--- /dev/null
+/*
+ * 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);
+}
Code Review / kvmfornfv.git / blobdiff