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Commit | Line | Data |
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08e875c1 CM |
1 | /* |
2 | * SMP initialisation and IPI support | |
3 | * Based on arch/arm/kernel/smp.c | |
4 | * | |
5 | * Copyright (C) 2012 ARM Ltd. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | * | |
11 | * This program is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
14 | * GNU General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU General Public License | |
17 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
18 | */ | |
19 | ||
20 | #include <linux/delay.h> | |
21 | #include <linux/init.h> | |
22 | #include <linux/spinlock.h> | |
23 | #include <linux/sched.h> | |
24 | #include <linux/interrupt.h> | |
25 | #include <linux/cache.h> | |
26 | #include <linux/profile.h> | |
27 | #include <linux/errno.h> | |
28 | #include <linux/mm.h> | |
29 | #include <linux/err.h> | |
30 | #include <linux/cpu.h> | |
31 | #include <linux/smp.h> | |
32 | #include <linux/seq_file.h> | |
33 | #include <linux/irq.h> | |
34 | #include <linux/percpu.h> | |
35 | #include <linux/clockchips.h> | |
36 | #include <linux/completion.h> | |
37 | #include <linux/of.h> | |
38 | ||
39 | #include <asm/atomic.h> | |
40 | #include <asm/cacheflush.h> | |
41 | #include <asm/cputype.h> | |
cd1aebf5 | 42 | #include <asm/cpu_ops.h> |
08e875c1 CM |
43 | #include <asm/mmu_context.h> |
44 | #include <asm/pgtable.h> | |
45 | #include <asm/pgalloc.h> | |
46 | #include <asm/processor.h> | |
4c7aa002 | 47 | #include <asm/smp_plat.h> |
08e875c1 CM |
48 | #include <asm/sections.h> |
49 | #include <asm/tlbflush.h> | |
50 | #include <asm/ptrace.h> | |
08e875c1 CM |
51 | |
52 | /* | |
53 | * as from 2.5, kernels no longer have an init_tasks structure | |
54 | * so we need some other way of telling a new secondary core | |
55 | * where to place its SVC stack | |
56 | */ | |
57 | struct secondary_data secondary_data; | |
08e875c1 CM |
58 | |
59 | enum ipi_msg_type { | |
60 | IPI_RESCHEDULE, | |
61 | IPI_CALL_FUNC, | |
62 | IPI_CALL_FUNC_SINGLE, | |
63 | IPI_CPU_STOP, | |
64 | }; | |
65 | ||
08e875c1 CM |
66 | /* |
67 | * Boot a secondary CPU, and assign it the specified idle task. | |
68 | * This also gives us the initial stack to use for this CPU. | |
69 | */ | |
b8c6453a | 70 | static int boot_secondary(unsigned int cpu, struct task_struct *idle) |
08e875c1 | 71 | { |
652af899 MR |
72 | if (cpu_ops[cpu]->cpu_boot) |
73 | return cpu_ops[cpu]->cpu_boot(cpu); | |
08e875c1 | 74 | |
652af899 | 75 | return -EOPNOTSUPP; |
08e875c1 CM |
76 | } |
77 | ||
78 | static DECLARE_COMPLETION(cpu_running); | |
79 | ||
b8c6453a | 80 | int __cpu_up(unsigned int cpu, struct task_struct *idle) |
08e875c1 CM |
81 | { |
82 | int ret; | |
83 | ||
84 | /* | |
85 | * We need to tell the secondary core where to find its stack and the | |
86 | * page tables. | |
87 | */ | |
88 | secondary_data.stack = task_stack_page(idle) + THREAD_START_SP; | |
89 | __flush_dcache_area(&secondary_data, sizeof(secondary_data)); | |
90 | ||
91 | /* | |
92 | * Now bring the CPU into our world. | |
93 | */ | |
94 | ret = boot_secondary(cpu, idle); | |
95 | if (ret == 0) { | |
96 | /* | |
97 | * CPU was successfully started, wait for it to come online or | |
98 | * time out. | |
99 | */ | |
100 | wait_for_completion_timeout(&cpu_running, | |
101 | msecs_to_jiffies(1000)); | |
102 | ||
103 | if (!cpu_online(cpu)) { | |
104 | pr_crit("CPU%u: failed to come online\n", cpu); | |
105 | ret = -EIO; | |
106 | } | |
107 | } else { | |
108 | pr_err("CPU%u: failed to boot: %d\n", cpu, ret); | |
109 | } | |
110 | ||
111 | secondary_data.stack = NULL; | |
112 | ||
113 | return ret; | |
114 | } | |
115 | ||
116 | /* | |
117 | * This is the secondary CPU boot entry. We're using this CPUs | |
118 | * idle thread stack, but a set of temporary page tables. | |
119 | */ | |
b8c6453a | 120 | asmlinkage void secondary_start_kernel(void) |
08e875c1 CM |
121 | { |
122 | struct mm_struct *mm = &init_mm; | |
123 | unsigned int cpu = smp_processor_id(); | |
124 | ||
125 | printk("CPU%u: Booted secondary processor\n", cpu); | |
126 | ||
127 | /* | |
128 | * All kernel threads share the same mm context; grab a | |
129 | * reference and switch to it. | |
130 | */ | |
131 | atomic_inc(&mm->mm_count); | |
132 | current->active_mm = mm; | |
133 | cpumask_set_cpu(cpu, mm_cpumask(mm)); | |
134 | ||
135 | /* | |
136 | * TTBR0 is only used for the identity mapping at this stage. Make it | |
137 | * point to zero page to avoid speculatively fetching new entries. | |
138 | */ | |
139 | cpu_set_reserved_ttbr0(); | |
140 | flush_tlb_all(); | |
141 | ||
142 | preempt_disable(); | |
143 | trace_hardirqs_off(); | |
144 | ||
652af899 MR |
145 | if (cpu_ops[cpu]->cpu_postboot) |
146 | cpu_ops[cpu]->cpu_postboot(); | |
08e875c1 | 147 | |
08e875c1 CM |
148 | /* |
149 | * OK, now it's safe to let the boot CPU continue. Wait for | |
150 | * the CPU migration code to notice that the CPU is online | |
151 | * before we continue. | |
152 | */ | |
153 | set_cpu_online(cpu, true); | |
b3770b32 | 154 | complete(&cpu_running); |
08e875c1 | 155 | |
53ae3acd CM |
156 | /* |
157 | * Enable GIC and timers. | |
158 | */ | |
159 | notify_cpu_starting(cpu); | |
160 | ||
161 | local_irq_enable(); | |
162 | local_fiq_enable(); | |
163 | ||
08e875c1 CM |
164 | /* |
165 | * OK, it's off to the idle thread for us | |
166 | */ | |
0087298f | 167 | cpu_startup_entry(CPUHP_ONLINE); |
08e875c1 CM |
168 | } |
169 | ||
9327e2c6 MR |
170 | #ifdef CONFIG_HOTPLUG_CPU |
171 | static int op_cpu_disable(unsigned int cpu) | |
172 | { | |
173 | /* | |
174 | * If we don't have a cpu_die method, abort before we reach the point | |
175 | * of no return. CPU0 may not have an cpu_ops, so test for it. | |
176 | */ | |
177 | if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_die) | |
178 | return -EOPNOTSUPP; | |
179 | ||
180 | /* | |
181 | * We may need to abort a hot unplug for some other mechanism-specific | |
182 | * reason. | |
183 | */ | |
184 | if (cpu_ops[cpu]->cpu_disable) | |
185 | return cpu_ops[cpu]->cpu_disable(cpu); | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | /* | |
191 | * __cpu_disable runs on the processor to be shutdown. | |
192 | */ | |
193 | int __cpu_disable(void) | |
194 | { | |
195 | unsigned int cpu = smp_processor_id(); | |
196 | int ret; | |
197 | ||
198 | ret = op_cpu_disable(cpu); | |
199 | if (ret) | |
200 | return ret; | |
201 | ||
202 | /* | |
203 | * Take this CPU offline. Once we clear this, we can't return, | |
204 | * and we must not schedule until we're ready to give up the cpu. | |
205 | */ | |
206 | set_cpu_online(cpu, false); | |
207 | ||
208 | /* | |
209 | * OK - migrate IRQs away from this CPU | |
210 | */ | |
211 | migrate_irqs(); | |
212 | ||
213 | /* | |
214 | * Remove this CPU from the vm mask set of all processes. | |
215 | */ | |
216 | clear_tasks_mm_cpumask(cpu); | |
217 | ||
218 | return 0; | |
219 | } | |
220 | ||
221 | static DECLARE_COMPLETION(cpu_died); | |
222 | ||
223 | /* | |
224 | * called on the thread which is asking for a CPU to be shutdown - | |
225 | * waits until shutdown has completed, or it is timed out. | |
226 | */ | |
227 | void __cpu_die(unsigned int cpu) | |
228 | { | |
229 | if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) { | |
230 | pr_crit("CPU%u: cpu didn't die\n", cpu); | |
231 | return; | |
232 | } | |
233 | pr_notice("CPU%u: shutdown\n", cpu); | |
234 | } | |
235 | ||
236 | /* | |
237 | * Called from the idle thread for the CPU which has been shutdown. | |
238 | * | |
239 | * Note that we disable IRQs here, but do not re-enable them | |
240 | * before returning to the caller. This is also the behaviour | |
241 | * of the other hotplug-cpu capable cores, so presumably coming | |
242 | * out of idle fixes this. | |
243 | */ | |
244 | void cpu_die(void) | |
245 | { | |
246 | unsigned int cpu = smp_processor_id(); | |
247 | ||
248 | idle_task_exit(); | |
249 | ||
250 | local_irq_disable(); | |
251 | ||
252 | /* Tell __cpu_die() that this CPU is now safe to dispose of */ | |
253 | complete(&cpu_died); | |
254 | ||
255 | /* | |
256 | * Actually shutdown the CPU. This must never fail. The specific hotplug | |
257 | * mechanism must perform all required cache maintenance to ensure that | |
258 | * no dirty lines are lost in the process of shutting down the CPU. | |
259 | */ | |
260 | cpu_ops[cpu]->cpu_die(cpu); | |
261 | ||
262 | BUG(); | |
263 | } | |
264 | #endif | |
265 | ||
08e875c1 CM |
266 | void __init smp_cpus_done(unsigned int max_cpus) |
267 | { | |
326b16db | 268 | pr_info("SMP: Total of %d processors activated.\n", num_online_cpus()); |
08e875c1 CM |
269 | } |
270 | ||
271 | void __init smp_prepare_boot_cpu(void) | |
272 | { | |
273 | } | |
274 | ||
275 | static void (*smp_cross_call)(const struct cpumask *, unsigned int); | |
d329de3f | 276 | |
08e875c1 | 277 | /* |
4c7aa002 JM |
278 | * Enumerate the possible CPU set from the device tree and build the |
279 | * cpu logical map array containing MPIDR values related to logical | |
280 | * cpus. Assumes that cpu_logical_map(0) has already been initialized. | |
08e875c1 CM |
281 | */ |
282 | void __init smp_init_cpus(void) | |
283 | { | |
08e875c1 | 284 | struct device_node *dn = NULL; |
cd1aebf5 | 285 | unsigned int i, cpu = 1; |
4c7aa002 | 286 | bool bootcpu_valid = false; |
08e875c1 CM |
287 | |
288 | while ((dn = of_find_node_by_type(dn, "cpu"))) { | |
72aea393 | 289 | const u32 *cell; |
4c7aa002 JM |
290 | u64 hwid; |
291 | ||
292 | /* | |
293 | * A cpu node with missing "reg" property is | |
294 | * considered invalid to build a cpu_logical_map | |
295 | * entry. | |
296 | */ | |
72aea393 WD |
297 | cell = of_get_property(dn, "reg", NULL); |
298 | if (!cell) { | |
4c7aa002 JM |
299 | pr_err("%s: missing reg property\n", dn->full_name); |
300 | goto next; | |
301 | } | |
72aea393 | 302 | hwid = of_read_number(cell, of_n_addr_cells(dn)); |
4c7aa002 JM |
303 | |
304 | /* | |
305 | * Non affinity bits must be set to 0 in the DT | |
306 | */ | |
307 | if (hwid & ~MPIDR_HWID_BITMASK) { | |
308 | pr_err("%s: invalid reg property\n", dn->full_name); | |
309 | goto next; | |
310 | } | |
311 | ||
312 | /* | |
313 | * Duplicate MPIDRs are a recipe for disaster. Scan | |
314 | * all initialized entries and check for | |
315 | * duplicates. If any is found just ignore the cpu. | |
316 | * cpu_logical_map was initialized to INVALID_HWID to | |
317 | * avoid matching valid MPIDR values. | |
318 | */ | |
319 | for (i = 1; (i < cpu) && (i < NR_CPUS); i++) { | |
320 | if (cpu_logical_map(i) == hwid) { | |
321 | pr_err("%s: duplicate cpu reg properties in the DT\n", | |
322 | dn->full_name); | |
323 | goto next; | |
324 | } | |
325 | } | |
326 | ||
327 | /* | |
328 | * The numbering scheme requires that the boot CPU | |
329 | * must be assigned logical id 0. Record it so that | |
330 | * the logical map built from DT is validated and can | |
331 | * be used. | |
332 | */ | |
333 | if (hwid == cpu_logical_map(0)) { | |
334 | if (bootcpu_valid) { | |
335 | pr_err("%s: duplicate boot cpu reg property in DT\n", | |
336 | dn->full_name); | |
337 | goto next; | |
338 | } | |
339 | ||
340 | bootcpu_valid = true; | |
341 | ||
342 | /* | |
343 | * cpu_logical_map has already been | |
344 | * initialized and the boot cpu doesn't need | |
345 | * the enable-method so continue without | |
346 | * incrementing cpu. | |
347 | */ | |
348 | continue; | |
349 | } | |
350 | ||
08e875c1 CM |
351 | if (cpu >= NR_CPUS) |
352 | goto next; | |
353 | ||
e8765b26 | 354 | if (cpu_read_ops(dn, cpu) != 0) |
08e875c1 | 355 | goto next; |
08e875c1 | 356 | |
cd1aebf5 | 357 | if (cpu_ops[cpu]->cpu_init(dn, cpu)) |
d329de3f MZ |
358 | goto next; |
359 | ||
4c7aa002 JM |
360 | pr_debug("cpu logical map 0x%llx\n", hwid); |
361 | cpu_logical_map(cpu) = hwid; | |
08e875c1 CM |
362 | next: |
363 | cpu++; | |
364 | } | |
365 | ||
366 | /* sanity check */ | |
367 | if (cpu > NR_CPUS) | |
368 | pr_warning("no. of cores (%d) greater than configured maximum of %d - clipping\n", | |
369 | cpu, NR_CPUS); | |
4c7aa002 JM |
370 | |
371 | if (!bootcpu_valid) { | |
372 | pr_err("DT missing boot CPU MPIDR, not enabling secondaries\n"); | |
373 | return; | |
374 | } | |
375 | ||
376 | /* | |
377 | * All the cpus that made it to the cpu_logical_map have been | |
378 | * validated so set them as possible cpus. | |
379 | */ | |
380 | for (i = 0; i < NR_CPUS; i++) | |
381 | if (cpu_logical_map(i) != INVALID_HWID) | |
382 | set_cpu_possible(i, true); | |
08e875c1 CM |
383 | } |
384 | ||
385 | void __init smp_prepare_cpus(unsigned int max_cpus) | |
386 | { | |
cd1aebf5 MR |
387 | int err; |
388 | unsigned int cpu, ncores = num_possible_cpus(); | |
08e875c1 CM |
389 | |
390 | /* | |
391 | * are we trying to boot more cores than exist? | |
392 | */ | |
393 | if (max_cpus > ncores) | |
394 | max_cpus = ncores; | |
395 | ||
d329de3f MZ |
396 | /* Don't bother if we're effectively UP */ |
397 | if (max_cpus <= 1) | |
398 | return; | |
399 | ||
08e875c1 CM |
400 | /* |
401 | * Initialise the present map (which describes the set of CPUs | |
402 | * actually populated at the present time) and release the | |
403 | * secondaries from the bootloader. | |
d329de3f MZ |
404 | * |
405 | * Make sure we online at most (max_cpus - 1) additional CPUs. | |
08e875c1 | 406 | */ |
d329de3f | 407 | max_cpus--; |
08e875c1 CM |
408 | for_each_possible_cpu(cpu) { |
409 | if (max_cpus == 0) | |
410 | break; | |
411 | ||
d329de3f MZ |
412 | if (cpu == smp_processor_id()) |
413 | continue; | |
414 | ||
cd1aebf5 | 415 | if (!cpu_ops[cpu]) |
08e875c1 CM |
416 | continue; |
417 | ||
cd1aebf5 | 418 | err = cpu_ops[cpu]->cpu_prepare(cpu); |
d329de3f MZ |
419 | if (err) |
420 | continue; | |
08e875c1 CM |
421 | |
422 | set_cpu_present(cpu, true); | |
423 | max_cpus--; | |
424 | } | |
08e875c1 CM |
425 | } |
426 | ||
427 | ||
428 | void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int)) | |
429 | { | |
430 | smp_cross_call = fn; | |
431 | } | |
432 | ||
433 | void arch_send_call_function_ipi_mask(const struct cpumask *mask) | |
434 | { | |
435 | smp_cross_call(mask, IPI_CALL_FUNC); | |
436 | } | |
437 | ||
438 | void arch_send_call_function_single_ipi(int cpu) | |
439 | { | |
440 | smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE); | |
441 | } | |
442 | ||
443 | static const char *ipi_types[NR_IPI] = { | |
444 | #define S(x,s) [x - IPI_RESCHEDULE] = s | |
445 | S(IPI_RESCHEDULE, "Rescheduling interrupts"), | |
446 | S(IPI_CALL_FUNC, "Function call interrupts"), | |
447 | S(IPI_CALL_FUNC_SINGLE, "Single function call interrupts"), | |
448 | S(IPI_CPU_STOP, "CPU stop interrupts"), | |
449 | }; | |
450 | ||
451 | void show_ipi_list(struct seq_file *p, int prec) | |
452 | { | |
453 | unsigned int cpu, i; | |
454 | ||
455 | for (i = 0; i < NR_IPI; i++) { | |
456 | seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i + IPI_RESCHEDULE, | |
457 | prec >= 4 ? " " : ""); | |
458 | for_each_present_cpu(cpu) | |
459 | seq_printf(p, "%10u ", | |
460 | __get_irq_stat(cpu, ipi_irqs[i])); | |
461 | seq_printf(p, " %s\n", ipi_types[i]); | |
462 | } | |
463 | } | |
464 | ||
465 | u64 smp_irq_stat_cpu(unsigned int cpu) | |
466 | { | |
467 | u64 sum = 0; | |
468 | int i; | |
469 | ||
470 | for (i = 0; i < NR_IPI; i++) | |
471 | sum += __get_irq_stat(cpu, ipi_irqs[i]); | |
472 | ||
473 | return sum; | |
474 | } | |
475 | ||
476 | static DEFINE_RAW_SPINLOCK(stop_lock); | |
477 | ||
478 | /* | |
479 | * ipi_cpu_stop - handle IPI from smp_send_stop() | |
480 | */ | |
481 | static void ipi_cpu_stop(unsigned int cpu) | |
482 | { | |
483 | if (system_state == SYSTEM_BOOTING || | |
484 | system_state == SYSTEM_RUNNING) { | |
485 | raw_spin_lock(&stop_lock); | |
486 | pr_crit("CPU%u: stopping\n", cpu); | |
487 | dump_stack(); | |
488 | raw_spin_unlock(&stop_lock); | |
489 | } | |
490 | ||
491 | set_cpu_online(cpu, false); | |
492 | ||
493 | local_fiq_disable(); | |
494 | local_irq_disable(); | |
495 | ||
496 | while (1) | |
497 | cpu_relax(); | |
498 | } | |
499 | ||
500 | /* | |
501 | * Main handler for inter-processor interrupts | |
502 | */ | |
503 | void handle_IPI(int ipinr, struct pt_regs *regs) | |
504 | { | |
505 | unsigned int cpu = smp_processor_id(); | |
506 | struct pt_regs *old_regs = set_irq_regs(regs); | |
507 | ||
508 | if (ipinr >= IPI_RESCHEDULE && ipinr < IPI_RESCHEDULE + NR_IPI) | |
509 | __inc_irq_stat(cpu, ipi_irqs[ipinr - IPI_RESCHEDULE]); | |
510 | ||
511 | switch (ipinr) { | |
512 | case IPI_RESCHEDULE: | |
513 | scheduler_ipi(); | |
514 | break; | |
515 | ||
516 | case IPI_CALL_FUNC: | |
517 | irq_enter(); | |
518 | generic_smp_call_function_interrupt(); | |
519 | irq_exit(); | |
520 | break; | |
521 | ||
522 | case IPI_CALL_FUNC_SINGLE: | |
523 | irq_enter(); | |
524 | generic_smp_call_function_single_interrupt(); | |
525 | irq_exit(); | |
526 | break; | |
527 | ||
528 | case IPI_CPU_STOP: | |
529 | irq_enter(); | |
530 | ipi_cpu_stop(cpu); | |
531 | irq_exit(); | |
532 | break; | |
533 | ||
534 | default: | |
535 | pr_crit("CPU%u: Unknown IPI message 0x%x\n", cpu, ipinr); | |
536 | break; | |
537 | } | |
538 | set_irq_regs(old_regs); | |
539 | } | |
540 | ||
541 | void smp_send_reschedule(int cpu) | |
542 | { | |
543 | smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE); | |
544 | } | |
545 | ||
546 | void smp_send_stop(void) | |
547 | { | |
548 | unsigned long timeout; | |
549 | ||
550 | if (num_online_cpus() > 1) { | |
551 | cpumask_t mask; | |
552 | ||
553 | cpumask_copy(&mask, cpu_online_mask); | |
554 | cpu_clear(smp_processor_id(), mask); | |
555 | ||
556 | smp_cross_call(&mask, IPI_CPU_STOP); | |
557 | } | |
558 | ||
559 | /* Wait up to one second for other CPUs to stop */ | |
560 | timeout = USEC_PER_SEC; | |
561 | while (num_online_cpus() > 1 && timeout--) | |
562 | udelay(1); | |
563 | ||
564 | if (num_online_cpus() > 1) | |
565 | pr_warning("SMP: failed to stop secondary CPUs\n"); | |
566 | } | |
567 | ||
568 | /* | |
569 | * not supported here | |
570 | */ | |
571 | int setup_profiling_timer(unsigned int multiplier) | |
572 | { | |
573 | return -EINVAL; | |
574 | } |