Merge /spare/repo/linux-2.6/
[linux-2.6] / 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/mmu_context.h>
28 #include <asm/pgtable.h>
29 #include <asm/pgalloc.h>
30 #include <asm/processor.h>
31 #include <asm/tlbflush.h>
32 #include <asm/ptrace.h>
33
34 /*
35  * bitmask of present and online CPUs.
36  * The present bitmask indicates that the CPU is physically present.
37  * The online bitmask indicates that the CPU is up and running.
38  */
39 cpumask_t cpu_present_mask;
40 cpumask_t cpu_online_map;
41
42 /*
43  * as from 2.5, kernels no longer have an init_tasks structure
44  * so we need some other way of telling a new secondary core
45  * where to place its SVC stack
46  */
47 struct secondary_data secondary_data;
48
49 /*
50  * structures for inter-processor calls
51  * - A collection of single bit ipi messages.
52  */
53 struct ipi_data {
54         spinlock_t lock;
55         unsigned long ipi_count;
56         unsigned long bits;
57 };
58
59 static DEFINE_PER_CPU(struct ipi_data, ipi_data) = {
60         .lock   = SPIN_LOCK_UNLOCKED,
61 };
62
63 enum ipi_msg_type {
64         IPI_TIMER,
65         IPI_RESCHEDULE,
66         IPI_CALL_FUNC,
67         IPI_CPU_STOP,
68 };
69
70 struct smp_call_struct {
71         void (*func)(void *info);
72         void *info;
73         int wait;
74         cpumask_t pending;
75         cpumask_t unfinished;
76 };
77
78 static struct smp_call_struct * volatile smp_call_function_data;
79 static DEFINE_SPINLOCK(smp_call_function_lock);
80
81 int __init __cpu_up(unsigned int cpu)
82 {
83         struct task_struct *idle;
84         pgd_t *pgd;
85         pmd_t *pmd;
86         int ret;
87
88         /*
89          * Spawn a new process manually.  Grab a pointer to
90          * its task struct so we can mess with it
91          */
92         idle = fork_idle(cpu);
93         if (IS_ERR(idle)) {
94                 printk(KERN_ERR "CPU%u: fork() failed\n", cpu);
95                 return PTR_ERR(idle);
96         }
97
98         /*
99          * Allocate initial page tables to allow the new CPU to
100          * enable the MMU safely.  This essentially means a set
101          * of our "standard" page tables, with the addition of
102          * a 1:1 mapping for the physical address of the kernel.
103          */
104         pgd = pgd_alloc(&init_mm);
105         pmd = pmd_offset(pgd, PHYS_OFFSET);
106         *pmd = __pmd((PHYS_OFFSET & PGDIR_MASK) |
107                      PMD_TYPE_SECT | PMD_SECT_AP_WRITE);
108
109         /*
110          * We need to tell the secondary core where to find
111          * its stack and the page tables.
112          */
113         secondary_data.stack = (void *)idle->thread_info + THREAD_SIZE - 8;
114         secondary_data.pgdir = virt_to_phys(pgd);
115         wmb();
116
117         /*
118          * Now bring the CPU into our world.
119          */
120         ret = boot_secondary(cpu, idle);
121         if (ret == 0) {
122                 unsigned long timeout;
123
124                 /*
125                  * CPU was successfully started, wait for it
126                  * to come online or time out.
127                  */
128                 timeout = jiffies + HZ;
129                 while (time_before(jiffies, timeout)) {
130                         if (cpu_online(cpu))
131                                 break;
132
133                         udelay(10);
134                         barrier();
135                 }
136
137                 if (!cpu_online(cpu))
138                         ret = -EIO;
139         }
140
141         secondary_data.stack = 0;
142         secondary_data.pgdir = 0;
143
144         *pmd_offset(pgd, PHYS_OFFSET) = __pmd(0);
145         pgd_free(pgd);
146
147         if (ret) {
148                 printk(KERN_CRIT "CPU%u: processor failed to boot\n", cpu);
149
150                 /*
151                  * FIXME: We need to clean up the new idle thread. --rmk
152                  */
153         }
154
155         return ret;
156 }
157
158 /*
159  * This is the secondary CPU boot entry.  We're using this CPUs
160  * idle thread stack, but a set of temporary page tables.
161  */
162 asmlinkage void __init secondary_start_kernel(void)
163 {
164         struct mm_struct *mm = &init_mm;
165         unsigned int cpu = smp_processor_id();
166
167         printk("CPU%u: Booted secondary processor\n", cpu);
168
169         /*
170          * All kernel threads share the same mm context; grab a
171          * reference and switch to it.
172          */
173         atomic_inc(&mm->mm_users);
174         atomic_inc(&mm->mm_count);
175         current->active_mm = mm;
176         cpu_set(cpu, mm->cpu_vm_mask);
177         cpu_switch_mm(mm->pgd, mm);
178         enter_lazy_tlb(mm, current);
179
180         cpu_init();
181
182         /*
183          * Give the platform a chance to do its own initialisation.
184          */
185         platform_secondary_init(cpu);
186
187         /*
188          * Enable local interrupts.
189          */
190         local_irq_enable();
191         local_fiq_enable();
192
193         calibrate_delay();
194
195         smp_store_cpu_info(cpu);
196
197         /*
198          * OK, now it's safe to let the boot CPU continue
199          */
200         cpu_set(cpu, cpu_online_map);
201
202         /*
203          * OK, it's off to the idle thread for us
204          */
205         cpu_idle();
206 }
207
208 /*
209  * Called by both boot and secondaries to move global data into
210  * per-processor storage.
211  */
212 void __init smp_store_cpu_info(unsigned int cpuid)
213 {
214         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
215
216         cpu_info->loops_per_jiffy = loops_per_jiffy;
217 }
218
219 void __init smp_cpus_done(unsigned int max_cpus)
220 {
221         int cpu;
222         unsigned long bogosum = 0;
223
224         for_each_online_cpu(cpu)
225                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
226
227         printk(KERN_INFO "SMP: Total of %d processors activated "
228                "(%lu.%02lu BogoMIPS).\n",
229                num_online_cpus(),
230                bogosum / (500000/HZ),
231                (bogosum / (5000/HZ)) % 100);
232 }
233
234 void __init smp_prepare_boot_cpu(void)
235 {
236         unsigned int cpu = smp_processor_id();
237
238         cpu_set(cpu, cpu_present_mask);
239         cpu_set(cpu, cpu_online_map);
240 }
241
242 static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg)
243 {
244         unsigned long flags;
245         unsigned int cpu;
246
247         local_irq_save(flags);
248
249         for_each_cpu_mask(cpu, callmap) {
250                 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
251
252                 spin_lock(&ipi->lock);
253                 ipi->bits |= 1 << msg;
254                 spin_unlock(&ipi->lock);
255         }
256
257         /*
258          * Call the platform specific cross-CPU call function.
259          */
260         smp_cross_call(callmap);
261
262         local_irq_restore(flags);
263 }
264
265 /*
266  * You must not call this function with disabled interrupts, from a
267  * hardware interrupt handler, nor from a bottom half handler.
268  */
269 int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry,
270                              int wait, cpumask_t callmap)
271 {
272         struct smp_call_struct data;
273         unsigned long timeout;
274         int ret = 0;
275
276         data.func = func;
277         data.info = info;
278         data.wait = wait;
279
280         cpu_clear(smp_processor_id(), callmap);
281         if (cpus_empty(callmap))
282                 goto out;
283
284         data.pending = callmap;
285         if (wait)
286                 data.unfinished = callmap;
287
288         /*
289          * try to get the mutex on smp_call_function_data
290          */
291         spin_lock(&smp_call_function_lock);
292         smp_call_function_data = &data;
293
294         send_ipi_message(callmap, IPI_CALL_FUNC);
295
296         timeout = jiffies + HZ;
297         while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
298                 barrier();
299
300         /*
301          * did we time out?
302          */
303         if (!cpus_empty(data.pending)) {
304                 /*
305                  * this may be causing our panic - report it
306                  */
307                 printk(KERN_CRIT
308                        "CPU%u: smp_call_function timeout for %p(%p)\n"
309                        "      callmap %lx pending %lx, %swait\n",
310                        smp_processor_id(), func, info, callmap, data.pending,
311                        wait ? "" : "no ");
312
313                 /*
314                  * TRACE
315                  */
316                 timeout = jiffies + (5 * HZ);
317                 while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
318                         barrier();
319
320                 if (cpus_empty(data.pending))
321                         printk(KERN_CRIT "     RESOLVED\n");
322                 else
323                         printk(KERN_CRIT "     STILL STUCK\n");
324         }
325
326         /*
327          * whatever happened, we're done with the data, so release it
328          */
329         smp_call_function_data = NULL;
330         spin_unlock(&smp_call_function_lock);
331
332         if (!cpus_empty(data.pending)) {
333                 ret = -ETIMEDOUT;
334                 goto out;
335         }
336
337         if (wait)
338                 while (!cpus_empty(data.unfinished))
339                         barrier();
340  out:
341
342         return 0;
343 }
344
345 int smp_call_function(void (*func)(void *info), void *info, int retry,
346                       int wait)
347 {
348         return smp_call_function_on_cpu(func, info, retry, wait,
349                                         cpu_online_map);
350 }
351
352 void show_ipi_list(struct seq_file *p)
353 {
354         unsigned int cpu;
355
356         seq_puts(p, "IPI:");
357
358         for_each_online_cpu(cpu)
359                 seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
360
361         seq_putc(p, '\n');
362 }
363
364 static void ipi_timer(struct pt_regs *regs)
365 {
366         int user = user_mode(regs);
367
368         irq_enter();
369         profile_tick(CPU_PROFILING, regs);
370         update_process_times(user);
371         irq_exit();
372 }
373
374 /*
375  * ipi_call_function - handle IPI from smp_call_function()
376  *
377  * Note that we copy data out of the cross-call structure and then
378  * let the caller know that we're here and have done with their data
379  */
380 static void ipi_call_function(unsigned int cpu)
381 {
382         struct smp_call_struct *data = smp_call_function_data;
383         void (*func)(void *info) = data->func;
384         void *info = data->info;
385         int wait = data->wait;
386
387         cpu_clear(cpu, data->pending);
388
389         func(info);
390
391         if (wait)
392                 cpu_clear(cpu, data->unfinished);
393 }
394
395 static DEFINE_SPINLOCK(stop_lock);
396
397 /*
398  * ipi_cpu_stop - handle IPI from smp_send_stop()
399  */
400 static void ipi_cpu_stop(unsigned int cpu)
401 {
402         spin_lock(&stop_lock);
403         printk(KERN_CRIT "CPU%u: stopping\n", cpu);
404         dump_stack();
405         spin_unlock(&stop_lock);
406
407         cpu_clear(cpu, cpu_online_map);
408
409         local_fiq_disable();
410         local_irq_disable();
411
412         while (1)
413                 cpu_relax();
414 }
415
416 /*
417  * Main handler for inter-processor interrupts
418  *
419  * For ARM, the ipimask now only identifies a single
420  * category of IPI (Bit 1 IPIs have been replaced by a
421  * different mechanism):
422  *
423  *  Bit 0 - Inter-processor function call
424  */
425 void do_IPI(struct pt_regs *regs)
426 {
427         unsigned int cpu = smp_processor_id();
428         struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
429
430         ipi->ipi_count++;
431
432         for (;;) {
433                 unsigned long msgs;
434
435                 spin_lock(&ipi->lock);
436                 msgs = ipi->bits;
437                 ipi->bits = 0;
438                 spin_unlock(&ipi->lock);
439
440                 if (!msgs)
441                         break;
442
443                 do {
444                         unsigned nextmsg;
445
446                         nextmsg = msgs & -msgs;
447                         msgs &= ~nextmsg;
448                         nextmsg = ffz(~nextmsg);
449
450                         switch (nextmsg) {
451                         case IPI_TIMER:
452                                 ipi_timer(regs);
453                                 break;
454
455                         case IPI_RESCHEDULE:
456                                 /*
457                                  * nothing more to do - eveything is
458                                  * done on the interrupt return path
459                                  */
460                                 break;
461
462                         case IPI_CALL_FUNC:
463                                 ipi_call_function(cpu);
464                                 break;
465
466                         case IPI_CPU_STOP:
467                                 ipi_cpu_stop(cpu);
468                                 break;
469
470                         default:
471                                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
472                                        cpu, nextmsg);
473                                 break;
474                         }
475                 } while (msgs);
476         }
477 }
478
479 void smp_send_reschedule(int cpu)
480 {
481         send_ipi_message(cpumask_of_cpu(cpu), IPI_RESCHEDULE);
482 }
483
484 void smp_send_timer(void)
485 {
486         cpumask_t mask = cpu_online_map;
487         cpu_clear(smp_processor_id(), mask);
488         send_ipi_message(mask, IPI_TIMER);
489 }
490
491 void smp_send_stop(void)
492 {
493         cpumask_t mask = cpu_online_map;
494         cpu_clear(smp_processor_id(), mask);
495         send_ipi_message(mask, IPI_CPU_STOP);
496 }
497
498 /*
499  * not supported here
500  */
501 int __init setup_profiling_timer(unsigned int multiplier)
502 {
503         return -EINVAL;
504 }