1/*
  2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include "linux/percpu.h"
  7#include "asm/pgalloc.h"
  8#include "asm/tlb.h"
  9
 10#ifdef CONFIG_SMP
 11
 12#include "linux/sched.h"
 13#include "linux/module.h"
 14#include "linux/threads.h"
 15#include "linux/interrupt.h"
 16#include "linux/err.h"
 17#include "linux/hardirq.h"
 18#include "asm/smp.h"
 19#include "asm/processor.h"
 20#include "asm/spinlock.h"
 21#include "kern.h"
 22#include "irq_user.h"
 23#include "os.h"
 24
 25/* Per CPU bogomips and other parameters
 26 * The only piece used here is the ipi pipe, which is set before SMP is
 27 * started and never changed.
 28 */
 29struct cpuinfo_um cpu_data[NR_CPUS];
 30
 31/* A statistic, can be a little off */
 32int num_reschedules_sent = 0;
 33
 34/* Not changed after boot */
 35struct task_struct *idle_threads[NR_CPUS];
 36
 37void smp_send_reschedule(int cpu)
 38{
 39	os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
 40	num_reschedules_sent++;
 41}
 42
 43void smp_send_stop(void)
 44{
 45	int i;
 46
 47	printk(KERN_INFO "Stopping all CPUs...");
 48	for (i = 0; i < num_online_cpus(); i++) {
 49		if (i == current_thread->cpu)
 50			continue;
 51		os_write_file(cpu_data[i].ipi_pipe[1], "S", 1);
 52	}
 53	printk(KERN_CONT "done\n");
 54}
 55
 56static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
 57static cpumask_t cpu_callin_map = CPU_MASK_NONE;
 58
 59static int idle_proc(void *cpup)
 60{
 61	int cpu = (int) cpup, err;
 62
 63	err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1);
 64	if (err < 0)
 65		panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err);
 66
 67	os_set_fd_async(cpu_data[cpu].ipi_pipe[0]);
 68
 69	wmb();
 70	if (cpu_test_and_set(cpu, cpu_callin_map)) {
 71		printk(KERN_ERR "huh, CPU#%d already present??\n", cpu);
 72		BUG();
 73	}
 74
 75	while (!cpu_isset(cpu, smp_commenced_mask))
 76		cpu_relax();
 77
 78	notify_cpu_starting(cpu);
 79	set_cpu_online(cpu, true);
 80	default_idle();
 81	return 0;
 82}
 83
 84static struct task_struct *idle_thread(int cpu)
 85{
 86	struct task_struct *new_task;
 87
 88	current->thread.request.u.thread.proc = idle_proc;
 89	current->thread.request.u.thread.arg = (void *) cpu;
 90	new_task = fork_idle(cpu);
 91	if (IS_ERR(new_task))
 92		panic("copy_process failed in idle_thread, error = %ld",
 93		      PTR_ERR(new_task));
 94
 95	cpu_tasks[cpu] = ((struct cpu_task)
 96		          { .pid = 	new_task->thread.mode.tt.extern_pid,
 97			    .task = 	new_task } );
 98	idle_threads[cpu] = new_task;
 99	panic("skas mode doesn't support SMP");
100	return new_task;
101}
102
103void smp_prepare_cpus(unsigned int maxcpus)
104{
105	struct task_struct *idle;
106	unsigned long waittime;
107	int err, cpu, me = smp_processor_id();
108	int i;
109
110	for (i = 0; i < ncpus; ++i)
111		set_cpu_possible(i, true);
112
113	set_cpu_online(me, true);
114	cpu_set(me, cpu_callin_map);
115
116	err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
117	if (err < 0)
118		panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
119
120	os_set_fd_async(cpu_data[me].ipi_pipe[0]);
121
122	for (cpu = 1; cpu < ncpus; cpu++) {
123		printk(KERN_INFO "Booting processor %d...\n", cpu);
124
125		idle = idle_thread(cpu);
126
127		init_idle(idle, cpu);
128
129		waittime = 200000000;
130		while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
131			cpu_relax();
132
133		printk(KERN_INFO "%s\n",
134		       cpu_isset(cpu, cpu_calling_map) ? "done" : "failed");
135	}
136}
137
138void smp_prepare_boot_cpu(void)
139{
140	set_cpu_online(smp_processor_id(), true);
141}
142
143int __cpu_up(unsigned int cpu, struct task_struct *tidle)
144{
145	cpu_set(cpu, smp_commenced_mask);
146	while (!cpu_online(cpu))
147		mb();
148	return 0;
149}
150
151int setup_profiling_timer(unsigned int multiplier)
152{
153	printk(KERN_INFO "setup_profiling_timer\n");
154	return 0;
155}
156
157void smp_call_function_slave(int cpu);
158
159void IPI_handler(int cpu)
160{
161	unsigned char c;
162	int fd;
163
164	fd = cpu_data[cpu].ipi_pipe[0];
165	while (os_read_file(fd, &c, 1) == 1) {
166		switch (c) {
167		case 'C':
168			smp_call_function_slave(cpu);
169			break;
170
171		case 'R':
172			scheduler_ipi();
173			break;
174
175		case 'S':
176			printk(KERN_INFO "CPU#%d stopping\n", cpu);
177			while (1)
178				pause();
179			break;
180
181		default:
182			printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n",
183			       cpu, c);
184			break;
185		}
186	}
187}
188
189int hard_smp_processor_id(void)
190{
191	return pid_to_processor_id(os_getpid());
192}
193
194static DEFINE_SPINLOCK(call_lock);
195static atomic_t scf_started;
196static atomic_t scf_finished;
197static void (*func)(void *info);
198static void *info;
199
200void smp_call_function_slave(int cpu)
201{
202	atomic_inc(&scf_started);
203	(*func)(info);
204	atomic_inc(&scf_finished);
205}
206
207int smp_call_function(void (*_func)(void *info), void *_info, int wait)
208{
209	int cpus = num_online_cpus() - 1;
210	int i;
211
212	if (!cpus)
213		return 0;
214
215	/* Can deadlock when called with interrupts disabled */
216	WARN_ON(irqs_disabled());
217
218	spin_lock_bh(&call_lock);
219	atomic_set(&scf_started, 0);
220	atomic_set(&scf_finished, 0);
221	func = _func;
222	info = _info;
223
224	for_each_online_cpu(i)
225		os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
226
227	while (atomic_read(&scf_started) != cpus)
228		barrier();
229
230	if (wait)
231		while (atomic_read(&scf_finished) != cpus)
232			barrier();
233
234	spin_unlock_bh(&call_lock);
235	return 0;
236}
237
238#endif