipi_send;
 
 	/* Setup the boot CPU immediately */
 	ipi_setup(smp_processor_id());