linux-kernel - [PATCH 7/8] RISC-V: Comment on the TLB flush in smp

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Date:   Mon, 27 Aug 2018 11:42:42 -0700
From:   Palmer Dabbelt <palmer@...ive.com>
To:      linux-riscv@...ts.infradead.org
Cc:     Palmer Dabbelt <palmer@...ive.com>, aou@...s.berkeley.edu,
        daniel.lezcano@...aro.org, tglx@...utronix.de,
        jason@...edaemon.net, marc.zyngier@....com, atish.patra@....com,
        dmitriy@...-tech.org, catalin.marinas@....com,
        ard.biesheuvel@...aro.org, Greg KH <gregkh@...uxfoundation.org>,
        jeremy.linton@....com, linux-riscv@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 7/8] RISC-V: Comment on the TLB flush in smp_callin()

This isn't readily apparent from reading the code.

Signed-off-by: Palmer Dabbelt <palmer@...ive.com>
---
 arch/riscv/kernel/smpboot.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c
index 5437a04babcd..953bc540207d 100644
--- a/arch/riscv/kernel/smpboot.c
+++ b/arch/riscv/kernel/smpboot.c
@@ -107,6 +107,8 @@ 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();
-- 
2.16.4