aboutsummaryrefslogtreecommitdiff
path: root/arch/powerpc/platforms/pseries/smp.c
blob: ac61098ff401ca90c586243cb7f3b17eacdf5a1a (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
/*
 * SMP support for pSeries machines.
 *
 * Dave Engebretsen, Peter Bergner, and
 * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
 *
 * Plus various changes from other IBM teams...
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#undef DEBUG

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/err.h>
#include <linux/sysdev.h>
#include <linux/cpu.h>

#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/irq.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/smp.h>
#include <asm/paca.h>
#include <asm/time.h>
#include <asm/machdep.h>
#include "xics.h"
#include <asm/cputable.h>
#include <asm/firmware.h>
#include <asm/system.h>
#include <asm/rtas.h>
#include <asm/pSeries_reconfig.h>
#include <asm/mpic.h>
#include <asm/vdso_datapage.h>

#include "plpar_wrappers.h"

#ifdef DEBUG
#include <asm/udbg.h>
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

/*
 * The primary thread of each non-boot processor is recorded here before
 * smp init.
 */
static cpumask_t of_spin_map;

extern void pSeries_secondary_smp_init(unsigned long);

#ifdef CONFIG_HOTPLUG_CPU

/* Get state of physical CPU.
 * Return codes:
 *	0	- The processor is in the RTAS stopped state
 *	1	- stop-self is in progress
 *	2	- The processor is not in the RTAS stopped state
 *	-1	- Hardware Error
 *	-2	- Hardware Busy, Try again later.
 */
static int query_cpu_stopped(unsigned int pcpu)
{
	int cpu_status;
	int status, qcss_tok;

	qcss_tok = rtas_token("query-cpu-stopped-state");
	if (qcss_tok == RTAS_UNKNOWN_SERVICE)
		return -1;
	status = rtas_call(qcss_tok, 1, 2, &cpu_status, pcpu);
	if (status != 0) {
		printk(KERN_ERR
		       "RTAS query-cpu-stopped-state failed: %i\n", status);
		return status;
	}

	return cpu_status;
}

static int pSeries_cpu_disable(void)
{
	int cpu = smp_processor_id();

	cpu_clear(cpu, cpu_online_map);
	vdso_data->processorCount--;

	/*fix boot_cpuid here*/
	if (cpu == boot_cpuid)
		boot_cpuid = any_online_cpu(cpu_online_map);

	/* FIXME: abstract this to not be platform specific later on */
	xics_migrate_irqs_away();
	return 0;
}

static void pSeries_cpu_die(unsigned int cpu)
{
	int tries;
	int cpu_status;
	unsigned int pcpu = get_hard_smp_processor_id(cpu);

	for (tries = 0; tries < 25; tries++) {
		cpu_status = query_cpu_stopped(pcpu);
		if (cpu_status == 0 || cpu_status == -1)
			break;
		msleep(200);
	}
	if (cpu_status != 0) {
		printk("Querying DEAD? cpu %i (%i) shows %i\n",
		       cpu, pcpu, cpu_status);
	}

	/* Isolation and deallocation are definatly done by
	 * drslot_chrp_cpu.  If they were not they would be
	 * done here.  Change isolate state to Isolate and
	 * change allocation-state to Unusable.
	 */
	paca[cpu].cpu_start = 0;
}

/*
 * Update cpu_present_map and paca(s) for a new cpu node.  The wrinkle
 * here is that a cpu device node may represent up to two logical cpus
 * in the SMT case.  We must honor the assumption in other code that
 * the logical ids for sibling SMT threads x and y are adjacent, such
 * that x^1 == y and y^1 == x.
 */
static int pSeries_add_processor(struct device_node *np)
{
	unsigned int cpu;
	cpumask_t candidate_map, tmp = CPU_MASK_NONE;
	int err = -ENOSPC, len, nthreads, i;
	u32 *intserv;

	intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
	if (!intserv)
		return 0;

	nthreads = len / sizeof(u32);
	for (i = 0; i < nthreads; i++)
		cpu_set(i, tmp);

	lock_cpu_hotplug();

	BUG_ON(!cpus_subset(cpu_present_map, cpu_possible_map));

	/* Get a bitmap of unoccupied slots. */
	cpus_xor(candidate_map, cpu_possible_map, cpu_present_map);
	if (cpus_empty(candidate_map)) {
		/* If we get here, it most likely means that NR_CPUS is
		 * less than the partition's max processors setting.
		 */
		printk(KERN_ERR "Cannot add cpu %s; this system configuration"
		       " supports %d logical cpus.\n", np->full_name,
		       cpus_weight(cpu_possible_map));
		goto out_unlock;
	}

	while (!cpus_empty(tmp))
		if (cpus_subset(tmp, candidate_map))
			/* Found a range where we can insert the new cpu(s) */
			break;
		else
			cpus_shift_left(tmp, tmp, nthreads);

	if (cpus_empty(tmp)) {
		printk(KERN_ERR "Unable to find space in cpu_present_map for"
		       " processor %s with %d thread(s)\n", np->name,
		       nthreads);
		goto out_unlock;
	}

	for_each_cpu_mask(cpu, tmp) {
		BUG_ON(cpu_isset(cpu, cpu_present_map));
		cpu_set(cpu, cpu_present_map);
		set_hard_smp_processor_id(cpu, *intserv++);
	}
	err = 0;
out_unlock:
	unlock_cpu_hotplug();
	return err;
}

/*
 * Update the present map for a cpu node which is going away, and set
 * the hard id in the paca(s) to -1 to be consistent with boot time
 * convention for non-present cpus.
 */
static void pSeries_remove_processor(struct device_node *np)
{
	unsigned int cpu;
	int len, nthreads, i;
	u32 *intserv;

	intserv = (u32 *)get_property(np, "ibm,ppc-interrupt-server#s", &len);
	if (!intserv)
		return;

	nthreads = len / sizeof(u32);

	lock_cpu_hotplug();
	for (i = 0; i < nthreads; i++) {
		for_each_present_cpu(cpu) {
			if (get_hard_smp_processor_id(cpu) != intserv[i])
				continue;
			BUG_ON(cpu_online(cpu));
			cpu_clear(cpu, cpu_present_map);
			set_hard_smp_processor_id(cpu, -1);
			break;
		}
		if (cpu == NR_CPUS)
			printk(KERN_WARNING "Could not find cpu to remove "
			       "with physical id 0x%x\n", intserv[i]);
	}
	unlock_cpu_hotplug();
}

static int pSeries_smp_notifier(struct notifier_block *nb, unsigned long action, void *node)
{
	int err = NOTIFY_OK;

	switch (action) {
	case PSERIES_RECONFIG_ADD:
		if (pSeries_add_processor(node))
			err = NOTIFY_BAD;
		break;
	case PSERIES_RECONFIG_REMOVE:
		pSeries_remove_processor(node);
		break;
	default:
		err = NOTIFY_DONE;
		break;
	}
	return err;
}

static struct notifier_block pSeries_smp_nb = {
	.notifier_call = pSeries_smp_notifier,
};

#endif /* CONFIG_HOTPLUG_CPU */

/**
 * smp_startup_cpu() - start the given cpu
 *
 * At boot time, there is nothing to do for primary threads which were
 * started from Open Firmware.  For anything else, call RTAS with the
 * appropriate start location.
 *
 * Returns:
 *	0	- failure
 *	1	- success
 */
static inline int __devinit smp_startup_cpu(unsigned int lcpu)
{
	int status;
	unsigned long start_here = __pa((u32)*((unsigned long *)
					       pSeries_secondary_smp_init));
	unsigned int pcpu;
	int start_cpu;

	if (cpu_isset(lcpu, of_spin_map))
		/* Already started by OF and sitting in spin loop */
		return 1;

	pcpu = get_hard_smp_processor_id(lcpu);

	/* Fixup atomic count: it exited inside IRQ handler. */
	task_thread_info(paca[lcpu].__current)->preempt_count	= 0;

	/* 
	 * If the RTAS start-cpu token does not exist then presume the
	 * cpu is already spinning.
	 */
	start_cpu = rtas_token("start-cpu");
	if (start_cpu == RTAS_UNKNOWN_SERVICE)
		return 1;

	status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, pcpu);
	if (status != 0) {
		printk(KERN_ERR "start-cpu failed: %i\n", status);
		return 0;
	}

	return 1;
}

#ifdef CONFIG_XICS
static inline void smp_xics_do_message(int cpu, int msg)
{
	set_bit(msg, &xics_ipi_message[cpu].value);
	mb();
	xics_cause_IPI(cpu);
}

static void smp_xics_message_pass(int target, int msg)
{
	unsigned int i;

	if (target < NR_CPUS) {
		smp_xics_do_message(target, msg);
	} else {
		for_each_online_cpu(i) {
			if (target == MSG_ALL_BUT_SELF
			    && i == smp_processor_id())
				continue;
			smp_xics_do_message(i, msg);
		}
	}
}

static int __init smp_xics_probe(void)
{
	xics_request_IPIs();

	return cpus_weight(cpu_possible_map);
}

static void __devinit smp_xics_setup_cpu(int cpu)
{
	if (cpu != boot_cpuid)
		xics_setup_cpu();

	if (firmware_has_feature(FW_FEATURE_SPLPAR))
		vpa_init(cpu);

	cpu_clear(cpu, of_spin_map);

}
#endif /* CONFIG_XICS */

static DEFINE_SPINLOCK(timebase_lock);
static unsigned long timebase = 0;

static void __devinit pSeries_give_timebase(void)
{
	spin_lock(&timebase_lock);
	rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
	timebase = get_tb();
	spin_unlock(&timebase_lock);

	while (timebase)
		barrier();
	rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
}

static void __devinit pSeries_take_timebase(void)
{
	while (!timebase)
		barrier();
	spin_lock(&timebase_lock);
	set_tb(timebase >> 32, timebase & 0xffffffff);
	timebase = 0;
	spin_unlock(&timebase_lock);
}

static void __devinit smp_pSeries_kick_cpu(int nr)
{
	BUG_ON(nr < 0 || nr >= NR_CPUS);

	if (!smp_startup_cpu(nr))
		return;

	/*
	 * The processor is currently spinning, waiting for the
	 * cpu_start field to become non-zero After we set cpu_start,
	 * the processor will continue on to secondary_start
	 */
	paca[nr].cpu_start = 1;
}

static int smp_pSeries_cpu_bootable(unsigned int nr)
{
	/* Special case - we inhibit secondary thread startup
	 * during boot if the user requests it.  Odd-numbered
	 * cpus are assumed to be secondary threads.
	 */
	if (system_state < SYSTEM_RUNNING &&
	    cpu_has_feature(CPU_FTR_SMT) &&
	    !smt_enabled_at_boot && nr % 2 != 0)
		return 0;

	return 1;
}
#ifdef CONFIG_MPIC
static struct smp_ops_t pSeries_mpic_smp_ops = {
	.message_pass	= smp_mpic_message_pass,
	.probe		= smp_mpic_probe,
	.kick_cpu	= smp_pSeries_kick_cpu,
	.setup_cpu	= smp_mpic_setup_cpu,
};
#endif
#ifdef CONFIG_XICS
static struct smp_ops_t pSeries_xics_smp_ops = {
	.message_pass	= smp_xics_message_pass,
	.probe		= smp_xics_probe,
	.kick_cpu	= smp_pSeries_kick_cpu,
	.setup_cpu	= smp_xics_setup_cpu,
	.cpu_bootable	= smp_pSeries_cpu_bootable,
};
#endif

/* This is called very early */
static void __init smp_init_pseries(void)
{
	int i;

	DBG(" -> smp_init_pSeries()\n");

#ifdef CONFIG_HOTPLUG_CPU
	smp_ops->cpu_disable = pSeries_cpu_disable;
	smp_ops->cpu_die = pSeries_cpu_die;

	/* Processors can be added/removed only on LPAR */
	if (firmware_has_feature(FW_FEATURE_LPAR))
		pSeries_reconfig_notifier_register(&pSeries_smp_nb);
#endif

	/* Mark threads which are still spinning in hold loops. */
	if (cpu_has_feature(CPU_FTR_SMT)) {
		for_each_present_cpu(i) { 
			if (i % 2 == 0)
				/*
				 * Even-numbered logical cpus correspond to
				 * primary threads.
				 */
				cpu_set(i, of_spin_map);
		}
	} else {
		of_spin_map = cpu_present_map;
	}

	cpu_clear(boot_cpuid, of_spin_map);

	/* Non-lpar has additional take/give timebase */
	if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
		smp_ops->give_timebase = pSeries_give_timebase;
		smp_ops->take_timebase = pSeries_take_timebase;
	}

	DBG(" <- smp_init_pSeries()\n");
}

#ifdef CONFIG_MPIC
void __init smp_init_pseries_mpic(void)
{
	smp_ops = &pSeries_mpic_smp_ops;

	smp_init_pseries();
}
#endif

void __init smp_init_pseries_xics(void)
{
	smp_ops = &pSeries_xics_smp_ops;

	smp_init_pseries();
}