2 * Copyright 2010 Tilera Corporation. All Rights Reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation, version 2.
8 * This program is distributed in the hope that it will be useful, but
9 * WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
11 * NON INFRINGEMENT. See the GNU General Public License for
15 #include <linux/module.h>
16 #include <linux/init.h>
17 #include <linux/kernel.h>
19 #include <linux/sched.h>
20 #include <linux/kernel_stat.h>
21 #include <linux/smp_lock.h>
22 #include <linux/bootmem.h>
23 #include <linux/notifier.h>
24 #include <linux/cpu.h>
25 #include <linux/percpu.h>
26 #include <linux/delay.h>
27 #include <linux/err.h>
28 #include <linux/irq.h>
29 #include <asm/mmu_context.h>
30 #include <asm/tlbflush.h>
31 #include <asm/sections.h>
33 /* State of each CPU. */
34 static DEFINE_PER_CPU(int, cpu_state) = { 0 };
36 /* The messaging code jumps to this pointer during boot-up */
37 unsigned long start_cpu_function_addr;
39 /* Called very early during startup to mark boot cpu as online */
40 void __init smp_prepare_boot_cpu(void)
42 int cpu = smp_processor_id();
43 set_cpu_online(cpu, 1);
44 set_cpu_present(cpu, 1);
45 __get_cpu_var(cpu_state) = CPU_ONLINE;
50 static void start_secondary(void);
53 * Called at the top of init() to launch all the other CPUs.
54 * They run free to complete their initialization and then wait
55 * until they get an IPI from the boot cpu to come online.
57 void __init smp_prepare_cpus(unsigned int max_cpus)
61 int boot_cpu = smp_processor_id();
63 current_thread_info()->cpu = boot_cpu;
66 * Pin this task to the boot CPU while we bring up the others,
67 * just to make sure we don't uselessly migrate as they come up.
69 rc = sched_setaffinity(current->pid, cpumask_of(boot_cpu));
71 pr_err("Couldn't set init affinity to boot cpu (%ld)\n", rc);
73 /* Print information about disabled and dataplane cpus. */
74 print_disabled_cpus();
77 * Tell the messaging subsystem how to respond to the
78 * startup message. We use a level of indirection to avoid
79 * confusing the linker with the fact that the messaging
80 * subsystem is calling __init code.
82 start_cpu_function_addr = (unsigned long) &online_secondary;
84 /* Set up thread context for all new processors. */
86 for (cpu = 0; cpu < NR_CPUS; ++cpu) {
87 struct task_struct *idle;
92 if (!cpu_possible(cpu)) {
94 * Make this processor do nothing on boot.
95 * Note that we don't give the boot_pc function
96 * a stack, so it has to be assembly code.
98 per_cpu(boot_sp, cpu) = 0;
99 per_cpu(boot_pc, cpu) = (unsigned long) smp_nap;
103 /* Create a new idle thread to run start_secondary() */
104 idle = fork_idle(cpu);
106 panic("failed fork for CPU %d", cpu);
107 idle->thread.pc = (unsigned long) start_secondary;
109 /* Make this thread the boot thread for this processor */
110 per_cpu(boot_sp, cpu) = task_ksp0(idle);
111 per_cpu(boot_pc, cpu) = idle->thread.pc;
115 BUG_ON(cpu_count > (max_cpus ? max_cpus : 1));
117 /* Fire up the other tiles, if any */
118 init_cpu_present(cpu_possible_mask);
119 if (cpumask_weight(cpu_present_mask) > 1) {
120 mb(); /* make sure all data is visible to new processors */
121 hv_start_all_tiles();
125 static __initdata struct cpumask init_affinity;
127 static __init int reset_init_affinity(void)
129 long rc = sched_setaffinity(current->pid, &init_affinity);
131 pr_warning("couldn't reset init affinity (%ld)\n",
135 late_initcall(reset_init_affinity);
137 static struct cpumask cpu_started __cpuinitdata;
140 * Activate a secondary processor. Very minimal; don't add anything
141 * to this path without knowing what you're doing, since SMP booting
144 static void __cpuinit start_secondary(void)
146 int cpuid = smp_processor_id();
148 /* Set our thread pointer appropriately. */
149 set_my_cpu_offset(__per_cpu_offset[cpuid]);
154 * In large machines even this will slow us down, since we
155 * will be contending for for the printk spinlock.
157 /* printk(KERN_DEBUG "Initializing CPU#%d\n", cpuid); */
159 /* Initialize the current asid for our first page table. */
160 __get_cpu_var(current_asid) = min_asid;
162 /* Set up this thread as another owner of the init_mm */
163 atomic_inc(&init_mm.mm_count);
164 current->active_mm = &init_mm;
167 enter_lazy_tlb(&init_mm, current);
169 /* Allow hypervisor messages to be received */
173 /* Indicate that we're ready to come up. */
174 /* Must not do this before we're ready to receive messages */
175 if (cpumask_test_and_set_cpu(cpuid, &cpu_started)) {
176 pr_warning("CPU#%d already started!\n", cpuid);
185 * Bring a secondary processor online.
187 void __cpuinit online_secondary(void)
190 * low-memory mappings have been cleared, flush them from
191 * the local TLBs too.
195 BUG_ON(in_interrupt());
197 /* This must be done before setting cpu_online_mask */
201 * We need to hold call_lock, so there is no inconsistency
202 * between the time smp_call_function() determines number of
203 * IPI recipients, and the time when the determination is made
204 * for which cpus receive the IPI. Holding this
205 * lock helps us to not include this cpu in a currently in progress
206 * smp_call_function().
209 set_cpu_online(smp_processor_id(), 1);
211 __get_cpu_var(cpu_state) = CPU_ONLINE;
213 /* Set up tile-specific state for this cpu. */
216 /* Set up tile-timer clock-event device on this cpu */
224 int __cpuinit __cpu_up(unsigned int cpu)
226 /* Wait 5s total for all CPUs for them to come online */
228 for (; !cpumask_test_cpu(cpu, &cpu_started); timeout++) {
229 if (timeout >= 50000) {
230 pr_info("skipping unresponsive cpu%d\n", cpu);
238 per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
240 /* Unleash the CPU! */
241 send_IPI_single(cpu, MSG_TAG_START_CPU);
242 while (!cpumask_test_cpu(cpu, cpu_online_mask))
247 static void panic_start_cpu(void)
249 panic("Received a MSG_START_CPU IPI after boot finished.");
252 void __init smp_cpus_done(unsigned int max_cpus)
256 /* Reset the response to a (now illegal) MSG_START_CPU IPI. */
257 start_cpu_function_addr = (unsigned long) &panic_start_cpu;
259 cpumask_copy(&init_affinity, cpu_online_mask);
262 * Pin ourselves to a single cpu in the initial affinity set
263 * so that kernel mappings for the rootfs are not in the dataplane,
264 * if set, and to avoid unnecessary migrating during bringup.
265 * Use the last cpu just in case the whole chip has been
266 * isolated from the scheduler, to keep init away from likely
267 * more useful user code. This also ensures that work scheduled
268 * via schedule_delayed_work() in the init routines will land
271 for (cpu = cpumask_first(&init_affinity);
272 (next = cpumask_next(cpu, &init_affinity)) < nr_cpu_ids;
275 rc = sched_setaffinity(current->pid, cpumask_of(cpu));
277 pr_err("Couldn't set init affinity to cpu %d (%d)\n", cpu, rc);