add new system file

hc

2024-02-20 102a0743326a03cd1a1202ceda21e175b7d3575c

 kernel/arch/arm/kernel/smp.c
..
..
@@ -675,7 +675,9 @@
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 		break;
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 	case IPI_CPU_BACKTRACE:
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+		printk_nmi_enter();
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 		nmi_cpu_backtrace(get_irq_regs());
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+		printk_nmi_exit();
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 		break;
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 	default: