Linux-2.6.12-rc2
[muen/linux.git] / arch / arm / kernel / smp.c
1 /*
2  *  linux/arch/arm/kernel/smp.c
3  *
4  *  Copyright (C) 2002 ARM Limited, All Rights Reserved.
5  *
6  * This program is free software; you can redistribute it and/or modify
7  * it under the terms of the GNU General Public License version 2 as
8  * published by the Free Software Foundation.
9  */
10 #include <linux/config.h>
11 #include <linux/delay.h>
12 #include <linux/init.h>
13 #include <linux/spinlock.h>
14 #include <linux/sched.h>
15 #include <linux/interrupt.h>
16 #include <linux/cache.h>
17 #include <linux/profile.h>
18 #include <linux/errno.h>
19 #include <linux/mm.h>
20 #include <linux/cpu.h>
21 #include <linux/smp.h>
22 #include <linux/seq_file.h>
23
24 #include <asm/atomic.h>
25 #include <asm/cacheflush.h>
26 #include <asm/cpu.h>
27 #include <asm/processor.h>
28 #include <asm/tlbflush.h>
29 #include <asm/ptrace.h>
30
31 /*
32  * bitmask of present and online CPUs.
33  * The present bitmask indicates that the CPU is physically present.
34  * The online bitmask indicates that the CPU is up and running.
35  */
36 cpumask_t cpu_present_mask;
37 cpumask_t cpu_online_map;
38
39 /*
40  * structures for inter-processor calls
41  * - A collection of single bit ipi messages.
42  */
43 struct ipi_data {
44         spinlock_t lock;
45         unsigned long ipi_count;
46         unsigned long bits;
47 };
48
49 static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
50         .lock   = SPIN_LOCK_UNLOCKED,
51 };
52
53 enum ipi_msg_type {
54         IPI_TIMER,
55         IPI_RESCHEDULE,
56         IPI_CALL_FUNC,
57         IPI_CPU_STOP,
58 };
59
60 struct smp_call_struct {
61         void (*func)(void *info);
62         void *info;
63         int wait;
64         cpumask_t pending;
65         cpumask_t unfinished;
66 };
67
68 static struct smp_call_struct * volatile smp_call_function_data;
69 static DEFINE_SPINLOCK(smp_call_function_lock);
70
71 int __init __cpu_up(unsigned int cpu)
72 {
73         struct task_struct *idle;
74         int ret;
75
76         /*
77          * Spawn a new process manually.  Grab a pointer to
78          * its task struct so we can mess with it
79          */
80         idle = fork_idle(cpu);
81         if (IS_ERR(idle)) {
82                 printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
83                 return PTR_ERR(idle);
84         }
85
86         /*
87          * Now bring the CPU into our world.
88          */
89         ret = boot_secondary(cpu, idle);
90         if (ret) {
91                 printk(KERN_CRIT "cpu_up: processor %d failed to boot\n", cpu);
92                 /*
93                  * FIXME: We need to clean up the new idle thread. --rmk
94                  */
95         }
96
97         return ret;
98 }
99
100 /*
101  * Called by both boot and secondaries to move global data into
102  * per-processor storage.
103  */
104 void __init smp_store_cpu_info(unsigned int cpuid)
105 {
106         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
107
108         cpu_info->loops_per_jiffy = loops_per_jiffy;
109 }
110
111 void __init smp_cpus_done(unsigned int max_cpus)
112 {
113         int cpu;
114         unsigned long bogosum = 0;
115
116         for_each_online_cpu(cpu)
117                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
118
119         printk(KERN_INFO "SMP: Total of %d processors activated "
120                "(%lu.%02lu BogoMIPS).\n",
121                num_online_cpus(),
122                bogosum / (500000/HZ),
123                (bogosum / (5000/HZ)) % 100);
124 }
125
126 void __init smp_prepare_boot_cpu(void)
127 {
128         unsigned int cpu = smp_processor_id();
129
130         cpu_set(cpu, cpu_present_mask);
131         cpu_set(cpu, cpu_online_map);
132 }
133
134 static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg)
135 {
136         unsigned long flags;
137         unsigned int cpu;
138
139         local_irq_save(flags);
140
141         for_each_cpu_mask(cpu, callmap) {
142                 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
143
144                 spin_lock(&ipi->lock);
145                 ipi->bits |= 1 << msg;
146                 spin_unlock(&ipi->lock);
147         }
148
149         /*
150          * Call the platform specific cross-CPU call function.
151          */
152         smp_cross_call(callmap);
153
154         local_irq_restore(flags);
155 }
156
157 /*
158  * You must not call this function with disabled interrupts, from a
159  * hardware interrupt handler, nor from a bottom half handler.
160  */
161 int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry,
162                              int wait, cpumask_t callmap)
163 {
164         struct smp_call_struct data;
165         unsigned long timeout;
166         int ret = 0;
167
168         data.func = func;
169         data.info = info;
170         data.wait = wait;
171
172         cpu_clear(smp_processor_id(), callmap);
173         if (cpus_empty(callmap))
174                 goto out;
175
176         data.pending = callmap;
177         if (wait)
178                 data.unfinished = callmap;
179
180         /*
181          * try to get the mutex on smp_call_function_data
182          */
183         spin_lock(&smp_call_function_lock);
184         smp_call_function_data = &data;
185
186         send_ipi_message(callmap, IPI_CALL_FUNC);
187
188         timeout = jiffies + HZ;
189         while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
190                 barrier();
191
192         /*
193          * did we time out?
194          */
195         if (!cpus_empty(data.pending)) {
196                 /*
197                  * this may be causing our panic - report it
198                  */
199                 printk(KERN_CRIT
200                        "CPU%u: smp_call_function timeout for %p(%p)\n"
201                        "      callmap %lx pending %lx, %swait\n",
202                        smp_processor_id(), func, info, callmap, data.pending,
203                        wait ? "" : "no ");
204
205                 /*
206                  * TRACE
207                  */
208                 timeout = jiffies + (5 * HZ);
209                 while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
210                         barrier();
211
212                 if (cpus_empty(data.pending))
213                         printk(KERN_CRIT "     RESOLVED\n");
214                 else
215                         printk(KERN_CRIT "     STILL STUCK\n");
216         }
217
218         /*
219          * whatever happened, we're done with the data, so release it
220          */
221         smp_call_function_data = NULL;
222         spin_unlock(&smp_call_function_lock);
223
224         if (!cpus_empty(data.pending)) {
225                 ret = -ETIMEDOUT;
226                 goto out;
227         }
228
229         if (wait)
230                 while (!cpus_empty(data.unfinished))
231                         barrier();
232  out:
233
234         return 0;
235 }
236
237 int smp_call_function(void (*func)(void *info), void *info, int retry,
238                       int wait)
239 {
240         return smp_call_function_on_cpu(func, info, retry, wait,
241                                         cpu_online_map);
242 }
243
244 void show_ipi_list(struct seq_file *p)
245 {
246         unsigned int cpu;
247
248         seq_puts(p, "IPI:");
249
250         for_each_online_cpu(cpu)
251                 seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
252
253         seq_putc(p, '\n');
254 }
255
256 static void ipi_timer(struct pt_regs *regs)
257 {
258         int user = user_mode(regs);
259
260         irq_enter();
261         profile_tick(CPU_PROFILING, regs);
262         update_process_times(user);
263         irq_exit();
264 }
265
266 /*
267  * ipi_call_function - handle IPI from smp_call_function()
268  *
269  * Note that we copy data out of the cross-call structure and then
270  * let the caller know that we're here and have done with their data
271  */
272 static void ipi_call_function(unsigned int cpu)
273 {
274         struct smp_call_struct *data = smp_call_function_data;
275         void (*func)(void *info) = data->func;
276         void *info = data->info;
277         int wait = data->wait;
278
279         cpu_clear(cpu, data->pending);
280
281         func(info);
282
283         if (wait)
284                 cpu_clear(cpu, data->unfinished);
285 }
286
287 static DEFINE_SPINLOCK(stop_lock);
288
289 /*
290  * ipi_cpu_stop - handle IPI from smp_send_stop()
291  */
292 static void ipi_cpu_stop(unsigned int cpu)
293 {
294         spin_lock(&stop_lock);
295         printk(KERN_CRIT "CPU%u: stopping\n", cpu);
296         dump_stack();
297         spin_unlock(&stop_lock);
298
299         cpu_clear(cpu, cpu_online_map);
300
301         local_fiq_disable();
302         local_irq_disable();
303
304         while (1)
305                 cpu_relax();
306 }
307
308 /*
309  * Main handler for inter-processor interrupts
310  *
311  * For ARM, the ipimask now only identifies a single
312  * category of IPI (Bit 1 IPIs have been replaced by a
313  * different mechanism):
314  *
315  *  Bit 0 - Inter-processor function call
316  */
317 void do_IPI(struct pt_regs *regs)
318 {
319         unsigned int cpu = smp_processor_id();
320         struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
321
322         ipi->ipi_count++;
323
324         for (;;) {
325                 unsigned long msgs;
326
327                 spin_lock(&ipi->lock);
328                 msgs = ipi->bits;
329                 ipi->bits = 0;
330                 spin_unlock(&ipi->lock);
331
332                 if (!msgs)
333                         break;
334
335                 do {
336                         unsigned nextmsg;
337
338                         nextmsg = msgs & -msgs;
339                         msgs &= ~nextmsg;
340                         nextmsg = ffz(~nextmsg);
341
342                         switch (nextmsg) {
343                         case IPI_TIMER:
344                                 ipi_timer(regs);
345                                 break;
346
347                         case IPI_RESCHEDULE:
348                                 /*
349                                  * nothing more to do - eveything is
350                                  * done on the interrupt return path
351                                  */
352                                 break;
353
354                         case IPI_CALL_FUNC:
355                                 ipi_call_function(cpu);
356                                 break;
357
358                         case IPI_CPU_STOP:
359                                 ipi_cpu_stop(cpu);
360                                 break;
361
362                         default:
363                                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
364                                        cpu, nextmsg);
365                                 break;
366                         }
367                 } while (msgs);
368         }
369 }
370
371 void smp_send_reschedule(int cpu)
372 {
373         send_ipi_message(cpumask_of_cpu(cpu), IPI_RESCHEDULE);
374 }
375
376 void smp_send_timer(void)
377 {
378         cpumask_t mask = cpu_online_map;
379         cpu_clear(smp_processor_id(), mask);
380         send_ipi_message(mask, IPI_TIMER);
381 }
382
383 void smp_send_stop(void)
384 {
385         cpumask_t mask = cpu_online_map;
386         cpu_clear(smp_processor_id(), mask);
387         send_ipi_message(mask, IPI_CPU_STOP);
388 }
389
390 /*
391  * not supported here
392  */
393 int __init setup_profiling_timer(unsigned int multiplier)
394 {
395         return -EINVAL;
396 }