[PATCH] ARM SMP: Add support for startup of secondary processors
[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_up: processor %d failed to boot\n", cpu);
149                 /*
150                  * FIXME: We need to clean up the new idle thread. --rmk
151                  */
152         }
153
154         return ret;
155 }
156
157 /*
158  * This is the secondary CPU boot entry.  We're using this CPUs
159  * idle thread stack, but a set of temporary page tables.
160  */
161 asmlinkage void __init secondary_start_kernel(void)
162 {
163         struct mm_struct *mm = &init_mm;
164         unsigned int cpu = smp_processor_id();
165
166         printk("CPU%u: Booted secondary processor\n", cpu);
167
168         /*
169          * All kernel threads share the same mm context; grab a
170          * reference and switch to it.
171          */
172         atomic_inc(&mm->mm_users);
173         atomic_inc(&mm->mm_count);
174         current->active_mm = mm;
175         cpu_set(cpu, mm->cpu_vm_mask);
176         cpu_switch_mm(mm->pgd, mm);
177         enter_lazy_tlb(mm, current);
178
179         cpu_init();
180
181         /*
182          * Give the platform a chance to do its own initialisation.
183          */
184         platform_secondary_init(cpu);
185
186         /*
187          * Enable local interrupts.
188          */
189         local_irq_enable();
190         local_fiq_enable();
191
192         calibrate_delay();
193
194         smp_store_cpu_info(cpu);
195
196         /*
197          * OK, now it's safe to let the boot CPU continue
198          */
199         cpu_set(cpu, cpu_online_map);
200
201         /*
202          * OK, it's off to the idle thread for us
203          */
204         cpu_idle();
205 }
206
207 /*
208  * Called by both boot and secondaries to move global data into
209  * per-processor storage.
210  */
211 void __init smp_store_cpu_info(unsigned int cpuid)
212 {
213         struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid);
214
215         cpu_info->loops_per_jiffy = loops_per_jiffy;
216 }
217
218 void __init smp_cpus_done(unsigned int max_cpus)
219 {
220         int cpu;
221         unsigned long bogosum = 0;
222
223         for_each_online_cpu(cpu)
224                 bogosum += per_cpu(cpu_data, cpu).loops_per_jiffy;
225
226         printk(KERN_INFO "SMP: Total of %d processors activated "
227                "(%lu.%02lu BogoMIPS).\n",
228                num_online_cpus(),
229                bogosum / (500000/HZ),
230                (bogosum / (5000/HZ)) % 100);
231 }
232
233 void __init smp_prepare_boot_cpu(void)
234 {
235         unsigned int cpu = smp_processor_id();
236
237         cpu_set(cpu, cpu_present_mask);
238         cpu_set(cpu, cpu_online_map);
239 }
240
241 static void send_ipi_message(cpumask_t callmap, enum ipi_msg_type msg)
242 {
243         unsigned long flags;
244         unsigned int cpu;
245
246         local_irq_save(flags);
247
248         for_each_cpu_mask(cpu, callmap) {
249                 struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
250
251                 spin_lock(&ipi->lock);
252                 ipi->bits |= 1 << msg;
253                 spin_unlock(&ipi->lock);
254         }
255
256         /*
257          * Call the platform specific cross-CPU call function.
258          */
259         smp_cross_call(callmap);
260
261         local_irq_restore(flags);
262 }
263
264 /*
265  * You must not call this function with disabled interrupts, from a
266  * hardware interrupt handler, nor from a bottom half handler.
267  */
268 int smp_call_function_on_cpu(void (*func)(void *info), void *info, int retry,
269                              int wait, cpumask_t callmap)
270 {
271         struct smp_call_struct data;
272         unsigned long timeout;
273         int ret = 0;
274
275         data.func = func;
276         data.info = info;
277         data.wait = wait;
278
279         cpu_clear(smp_processor_id(), callmap);
280         if (cpus_empty(callmap))
281                 goto out;
282
283         data.pending = callmap;
284         if (wait)
285                 data.unfinished = callmap;
286
287         /*
288          * try to get the mutex on smp_call_function_data
289          */
290         spin_lock(&smp_call_function_lock);
291         smp_call_function_data = &data;
292
293         send_ipi_message(callmap, IPI_CALL_FUNC);
294
295         timeout = jiffies + HZ;
296         while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
297                 barrier();
298
299         /*
300          * did we time out?
301          */
302         if (!cpus_empty(data.pending)) {
303                 /*
304                  * this may be causing our panic - report it
305                  */
306                 printk(KERN_CRIT
307                        "CPU%u: smp_call_function timeout for %p(%p)\n"
308                        "      callmap %lx pending %lx, %swait\n",
309                        smp_processor_id(), func, info, callmap, data.pending,
310                        wait ? "" : "no ");
311
312                 /*
313                  * TRACE
314                  */
315                 timeout = jiffies + (5 * HZ);
316                 while (!cpus_empty(data.pending) && time_before(jiffies, timeout))
317                         barrier();
318
319                 if (cpus_empty(data.pending))
320                         printk(KERN_CRIT "     RESOLVED\n");
321                 else
322                         printk(KERN_CRIT "     STILL STUCK\n");
323         }
324
325         /*
326          * whatever happened, we're done with the data, so release it
327          */
328         smp_call_function_data = NULL;
329         spin_unlock(&smp_call_function_lock);
330
331         if (!cpus_empty(data.pending)) {
332                 ret = -ETIMEDOUT;
333                 goto out;
334         }
335
336         if (wait)
337                 while (!cpus_empty(data.unfinished))
338                         barrier();
339  out:
340
341         return 0;
342 }
343
344 int smp_call_function(void (*func)(void *info), void *info, int retry,
345                       int wait)
346 {
347         return smp_call_function_on_cpu(func, info, retry, wait,
348                                         cpu_online_map);
349 }
350
351 void show_ipi_list(struct seq_file *p)
352 {
353         unsigned int cpu;
354
355         seq_puts(p, "IPI:");
356
357         for_each_online_cpu(cpu)
358                 seq_printf(p, " %10lu", per_cpu(ipi_data, cpu).ipi_count);
359
360         seq_putc(p, '\n');
361 }
362
363 static void ipi_timer(struct pt_regs *regs)
364 {
365         int user = user_mode(regs);
366
367         irq_enter();
368         profile_tick(CPU_PROFILING, regs);
369         update_process_times(user);
370         irq_exit();
371 }
372
373 /*
374  * ipi_call_function - handle IPI from smp_call_function()
375  *
376  * Note that we copy data out of the cross-call structure and then
377  * let the caller know that we're here and have done with their data
378  */
379 static void ipi_call_function(unsigned int cpu)
380 {
381         struct smp_call_struct *data = smp_call_function_data;
382         void (*func)(void *info) = data->func;
383         void *info = data->info;
384         int wait = data->wait;
385
386         cpu_clear(cpu, data->pending);
387
388         func(info);
389
390         if (wait)
391                 cpu_clear(cpu, data->unfinished);
392 }
393
394 static DEFINE_SPINLOCK(stop_lock);
395
396 /*
397  * ipi_cpu_stop - handle IPI from smp_send_stop()
398  */
399 static void ipi_cpu_stop(unsigned int cpu)
400 {
401         spin_lock(&stop_lock);
402         printk(KERN_CRIT "CPU%u: stopping\n", cpu);
403         dump_stack();
404         spin_unlock(&stop_lock);
405
406         cpu_clear(cpu, cpu_online_map);
407
408         local_fiq_disable();
409         local_irq_disable();
410
411         while (1)
412                 cpu_relax();
413 }
414
415 /*
416  * Main handler for inter-processor interrupts
417  *
418  * For ARM, the ipimask now only identifies a single
419  * category of IPI (Bit 1 IPIs have been replaced by a
420  * different mechanism):
421  *
422  *  Bit 0 - Inter-processor function call
423  */
424 void do_IPI(struct pt_regs *regs)
425 {
426         unsigned int cpu = smp_processor_id();
427         struct ipi_data *ipi = &per_cpu(ipi_data, cpu);
428
429         ipi->ipi_count++;
430
431         for (;;) {
432                 unsigned long msgs;
433
434                 spin_lock(&ipi->lock);
435                 msgs = ipi->bits;
436                 ipi->bits = 0;
437                 spin_unlock(&ipi->lock);
438
439                 if (!msgs)
440                         break;
441
442                 do {
443                         unsigned nextmsg;
444
445                         nextmsg = msgs & -msgs;
446                         msgs &= ~nextmsg;
447                         nextmsg = ffz(~nextmsg);
448
449                         switch (nextmsg) {
450                         case IPI_TIMER:
451                                 ipi_timer(regs);
452                                 break;
453
454                         case IPI_RESCHEDULE:
455                                 /*
456                                  * nothing more to do - eveything is
457                                  * done on the interrupt return path
458                                  */
459                                 break;
460
461                         case IPI_CALL_FUNC:
462                                 ipi_call_function(cpu);
463                                 break;
464
465                         case IPI_CPU_STOP:
466                                 ipi_cpu_stop(cpu);
467                                 break;
468
469                         default:
470                                 printk(KERN_CRIT "CPU%u: Unknown IPI message 0x%x\n",
471                                        cpu, nextmsg);
472                                 break;
473                         }
474                 } while (msgs);
475         }
476 }
477
478 void smp_send_reschedule(int cpu)
479 {
480         send_ipi_message(cpumask_of_cpu(cpu), IPI_RESCHEDULE);
481 }
482
483 void smp_send_timer(void)
484 {
485         cpumask_t mask = cpu_online_map;
486         cpu_clear(smp_processor_id(), mask);
487         send_ipi_message(mask, IPI_TIMER);
488 }
489
490 void smp_send_stop(void)
491 {
492         cpumask_t mask = cpu_online_map;
493         cpu_clear(smp_processor_id(), mask);
494         send_ipi_message(mask, IPI_CPU_STOP);
495 }
496
497 /*
498  * not supported here
499  */
500 int __init setup_profiling_timer(unsigned int multiplier)
501 {
502         return -EINVAL;
503 }