PageRenderTime 54ms CodeModel.GetById 19ms app.highlight 29ms RepoModel.GetById 2ms app.codeStats 0ms

/arch/um/kernel/smp.c

https://bitbucket.org/evzijst/gittest
C | 269 lines | 192 code | 54 blank | 23 comment | 24 complexity | 27bbe210aba58770e8321a0506af6138 MD5 | raw file
  1/* 
  2 * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.com)
  3 * Licensed under the GPL
  4 */
  5
  6#include "linux/config.h"
  7#include "linux/percpu.h"
  8#include "asm/pgalloc.h"
  9#include "asm/tlb.h"
 10
 11/* For some reason, mmu_gathers are referenced when CONFIG_SMP is off. */
 12DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
 13
 14#ifdef CONFIG_SMP
 15
 16#include "linux/sched.h"
 17#include "linux/module.h"
 18#include "linux/threads.h"
 19#include "linux/interrupt.h"
 20#include "linux/err.h"
 21#include "linux/hardirq.h"
 22#include "asm/smp.h"
 23#include "asm/processor.h"
 24#include "asm/spinlock.h"
 25#include "user_util.h"
 26#include "kern_util.h"
 27#include "kern.h"
 28#include "irq_user.h"
 29#include "os.h"
 30
 31/* CPU online map, set by smp_boot_cpus */
 32cpumask_t cpu_online_map = CPU_MASK_NONE;
 33cpumask_t cpu_possible_map = CPU_MASK_NONE;
 34
 35EXPORT_SYMBOL(cpu_online_map);
 36EXPORT_SYMBOL(cpu_possible_map);
 37
 38/* Per CPU bogomips and other parameters
 39 * The only piece used here is the ipi pipe, which is set before SMP is
 40 * started and never changed.
 41 */
 42struct cpuinfo_um cpu_data[NR_CPUS];
 43
 44/* A statistic, can be a little off */
 45int num_reschedules_sent = 0;
 46
 47/* Not changed after boot */
 48struct task_struct *idle_threads[NR_CPUS];
 49
 50void smp_send_reschedule(int cpu)
 51{
 52	os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
 53	num_reschedules_sent++;
 54}
 55
 56void smp_send_stop(void)
 57{
 58	int i;
 59
 60	printk(KERN_INFO "Stopping all CPUs...");
 61	for(i = 0; i < num_online_cpus(); i++){
 62		if(i == current_thread->cpu)
 63			continue;
 64		os_write_file(cpu_data[i].ipi_pipe[1], "S", 1);
 65	}
 66	printk("done\n");
 67}
 68
 69static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
 70static cpumask_t cpu_callin_map = CPU_MASK_NONE;
 71
 72static int idle_proc(void *cpup)
 73{
 74	int cpu = (int) cpup, err;
 75
 76	err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1);
 77	if(err < 0)
 78		panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err);
 79
 80	activate_ipi(cpu_data[cpu].ipi_pipe[0], 
 81		     current->thread.mode.tt.extern_pid);
 82 
 83	wmb();
 84	if (cpu_test_and_set(cpu, cpu_callin_map)) {
 85		printk("huh, CPU#%d already present??\n", cpu);
 86		BUG();
 87	}
 88
 89	while (!cpu_isset(cpu, smp_commenced_mask))
 90		cpu_relax();
 91
 92	cpu_set(cpu, cpu_online_map);
 93	default_idle();
 94	return(0);
 95}
 96
 97static struct task_struct *idle_thread(int cpu)
 98{
 99	struct task_struct *new_task;
100	unsigned char c;
101
102        current->thread.request.u.thread.proc = idle_proc;
103        current->thread.request.u.thread.arg = (void *) cpu;
104	new_task = fork_idle(cpu);
105	if(IS_ERR(new_task))
106		panic("copy_process failed in idle_thread, error = %ld",
107		      PTR_ERR(new_task));
108
109	cpu_tasks[cpu] = ((struct cpu_task) 
110		          { .pid = 	new_task->thread.mode.tt.extern_pid,
111			    .task = 	new_task } );
112	idle_threads[cpu] = new_task;
113	CHOOSE_MODE(os_write_file(new_task->thread.mode.tt.switch_pipe[1], &c,
114			  sizeof(c)),
115		    ({ panic("skas mode doesn't support SMP"); }));
116	return(new_task);
117}
118
119void smp_prepare_cpus(unsigned int maxcpus)
120{
121	struct task_struct *idle;
122	unsigned long waittime;
123	int err, cpu, me = smp_processor_id();
124	int i;
125
126	for (i = 0; i < ncpus; ++i)
127		cpu_set(i, cpu_possible_map);
128
129	cpu_clear(me, cpu_online_map);
130	cpu_set(me, cpu_online_map);
131	cpu_set(me, cpu_callin_map);
132
133	err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
134	if(err < 0)
135		panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
136
137	activate_ipi(cpu_data[me].ipi_pipe[0],
138		     current->thread.mode.tt.extern_pid);
139
140	for(cpu = 1; cpu < ncpus; cpu++){
141		printk("Booting processor %d...\n", cpu);
142		
143		idle = idle_thread(cpu);
144
145		init_idle(idle, cpu);
146		unhash_process(idle);
147
148		waittime = 200000000;
149		while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
150			cpu_relax();
151
152		if (cpu_isset(cpu, cpu_callin_map))
153			printk("done\n");
154		else printk("failed\n");
155	}
156}
157
158void smp_prepare_boot_cpu(void)
159{
160	cpu_set(smp_processor_id(), cpu_online_map);
161}
162
163int __cpu_up(unsigned int cpu)
164{
165	cpu_set(cpu, smp_commenced_mask);
166	while (!cpu_isset(cpu, cpu_online_map))
167		mb();
168	return(0);
169}
170
171int setup_profiling_timer(unsigned int multiplier)
172{
173	printk(KERN_INFO "setup_profiling_timer\n");
174	return(0);
175}
176
177void smp_call_function_slave(int cpu);
178
179void IPI_handler(int cpu)
180{
181	unsigned char c;
182	int fd;
183
184	fd = cpu_data[cpu].ipi_pipe[0];
185	while (os_read_file(fd, &c, 1) == 1) {
186		switch (c) {
187		case 'C':
188			smp_call_function_slave(cpu);
189			break;
190
191		case 'R':
192			set_tsk_need_resched(current);
193			break;
194
195		case 'S':
196			printk("CPU#%d stopping\n", cpu);
197			while(1)
198				pause();
199			break;
200
201		default:
202			printk("CPU#%d received unknown IPI [%c]!\n", cpu, c);
203			break;
204		}
205	}
206}
207
208int hard_smp_processor_id(void)
209{
210	return(pid_to_processor_id(os_getpid()));
211}
212
213static DEFINE_SPINLOCK(call_lock);
214static atomic_t scf_started;
215static atomic_t scf_finished;
216static void (*func)(void *info);
217static void *info;
218
219void smp_call_function_slave(int cpu)
220{
221	atomic_inc(&scf_started);
222	(*func)(info);
223	atomic_inc(&scf_finished);
224}
225
226int smp_call_function(void (*_func)(void *info), void *_info, int nonatomic, 
227		      int wait)
228{
229	int cpus = num_online_cpus() - 1;
230	int i;
231
232	if (!cpus)
233		return 0;
234
235	/* Can deadlock when called with interrupts disabled */
236	WARN_ON(irqs_disabled());
237
238	spin_lock_bh(&call_lock);
239	atomic_set(&scf_started, 0);
240	atomic_set(&scf_finished, 0);
241	func = _func;
242	info = _info;
243
244	for_each_online_cpu(i)
245		os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
246
247	while (atomic_read(&scf_started) != cpus)
248		barrier();
249
250	if (wait)
251		while (atomic_read(&scf_finished) != cpus)
252			barrier();
253
254	spin_unlock_bh(&call_lock);
255	return 0;
256}
257
258#endif
259
260/*
261 * Overrides for Emacs so that we follow Linus's tabbing style.
262 * Emacs will notice this stuff at the end of the file and automatically
263 * adjust the settings for this buffer only.  This must remain at the end
264 * of the file.
265 * ---------------------------------------------------------------------------
266 * Local variables:
267 * c-file-style: "linux"
268 * End:
269 */