[PATCH] riscv: don't stop itself in smp_send_stop

From: Andreas Schwab <schwab@suse.de>
To: linux-riscv@lists.infradead.org
Subject: [PATCH] riscv: don't stop itself in smp_send_stop
Date: Thu, 29 Nov 2018 17:32:03 +0100	[thread overview]
Message-ID: <mvmbm67etfg.fsf@suse.de> (raw)

Only run ipi_stop on other cpus, not itself.  Don't wait for ipi_stop to
return, since it never does.  Also, mark each cpu offline.

Signed-off-by: Andreas Schwab <schwab@suse.de>
---
 arch/riscv/kernel/smp.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/smp.c b/arch/riscv/kernel/smp.c
index 57b1383e5e..5c6bb5fe5a 100644
--- a/arch/riscv/kernel/smp.c
+++ b/arch/riscv/kernel/smp.c
@@ -23,6 +23,7 @@
 #include <linux/smp.h>
 #include <linux/sched.h>
 #include <linux/seq_file.h>
+#include <linux/delay.h>
 
 #include <asm/sbi.h>
 #include <asm/tlbflush.h>
@@ -148,13 +149,27 @@ void arch_send_call_function_single_ipi(int cpu)
 
 static void ipi_stop(void *unused)
 {
+	set_cpu_online (smp_processor_id(), false);
 	while (1)
 		wait_for_interrupt();
 }
 
 void smp_send_stop(void)
 {
-	on_each_cpu(ipi_stop, NULL, 1);
+	unsigned long timeout;
+	struct cpumask mask;
+
+	cpumask_copy (&mask, cpu_online_mask);
+	cpumask_clear_cpu (smp_processor_id (), &mask);
+	on_each_cpu_mask(&mask, ipi_stop, NULL, 0);
+
+	/* Wait up to one second for other CPUs to stop */
+	timeout = USEC_PER_SEC;
+	while (num_online_cpus() > 1 && timeout--)
+		udelay(1);
+
+	if (num_online_cpus() > 1)
+		pr_warn("SMP: failed to stop secondary CPUs\n");
 }
 
 void smp_send_reschedule(int cpu)
-- 
2.19.2


-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
GPG Key fingerprint = 0196 BAD8 1CE9 1970 F4BE  1748 E4D4 88E3 0EEA B9D7
"And now for something completely different."

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