v4.19.13 snapshot.
diff --git a/arch/mips/kernel/smp-cmp.c b/arch/mips/kernel/smp-cmp.c
new file mode 100644
index 0000000..a232200
--- /dev/null
+++ b/arch/mips/kernel/smp-cmp.c
@@ -0,0 +1,159 @@
+/*
+ *  This program is free software; you can distribute it and/or modify it
+ *  under the terms of the GNU General Public License (Version 2) as
+ *  published by the Free Software Foundation.
+ *
+ *  This program is distributed in the hope it will be useful, but WITHOUT
+ *  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ *  FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ *  for more details.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  59 Temple Place - Suite 330, Boston MA 02111-1307, USA.
+ *
+ * Copyright (C) 2007 MIPS Technologies, Inc.
+ *    Chris Dearman (chris@mips.com)
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/sched/task_stack.h>
+#include <linux/smp.h>
+#include <linux/cpumask.h>
+#include <linux/interrupt.h>
+#include <linux/compiler.h>
+
+#include <linux/atomic.h>
+#include <asm/cacheflush.h>
+#include <asm/cpu.h>
+#include <asm/processor.h>
+#include <asm/hardirq.h>
+#include <asm/mmu_context.h>
+#include <asm/smp.h>
+#include <asm/time.h>
+#include <asm/mipsregs.h>
+#include <asm/mipsmtregs.h>
+#include <asm/mips_mt.h>
+#include <asm/amon.h>
+
+static void cmp_init_secondary(void)
+{
+	struct cpuinfo_mips *c __maybe_unused = &current_cpu_data;
+
+	/* Assume GIC is present */
+	change_c0_status(ST0_IM, STATUSF_IP2 | STATUSF_IP3 | STATUSF_IP4 |
+				 STATUSF_IP5 | STATUSF_IP6 | STATUSF_IP7);
+
+	/* Enable per-cpu interrupts: platform specific */
+
+#ifdef CONFIG_MIPS_MT_SMP
+	if (cpu_has_mipsmt)
+		cpu_set_vpe_id(c, (read_c0_tcbind() >> TCBIND_CURVPE_SHIFT) &
+				  TCBIND_CURVPE);
+#endif
+}
+
+static void cmp_smp_finish(void)
+{
+	pr_debug("SMPCMP: CPU%d: %s\n", smp_processor_id(), __func__);
+
+	/* CDFIXME: remove this? */
+	write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency / HZ));
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+	/* If we have an FPU, enroll ourselves in the FPU-full mask */
+	if (cpu_has_fpu)
+		cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask);
+#endif /* CONFIG_MIPS_MT_FPAFF */
+
+	local_irq_enable();
+}
+
+/*
+ * Setup the PC, SP, and GP of a secondary processor and start it running
+ * smp_bootstrap is the place to resume from
+ * __KSTK_TOS(idle) is apparently the stack pointer
+ * (unsigned long)idle->thread_info the gp
+ */
+static int cmp_boot_secondary(int cpu, struct task_struct *idle)
+{
+	struct thread_info *gp = task_thread_info(idle);
+	unsigned long sp = __KSTK_TOS(idle);
+	unsigned long pc = (unsigned long)&smp_bootstrap;
+	unsigned long a0 = 0;
+
+	pr_debug("SMPCMP: CPU%d: %s cpu %d\n", smp_processor_id(),
+		__func__, cpu);
+
+#if 0
+	/* Needed? */
+	flush_icache_range((unsigned long)gp,
+			   (unsigned long)(gp + sizeof(struct thread_info)));
+#endif
+
+	amon_cpu_start(cpu, pc, sp, (unsigned long)gp, a0);
+	return 0;
+}
+
+/*
+ * Common setup before any secondaries are started
+ */
+void __init cmp_smp_setup(void)
+{
+	int i;
+	int ncpu = 0;
+
+	pr_debug("SMPCMP: CPU%d: %s\n", smp_processor_id(), __func__);
+
+#ifdef CONFIG_MIPS_MT_FPAFF
+	/* If we have an FPU, enroll ourselves in the FPU-full mask */
+	if (cpu_has_fpu)
+		cpumask_set_cpu(0, &mt_fpu_cpumask);
+#endif /* CONFIG_MIPS_MT_FPAFF */
+
+	for (i = 1; i < NR_CPUS; i++) {
+		if (amon_cpu_avail(i)) {
+			set_cpu_possible(i, true);
+			__cpu_number_map[i]	= ++ncpu;
+			__cpu_logical_map[ncpu] = i;
+		}
+	}
+
+	if (cpu_has_mipsmt) {
+		unsigned int nvpe = 1;
+#ifdef CONFIG_MIPS_MT_SMP
+		unsigned int mvpconf0 = read_c0_mvpconf0();
+
+		nvpe = ((mvpconf0 & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
+#endif
+		smp_num_siblings = nvpe;
+	}
+	pr_info("Detected %i available secondary CPU(s)\n", ncpu);
+}
+
+void __init cmp_prepare_cpus(unsigned int max_cpus)
+{
+	pr_debug("SMPCMP: CPU%d: %s max_cpus=%d\n",
+		 smp_processor_id(), __func__, max_cpus);
+
+#ifdef CONFIG_MIPS_MT
+	/*
+	 * FIXME: some of these options are per-system, some per-core and
+	 * some per-cpu
+	 */
+	mips_mt_set_cpuoptions();
+#endif
+
+}
+
+const struct plat_smp_ops cmp_smp_ops = {
+	.send_ipi_single	= mips_smp_send_ipi_single,
+	.send_ipi_mask		= mips_smp_send_ipi_mask,
+	.init_secondary		= cmp_init_secondary,
+	.smp_finish		= cmp_smp_finish,
+	.boot_secondary		= cmp_boot_secondary,
+	.smp_setup		= cmp_smp_setup,
+	.prepare_cpus		= cmp_prepare_cpus,
+};