aboutsummaryrefslogtreecommitdiff
path: root/arch/x86/kernel/smpboot.c
blob: 5bff87e99898fe7d6f86c86e8abcc0937831b0df (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
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/percpu.h>
#include <linux/bootmem.h>

#include <asm/nmi.h>
#include <asm/irq.h>
#include <asm/smp.h>
#include <asm/cpu.h>
#include <asm/numa.h>

#include <mach_apic.h>

/* Number of siblings per CPU package */
int smp_num_siblings = 1;
EXPORT_SYMBOL(smp_num_siblings);

/* Last level cache ID of each logical CPU */
DEFINE_PER_CPU(u16, cpu_llc_id) = BAD_APICID;

/* bitmap of online cpus */
cpumask_t cpu_online_map __read_mostly;
EXPORT_SYMBOL(cpu_online_map);

cpumask_t cpu_callin_map;
cpumask_t cpu_callout_map;
cpumask_t cpu_possible_map;
EXPORT_SYMBOL(cpu_possible_map);

/* representing HT siblings of each logical CPU */
DEFINE_PER_CPU(cpumask_t, cpu_sibling_map);
EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);

/* representing HT and core siblings of each logical CPU */
DEFINE_PER_CPU(cpumask_t, cpu_core_map);
EXPORT_PER_CPU_SYMBOL(cpu_core_map);

/* Per CPU bogomips and other parameters */
DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
EXPORT_PER_CPU_SYMBOL(cpu_info);

/* ready for x86_64, no harm for x86, since it will overwrite after alloc */
unsigned char *trampoline_base = __va(SMP_TRAMPOLINE_BASE);

/* representing cpus for which sibling maps can be computed */
static cpumask_t cpu_sibling_setup_map;

/* Set if we find a B stepping CPU */
int __cpuinitdata smp_b_stepping;

#if defined(CONFIG_NUMA) && defined(CONFIG_X86_32)

/* which logical CPUs are on which nodes */
cpumask_t node_to_cpumask_map[MAX_NUMNODES] __read_mostly =
				{ [0 ... MAX_NUMNODES-1] = CPU_MASK_NONE };
EXPORT_SYMBOL(node_to_cpumask_map);
/* which node each logical CPU is on */
int cpu_to_node_map[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0 };
EXPORT_SYMBOL(cpu_to_node_map);

/* set up a mapping between cpu and node. */
static void map_cpu_to_node(int cpu, int node)
{
	printk(KERN_INFO "Mapping cpu %d to node %d\n", cpu, node);
	cpu_set(cpu, node_to_cpumask_map[node]);
	cpu_to_node_map[cpu] = node;
}

/* undo a mapping between cpu and node. */
static void unmap_cpu_to_node(int cpu)
{
	int node;

	printk(KERN_INFO "Unmapping cpu %d from all nodes\n", cpu);
	for (node = 0; node < MAX_NUMNODES; node++)
		cpu_clear(cpu, node_to_cpumask_map[node]);
	cpu_to_node_map[cpu] = 0;
}
#else /* !(CONFIG_NUMA && CONFIG_X86_32) */
#define map_cpu_to_node(cpu, node)	({})
#define unmap_cpu_to_node(cpu)	({})
#endif

#ifdef CONFIG_X86_32
u8 cpu_2_logical_apicid[NR_CPUS] __read_mostly =
					{ [0 ... NR_CPUS-1] = BAD_APICID };

void map_cpu_to_logical_apicid(void)
{
	int cpu = smp_processor_id();
	int apicid = logical_smp_processor_id();
	int node = apicid_to_node(apicid);

	if (!node_online(node))
		node = first_online_node;

	cpu_2_logical_apicid[cpu] = apicid;
	map_cpu_to_node(cpu, node);
}

void unmap_cpu_to_logical_apicid(int cpu)
{
	cpu_2_logical_apicid[cpu] = BAD_APICID;
	unmap_cpu_to_node(cpu);
}
#else
#define unmap_cpu_to_logical_apicid(cpu) do {} while (0)
#define map_cpu_to_logical_apicid()  do {} while (0)
#endif

static void __cpuinit smp_apply_quirks(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_X86_32
	/*
	 * Mask B, Pentium, but not Pentium MMX
	 */
	if (c->x86_vendor == X86_VENDOR_INTEL &&
	    c->x86 == 5 &&
	    c->x86_mask >= 1 && c->x86_mask <= 4 &&
	    c->x86_model <= 3)
		/*
		 * Remember we have B step Pentia with bugs
		 */
		smp_b_stepping = 1;

	/*
	 * Certain Athlons might work (for various values of 'work') in SMP
	 * but they are not certified as MP capable.
	 */
	if ((c->x86_vendor == X86_VENDOR_AMD) && (c->x86 == 6)) {

		if (num_possible_cpus() == 1)
			goto valid_k7;

		/* Athlon 660/661 is valid. */
		if ((c->x86_model == 6) && ((c->x86_mask == 0) ||
		    (c->x86_mask == 1)))
			goto valid_k7;

		/* Duron 670 is valid */
		if ((c->x86_model == 7) && (c->x86_mask == 0))
			goto valid_k7;

		/*
		 * Athlon 662, Duron 671, and Athlon >model 7 have capability
		 * bit. It's worth noting that the A5 stepping (662) of some
		 * Athlon XP's have the MP bit set.
		 * See http://www.heise.de/newsticker/data/jow-18.10.01-000 for
		 * more.
		 */
		if (((c->x86_model == 6) && (c->x86_mask >= 2)) ||
		    ((c->x86_model == 7) && (c->x86_mask >= 1)) ||
		     (c->x86_model > 7))
			if (cpu_has_mp)
				goto valid_k7;

		/* If we get here, not a certified SMP capable AMD system. */
		add_taint(TAINT_UNSAFE_SMP);
	}

valid_k7:
	;
#endif
}

void smp_checks(void)
{
	if (smp_b_stepping)
		printk(KERN_WARNING "WARNING: SMP operation may be unreliable"
				    "with B stepping processors.\n");

	/*
	 * Don't taint if we are running SMP kernel on a single non-MP
	 * approved Athlon
	 */
	if (tainted & TAINT_UNSAFE_SMP) {
		if (num_online_cpus())
			printk(KERN_INFO "WARNING: This combination of AMD"
				"processors is not suitable for SMP.\n");
		else
			tainted &= ~TAINT_UNSAFE_SMP;
	}
}

/*
 * The bootstrap kernel entry code has set these up. Save them for
 * a given CPU
 */

void __cpuinit smp_store_cpu_info(int id)
{
	struct cpuinfo_x86 *c = &cpu_data(id);

	*c = boot_cpu_data;
	c->cpu_index = id;
	if (id != 0)
		identify_secondary_cpu(c);
	smp_apply_quirks(c);
}


void __cpuinit set_cpu_sibling_map(int cpu)
{
	int i;
	struct cpuinfo_x86 *c = &cpu_data(cpu);

	cpu_set(cpu, cpu_sibling_setup_map);

	if (smp_num_siblings > 1) {
		for_each_cpu_mask(i, cpu_sibling_setup_map) {
			if (c->phys_proc_id == cpu_data(i).phys_proc_id &&
			    c->cpu_core_id == cpu_data(i).cpu_core_id) {
				cpu_set(i, per_cpu(cpu_sibling_map, cpu));
				cpu_set(cpu, per_cpu(cpu_sibling_map, i));
				cpu_set(i, per_cpu(cpu_core_map, cpu));
				cpu_set(cpu, per_cpu(cpu_core_map, i));
				cpu_set(i, c->llc_shared_map);
				cpu_set(cpu, cpu_data(i).llc_shared_map);
			}
		}
	} else {
		cpu_set(cpu, per_cpu(cpu_sibling_map, cpu));
	}

	cpu_set(cpu, c->llc_shared_map);

	if (current_cpu_data.x86_max_cores == 1) {
		per_cpu(cpu_core_map, cpu) = per_cpu(cpu_sibling_map, cpu);
		c->booted_cores = 1;
		return;
	}

	for_each_cpu_mask(i, cpu_sibling_setup_map) {
		if (per_cpu(cpu_llc_id, cpu) != BAD_APICID &&
		    per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i)) {
			cpu_set(i, c->llc_shared_map);
			cpu_set(cpu, cpu_data(i).llc_shared_map);
		}
		if (c->phys_proc_id == cpu_data(i).phys_proc_id) {
			cpu_set(i, per_cpu(cpu_core_map, cpu));
			cpu_set(cpu, per_cpu(cpu_core_map, i));
			/*
			 *  Does this new cpu bringup a new core?
			 */
			if (cpus_weight(per_cpu(cpu_sibling_map, cpu)) == 1) {
				/*
				 * for each core in package, increment
				 * the booted_cores for this new cpu
				 */
				if (first_cpu(per_cpu(cpu_sibling_map, i)) == i)
					c->booted_cores++;
				/*
				 * increment the core count for all
				 * the other cpus in this package
				 */
				if (i != cpu)
					cpu_data(i).booted_cores++;
			} else if (i != cpu && !c->booted_cores)
				c->booted_cores = cpu_data(i).booted_cores;
		}
	}
}

/* maps the cpu to the sched domain representing multi-core */
cpumask_t cpu_coregroup_map(int cpu)
{
	struct cpuinfo_x86 *c = &cpu_data(cpu);
	/*
	 * For perf, we return last level cache shared map.
	 * And for power savings, we return cpu_core_map
	 */
	if (sched_mc_power_savings || sched_smt_power_savings)
		return per_cpu(cpu_core_map, cpu);
	else
		return c->llc_shared_map;
}

/*
 * Currently trivial. Write the real->protected mode
 * bootstrap into the page concerned. The caller
 * has made sure it's suitably aligned.
 */

unsigned long __cpuinit setup_trampoline(void)
{
	memcpy(trampoline_base, trampoline_data,
	       trampoline_end - trampoline_data);
	return virt_to_phys(trampoline_base);
}

#ifdef CONFIG_X86_32
/*
 * We are called very early to get the low memory for the
 * SMP bootup trampoline page.
 */
void __init smp_alloc_memory(void)
{
	trampoline_base = alloc_bootmem_low_pages(PAGE_SIZE);
	/*
	 * Has to be in very low memory so we can execute
	 * real-mode AP code.
	 */
	if (__pa(trampoline_base) >= 0x9F000)
		BUG();
}
#endif

void impress_friends(void)
{
	int cpu;
	unsigned long bogosum = 0;
	/*
	 * Allow the user to impress friends.
	 */
	Dprintk("Before bogomips.\n");
	for_each_possible_cpu(cpu)
		if (cpu_isset(cpu, cpu_callout_map))
			bogosum += cpu_data(cpu).loops_per_jiffy;
	printk(KERN_INFO
		"Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
		num_online_cpus(),
		bogosum/(500000/HZ),
		(bogosum/(5000/HZ))%100);

	Dprintk("Before bogocount - setting activated=1.\n");
}

#ifdef CONFIG_HOTPLUG_CPU
void remove_siblinginfo(int cpu)
{
	int sibling;
	struct cpuinfo_x86 *c = &cpu_data(cpu);

	for_each_cpu_mask(sibling, per_cpu(cpu_core_map, cpu)) {
		cpu_clear(cpu, per_cpu(cpu_core_map, sibling));
		/*/
		 * last thread sibling in this cpu core going down
		 */
		if (cpus_weight(per_cpu(cpu_sibling_map, cpu)) == 1)
			cpu_data(sibling).booted_cores--;
	}

	for_each_cpu_mask(sibling, per_cpu(cpu_sibling_map, cpu))
		cpu_clear(cpu, per_cpu(cpu_sibling_map, sibling));
	cpus_clear(per_cpu(cpu_sibling_map, cpu));
	cpus_clear(per_cpu(cpu_core_map, cpu));
	c->phys_proc_id = 0;
	c->cpu_core_id = 0;
	cpu_clear(cpu, cpu_sibling_setup_map);
}

int additional_cpus __initdata = -1;

static __init int setup_additional_cpus(char *s)
{
	return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;
}
early_param("additional_cpus", setup_additional_cpus);

/*
 * cpu_possible_map should be static, it cannot change as cpu's
 * are onlined, or offlined. The reason is per-cpu data-structures
 * are allocated by some modules at init time, and dont expect to
 * do this dynamically on cpu arrival/departure.
 * cpu_present_map on the other hand can change dynamically.
 * In case when cpu_hotplug is not compiled, then we resort to current
 * behaviour, which is cpu_possible == cpu_present.
 * - Ashok Raj
 *
 * Three ways to find out the number of additional hotplug CPUs:
 * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
 * - The user can overwrite it with additional_cpus=NUM
 * - Otherwise don't reserve additional CPUs.
 * We do this because additional CPUs waste a lot of memory.
 * -AK
 */
__init void prefill_possible_map(void)
{
	int i;
	int possible;

	if (additional_cpus == -1) {
		if (disabled_cpus > 0)
			additional_cpus = disabled_cpus;
		else
			additional_cpus = 0;
	}
	possible = num_processors + additional_cpus;
	if (possible > NR_CPUS)
		possible = NR_CPUS;

	printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
		possible, max_t(int, possible - num_processors, 0));

	for (i = 0; i < possible; i++)
		cpu_set(i, cpu_possible_map);
}

static void __ref remove_cpu_from_maps(int cpu)
{
	cpu_clear(cpu, cpu_online_map);
#ifdef CONFIG_X86_64
	cpu_clear(cpu, cpu_callout_map);
	cpu_clear(cpu, cpu_callin_map);
	/* was set by cpu_init() */
	clear_bit(cpu, (unsigned long *)&cpu_initialized);
	clear_node_cpumask(cpu);
#endif
}

int __cpu_disable(void)
{
	int cpu = smp_processor_id();

	/*
	 * Perhaps use cpufreq to drop frequency, but that could go
	 * into generic code.
	 *
	 * We won't take down the boot processor on i386 due to some
	 * interrupts only being able to be serviced by the BSP.
	 * Especially so if we're not using an IOAPIC	-zwane
	 */
	if (cpu == 0)
		return -EBUSY;

	if (nmi_watchdog == NMI_LOCAL_APIC)
		stop_apic_nmi_watchdog(NULL);
	clear_local_APIC();

	/*
	 * HACK:
	 * Allow any queued timer interrupts to get serviced
	 * This is only a temporary solution until we cleanup
	 * fixup_irqs as we do for IA64.
	 */
	local_irq_enable();
	mdelay(1);

	local_irq_disable();
	remove_siblinginfo(cpu);

	/* It's now safe to remove this processor from the online map */
	remove_cpu_from_maps(cpu);
	fixup_irqs(cpu_online_map);
	return 0;
}

void __cpu_die(unsigned int cpu)
{
	/* We don't do anything here: idle task is faking death itself. */
	unsigned int i;

	for (i = 0; i < 10; i++) {
		/* They ack this in play_dead by setting CPU_DEAD */
		if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
			printk(KERN_INFO "CPU %d is now offline\n", cpu);
			if (1 == num_online_cpus())
				alternatives_smp_switch(0);
			return;
		}
		msleep(100);
	}
	printk(KERN_ERR "CPU %u didn't die...\n", cpu);
}
#else /* ... !CONFIG_HOTPLUG_CPU */
int __cpu_disable(void)
{
	return -ENOSYS;
}

void __cpu_die(unsigned int cpu)
{
	/* We said "no" in __cpu_disable */
	BUG();
}
#endif

/*
 * If the BIOS enumerates physical processors before logical,
 * maxcpus=N at enumeration-time can be used to disable HT.
 */
static int __init parse_maxcpus(char *arg)
{
	extern unsigned int maxcpus;

	maxcpus = simple_strtoul(arg, NULL, 0);
	return 0;
}
early_param("maxcpus", parse_maxcpus);