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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dengcheng Zhu <dzhu@wavecomp.com>,
        Paul Burton <paul.burton@mips.com>, pburton@wavecomp.com,
        ralf@linux-mips.org, linux-mips@linux-mips.org,
        rachel.mozes@intel.com, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.9 07/83] MIPS: kexec: Mark CPU offline before disabling local IRQ
Date:   Mon, 19 Nov 2018 17:28:33 +0100
Message-Id: <20181119162613.458371436@linuxfoundation.org>
In-Reply-To: <20181119162612.046511542@linuxfoundation.org>
References: <20181119162612.046511542@linuxfoundation.org>
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4.9-stable review patch.  If anyone has any objections, please let me know.

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

From: Dengcheng Zhu <dzhu@wavecomp.com>

[ Upstream commit dc57aaf95a516f70e2d527d8287a0332c481a226 ]

After changing CPU online status, it will not be sent any IPIs such as in
__flush_cache_all() on software coherency systems. Do this before disabling
local IRQ.

Signed-off-by: Dengcheng Zhu <dzhu@wavecomp.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
Patchwork: https://patchwork.linux-mips.org/patch/20571/
Cc: pburton@wavecomp.com
Cc: ralf@linux-mips.org
Cc: linux-mips@linux-mips.org
Cc: rachel.mozes@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/mips/kernel/crash.c         |    3 +++
 arch/mips/kernel/machine_kexec.c |    3 +++
 2 files changed, 6 insertions(+)

--- a/arch/mips/kernel/crash.c
+++ b/arch/mips/kernel/crash.c
@@ -34,6 +34,9 @@ static void crash_shutdown_secondary(voi
 	if (!cpu_online(cpu))
 		return;
 
+	/* We won't be sent IPIs any more. */
+	set_cpu_online(cpu, false);
+
 	local_irq_disable();
 	if (!cpumask_test_cpu(cpu, &cpus_in_crash))
 		crash_save_cpu(regs, cpu);
--- a/arch/mips/kernel/machine_kexec.c
+++ b/arch/mips/kernel/machine_kexec.c
@@ -96,6 +96,9 @@ machine_kexec(struct kimage *image)
 			*ptr = (unsigned long) phys_to_virt(*ptr);
 	}
 
+	/* Mark offline BEFORE disabling local irq. */
+	set_cpu_online(smp_processor_id(), false);
+
 	/*
 	 * we do not want to be bothered.
 	 */