x86/ipi: Make platform IPI depend on APIC

The platform IPI vector is only installed when the local APIC is enabled. All
users of it depend on the local APIC anyway.

Make the related code conditional on CONFIG_X86_LOCAL_APIC=y.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170828064957.615286163@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/include/asm/entry_arch.h

@@ -17,8 +17,6 @@ BUILD_INTERRUPT(irq_move_cleanup_interrupt, IRQ_MOVE_CLEANUP_VECTOR)
 BUILD_INTERRUPT(reboot_interrupt, REBOOT_VECTOR)
 #endif
 
-BUILD_INTERRUPT(x86_platform_ipi, X86_PLATFORM_IPI_VECTOR)
-
 #ifdef CONFIG_HAVE_KVM
 BUILD_INTERRUPT(kvm_posted_intr_ipi, POSTED_INTR_VECTOR)
 BUILD_INTERRUPT(kvm_posted_intr_wakeup_ipi, POSTED_INTR_WAKEUP_VECTOR)
@@ -37,6 +35,7 @@ BUILD_INTERRUPT(kvm_posted_intr_nested_ipi, POSTED_INTR_NESTED_VECTOR)
 BUILD_INTERRUPT(apic_timer_interrupt,LOCAL_TIMER_VECTOR)
 BUILD_INTERRUPT(error_interrupt,ERROR_APIC_VECTOR)
 BUILD_INTERRUPT(spurious_interrupt,SPURIOUS_APIC_VECTOR)
+BUILD_INTERRUPT(x86_platform_ipi, X86_PLATFORM_IPI_VECTOR)
 
 #ifdef CONFIG_IRQ_WORK
 BUILD_INTERRUPT(irq_work_interrupt, IRQ_WORK_VECTOR)

arch/x86/kernel/irq.c

@@ -29,9 +29,6 @@ EXPORT_PER_CPU_SYMBOL(irq_regs);
 
 atomic_t irq_err_count;
 
-/* Function pointer for generic interrupt vector handling */
-void (*x86_platform_ipi_callback)(void) = NULL;
-
 /*
  * 'what should we do if we get a hw irq event on an illegal vector'.
  * each architecture has to answer this themselves.
@@ -87,13 +84,13 @@ int arch_show_interrupts(struct seq_file *p, int prec)
 	for_each_online_cpu(j)
 		seq_printf(p, "%10u ", irq_stats(j)->icr_read_retry_count);
 	seq_puts(p, "  APIC ICR read retries\n");
-#endif
 	if (x86_platform_ipi_callback) {
 		seq_printf(p, "%*s: ", prec, "PLT");
 		for_each_online_cpu(j)
 			seq_printf(p, "%10u ", irq_stats(j)->x86_platform_ipis);
 		seq_puts(p, "  Platform interrupts\n");
 	}
+#endif
 #ifdef CONFIG_SMP
 	seq_printf(p, "%*s: ", prec, "RES");
 	for_each_online_cpu(j)
@@ -183,9 +180,9 @@ u64 arch_irq_stat_cpu(unsigned int cpu)
 	sum += irq_stats(cpu)->apic_perf_irqs;
 	sum += irq_stats(cpu)->apic_irq_work_irqs;
 	sum += irq_stats(cpu)->icr_read_retry_count;
-#endif
 	if (x86_platform_ipi_callback)
 		sum += irq_stats(cpu)->x86_platform_ipis;
+#endif
 #ifdef CONFIG_SMP
 	sum += irq_stats(cpu)->irq_resched_count;
 	sum += irq_stats(cpu)->irq_call_count;
@@ -259,6 +256,9 @@ __visible unsigned int __irq_entry do_IRQ(struct pt_regs *regs)
 	return 1;
 }
 
+#ifdef CONFIG_X86_LOCAL_APIC
+/* Function pointer for generic interrupt vector handling */
+void (*x86_platform_ipi_callback)(void) = NULL;
 /*
  * Handler for X86_PLATFORM_IPI_VECTOR.
  */
@@ -275,6 +275,7 @@ __visible void __irq_entry smp_x86_platform_ipi(struct pt_regs *regs)
 	exiting_irq();
 	set_irq_regs(old_regs);
 }
+#endif
 
 #ifdef CONFIG_HAVE_KVM
 static void dummy_handler(void) {}