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