arm64: fix calling nmi_enter() repeatedly when IPI_CPU_CRASH_STOP

hulk inclusion
category: bugfix
bugzilla: 28145
CVE: NA

-------------------------------------------------

The nmi_enter() may has been called in el1_irq. When processing
IPI_CPU_CRASH_STOP in handle_IPI(), don't call nmi_enter() again if
interrupt is disabled (already in NMI context).

Fixes: e753aae7e448 ("arm64: Fix interrupt tracing in the presence of NMIs")
Signed-off-by: NWei Li <liwei391@huawei.com>
Reviewed-by: NHanjun Guo <guohanjun@huawei.com>
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

arch/arm64/kernel/smp.c

@@ -924,9 +924,10 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
 
 	case IPI_CPU_CRASH_STOP:
 		if (IS_ENABLED(CONFIG_KEXEC_CORE)) {
-			if (gic_supports_pseudo_nmis())
-				nmi_enter();
-			else
+			if (gic_supports_pseudo_nmis()) {
+				if (irqs_enabled)
+					nmi_enter();
+			} else
 				irq_enter();
 			ipi_cpu_crash_stop(cpu, regs);