From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Subject: [PATCH v2 1/3] powerpc: use NMI IPI for smp_send_stop
Date: Sun, 1 Apr 2018 20:36:13 +1000 [thread overview]
Message-ID: <20180401103615.15454-2-npiggin@gmail.com> (raw)
In-Reply-To: <20180401103615.15454-1-npiggin@gmail.com>
Use the NMI IPI rather than smp_call_function for smp_send_stop.
Have stopped CPUs hard disable interrupts rather than just soft
disable.
This function is used in crash/panic/shutdown paths to bring other
CPUs down as quickly and reliably as possible, and minimizing their
potential to cause trouble.
Avoiding the Linux smp_call_function infrastructure and (if supported)
using true NMI IPIs makes this more robust.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/kernel/smp.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index cfc08b099c49..db88660bf6bd 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -565,7 +565,11 @@ void crash_send_ipi(void (*crash_ipi_callback)(struct pt_regs *))
}
#endif
+#ifdef CONFIG_NMI_IPI
+static void stop_this_cpu(struct pt_regs *regs)
+#else
static void stop_this_cpu(void *dummy)
+#endif
{
/* Remove this CPU */
set_cpu_online(smp_processor_id(), false);
@@ -577,7 +581,11 @@ static void stop_this_cpu(void *dummy)
void smp_send_stop(void)
{
+#ifdef CONFIG_NMI_IPI
+ smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, stop_this_cpu, 1000000);
+#else
smp_call_function(stop_this_cpu, NULL, 0);
+#endif
}
struct thread_info *current_set[NR_CPUS];
--
2.16.3
next prev parent reply other threads:[~2018-04-01 10:36 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-01 10:36 [PATCH 0/3] stop secondaries for reboot/shutdown Nicholas Piggin
2018-04-01 10:36 ` Nicholas Piggin [this message]
2018-04-03 0:13 ` [PATCH v2 1/3] powerpc: use NMI IPI for smp_send_stop Balbir Singh
2018-04-03 2:35 ` Nicholas Piggin
2018-04-04 14:39 ` [v2,1/3] " Michael Ellerman
2018-04-01 10:36 ` [PATCH v2 2/3] powerpc: hard disable irqs in smp_send_stop loop Nicholas Piggin
2018-04-01 10:36 ` [PATCH v2 3/3] powerpc/powernv: Always stop secondaries before reboot/shutdown Nicholas Piggin
2018-04-03 4:36 ` Vasant Hegde
2018-04-02 14:52 ` [PATCH 0/3] stop secondaries for reboot/shutdown ppaidipe
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