15bb54365779c795aaa62be728007605919a3b4f
[linux-2.6.git] / arch / um / kernel / smp.c
1 /*
2  * Copyright (C) 2000 - 2003 Jeff Dike (jdike@addtoit.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 /* For some reason, mmu_gathers are referenced when CONFIG_SMP is off. */
11 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
12
13 #ifdef CONFIG_SMP
14
15 #include "linux/sched.h"
16 #include "linux/module.h"
17 #include "linux/threads.h"
18 #include "linux/interrupt.h"
19 #include "linux/err.h"
20 #include "linux/hardirq.h"
21 #include "asm/smp.h"
22 #include "asm/processor.h"
23 #include "asm/spinlock.h"
24 #include "kern_util.h"
25 #include "kern.h"
26 #include "irq_user.h"
27 #include "os.h"
28
29 /* CPU online map, set by smp_boot_cpus */
30 cpumask_t cpu_online_map = CPU_MASK_NONE;
31 cpumask_t cpu_possible_map = CPU_MASK_NONE;
32
33 EXPORT_SYMBOL(cpu_online_map);
34 EXPORT_SYMBOL(cpu_possible_map);
35
36 /* Per CPU bogomips and other parameters
37  * The only piece used here is the ipi pipe, which is set before SMP is
38  * started and never changed.
39  */
40 struct cpuinfo_um cpu_data[NR_CPUS];
41
42 /* A statistic, can be a little off */
43 int num_reschedules_sent = 0;
44
45 /* Not changed after boot */
46 struct task_struct *idle_threads[NR_CPUS];
47
48 void smp_send_reschedule(int cpu)
49 {
50         os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
51         num_reschedules_sent++;
52 }
53
54 void smp_send_stop(void)
55 {
56         int i;
57
58         printk(KERN_INFO "Stopping all CPUs...");
59         for(i = 0; i < num_online_cpus(); i++){
60                 if(i == current_thread->cpu)
61                         continue;
62                 os_write_file(cpu_data[i].ipi_pipe[1], "S", 1);
63         }
64         printk("done\n");
65 }
66
67 static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
68 static cpumask_t cpu_callin_map = CPU_MASK_NONE;
69
70 static int idle_proc(void *cpup)
71 {
72         int cpu = (int) cpup, err;
73
74         err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1);
75         if(err < 0)
76                 panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err);
77
78         os_set_fd_async(cpu_data[cpu].ipi_pipe[0],
79                      current->thread.mode.tt.extern_pid);
80
81         wmb();
82         if (cpu_test_and_set(cpu, cpu_callin_map)) {
83                 printk("huh, CPU#%d already present??\n", cpu);
84                 BUG();
85         }
86
87         while (!cpu_isset(cpu, smp_commenced_mask))
88                 cpu_relax();
89
90         cpu_set(cpu, cpu_online_map);
91         default_idle();
92         return 0;
93 }
94
95 static struct task_struct *idle_thread(int cpu)
96 {
97         struct task_struct *new_task;
98
99         current->thread.request.u.thread.proc = idle_proc;
100         current->thread.request.u.thread.arg = (void *) cpu;
101         new_task = fork_idle(cpu);
102         if(IS_ERR(new_task))
103                 panic("copy_process failed in idle_thread, error = %ld",
104                       PTR_ERR(new_task));
105
106         cpu_tasks[cpu] = ((struct cpu_task)
107                           { .pid =      new_task->thread.mode.tt.extern_pid,
108                             .task =     new_task } );
109         idle_threads[cpu] = new_task;
110         panic("skas mode doesn't support SMP");
111         return new_task;
112 }
113
114 void smp_prepare_cpus(unsigned int maxcpus)
115 {
116         struct task_struct *idle;
117         unsigned long waittime;
118         int err, cpu, me = smp_processor_id();
119         int i;
120
121         for (i = 0; i < ncpus; ++i)
122                 cpu_set(i, cpu_possible_map);
123
124         cpu_clear(me, cpu_online_map);
125         cpu_set(me, cpu_online_map);
126         cpu_set(me, cpu_callin_map);
127
128         err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
129         if(err < 0)
130                 panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
131
132         os_set_fd_async(cpu_data[me].ipi_pipe[0],
133                      current->thread.mode.tt.extern_pid);
134
135         for(cpu = 1; cpu < ncpus; cpu++){
136                 printk("Booting processor %d...\n", cpu);
137
138                 idle = idle_thread(cpu);
139
140                 init_idle(idle, cpu);
141
142                 waittime = 200000000;
143                 while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
144                         cpu_relax();
145
146                 if (cpu_isset(cpu, cpu_callin_map))
147                         printk("done\n");
148                 else printk("failed\n");
149         }
150 }
151
152 void smp_prepare_boot_cpu(void)
153 {
154         cpu_set(smp_processor_id(), cpu_online_map);
155 }
156
157 int __cpu_up(unsigned int cpu)
158 {
159         cpu_set(cpu, smp_commenced_mask);
160         while (!cpu_isset(cpu, cpu_online_map))
161                 mb();
162         return 0;
163 }
164
165 int setup_profiling_timer(unsigned int multiplier)
166 {
167         printk(KERN_INFO "setup_profiling_timer\n");
168         return 0;
169 }
170
171 void smp_call_function_slave(int cpu);
172
173 void IPI_handler(int cpu)
174 {
175         unsigned char c;
176         int fd;
177
178         fd = cpu_data[cpu].ipi_pipe[0];
179         while (os_read_file(fd, &c, 1) == 1) {
180                 switch (c) {
181                 case 'C':
182                         smp_call_function_slave(cpu);
183                         break;
184
185                 case 'R':
186                         set_tsk_need_resched(current);
187                         break;
188
189                 case 'S':
190                         printk("CPU#%d stopping\n", cpu);
191                         while(1)
192                                 pause();
193                         break;
194
195                 default:
196                         printk("CPU#%d received unknown IPI [%c]!\n", cpu, c);
197                         break;
198                 }
199         }
200 }
201
202 int hard_smp_processor_id(void)
203 {
204         return pid_to_processor_id(os_getpid());
205 }
206
207 static DEFINE_SPINLOCK(call_lock);
208 static atomic_t scf_started;
209 static atomic_t scf_finished;
210 static void (*func)(void *info);
211 static void *info;
212
213 void smp_call_function_slave(int cpu)
214 {
215         atomic_inc(&scf_started);
216         (*func)(info);
217         atomic_inc(&scf_finished);
218 }
219
220 int smp_call_function(void (*_func)(void *info), void *_info, int nonatomic,
221                       int wait)
222 {
223         int cpus = num_online_cpus() - 1;
224         int i;
225
226         if (!cpus)
227                 return 0;
228
229         /* Can deadlock when called with interrupts disabled */
230         WARN_ON(irqs_disabled());
231
232         spin_lock_bh(&call_lock);
233         atomic_set(&scf_started, 0);
234         atomic_set(&scf_finished, 0);
235         func = _func;
236         info = _info;
237
238         for_each_online_cpu(i)
239                 os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
240
241         while (atomic_read(&scf_started) != cpus)
242                 barrier();
243
244         if (wait)
245                 while (atomic_read(&scf_finished) != cpus)
246                         barrier();
247
248         spin_unlock_bh(&call_lock);
249         return 0;
250 }
251
252 #endif