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-rw-r--r--arch/powerpc/kernel/smp.c49
1 files changed, 42 insertions, 7 deletions
diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index e16ec7b3b427..9ca7148b5881 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -566,10 +566,35 @@ 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 nmi_stop_this_cpu(struct pt_regs *regs)
+{
+ /*
+ * This is a special case because it never returns, so the NMI IPI
+ * handling would never mark it as done, which makes any later
+ * smp_send_nmi_ipi() call spin forever. Mark it done now.
+ *
+ * IRQs are already hard disabled by the smp_handle_nmi_ipi.
+ */
+ nmi_ipi_lock();
+ nmi_ipi_busy_count--;
+ nmi_ipi_unlock();
+
+ /* Remove this CPU */
+ set_cpu_online(smp_processor_id(), false);
+
+ spin_begin();
+ while (1)
+ spin_cpu_relax();
+}
+
+void smp_send_stop(void)
+{
+ smp_send_nmi_ipi(NMI_IPI_ALL_OTHERS, nmi_stop_this_cpu, 1000000);
+}
+
+#else /* CONFIG_NMI_IPI */
+
static void stop_this_cpu(void *dummy)
-#endif
{
/* Remove this CPU */
set_cpu_online(smp_processor_id(), false);
@@ -582,12 +607,22 @@ 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
+ static bool stopped = false;
+
+ /*
+ * Prevent waiting on csd lock from a previous smp_send_stop.
+ * This is racy, but in general callers try to do the right
+ * thing and only fire off one smp_send_stop (e.g., see
+ * kernel/panic.c)
+ */
+ if (stopped)
+ return;
+
+ stopped = true;
+
smp_call_function(stop_this_cpu, NULL, 0);
-#endif
}
+#endif /* CONFIG_NMI_IPI */
struct thread_info *current_set[NR_CPUS];