Merge branch 'sis900-wol'
[linux-2.6] / 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/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. */
12 DEFINE_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 */
32 cpumask_t cpu_online_map = CPU_MASK_NONE;
33 cpumask_t cpu_possible_map = CPU_MASK_NONE;
34
35 EXPORT_SYMBOL(cpu_online_map);
36 EXPORT_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  */
42 struct cpuinfo_um cpu_data[NR_CPUS];
43
44 /* A statistic, can be a little off */
45 int num_reschedules_sent = 0;
46
47 /* Not changed after boot */
48 struct task_struct *idle_threads[NR_CPUS];
49
50 void smp_send_reschedule(int cpu)
51 {
52         os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
53         num_reschedules_sent++;
54 }
55
56 void 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
69 static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
70 static cpumask_t cpu_callin_map = CPU_MASK_NONE;
71
72 static 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
97 static 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
119 void 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
158 void smp_prepare_boot_cpu(void)
159 {
160         cpu_set(smp_processor_id(), cpu_online_map);
161 }
162
163 int __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
171 int setup_profiling_timer(unsigned int multiplier)
172 {
173         printk(KERN_INFO "setup_profiling_timer\n");
174         return(0);
175 }
176
177 void smp_call_function_slave(int cpu);
178
179 void 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
208 int hard_smp_processor_id(void)
209 {
210         return(pid_to_processor_id(os_getpid()));
211 }
212
213 static DEFINE_SPINLOCK(call_lock);
214 static atomic_t scf_started;
215 static atomic_t scf_finished;
216 static void (*func)(void *info);
217 static void *info;
218
219 void smp_call_function_slave(int cpu)
220 {
221         atomic_inc(&scf_started);
222         (*func)(info);
223         atomic_inc(&scf_finished);
224 }
225
226 int 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  */