RISC-V: Comment on the TLB flush in smp_callin()

palmer-dabbelt · palmer-dabbelt · commit b18d6f05252d · 2018-10-22T17:03:36.000-07:00
This isn't readily apparent from reading the code.

Signed-off-by: Palmer Dabbelt &lt;palmer@sifive.com&gt;
[Atish: code comment formatting update]
Signed-off-by: Atish Patra &lt;atish.patra@wdc.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Signed-off-by: Palmer Dabbelt &lt;palmer@sifive.com&gt;
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
@@ -106,6 +106,10 @@ asmlinkage void __init smp_callin(void)
 	trap_init();
 	notify_cpu_starting(smp_processor_id());
 	set_cpu_online(smp_processor_id(), 1);
+	/*
+	 * Remote TLB flushes are ignored while the CPU is offline, so emit
+	 * a local TLB flush right now just in case.
+	 */
 	local_flush_tlb_all();
 	local_irq_enable();
 	preempt_disable();
