summaryrefslogtreecommitdiff
path: root/arch/xtensa/kernel/smp.c
blob: 83b244ce61eeb4740b72d6b7a1111093e0ff66d3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
/*
 * Xtensa SMP support functions.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2008 - 2013 Tensilica Inc.
 *
 * Chris Zankel <chris@zankel.net>
 * Joe Taylor <joe@tensilica.com>
 * Pete Delaney <piet@tensilica.com
 */

#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irqdomain.h>
#include <linux/irq.h>
#include <linux/kdebug.h>
#include <linux/module.h>
#include <linux/sched/mm.h>
#include <linux/sched/hotplug.h>
#include <linux/sched/task_stack.h>
#include <linux/reboot.h>
#include <linux/seq_file.h>
#include <linux/smp.h>
#include <linux/thread_info.h>

#include <asm/cacheflush.h>
#include <asm/kdebug.h>
#include <asm/mmu_context.h>
#include <asm/mxregs.h>
#include <asm/platform.h>
#include <asm/tlbflush.h>
#include <asm/traps.h>

#ifdef CONFIG_SMP
# if XCHAL_HAVE_S32C1I == 0
#  error "The S32C1I option is required for SMP."
# endif
#endif

static void system_invalidate_dcache_range(unsigned long start,
		unsigned long size);
static void system_flush_invalidate_dcache_range(unsigned long start,
		unsigned long size);

/* IPI (Inter Process Interrupt) */

#define IPI_IRQ	0

static irqreturn_t ipi_interrupt(int irq, void *dev_id);
static struct irqaction ipi_irqaction = {
	.handler =	ipi_interrupt,
	.flags =	IRQF_PERCPU,
	.name =		"ipi",
};

void ipi_init(void)
{
	unsigned irq = irq_create_mapping(NULL, IPI_IRQ);
	setup_irq(irq, &ipi_irqaction);
}

static inline unsigned int get_core_count(void)
{
	/* Bits 18..21 of SYSCFGID contain the core count minus 1. */
	unsigned int syscfgid = get_er(SYSCFGID);
	return ((syscfgid >> 18) & 0xf) + 1;
}

static inline int get_core_id(void)
{
	/* Bits 0...18 of SYSCFGID contain the core id  */
	unsigned int core_id = get_er(SYSCFGID);
	return core_id & 0x3fff;
}

void __init smp_prepare_cpus(unsigned int max_cpus)
{
	unsigned i;

	for_each_possible_cpu(i)
		set_cpu_present(i, true);
}

void __init smp_init_cpus(void)
{
	unsigned i;
	unsigned int ncpus = get_core_count();
	unsigned int core_id = get_core_id();

	pr_info("%s: Core Count = %d\n", __func__, ncpus);
	pr_info("%s: Core Id = %d\n", __func__, core_id);

	if (ncpus > NR_CPUS) {
		ncpus = NR_CPUS;
		pr_info("%s: limiting core count by %d\n", __func__, ncpus);
	}

	for (i = 0; i < ncpus; ++i)
		set_cpu_possible(i, true);
}

void __init smp_prepare_boot_cpu(void)
{
	unsigned int cpu = smp_processor_id();
	BUG_ON(cpu != 0);
	cpu_asid_cache(cpu) = ASID_USER_FIRST;
}

void __init smp_cpus_done(unsigned int max_cpus)
{
}

static int boot_secondary_processors = 1; /* Set with xt-gdb via .xt-gdb */
static DECLARE_COMPLETION(cpu_running);

void secondary_start_kernel(void)
{
	struct mm_struct *mm = &init_mm;
	unsigned int cpu = smp_processor_id();

	init_mmu();

#ifdef CONFIG_DEBUG_MISC
	if (boot_secondary_processors == 0) {
		pr_debug("%s: boot_secondary_processors:%d; Hanging cpu:%d\n",
			__func__, boot_secondary_processors, cpu);
		for (;;)
			__asm__ __volatile__ ("waiti " __stringify(LOCKLEVEL));
	}

	pr_debug("%s: boot_secondary_processors:%d; Booting cpu:%d\n",
		__func__, boot_secondary_processors, cpu);
#endif
	/* Init EXCSAVE1 */

	secondary_trap_init();

	/* All kernel threads share the same mm context. */

	mmget(mm);
	mmgrab(mm);
	current->active_mm = mm;
	cpumask_set_cpu(cpu, mm_cpumask(mm));
	enter_lazy_tlb(mm, current);

	preempt_disable();
	trace_hardirqs_off();

	calibrate_delay();

	notify_cpu_starting(cpu);

	secondary_init_irq();
	local_timer_setup(cpu);

	set_cpu_online(cpu, true);

	local_irq_enable();

	complete(&cpu_running);

	cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}

static void mx_cpu_start(void *p)
{
	unsigned cpu = (unsigned)p;
	unsigned long run_stall_mask = get_er(MPSCORE);

	set_er(run_stall_mask & ~(1u << cpu), MPSCORE);
	pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
			__func__, cpu, run_stall_mask, get_er(MPSCORE));
}

static void mx_cpu_stop(void *p)
{
	unsigned cpu = (unsigned)p;
	unsigned long run_stall_mask = get_er(MPSCORE);

	set_er(run_stall_mask | (1u << cpu), MPSCORE);
	pr_debug("%s: cpu: %d, run_stall_mask: %lx ---> %lx\n",
			__func__, cpu, run_stall_mask, get_er(MPSCORE));
}

#ifdef CONFIG_HOTPLUG_CPU
unsigned long cpu_start_id __cacheline_aligned;
#endif
unsigned long cpu_start_ccount;

static int boot_secondary(unsigned int cpu, struct task_struct *ts)
{
	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
	unsigned long ccount;
	int i;

#ifdef CONFIG_HOTPLUG_CPU
	WRITE_ONCE(cpu_start_id, cpu);
	/* Pairs with the third memw in the cpu_restart */
	mb();
	system_flush_invalidate_dcache_range((unsigned long)&cpu_start_id,
					     sizeof(cpu_start_id));
#endif
	smp_call_function_single(0, mx_cpu_start, (void *)cpu, 1);

	for (i = 0; i < 2; ++i) {
		do
			ccount = get_ccount();
		while (!ccount);

		WRITE_ONCE(cpu_start_ccount, ccount);

		do {
			/*
			 * Pairs with the first two memws in the
			 * .Lboot_secondary.
			 */
			mb();
			ccount = READ_ONCE(cpu_start_ccount);
		} while (ccount && time_before(jiffies, timeout));

		if (ccount) {
			smp_call_function_single(0, mx_cpu_stop,
						 (void *)cpu, 1);
			WRITE_ONCE(cpu_start_ccount, 0);
			return -EIO;
		}
	}
	return 0;
}

int __cpu_up(unsigned int cpu, struct task_struct *idle)
{
	int ret = 0;

	if (cpu_asid_cache(cpu) == 0)
		cpu_asid_cache(cpu) = ASID_USER_FIRST;

	start_info.stack = (unsigned long)task_pt_regs(idle);
	wmb();

	pr_debug("%s: Calling wakeup_secondary(cpu:%d, idle:%p, sp: %08lx)\n",
			__func__, cpu, idle, start_info.stack);

	init_completion(&cpu_running);
	ret = boot_secondary(cpu, idle);
	if (ret == 0) {
		wait_for_completion_timeout(&cpu_running,
				msecs_to_jiffies(1000));
		if (!cpu_online(cpu))
			ret = -EIO;
	}

	if (ret)
		pr_err("CPU %u failed to boot\n", cpu);

	return ret;
}

#ifdef CONFIG_HOTPLUG_CPU

/*
 * __cpu_disable runs on the processor to be shutdown.
 */
int __cpu_disable(void)
{
	unsigned int cpu = smp_processor_id();

	/*
	 * Take this CPU offline.  Once we clear this, we can't return,
	 * and we must not schedule until we're ready to give up the cpu.
	 */
	set_cpu_online(cpu, false);

	/*
	 * OK - migrate IRQs away from this CPU
	 */
	migrate_irqs();

	/*
	 * Flush user cache and TLB mappings, and then remove this CPU
	 * from the vm mask set of all processes.
	 */
	local_flush_cache_all();
	local_flush_tlb_all();
	invalidate_page_directory();

	clear_tasks_mm_cpumask(cpu);

	return 0;
}

static void platform_cpu_kill(unsigned int cpu)
{
	smp_call_function_single(0, mx_cpu_stop, (void *)cpu, true);
}

/*
 * called on the thread which is asking for a CPU to be shutdown -
 * waits until shutdown has completed, or it is timed out.
 */
void __cpu_die(unsigned int cpu)
{
	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
	while (time_before(jiffies, timeout)) {
		system_invalidate_dcache_range((unsigned long)&cpu_start_id,
					       sizeof(cpu_start_id));
		/* Pairs with the second memw in the cpu_restart */
		mb();
		if (READ_ONCE(cpu_start_id) == -cpu) {
			platform_cpu_kill(cpu);
			return;
		}
	}
	pr_err("CPU%u: unable to kill\n", cpu);
}

void arch_cpu_idle_dead(void)
{
	cpu_die();
}
/*
 * Called from the idle thread for the CPU which has been shutdown.
 *
 * Note that we disable IRQs here, but do not re-enable them
 * before returning to the caller. This is also the behaviour
 * of the other hotplug-cpu capable cores, so presumably coming
 * out of idle fixes this.
 */
void __ref cpu_die(void)
{
	idle_task_exit();
	local_irq_disable();
	__asm__ __volatile__(
			"	movi	a2, cpu_restart\n"
			"	jx	a2\n");
}

#endif /* CONFIG_HOTPLUG_CPU */

enum ipi_msg_type {
	IPI_RESCHEDULE = 0,
	IPI_CALL_FUNC,
	IPI_CPU_STOP,
	IPI_MAX
};

static const struct {
	const char *short_text;
	const char *long_text;
} ipi_text[] = {
	{ .short_text = "RES", .long_text = "Rescheduling interrupts" },
	{ .short_text = "CAL", .long_text = "Function call interrupts" },
	{ .short_text = "DIE", .long_text = "CPU shutdown interrupts" },
};

struct ipi_data {
	unsigned long ipi_count[IPI_MAX];
};

static DEFINE_PER_CPU(struct ipi_data, ipi_data);

static void send_ipi_message(const struct cpumask *callmask,
		enum ipi_msg_type msg_id)
{
	int index;
	unsigned long mask = 0;

	for_each_cpu(index, callmask)
		mask |= 1 << index;

	set_er(mask, MIPISET(msg_id));
}

void arch_send_call_function_ipi_mask(const struct cpumask *mask)
{
	send_ipi_message(mask, IPI_CALL_FUNC);
}

void arch_send_call_function_single_ipi(int cpu)
{
	send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC);
}

void smp_send_reschedule(int cpu)
{
	send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE);
}

void smp_send_stop(void)
{
	struct cpumask targets;

	cpumask_copy(&targets, cpu_online_mask);
	cpumask_clear_cpu(smp_processor_id(), &targets);
	send_ipi_message(&targets, IPI_CPU_STOP);
}

static void ipi_cpu_stop(unsigned int cpu)
{
	set_cpu_online(cpu, false);
	machine_halt();
}

irqreturn_t ipi_interrupt(int irq, void *dev_id)
{
	unsigned int cpu = smp_processor_id();
	struct ipi_data *ipi = &per_cpu(ipi_data, cpu);

	for (;;) {
		unsigned int msg;

		msg = get_er(MIPICAUSE(cpu));
		set_er(msg, MIPICAUSE(cpu));

		if (!msg)
			break;

		if (msg & (1 << IPI_CALL_FUNC)) {
			++ipi->ipi_count[IPI_CALL_FUNC];
			generic_smp_call_function_interrupt();
		}

		if (msg & (1 << IPI_RESCHEDULE)) {
			++ipi->ipi_count[IPI_RESCHEDULE];
			scheduler_ipi();
		}

		if (msg & (1 << IPI_CPU_STOP)) {
			++ipi->ipi_count[IPI_CPU_STOP];
			ipi_cpu_stop(cpu);
		}
	}

	return IRQ_HANDLED;
}

void show_ipi_list(struct seq_file *p, int prec)
{
	unsigned int cpu;
	unsigned i;

	for (i = 0; i < IPI_MAX; ++i) {
		seq_printf(p, "%*s:", prec, ipi_text[i].short_text);
		for_each_online_cpu(cpu)
			seq_printf(p, " %10lu",
					per_cpu(ipi_data, cpu).ipi_count[i]);
		seq_printf(p, "   %s\n", ipi_text[i].long_text);
	}
}

int setup_profiling_timer(unsigned int multiplier)
{
	pr_debug("setup_profiling_timer %d\n", multiplier);
	return 0;
}

/* TLB flush functions */

struct flush_data {
	struct vm_area_struct *vma;
	unsigned long addr1;
	unsigned long addr2;
};

static void ipi_flush_tlb_all(void *arg)
{
	local_flush_tlb_all();
}

void flush_tlb_all(void)
{
	on_each_cpu(ipi_flush_tlb_all, NULL, 1);
}

static void ipi_flush_tlb_mm(void *arg)
{
	local_flush_tlb_mm(arg);
}

void flush_tlb_mm(struct mm_struct *mm)
{
	on_each_cpu(ipi_flush_tlb_mm, mm, 1);
}

static void ipi_flush_tlb_page(void *arg)
{
	struct flush_data *fd = arg;
	local_flush_tlb_page(fd->vma, fd->addr1);
}

void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
{
	struct flush_data fd = {
		.vma = vma,
		.addr1 = addr,
	};
	on_each_cpu(ipi_flush_tlb_page, &fd, 1);
}

static void ipi_flush_tlb_range(void *arg)
{
	struct flush_data *fd = arg;
	local_flush_tlb_range(fd->vma, fd->addr1, fd->addr2);
}

void flush_tlb_range(struct vm_area_struct *vma,
		     unsigned long start, unsigned long end)
{
	struct flush_data fd = {
		.vma = vma,
		.addr1 = start,
		.addr2 = end,
	};
	on_each_cpu(ipi_flush_tlb_range, &fd, 1);
}

static void ipi_flush_tlb_kernel_range(void *arg)
{
	struct flush_data *fd = arg;
	local_flush_tlb_kernel_range(fd->addr1, fd->addr2);
}

void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
	struct flush_data fd = {
		.addr1 = start,
		.addr2 = end,
	};
	on_each_cpu(ipi_flush_tlb_kernel_range, &fd, 1);
}

/* Cache flush functions */

static void ipi_flush_cache_all(void *arg)
{
	local_flush_cache_all();
}

void flush_cache_all(void)
{
	on_each_cpu(ipi_flush_cache_all, NULL, 1);
}

static void ipi_flush_cache_page(void *arg)
{
	struct flush_data *fd = arg;
	local_flush_cache_page(fd->vma, fd->addr1, fd->addr2);
}

void flush_cache_page(struct vm_area_struct *vma,
		     unsigned long address, unsigned long pfn)
{
	struct flush_data fd = {
		.vma = vma,
		.addr1 = address,
		.addr2 = pfn,
	};
	on_each_cpu(ipi_flush_cache_page, &fd, 1);
}

static void ipi_flush_cache_range(void *arg)
{
	struct flush_data *fd = arg;
	local_flush_cache_range(fd->vma, fd->addr1, fd->addr2);
}

void flush_cache_range(struct vm_area_struct *vma,
		     unsigned long start, unsigned long end)
{
	struct flush_data fd = {
		.vma = vma,
		.addr1 = start,
		.addr2 = end,
	};
	on_each_cpu(ipi_flush_cache_range, &fd, 1);
}

static void ipi_flush_icache_range(void *arg)
{
	struct flush_data *fd = arg;
	local_flush_icache_range(fd->addr1, fd->addr2);
}

void flush_icache_range(unsigned long start, unsigned long end)
{
	struct flush_data fd = {
		.addr1 = start,
		.addr2 = end,
	};
	on_each_cpu(ipi_flush_icache_range, &fd, 1);
}
EXPORT_SYMBOL(flush_icache_range);

/* ------------------------------------------------------------------------- */

static void ipi_invalidate_dcache_range(void *arg)
{
	struct flush_data *fd = arg;
	__invalidate_dcache_range(fd->addr1, fd->addr2);
}

static void system_invalidate_dcache_range(unsigned long start,
		unsigned long size)
{
	struct flush_data fd = {
		.addr1 = start,
		.addr2 = size,
	};
	on_each_cpu(ipi_invalidate_dcache_range, &fd, 1);
}

static void ipi_flush_invalidate_dcache_range(void *arg)
{
	struct flush_data *fd = arg;
	__flush_invalidate_dcache_range(fd->addr1, fd->addr2);
}

static void system_flush_invalidate_dcache_range(unsigned long start,
		unsigned long size)
{
	struct flush_data fd = {
		.addr1 = start,
		.addr2 = size,
	};
	on_each_cpu(ipi_flush_invalidate_dcache_range, &fd, 1);
}