arm: turn off cpu on panic

Since interrupts are disabled on panic, linux cannot reset a
panic'd core when NMI are disabled (for e.g. mcreboot/mcstop)

Just always offline it, so linux can get it back

Change-Id: If8107172375f2924e02bd4c36e24645ec38a8999

arch/arm64/kernel/cpu.c

@@ -1274,7 +1274,7 @@ void ihk_mc_delay_us(int us)
 	arch_delay(us);
 }
 
-void arch_print_stack()
+void arch_print_stack(void)
 {
 }
 
@@ -1310,6 +1310,11 @@ void arch_show_interrupt_context(const void *reg)
 	kprintf("  syscallno : %016lx\n", regs->syscallno);
 }
 
+void arch_cpu_stop(void)
+{
+	psci_cpu_off();
+}
+
 /*@
   @ behavior fs_base:
   @   assumes type == IHK_ASR_X86_FS;

arch/x86_64/kernel/cpu.c

@@ -1551,7 +1551,8 @@ void arch_print_pre_interrupt_stack(const struct x86_basic_regs *regs) {
 	__print_stack(rbp, regs->rip);
 }
 
-void arch_print_stack() {
+void arch_print_stack(void)
+{
 	struct stack *rbp;
 
 	__kprintf("Approximative stack trace:\n");
@@ -1599,6 +1600,13 @@ return;
 	kprintf_unlock(irqflags);
 }
 
+void arch_cpu_stop(void)
+{
+	while (1) {
+		cpu_halt();
+	}
+}
+
 /*@
   @ behavior fs_base:
   @   assumes type == IHK_ASR_X86_FS;

lib/abort.c

@@ -4,8 +4,9 @@
 #include <ihk/monitor.h>
 
 extern struct cpu_local_var *clv;
-extern void eventfd(int type);
+void eventfd(int type);
-extern void arch_print_stack();
+void arch_print_stack(void);
+void arch_cpu_stop(void);
 
 void panic(const char *msg)
 {
@@ -21,6 +22,9 @@ void panic(const char *msg)
 
 	arch_print_stack();
 
+	/* do not assume anything after this is executed */
+	arch_cpu_stop();
+
 	while (1) {
 		cpu_halt();
 	}