smpboot.c 34.0 KB
Newer Older
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
/*
 *	x86 SMP booting functions
 *
 *	(c) 1995 Alan Cox, Building #3 <alan@redhat.com>
 *	(c) 1998, 1999, 2000 Ingo Molnar <mingo@redhat.com>
 *	Copyright 2001 Andi Kleen, SuSE Labs.
 *
 *	Much of the core SMP work is based on previous work by Thomas Radke, to
 *	whom a great many thanks are extended.
 *
 *	Thanks to Intel for making available several different Pentium,
 *	Pentium Pro and Pentium-II/Xeon MP machines.
 *	Original development of Linux SMP code supported by Caldera.
 *
 *	This code is released under the GNU General Public License version 2 or
 *	later.
 *
 *	Fixes
 *		Felix Koop	:	NR_CPUS used properly
 *		Jose Renau	:	Handle single CPU case.
 *		Alan Cox	:	By repeated request 8) - Total BogoMIPS report.
 *		Greg Wright	:	Fix for kernel stacks panic.
 *		Erich Boleyn	:	MP v1.4 and additional changes.
 *	Matthias Sattler	:	Changes for 2.1 kernel map.
 *	Michel Lespinasse	:	Changes for 2.1 kernel map.
 *	Michael Chastain	:	Change trampoline.S to gnu as.
 *		Alan Cox	:	Dumb bug: 'B' step PPro's are fine
 *		Ingo Molnar	:	Added APIC timers, based on code
 *					from Jose Renau
 *		Ingo Molnar	:	various cleanups and rewrites
 *		Tigran Aivazian	:	fixed "0.00 in /proc/uptime on SMP" bug.
 *	Maciej W. Rozycki	:	Bits for genuine 82489DX APICs
 *	Andi Kleen		:	Changed for SMP boot into long mode.
 *		Martin J. Bligh	: 	Added support for multi-quad systems
 *		Dave Jones	:	Report invalid combinations of Athlon CPUs.
 *		Rusty Russell	:	Hacked into shape for new "hotplug" boot process.
 *      Andi Kleen              :       Converted to new state machine.
 *	Ashok Raj		: 	CPU hotplug support
 *	Glauber Costa		:	i386 and x86_64 integration
 */

42 43
#include <linux/init.h>
#include <linux/smp.h>
44
#include <linux/module.h>
45
#include <linux/sched.h>
46
#include <linux/percpu.h>
G
Glauber Costa 已提交
47
#include <linux/bootmem.h>
48 49
#include <linux/err.h>
#include <linux/nmi.h>
50

51
#include <asm/acpi.h>
52
#include <asm/desc.h>
53 54 55
#include <asm/nmi.h>
#include <asm/irq.h>
#include <asm/smp.h>
56
#include <asm/trampoline.h>
57 58
#include <asm/cpu.h>
#include <asm/numa.h>
59 60 61
#include <asm/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/mtrr.h>
62
#include <asm/vmi.h>
J
Jack Steiner 已提交
63
#include <asm/genapic.h>
64
#include <linux/mc146818rtc.h>
65

66
#include <mach_apic.h>
67 68 69
#include <mach_wakecpu.h>
#include <smpboot_hooks.h>

70
#ifdef CONFIG_X86_32
71
u8 apicid_2_node[MAX_APICID];
72
static int low_mappings;
73 74
#endif

75 76 77
/* State of each CPU */
DEFINE_PER_CPU(int, cpu_state) = { 0 };

78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94
/* Store all idle threads, this can be reused instead of creating
* a new thread. Also avoids complicated thread destroy functionality
* for idle threads.
*/
#ifdef CONFIG_HOTPLUG_CPU
/*
 * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
 * removed after init for !CONFIG_HOTPLUG_CPU.
 */
static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
#define get_idle_for_cpu(x)      (per_cpu(idle_thread_array, x))
#define set_idle_for_cpu(x, p)   (per_cpu(idle_thread_array, x) = (p))
#else
struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
#define get_idle_for_cpu(x)      (idle_thread_array[(x)])
#define set_idle_for_cpu(x, p)   (idle_thread_array[(x)] = (p))
#endif
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
/* 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);
123

124 125
static atomic_t init_deasserted;

126 127
static int boot_cpu_logical_apicid;

128 129 130
/* representing cpus for which sibling maps can be computed */
static cpumask_t cpu_sibling_setup_map;

131 132 133
/* Set if we find a B stepping CPU */
int __cpuinitdata smp_b_stepping;

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
#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 };

I
Ingo Molnar 已提交
171
static void map_cpu_to_logical_apicid(void)
172 173 174 175 176 177 178 179 180 181 182 183
{
	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);
}

184
void numa_remove_cpu(int cpu)
185 186 187 188 189 190 191 192
{
	cpu_2_logical_apicid[cpu] = BAD_APICID;
	unmap_cpu_to_node(cpu);
}
#else
#define map_cpu_to_logical_apicid()  do {} while (0)
#endif

193 194 195 196
/*
 * Report back to the Boot Processor.
 * Running on AP.
 */
I
Ingo Molnar 已提交
197
static void __cpuinit smp_callin(void)
198 199 200 201 202 203 204 205 206 207 208 209 210 211 212
{
	int cpuid, phys_id;
	unsigned long timeout;

	/*
	 * If waken up by an INIT in an 82489DX configuration
	 * we may get here before an INIT-deassert IPI reaches
	 * our local APIC.  We have to wait for the IPI or we'll
	 * lock up on an APIC access.
	 */
	wait_for_init_deassert(&init_deasserted);

	/*
	 * (This works even if the APIC is not enabled.)
	 */
213
	phys_id = GET_APIC_ID(read_apic_id());
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
	cpuid = smp_processor_id();
	if (cpu_isset(cpuid, cpu_callin_map)) {
		panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__,
					phys_id, cpuid);
	}
	Dprintk("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);

	/*
	 * STARTUP IPIs are fragile beasts as they might sometimes
	 * trigger some glue motherboard logic. Complete APIC bus
	 * silence for 1 second, this overestimates the time the
	 * boot CPU is spending to send the up to 2 STARTUP IPIs
	 * by a factor of two. This should be enough.
	 */

	/*
	 * Waiting 2s total for startup (udelay is not yet working)
	 */
	timeout = jiffies + 2*HZ;
	while (time_before(jiffies, timeout)) {
		/*
		 * Has the boot CPU finished it's STARTUP sequence?
		 */
		if (cpu_isset(cpuid, cpu_callout_map))
			break;
		cpu_relax();
	}

	if (!time_before(jiffies, timeout)) {
		panic("%s: CPU%d started up but did not get a callout!\n",
		      __func__, cpuid);
	}

	/*
	 * the boot CPU has finished the init stage and is spinning
	 * on callin_map until we finish. We are free to set up this
	 * CPU, first the APIC. (this is probably redundant on most
	 * boards)
	 */

	Dprintk("CALLIN, before setup_local_APIC().\n");
	smp_callin_clear_local_apic();
	setup_local_APIC();
	end_local_APIC_setup();
	map_cpu_to_logical_apicid();

	/*
	 * Get our bogomips.
	 *
	 * Need to enable IRQs because it can take longer and then
	 * the NMI watchdog might kill us.
	 */
	local_irq_enable();
	calibrate_delay();
	local_irq_disable();
	Dprintk("Stack at about %p\n", &cpuid);

	/*
	 * Save our processor parameters
	 */
	smp_store_cpu_info(cpuid);

	/*
	 * Allow the master to continue.
	 */
	cpu_set(cpuid, cpu_callin_map);
}

282 283 284
/*
 * Activate a secondary processor.
 */
A
Adrian Bunk 已提交
285
static void __cpuinit start_secondary(void *unused)
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
{
	/*
	 * Don't put *anything* before cpu_init(), SMP booting is too
	 * fragile that we want to limit the things done here to the
	 * most necessary things.
	 */
#ifdef CONFIG_VMI
	vmi_bringup();
#endif
	cpu_init();
	preempt_disable();
	smp_callin();

	/* otherwise gcc will move up smp_processor_id before the cpu_init */
	barrier();
	/*
	 * Check TSC synchronization with the BP:
	 */
	check_tsc_sync_target();

	if (nmi_watchdog == NMI_IO_APIC) {
		disable_8259A_irq(0);
		enable_NMI_through_LVT0();
		enable_8259A_irq(0);
	}

312 313 314 315 316 317
#ifdef CONFIG_X86_32
	while (low_mappings)
		cpu_relax();
	__flush_tlb_all();
#endif

318 319 320 321 322 323 324 325 326 327 328 329
	/* This must be done before setting cpu_online_map */
	set_cpu_sibling_map(raw_smp_processor_id());
	wmb();

	/*
	 * We need to hold call_lock, so there is no inconsistency
	 * between the time smp_call_function() determines number of
	 * IPI recipients, and the time when the determination is made
	 * for which cpus receive the IPI. Holding this
	 * lock helps us to not include this cpu in a currently in progress
	 * smp_call_function().
	 */
330
	ipi_call_lock_irq();
331 332
#ifdef CONFIG_X86_IO_APIC
	setup_vector_irq(smp_processor_id());
333 334
#endif
	cpu_set(smp_processor_id(), cpu_online_map);
335
	ipi_call_unlock_irq();
336 337 338 339 340 341 342 343
	per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;

	setup_secondary_clock();

	wmb();
	cpu_idle();
}

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
static void __cpuinit smp_apply_quirks(struct cpuinfo_x86 *c)
{
	/*
	 * 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:
	;
}

I
Ingo Molnar 已提交
397
static void __cpuinit smp_checks(void)
398 399 400 401 402 403 404 405 406 407
{
	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) {
408
		if (num_online_cpus())
409 410 411 412 413 414 415
			printk(KERN_INFO "WARNING: This combination of AMD"
				"processors is not suitable for SMP.\n");
		else
			tainted &= ~TAINT_UNSAFE_SMP;
	}
}

416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432
/*
 * 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);
}


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
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;
		}
	}
}

495 496 497 498 499 500 501 502 503 504 505 506 507 508
/* 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;
}

I
Ingo Molnar 已提交
509
static void impress_friends(void)
510 511 512 513 514 515 516 517 518 519 520 521
{
	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",
522
		num_online_cpus(),
523 524 525 526 527 528
		bogosum/(500000/HZ),
		(bogosum/(5000/HZ))%100);

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

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
static inline void __inquire_remote_apic(int apicid)
{
	unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
	char *names[] = { "ID", "VERSION", "SPIV" };
	int timeout;
	u32 status;

	printk(KERN_INFO "Inquiring remote APIC #%d...\n", apicid);

	for (i = 0; i < ARRAY_SIZE(regs); i++) {
		printk(KERN_INFO "... APIC #%d %s: ", apicid, names[i]);

		/*
		 * Wait for idle.
		 */
		status = safe_apic_wait_icr_idle();
		if (status)
			printk(KERN_CONT
			       "a previous APIC delivery may have failed\n");

		apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(apicid));
		apic_write_around(APIC_ICR, APIC_DM_REMRD | regs[i]);

		timeout = 0;
		do {
			udelay(100);
			status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
		} while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);

		switch (status) {
		case APIC_ICR_RR_VALID:
			status = apic_read(APIC_RRR);
			printk(KERN_CONT "%08x\n", status);
			break;
		default:
			printk(KERN_CONT "failed\n");
		}
	}
}

#ifdef WAKE_SECONDARY_VIA_NMI
/*
 * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
 * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
 * won't ... remember to clear down the APIC, etc later.
 */
static int __devinit
wakeup_secondary_cpu(int logical_apicid, unsigned long start_eip)
{
	unsigned long send_status, accept_status = 0;
	int maxlvt;

	/* Target chip */
	apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(logical_apicid));

	/* Boot on the stack */
	/* Kick the second */
	apic_write_around(APIC_ICR, APIC_DM_NMI | APIC_DEST_LOGICAL);

	Dprintk("Waiting for send to finish...\n");
	send_status = safe_apic_wait_icr_idle();

	/*
	 * Give the other CPU some time to accept the IPI.
	 */
	udelay(200);
	/*
	 * Due to the Pentium erratum 3AP.
	 */
	maxlvt = lapic_get_maxlvt();
	if (maxlvt > 3) {
		apic_read_around(APIC_SPIV);
		apic_write(APIC_ESR, 0);
	}
	accept_status = (apic_read(APIC_ESR) & 0xEF);
	Dprintk("NMI sent.\n");

	if (send_status)
		printk(KERN_ERR "APIC never delivered???\n");
	if (accept_status)
		printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);

	return (send_status | accept_status);
}
#endif	/* WAKE_SECONDARY_VIA_NMI */

#ifdef WAKE_SECONDARY_VIA_INIT
static int __devinit
wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip)
{
	unsigned long send_status, accept_status = 0;
	int maxlvt, num_starts, j;

J
Jack Steiner 已提交
622 623 624 625 626 627
	if (get_uv_system_type() == UV_NON_UNIQUE_APIC) {
		send_status = uv_wakeup_secondary(phys_apicid, start_eip);
		atomic_set(&init_deasserted, 1);
		return send_status;
	}

628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764
	/*
	 * Be paranoid about clearing APIC errors.
	 */
	if (APIC_INTEGRATED(apic_version[phys_apicid])) {
		apic_read_around(APIC_SPIV);
		apic_write(APIC_ESR, 0);
		apic_read(APIC_ESR);
	}

	Dprintk("Asserting INIT.\n");

	/*
	 * Turn INIT on target chip
	 */
	apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));

	/*
	 * Send IPI
	 */
	apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_INT_ASSERT
				| APIC_DM_INIT);

	Dprintk("Waiting for send to finish...\n");
	send_status = safe_apic_wait_icr_idle();

	mdelay(10);

	Dprintk("Deasserting INIT.\n");

	/* Target chip */
	apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));

	/* Send IPI */
	apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_DM_INIT);

	Dprintk("Waiting for send to finish...\n");
	send_status = safe_apic_wait_icr_idle();

	mb();
	atomic_set(&init_deasserted, 1);

	/*
	 * Should we send STARTUP IPIs ?
	 *
	 * Determine this based on the APIC version.
	 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
	 */
	if (APIC_INTEGRATED(apic_version[phys_apicid]))
		num_starts = 2;
	else
		num_starts = 0;

	/*
	 * Paravirt / VMI wants a startup IPI hook here to set up the
	 * target processor state.
	 */
	startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
			 (unsigned long)stack_start.sp);

	/*
	 * Run STARTUP IPI loop.
	 */
	Dprintk("#startup loops: %d.\n", num_starts);

	maxlvt = lapic_get_maxlvt();

	for (j = 1; j <= num_starts; j++) {
		Dprintk("Sending STARTUP #%d.\n", j);
		apic_read_around(APIC_SPIV);
		apic_write(APIC_ESR, 0);
		apic_read(APIC_ESR);
		Dprintk("After apic_write.\n");

		/*
		 * STARTUP IPI
		 */

		/* Target chip */
		apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));

		/* Boot on the stack */
		/* Kick the second */
		apic_write_around(APIC_ICR, APIC_DM_STARTUP
					| (start_eip >> 12));

		/*
		 * Give the other CPU some time to accept the IPI.
		 */
		udelay(300);

		Dprintk("Startup point 1.\n");

		Dprintk("Waiting for send to finish...\n");
		send_status = safe_apic_wait_icr_idle();

		/*
		 * Give the other CPU some time to accept the IPI.
		 */
		udelay(200);
		/*
		 * Due to the Pentium erratum 3AP.
		 */
		if (maxlvt > 3) {
			apic_read_around(APIC_SPIV);
			apic_write(APIC_ESR, 0);
		}
		accept_status = (apic_read(APIC_ESR) & 0xEF);
		if (send_status || accept_status)
			break;
	}
	Dprintk("After Startup.\n");

	if (send_status)
		printk(KERN_ERR "APIC never delivered???\n");
	if (accept_status)
		printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);

	return (send_status | accept_status);
}
#endif	/* WAKE_SECONDARY_VIA_INIT */

struct create_idle {
	struct work_struct work;
	struct task_struct *idle;
	struct completion done;
	int cpu;
};

static void __cpuinit do_fork_idle(struct work_struct *work)
{
	struct create_idle *c_idle =
		container_of(work, struct create_idle, work);

	c_idle->idle = fork_idle(c_idle->cpu);
	complete(&c_idle->done);
}

765
#ifdef CONFIG_X86_64
766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801
/*
 * Allocate node local memory for the AP pda.
 *
 * Must be called after the _cpu_pda pointer table is initialized.
 */
static int __cpuinit get_local_pda(int cpu)
{
	struct x8664_pda *oldpda, *newpda;
	unsigned long size = sizeof(struct x8664_pda);
	int node = cpu_to_node(cpu);

	if (cpu_pda(cpu) && !cpu_pda(cpu)->in_bootmem)
		return 0;

	oldpda = cpu_pda(cpu);
	newpda = kmalloc_node(size, GFP_ATOMIC, node);
	if (!newpda) {
		printk(KERN_ERR "Could not allocate node local PDA "
			"for CPU %d on node %d\n", cpu, node);

		if (oldpda)
			return 0;	/* have a usable pda */
		else
			return -1;
	}

	if (oldpda) {
		memcpy(newpda, oldpda, size);
		if (!after_bootmem)
			free_bootmem((unsigned long)oldpda, size);
	}

	newpda->in_bootmem = 0;
	cpu_pda(cpu) = newpda;
	return 0;
}
802
#endif /* CONFIG_X86_64 */
803

804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820
static int __cpuinit do_boot_cpu(int apicid, int cpu)
/*
 * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
 * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
 * Returns zero if CPU booted OK, else error code from wakeup_secondary_cpu.
 */
{
	unsigned long boot_error = 0;
	int timeout;
	unsigned long start_ip;
	unsigned short nmi_high = 0, nmi_low = 0;
	struct create_idle c_idle = {
		.cpu = cpu,
		.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
	};
	INIT_WORK(&c_idle.work, do_fork_idle);

821
#ifdef CONFIG_X86_64
822
	/* Allocate node local memory for AP pdas */
823 824 825 826 827
	if (cpu > 0) {
		boot_error = get_local_pda(cpu);
		if (boot_error)
			goto restore_state;
			/* if can't get pda memory, can't start cpu */
828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868
	}
#endif

	alternatives_smp_switch(1);

	c_idle.idle = get_idle_for_cpu(cpu);

	/*
	 * We can't use kernel_thread since we must avoid to
	 * reschedule the child.
	 */
	if (c_idle.idle) {
		c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)
			(THREAD_SIZE +  task_stack_page(c_idle.idle))) - 1);
		init_idle(c_idle.idle, cpu);
		goto do_rest;
	}

	if (!keventd_up() || current_is_keventd())
		c_idle.work.func(&c_idle.work);
	else {
		schedule_work(&c_idle.work);
		wait_for_completion(&c_idle.done);
	}

	if (IS_ERR(c_idle.idle)) {
		printk("failed fork for CPU %d\n", cpu);
		return PTR_ERR(c_idle.idle);
	}

	set_idle_for_cpu(cpu, c_idle.idle);
do_rest:
#ifdef CONFIG_X86_32
	per_cpu(current_task, cpu) = c_idle.idle;
	init_gdt(cpu);
	/* Stack for startup_32 can be just as for start_secondary onwards */
	irq_ctx_init(cpu);
#else
	cpu_pda(cpu)->pcurrent = c_idle.idle;
	clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
#endif
869
	early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
870
	initial_code = (unsigned long)start_secondary;
G
Glauber Costa 已提交
871
	stack_start.sp = (void *) c_idle.idle->thread.sp;
872 873 874 875 876 877 878 879 880 881 882 883 884 885 886

	/* start_ip had better be page-aligned! */
	start_ip = setup_trampoline();

	/* So we see what's up   */
	printk(KERN_INFO "Booting processor %d/%d ip %lx\n",
			  cpu, apicid, start_ip);

	/*
	 * This grunge runs the startup process for
	 * the targeted processor.
	 */

	atomic_set(&init_deasserted, 0);

J
Jack Steiner 已提交
887
	if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
888

J
Jack Steiner 已提交
889
		Dprintk("Setting warm reset code and vector.\n");
890

J
Jack Steiner 已提交
891 892 893 894 895 896 897 898 899
		store_NMI_vector(&nmi_high, &nmi_low);

		smpboot_setup_warm_reset_vector(start_ip);
		/*
		 * Be paranoid about clearing APIC errors.
	 	*/
		apic_write(APIC_ESR, 0);
		apic_read(APIC_ESR);
	}
900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937

	/*
	 * Starting actual IPI sequence...
	 */
	boot_error = wakeup_secondary_cpu(apicid, start_ip);

	if (!boot_error) {
		/*
		 * allow APs to start initializing.
		 */
		Dprintk("Before Callout %d.\n", cpu);
		cpu_set(cpu, cpu_callout_map);
		Dprintk("After Callout %d.\n", cpu);

		/*
		 * Wait 5s total for a response
		 */
		for (timeout = 0; timeout < 50000; timeout++) {
			if (cpu_isset(cpu, cpu_callin_map))
				break;	/* It has booted */
			udelay(100);
		}

		if (cpu_isset(cpu, cpu_callin_map)) {
			/* number CPUs logically, starting from 1 (BSP is 0) */
			Dprintk("OK.\n");
			printk(KERN_INFO "CPU%d: ", cpu);
			print_cpu_info(&cpu_data(cpu));
			Dprintk("CPU has booted.\n");
		} else {
			boot_error = 1;
			if (*((volatile unsigned char *)trampoline_base)
					== 0xA5)
				/* trampoline started but...? */
				printk(KERN_ERR "Stuck ??\n");
			else
				/* trampoline code not run */
				printk(KERN_ERR "Not responding.\n");
J
Jack Steiner 已提交
938 939
			if (get_uv_system_type() != UV_NON_UNIQUE_APIC)
				inquire_remote_apic(apicid);
940 941
		}
	}
942
#ifdef CONFIG_X86_64
943
restore_state:
944
#endif
945 946
	if (boot_error) {
		/* Try to put things back the way they were before ... */
947
		numa_remove_cpu(cpu); /* was set by numa_add_cpu */
948 949 950 951 952 953 954 955 956
		cpu_clear(cpu, cpu_callout_map); /* was set by do_boot_cpu() */
		cpu_clear(cpu, cpu_initialized); /* was set by cpu_init() */
		cpu_clear(cpu, cpu_present_map);
		per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
	}

	/* mark "stuck" area as not stuck */
	*((volatile unsigned long *)trampoline_base) = 0;

957 958 959 960 961
	/*
	 * Cleanup possible dangling ends...
	 */
	smpboot_restore_warm_reset_vector();

962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998
	return boot_error;
}

int __cpuinit native_cpu_up(unsigned int cpu)
{
	int apicid = cpu_present_to_apicid(cpu);
	unsigned long flags;
	int err;

	WARN_ON(irqs_disabled());

	Dprintk("++++++++++++++++++++=_---CPU UP  %u\n", cpu);

	if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid ||
	    !physid_isset(apicid, phys_cpu_present_map)) {
		printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu);
		return -EINVAL;
	}

	/*
	 * Already booted CPU?
	 */
	if (cpu_isset(cpu, cpu_callin_map)) {
		Dprintk("do_boot_cpu %d Already started\n", cpu);
		return -ENOSYS;
	}

	/*
	 * Save current MTRR state in case it was changed since early boot
	 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
	 */
	mtrr_save_state();

	per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;

#ifdef CONFIG_X86_32
	/* init low mem mapping */
J
Jeremy Fitzhardinge 已提交
999
	clone_pgd_range(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
1000
		min_t(unsigned long, KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
1001
	flush_tlb_all();
1002
	low_mappings = 1;
1003 1004

	err = do_boot_cpu(apicid, cpu);
1005 1006 1007 1008 1009 1010 1011

	zap_low_mappings();
	low_mappings = 0;
#else
	err = do_boot_cpu(apicid, cpu);
#endif
	if (err) {
1012
		Dprintk("do_boot_cpu failed %d\n", err);
1013
		return -EIO;
1014 1015 1016 1017 1018 1019 1020 1021 1022 1023
	}

	/*
	 * Check TSC synchronization with the AP (keep irqs disabled
	 * while doing so):
	 */
	local_irq_save(flags);
	check_tsc_sync_source(cpu);
	local_irq_restore(flags);

1024
	while (!cpu_online(cpu)) {
1025 1026 1027 1028 1029 1030 1031
		cpu_relax();
		touch_nmi_watchdog();
	}

	return 0;
}

1032 1033 1034 1035 1036 1037 1038 1039 1040 1041
/*
 * Fall back to non SMP mode after errors.
 *
 * RED-PEN audit/test this more. I bet there is more state messed up here.
 */
static __init void disable_smp(void)
{
	cpu_present_map = cpumask_of_cpu(0);
	cpu_possible_map = cpumask_of_cpu(0);
	smpboot_clear_io_apic_irqs();
1042

1043
	if (smp_found_config)
1044
		physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
1045
	else
1046
		physid_set_mask_of_physid(0, &phys_cpu_present_map);
1047 1048 1049 1050 1051 1052 1053 1054 1055 1056
	map_cpu_to_logical_apicid();
	cpu_set(0, per_cpu(cpu_sibling_map, 0));
	cpu_set(0, per_cpu(cpu_core_map, 0));
}

/*
 * Various sanity checks.
 */
static int __init smp_sanity_check(unsigned max_cpus)
{
J
Jack Steiner 已提交
1057
	preempt_disable();
1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
	if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
		printk(KERN_WARNING "weird, boot CPU (#%d) not listed"
				    "by the BIOS.\n", hard_smp_processor_id());
		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
	}

	/*
	 * If we couldn't find an SMP configuration at boot time,
	 * get out of here now!
	 */
	if (!smp_found_config && !acpi_lapic) {
J
Jack Steiner 已提交
1069
		preempt_enable();
1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087
		printk(KERN_NOTICE "SMP motherboard not detected.\n");
		disable_smp();
		if (APIC_init_uniprocessor())
			printk(KERN_NOTICE "Local APIC not detected."
					   " Using dummy APIC emulation.\n");
		return -1;
	}

	/*
	 * Should not be necessary because the MP table should list the boot
	 * CPU too, but we do it for the sake of robustness anyway.
	 */
	if (!check_phys_apicid_present(boot_cpu_physical_apicid)) {
		printk(KERN_NOTICE
			"weird, boot CPU (#%d) not listed by the BIOS.\n",
			boot_cpu_physical_apicid);
		physid_set(hard_smp_processor_id(), phys_cpu_present_map);
	}
J
Jack Steiner 已提交
1088
	preempt_enable();
1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108

	/*
	 * If we couldn't find a local APIC, then get out of here now!
	 */
	if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
	    !cpu_has_apic) {
		printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
			boot_cpu_physical_apicid);
		printk(KERN_ERR "... forcing use of dummy APIC emulation."
				"(tell your hw vendor)\n");
		smpboot_clear_io_apic();
		return -1;
	}

	verify_local_APIC();

	/*
	 * If SMP should be disabled, then really disable it!
	 */
	if (!max_cpus) {
1109
		printk(KERN_INFO "SMP mode deactivated.\n");
1110
		smpboot_clear_io_apic();
1111 1112 1113

		localise_nmi_watchdog();

1114 1115 1116
		connect_bsp_APIC();
		setup_local_APIC();
		end_local_APIC_setup();
1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127
		return -1;
	}

	return 0;
}

static void __init smp_cpu_index_default(void)
{
	int i;
	struct cpuinfo_x86 *c;

1128
	for_each_possible_cpu(i) {
1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140
		c = &cpu_data(i);
		/* mark all to hotplug */
		c->cpu_index = NR_CPUS;
	}
}

/*
 * Prepare for SMP bootup.  The MP table or ACPI has been read
 * earlier.  Just do some sanity checking here and enable APIC mode.
 */
void __init native_smp_prepare_cpus(unsigned int max_cpus)
{
1141
	preempt_disable();
1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156
	smp_cpu_index_default();
	current_cpu_data = boot_cpu_data;
	cpu_callin_map = cpumask_of_cpu(0);
	mb();
	/*
	 * Setup boot CPU information
	 */
	smp_store_cpu_info(0); /* Final full version of the data */
	boot_cpu_logical_apicid = logical_smp_processor_id();
	current_thread_info()->cpu = 0;  /* needed? */
	set_cpu_sibling_map(0);

	if (smp_sanity_check(max_cpus) < 0) {
		printk(KERN_INFO "SMP disabled\n");
		disable_smp();
1157
		goto out;
1158 1159
	}

J
Jack Steiner 已提交
1160
	preempt_disable();
1161
	if (GET_APIC_ID(read_apic_id()) != boot_cpu_physical_apicid) {
1162
		panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
1163
		     GET_APIC_ID(read_apic_id()), boot_cpu_physical_apicid);
1164 1165
		/* Or can we switch back to PIC here? */
	}
J
Jack Steiner 已提交
1166
	preempt_enable();
1167 1168

	connect_bsp_APIC();
1169

1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195
	/*
	 * Switch from PIC to APIC mode.
	 */
	setup_local_APIC();

#ifdef CONFIG_X86_64
	/*
	 * Enable IO APIC before setting up error vector
	 */
	if (!skip_ioapic_setup && nr_ioapics)
		enable_IO_APIC();
#endif
	end_local_APIC_setup();

	map_cpu_to_logical_apicid();

	setup_portio_remap();

	smpboot_setup_io_apic();
	/*
	 * Set up local APIC timer on boot CPU.
	 */

	printk(KERN_INFO "CPU%d: ", 0);
	print_cpu_info(&cpu_data(0));
	setup_boot_clock();
1196 1197
out:
	preempt_enable();
1198
}
1199 1200 1201 1202 1203 1204 1205 1206 1207
/*
 * Early setup to make printk work.
 */
void __init native_smp_prepare_boot_cpu(void)
{
	int me = smp_processor_id();
#ifdef CONFIG_X86_32
	init_gdt(me);
#endif
1208
	switch_to_new_gdt();
1209 1210 1211 1212 1213
	/* already set me in cpu_online_map in boot_cpu_init() */
	cpu_set(me, cpu_callout_map);
	per_cpu(cpu_state, me) = CPU_ONLINE;
}

1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225
void __init native_smp_cpus_done(unsigned int max_cpus)
{
	Dprintk("Boot done.\n");

	impress_friends();
	smp_checks();
#ifdef CONFIG_X86_IO_APIC
	setup_ioapic_dest();
#endif
	check_nmi_watchdog();
}

1226
#ifdef CONFIG_HOTPLUG_CPU
1227

I
Ingo Molnar 已提交
1228
static void remove_siblinginfo(int cpu)
1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249
{
	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);
}
1250

A
Adrian Bunk 已提交
1251
static int additional_cpus __initdata = -1;
1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280

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;

1281 1282 1283 1284 1285
	/* no processor from mptable or madt */
	if (!num_processors)
		num_processors = 1;

#ifdef CONFIG_HOTPLUG_CPU
1286 1287 1288 1289 1290 1291
	if (additional_cpus == -1) {
		if (disabled_cpus > 0)
			additional_cpus = disabled_cpus;
		else
			additional_cpus = 0;
	}
1292 1293 1294
#else
	additional_cpus = 0;
#endif
1295 1296 1297 1298 1299 1300 1301 1302 1303
	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);
1304 1305

	nr_cpu_ids = possible;
1306
}
1307 1308 1309 1310 1311 1312 1313 1314

static void __ref remove_cpu_from_maps(int cpu)
{
	cpu_clear(cpu, cpu_online_map);
	cpu_clear(cpu, cpu_callout_map);
	cpu_clear(cpu, cpu_callin_map);
	/* was set by cpu_init() */
	clear_bit(cpu, (unsigned long *)&cpu_initialized);
1315
	numa_remove_cpu(cpu);
1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382
}

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();
}
1383 1384
#endif

1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396
/*
 * 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);