155206a6690879da2e6521c7604d74ad8f9e52a0
[linux-2.6.git] / arch / um / kernel / smp.c
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  */
29 struct cpuinfo_um cpu_data[NR_CPUS];
30
31 /* A statistic, can be a little off */
32 int num_reschedules_sent = 0;
33
34 /* Not changed after boot */
35 struct task_struct *idle_threads[NR_CPUS];
36
37 void smp_send_reschedule(int cpu)
38 {
39         os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
40         num_reschedules_sent++;
41 }
42
43 void 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
56 static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
57 static cpumask_t cpu_callin_map = CPU_MASK_NONE;
58
59 static 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         cpu_set(cpu, cpu_online_map);
80         default_idle();
81         return 0;
82 }
83
84 static 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
103 void 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         cpu_clear(me, cpu_online_map);
114         cpu_set(me, cpu_online_map);
115         cpu_set(me, cpu_callin_map);
116
117         err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
118         if (err < 0)
119                 panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
120
121         os_set_fd_async(cpu_data[me].ipi_pipe[0]);
122
123         for (cpu = 1; cpu < ncpus; cpu++) {
124                 printk(KERN_INFO "Booting processor %d...\n", cpu);
125
126                 idle = idle_thread(cpu);
127
128                 init_idle(idle, cpu);
129
130                 waittime = 200000000;
131                 while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
132                         cpu_relax();
133
134                 printk(KERN_INFO "%s\n",
135                        cpu_isset(cpu, cpu_calling_map) ? "done" : "failed");
136         }
137 }
138
139 void smp_prepare_boot_cpu(void)
140 {
141         cpu_set(smp_processor_id(), cpu_online_map);
142 }
143
144 int __cpu_up(unsigned int cpu)
145 {
146         cpu_set(cpu, smp_commenced_mask);
147         while (!cpu_isset(cpu, cpu_online_map))
148                 mb();
149         return 0;
150 }
151
152 int setup_profiling_timer(unsigned int multiplier)
153 {
154         printk(KERN_INFO "setup_profiling_timer\n");
155         return 0;
156 }
157
158 void smp_call_function_slave(int cpu);
159
160 void IPI_handler(int cpu)
161 {
162         unsigned char c;
163         int fd;
164
165         fd = cpu_data[cpu].ipi_pipe[0];
166         while (os_read_file(fd, &c, 1) == 1) {
167                 switch (c) {
168                 case 'C':
169                         smp_call_function_slave(cpu);
170                         break;
171
172                 case 'R':
173                         scheduler_ipi();
174                         break;
175
176                 case 'S':
177                         printk(KERN_INFO "CPU#%d stopping\n", cpu);
178                         while (1)
179                                 pause();
180                         break;
181
182                 default:
183                         printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n",
184                                cpu, c);
185                         break;
186                 }
187         }
188 }
189
190 int hard_smp_processor_id(void)
191 {
192         return pid_to_processor_id(os_getpid());
193 }
194
195 static DEFINE_SPINLOCK(call_lock);
196 static atomic_t scf_started;
197 static atomic_t scf_finished;
198 static void (*func)(void *info);
199 static void *info;
200
201 void smp_call_function_slave(int cpu)
202 {
203         atomic_inc(&scf_started);
204         (*func)(info);
205         atomic_inc(&scf_finished);
206 }
207
208 int smp_call_function(void (*_func)(void *info), void *_info, int wait)
209 {
210         int cpus = num_online_cpus() - 1;
211         int i;
212
213         if (!cpus)
214                 return 0;
215
216         /* Can deadlock when called with interrupts disabled */
217         WARN_ON(irqs_disabled());
218
219         spin_lock_bh(&call_lock);
220         atomic_set(&scf_started, 0);
221         atomic_set(&scf_finished, 0);
222         func = _func;
223         info = _info;
224
225         for_each_online_cpu(i)
226                 os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
227
228         while (atomic_read(&scf_started) != cpus)
229                 barrier();
230
231         if (wait)
232                 while (atomic_read(&scf_finished) != cpus)
233                         barrier();
234
235         spin_unlock_bh(&call_lock);
236         return 0;
237 }
238
239 #endif