1 files changed, 330 insertions, 0 deletions
diff --git a/arch/openrisc/kernel/smp.c b/arch/openrisc/kernel/smp.c
new file mode 100644
index 000000000..e1419095a
--- /dev/null
+++ b/arch/openrisc/kernel/smp.c
@@ -0,0 +1,330 @@
+/*
+ * Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
+ * Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
+ *
+ * Based on arm64 and arc implementations
+ * Copyright (C) 2013 ARM Ltd.
+ * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/smp.h>
+#include <linux/cpu.h>
+#include <linux/sched.h>
+#include <linux/sched/mm.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <asm/cpuinfo.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+#include <asm/time.h>
+
+static void (*smp_cross_call)(const struct cpumask *, unsigned int);
+
+unsigned long secondary_release = -1;
+struct thread_info *secondary_thread_info;
+
+enum ipi_msg_type {
+	IPI_WAKEUP,
+	IPI_RESCHEDULE,
+	IPI_CALL_FUNC,
+	IPI_CALL_FUNC_SINGLE,
+};
+
+static DEFINE_SPINLOCK(boot_lock);
+
+static void boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	/*
+	 * set synchronisation state between this boot processor
+	 * and the secondary one
+	 */
+	spin_lock(&boot_lock);
+
+	secondary_release = cpu;
+	smp_cross_call(cpumask_of(cpu), IPI_WAKEUP);
+
+	/*
+	 * now the secondary core is starting up let it run its
+	 * calibrations, then wait for it to finish
+	 */
+	spin_unlock(&boot_lock);
+}
+
+void __init smp_prepare_boot_cpu(void)
+{
+}
+
+void __init smp_init_cpus(void)
+{
+	struct device_node *cpu;
+	u32 cpu_id;
+
+	for_each_of_cpu_node(cpu) {
+		cpu_id = of_get_cpu_hwid(cpu, 0);
+		if (cpu_id < NR_CPUS)
+			set_cpu_possible(cpu_id, true);
+	}
+}
+
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+	unsigned int cpu;
+
+	/*
+	 * Initialise the present map, which describes the set of CPUs
+	 * actually populated at the present time.
+	 */
+	for_each_possible_cpu(cpu) {
+		if (cpu < max_cpus)
+			set_cpu_present(cpu, true);
+	}
+}
+
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+}
+
+static DECLARE_COMPLETION(cpu_running);
+
+int __cpu_up(unsigned int cpu, struct task_struct *idle)
+{
+	if (smp_cross_call == NULL) {
+		pr_warn("CPU%u: failed to start, IPI controller missing",
+			cpu);
+		return -EIO;
+	}
+
+	secondary_thread_info = task_thread_info(idle);
+	current_pgd[cpu] = init_mm.pgd;
+
+	boot_secondary(cpu, idle);
+	if (!wait_for_completion_timeout(&cpu_running,
+					msecs_to_jiffies(1000))) {
+		pr_crit("CPU%u: failed to start\n", cpu);
+		return -EIO;
+	}
+	synchronise_count_master(cpu);
+
+	return 0;
+}
+
+asmlinkage __init void secondary_start_kernel(void)
+{
+	struct mm_struct *mm = &init_mm;
+	unsigned int cpu = smp_processor_id();
+	/*
+	 * All kernel threads share the same mm context; grab a
+	 * reference and switch to it.
+	 */
+	mmgrab(mm);
+	current->active_mm = mm;
+	cpumask_set_cpu(cpu, mm_cpumask(mm));
+
+	pr_info("CPU%u: Booted secondary processor\n", cpu);
+
+	setup_cpuinfo();
+	openrisc_clockevent_init();
+
+	notify_cpu_starting(cpu);
+
+	/*
+	 * OK, now it's safe to let the boot CPU continue
+	 */
+	complete(&cpu_running);
+
+	synchronise_count_slave(cpu);
+	set_cpu_online(cpu, true);
+
+	local_irq_enable();
+	/*
+	 * OK, it's off to the idle thread for us
+	 */
+	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
+}
+
+void handle_IPI(unsigned int ipi_msg)
+{
+	unsigned int cpu = smp_processor_id();
+
+	switch (ipi_msg) {
+	case IPI_WAKEUP:
+		break;
+
+	case IPI_RESCHEDULE:
+		scheduler_ipi();
+		break;
+
+	case IPI_CALL_FUNC:
+		generic_smp_call_function_interrupt();
+		break;
+
+	case IPI_CALL_FUNC_SINGLE:
+		generic_smp_call_function_single_interrupt();
+		break;
+
+	default:
+		WARN(1, "CPU%u: Unknown IPI message 0x%x\n", cpu, ipi_msg);
+		break;
+	}
+}
+
+void smp_send_reschedule(int cpu)
+{
+	smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
+}
+
+static void stop_this_cpu(void *dummy)
+{
+	/* Remove this CPU */
+	set_cpu_online(smp_processor_id(), false);
+
+	local_irq_disable();
+	/* CPU Doze */
+	if (mfspr(SPR_UPR) & SPR_UPR_PMP)
+		mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
+	/* If that didn't work, infinite loop */
+	while (1)
+		;
+}
+
+void smp_send_stop(void)
+{
+	smp_call_function(stop_this_cpu, NULL, 0);
+}
+
+void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
+{
+	smp_cross_call = fn;
+}
+
+void arch_send_call_function_single_ipi(int cpu)
+{
+	smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
+}
+
+void arch_send_call_function_ipi_mask(const struct cpumask *mask)
+{
+	smp_cross_call(mask, IPI_CALL_FUNC);
+}
+
+/* TLB flush operations - Performed on each CPU*/
+static inline void ipi_flush_tlb_all(void *ignored)
+{
+	local_flush_tlb_all();
+}
+
+static inline void ipi_flush_tlb_mm(void *info)
+{
+	struct mm_struct *mm = (struct mm_struct *)info;
+
+	local_flush_tlb_mm(mm);
+}
+
+static void smp_flush_tlb_mm(struct cpumask *cmask, struct mm_struct *mm)
+{
+	unsigned int cpuid;
+
+	if (cpumask_empty(cmask))
+		return;
+
+	cpuid = get_cpu();
+
+	if (cpumask_any_but(cmask, cpuid) >= nr_cpu_ids) {
+		/* local cpu is the only cpu present in cpumask */
+		local_flush_tlb_mm(mm);
+	} else {
+		on_each_cpu_mask(cmask, ipi_flush_tlb_mm, mm, 1);
+	}
+	put_cpu();
+}
+
+struct flush_tlb_data {
+	unsigned long addr1;
+	unsigned long addr2;
+};
+
+static inline void ipi_flush_tlb_page(void *info)
+{
+	struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
+
+	local_flush_tlb_page(NULL, fd->addr1);
+}
+
+static inline void ipi_flush_tlb_range(void *info)
+{
+	struct flush_tlb_data *fd = (struct flush_tlb_data *)info;
+
+	local_flush_tlb_range(NULL, fd->addr1, fd->addr2);
+}
+
+static void smp_flush_tlb_range(const struct cpumask *cmask, unsigned long start,
+				unsigned long end)
+{
+	unsigned int cpuid;
+
+	if (cpumask_empty(cmask))
+		return;
+
+	cpuid = get_cpu();
+
+	if (cpumask_any_but(cmask, cpuid) >= nr_cpu_ids) {
+		/* local cpu is the only cpu present in cpumask */
+		if ((end - start) <= PAGE_SIZE)
+			local_flush_tlb_page(NULL, start);
+		else
+			local_flush_tlb_range(NULL, start, end);
+	} else {
+		struct flush_tlb_data fd;
+
+		fd.addr1 = start;
+		fd.addr2 = end;
+
+		if ((end - start) <= PAGE_SIZE)
+			on_each_cpu_mask(cmask, ipi_flush_tlb_page, &fd, 1);
+		else
+			on_each_cpu_mask(cmask, ipi_flush_tlb_range, &fd, 1);
+	}
+	put_cpu();
+}
+
+void flush_tlb_all(void)
+{
+	on_each_cpu(ipi_flush_tlb_all, NULL, 1);
+}
+
+void flush_tlb_mm(struct mm_struct *mm)
+{
+	smp_flush_tlb_mm(mm_cpumask(mm), mm);
+}
+
+void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
+{
+	smp_flush_tlb_range(mm_cpumask(vma->vm_mm), uaddr, uaddr + PAGE_SIZE);
+}
+
+void flush_tlb_range(struct vm_area_struct *vma,
+		     unsigned long start, unsigned long end)
+{
+	const struct cpumask *cmask = vma ? mm_cpumask(vma->vm_mm)
+					  : cpu_online_mask;
+	smp_flush_tlb_range(cmask, start, end);
+}
+
+/* Instruction cache invalidate - performed on each cpu */
+static void ipi_icache_page_inv(void *arg)
+{
+	struct page *page = arg;
+
+	local_icache_page_inv(page);
+}
+
+void smp_icache_page_inv(struct page *page)
+{
+	on_each_cpu(ipi_icache_page_inv, page, 1);
+}
+EXPORT_SYMBOL(smp_icache_page_inv);