1 files changed, 268 insertions, 0 deletions
diff --git a/arch/tile/kernel/smpboot.c b/arch/tile/kernel/smpboot.c
new file mode 100644
index 000000000..20d52a98e
--- /dev/null
+++ b/arch/tile/kernel/smpboot.c
@@ -0,0 +1,268 @@
+/*
+ * Copyright 2010 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/sched.h>
+#include <linux/kernel_stat.h>
+#include <linux/bootmem.h>
+#include <linux/notifier.h>
+#include <linux/cpu.h>
+#include <linux/percpu.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/irq.h>
+#include <asm/mmu_context.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+
+/* State of each CPU. */
+static DEFINE_PER_CPU(int, cpu_state) = { 0 };
+
+/* The messaging code jumps to this pointer during boot-up */
+unsigned long start_cpu_function_addr;
+
+/* Called very early during startup to mark boot cpu as online */
+void __init smp_prepare_boot_cpu(void)
+{
+	int cpu = smp_processor_id();
+	set_cpu_online(cpu, 1);
+	set_cpu_present(cpu, 1);
+	__this_cpu_write(cpu_state, CPU_ONLINE);
+
+	init_messaging();
+}
+
+static void start_secondary(void);
+
+/*
+ * Called at the top of init() to launch all the other CPUs.
+ * They run free to complete their initialization and then wait
+ * until they get an IPI from the boot cpu to come online.
+ */
+void __init smp_prepare_cpus(unsigned int max_cpus)
+{
+	long rc;
+	int cpu, cpu_count;
+	int boot_cpu = smp_processor_id();
+
+	current_thread_info()->cpu = boot_cpu;
+
+	/*
+	 * Pin this task to the boot CPU while we bring up the others,
+	 * just to make sure we don't uselessly migrate as they come up.
+	 */
+	rc = sched_setaffinity(current->pid, cpumask_of(boot_cpu));
+	if (rc != 0)
+		pr_err("Couldn't set init affinity to boot cpu (%ld)\n", rc);
+
+	/* Print information about disabled and dataplane cpus. */
+	print_disabled_cpus();
+
+	/*
+	 * Tell the messaging subsystem how to respond to the
+	 * startup message.  We use a level of indirection to avoid
+	 * confusing the linker with the fact that the messaging
+	 * subsystem is calling __init code.
+	 */
+	start_cpu_function_addr = (unsigned long) &online_secondary;
+
+	/* Set up thread context for all new processors. */
+	cpu_count = 1;
+	for (cpu = 0; cpu < NR_CPUS; ++cpu)	{
+		struct task_struct *idle;
+
+		if (cpu == boot_cpu)
+			continue;
+
+		if (!cpu_possible(cpu)) {
+			/*
+			 * Make this processor do nothing on boot.
+			 * Note that we don't give the boot_pc function
+			 * a stack, so it has to be assembly code.
+			 */
+			per_cpu(boot_sp, cpu) = 0;
+			per_cpu(boot_pc, cpu) = (unsigned long) smp_nap;
+			continue;
+		}
+
+		/* Create a new idle thread to run start_secondary() */
+		idle = fork_idle(cpu);
+		if (IS_ERR(idle))
+			panic("failed fork for CPU %d", cpu);
+		idle->thread.pc = (unsigned long) start_secondary;
+
+		/* Make this thread the boot thread for this processor */
+		per_cpu(boot_sp, cpu) = task_ksp0(idle);
+		per_cpu(boot_pc, cpu) = idle->thread.pc;
+
+		++cpu_count;
+	}
+	BUG_ON(cpu_count > (max_cpus ? max_cpus : 1));
+
+	/* Fire up the other tiles, if any */
+	init_cpu_present(cpu_possible_mask);
+	if (cpumask_weight(cpu_present_mask) > 1) {
+		mb();  /* make sure all data is visible to new processors */
+		hv_start_all_tiles();
+	}
+}
+
+static __initdata struct cpumask init_affinity;
+
+static __init int reset_init_affinity(void)
+{
+	long rc = sched_setaffinity(current->pid, &init_affinity);
+	if (rc != 0)
+		pr_warn("couldn't reset init affinity (%ld)\n", rc);
+	return 0;
+}
+late_initcall(reset_init_affinity);
+
+static struct cpumask cpu_started;
+
+/*
+ * Activate a secondary processor.  Very minimal; don't add anything
+ * to this path without knowing what you're doing, since SMP booting
+ * is pretty fragile.
+ */
+static void start_secondary(void)
+{
+	int cpuid;
+
+	preempt_disable();
+
+	cpuid = smp_processor_id();
+
+	/* Set our thread pointer appropriately. */
+	set_my_cpu_offset(__per_cpu_offset[cpuid]);
+
+	/*
+	 * In large machines even this will slow us down, since we
+	 * will be contending for for the printk spinlock.
+	 */
+	/* printk(KERN_DEBUG "Initializing CPU#%d\n", cpuid); */
+
+	/* Initialize the current asid for our first page table. */
+	__this_cpu_write(current_asid, min_asid);
+
+	/* Set up this thread as another owner of the init_mm */
+	atomic_inc(&init_mm.mm_count);
+	current->active_mm = &init_mm;
+	if (current->mm)
+		BUG();
+	enter_lazy_tlb(&init_mm, current);
+
+	/* Allow hypervisor messages to be received */
+	init_messaging();
+	local_irq_enable();
+
+	/* Indicate that we're ready to come up. */
+	/* Must not do this before we're ready to receive messages */
+	if (cpumask_test_and_set_cpu(cpuid, &cpu_started)) {
+		pr_warn("CPU#%d already started!\n", cpuid);
+		for (;;)
+			local_irq_enable();
+	}
+
+	smp_nap();
+}
+
+/*
+ * Bring a secondary processor online.
+ */
+void online_secondary(void)
+{
+	/*
+	 * low-memory mappings have been cleared, flush them from
+	 * the local TLBs too.
+	 */
+	local_flush_tlb();
+
+	BUG_ON(in_interrupt());
+
+	/* This must be done before setting cpu_online_mask */
+	wmb();
+
+	notify_cpu_starting(smp_processor_id());
+
+	set_cpu_online(smp_processor_id(), 1);
+	__this_cpu_write(cpu_state, CPU_ONLINE);
+
+	/* Set up tile-specific state for this cpu. */
+	setup_cpu(0);
+
+	/* Set up tile-timer clock-event device on this cpu */
+	setup_tile_timer();
+
+	cpu_startup_entry(CPUHP_ONLINE);
+}
+
+int __cpu_up(unsigned int cpu, struct task_struct *tidle)
+{
+	/* Wait 5s total for all CPUs for them to come online */
+	static int timeout;
+	for (; !cpumask_test_cpu(cpu, &cpu_started); timeout++) {
+		if (timeout >= 50000) {
+			pr_info("skipping unresponsive cpu%d\n", cpu);
+			local_irq_enable();
+			return -EIO;
+		}
+		udelay(100);
+	}
+
+	local_irq_enable();
+	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
+
+	/* Unleash the CPU! */
+	send_IPI_single(cpu, MSG_TAG_START_CPU);
+	while (!cpumask_test_cpu(cpu, cpu_online_mask))
+		cpu_relax();
+	return 0;
+}
+
+static void panic_start_cpu(void)
+{
+	panic("Received a MSG_START_CPU IPI after boot finished.");
+}
+
+void __init smp_cpus_done(unsigned int max_cpus)
+{
+	int cpu, next, rc;
+
+	/* Reset the response to a (now illegal) MSG_START_CPU IPI. */
+	start_cpu_function_addr = (unsigned long) &panic_start_cpu;
+
+	cpumask_copy(&init_affinity, cpu_online_mask);
+
+	/*
+	 * Pin ourselves to a single cpu in the initial affinity set
+	 * so that kernel mappings for the rootfs are not in the dataplane,
+	 * if set, and to avoid unnecessary migrating during bringup.
+	 * Use the last cpu just in case the whole chip has been
+	 * isolated from the scheduler, to keep init away from likely
+	 * more useful user code.  This also ensures that work scheduled
+	 * via schedule_delayed_work() in the init routines will land
+	 * on this cpu.
+	 */
+	for (cpu = cpumask_first(&init_affinity);
+	     (next = cpumask_next(cpu, &init_affinity)) < nr_cpu_ids;
+	     cpu = next)
+		;
+	rc = sched_setaffinity(current->pid, cpumask_of(cpu));
+	if (rc != 0)
+		pr_err("Couldn't set init affinity to cpu %d (%d)\n", cpu, rc);
+}