smpboot.c 35 KB

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  1. /*
  2. * x86 SMP booting functions
  3. *
  4. * (c) 1995 Alan Cox, Building #3 <alan@redhat.com>
  5. * (c) 1998, 1999, 2000 Ingo Molnar <mingo@redhat.com>
  6. * Copyright 2001 Andi Kleen, SuSE Labs.
  7. *
  8. * Much of the core SMP work is based on previous work by Thomas Radke, to
  9. * whom a great many thanks are extended.
  10. *
  11. * Thanks to Intel for making available several different Pentium,
  12. * Pentium Pro and Pentium-II/Xeon MP machines.
  13. * Original development of Linux SMP code supported by Caldera.
  14. *
  15. * This code is released under the GNU General Public License version 2 or
  16. * later.
  17. *
  18. * Fixes
  19. * Felix Koop : NR_CPUS used properly
  20. * Jose Renau : Handle single CPU case.
  21. * Alan Cox : By repeated request 8) - Total BogoMIPS report.
  22. * Greg Wright : Fix for kernel stacks panic.
  23. * Erich Boleyn : MP v1.4 and additional changes.
  24. * Matthias Sattler : Changes for 2.1 kernel map.
  25. * Michel Lespinasse : Changes for 2.1 kernel map.
  26. * Michael Chastain : Change trampoline.S to gnu as.
  27. * Alan Cox : Dumb bug: 'B' step PPro's are fine
  28. * Ingo Molnar : Added APIC timers, based on code
  29. * from Jose Renau
  30. * Ingo Molnar : various cleanups and rewrites
  31. * Tigran Aivazian : fixed "0.00 in /proc/uptime on SMP" bug.
  32. * Maciej W. Rozycki : Bits for genuine 82489DX APICs
  33. * Andi Kleen : Changed for SMP boot into long mode.
  34. * Martin J. Bligh : Added support for multi-quad systems
  35. * Dave Jones : Report invalid combinations of Athlon CPUs.
  36. * Rusty Russell : Hacked into shape for new "hotplug" boot process.
  37. * Andi Kleen : Converted to new state machine.
  38. * Ashok Raj : CPU hotplug support
  39. * Glauber Costa : i386 and x86_64 integration
  40. */
  41. #include <linux/init.h>
  42. #include <linux/smp.h>
  43. #include <linux/module.h>
  44. #include <linux/sched.h>
  45. #include <linux/percpu.h>
  46. #include <linux/bootmem.h>
  47. #include <linux/err.h>
  48. #include <linux/nmi.h>
  49. #include <asm/acpi.h>
  50. #include <asm/desc.h>
  51. #include <asm/nmi.h>
  52. #include <asm/irq.h>
  53. #include <asm/smp.h>
  54. #include <asm/trampoline.h>
  55. #include <asm/cpu.h>
  56. #include <asm/numa.h>
  57. #include <asm/pgtable.h>
  58. #include <asm/tlbflush.h>
  59. #include <asm/mtrr.h>
  60. #include <asm/vmi.h>
  61. #include <asm/genapic.h>
  62. #include <linux/mc146818rtc.h>
  63. #include <mach_apic.h>
  64. #include <mach_wakecpu.h>
  65. #include <smpboot_hooks.h>
  66. #ifdef CONFIG_X86_32
  67. u8 apicid_2_node[MAX_APICID];
  68. static int low_mappings;
  69. #endif
  70. /* State of each CPU */
  71. DEFINE_PER_CPU(int, cpu_state) = { 0 };
  72. /* Store all idle threads, this can be reused instead of creating
  73. * a new thread. Also avoids complicated thread destroy functionality
  74. * for idle threads.
  75. */
  76. #ifdef CONFIG_HOTPLUG_CPU
  77. /*
  78. * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
  79. * removed after init for !CONFIG_HOTPLUG_CPU.
  80. */
  81. static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
  82. #define get_idle_for_cpu(x) (per_cpu(idle_thread_array, x))
  83. #define set_idle_for_cpu(x, p) (per_cpu(idle_thread_array, x) = (p))
  84. #else
  85. struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
  86. #define get_idle_for_cpu(x) (idle_thread_array[(x)])
  87. #define set_idle_for_cpu(x, p) (idle_thread_array[(x)] = (p))
  88. #endif
  89. /* Number of siblings per CPU package */
  90. int smp_num_siblings = 1;
  91. EXPORT_SYMBOL(smp_num_siblings);
  92. /* Last level cache ID of each logical CPU */
  93. DEFINE_PER_CPU(u16, cpu_llc_id) = BAD_APICID;
  94. /* bitmap of online cpus */
  95. cpumask_t cpu_online_map __read_mostly;
  96. EXPORT_SYMBOL(cpu_online_map);
  97. cpumask_t cpu_callin_map;
  98. cpumask_t cpu_callout_map;
  99. cpumask_t cpu_possible_map;
  100. EXPORT_SYMBOL(cpu_possible_map);
  101. /* representing HT siblings of each logical CPU */
  102. DEFINE_PER_CPU(cpumask_t, cpu_sibling_map);
  103. EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  104. /* representing HT and core siblings of each logical CPU */
  105. DEFINE_PER_CPU(cpumask_t, cpu_core_map);
  106. EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  107. /* Per CPU bogomips and other parameters */
  108. DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
  109. EXPORT_PER_CPU_SYMBOL(cpu_info);
  110. static atomic_t init_deasserted;
  111. static int boot_cpu_logical_apicid;
  112. /* representing cpus for which sibling maps can be computed */
  113. static cpumask_t cpu_sibling_setup_map;
  114. /* Set if we find a B stepping CPU */
  115. int __cpuinitdata smp_b_stepping;
  116. #if defined(CONFIG_NUMA) && defined(CONFIG_X86_32)
  117. /* which logical CPUs are on which nodes */
  118. cpumask_t node_to_cpumask_map[MAX_NUMNODES] __read_mostly =
  119. { [0 ... MAX_NUMNODES-1] = CPU_MASK_NONE };
  120. EXPORT_SYMBOL(node_to_cpumask_map);
  121. /* which node each logical CPU is on */
  122. int cpu_to_node_map[NR_CPUS] __read_mostly = { [0 ... NR_CPUS-1] = 0 };
  123. EXPORT_SYMBOL(cpu_to_node_map);
  124. /* set up a mapping between cpu and node. */
  125. static void map_cpu_to_node(int cpu, int node)
  126. {
  127. printk(KERN_INFO "Mapping cpu %d to node %d\n", cpu, node);
  128. cpu_set(cpu, node_to_cpumask_map[node]);
  129. cpu_to_node_map[cpu] = node;
  130. }
  131. /* undo a mapping between cpu and node. */
  132. static void unmap_cpu_to_node(int cpu)
  133. {
  134. int node;
  135. printk(KERN_INFO "Unmapping cpu %d from all nodes\n", cpu);
  136. for (node = 0; node < MAX_NUMNODES; node++)
  137. cpu_clear(cpu, node_to_cpumask_map[node]);
  138. cpu_to_node_map[cpu] = 0;
  139. }
  140. #else /* !(CONFIG_NUMA && CONFIG_X86_32) */
  141. #define map_cpu_to_node(cpu, node) ({})
  142. #define unmap_cpu_to_node(cpu) ({})
  143. #endif
  144. #ifdef CONFIG_X86_32
  145. u8 cpu_2_logical_apicid[NR_CPUS] __read_mostly =
  146. { [0 ... NR_CPUS-1] = BAD_APICID };
  147. static void map_cpu_to_logical_apicid(void)
  148. {
  149. int cpu = smp_processor_id();
  150. int apicid = logical_smp_processor_id();
  151. int node = apicid_to_node(apicid);
  152. if (!node_online(node))
  153. node = first_online_node;
  154. cpu_2_logical_apicid[cpu] = apicid;
  155. map_cpu_to_node(cpu, node);
  156. }
  157. static void unmap_cpu_to_logical_apicid(int cpu)
  158. {
  159. cpu_2_logical_apicid[cpu] = BAD_APICID;
  160. unmap_cpu_to_node(cpu);
  161. }
  162. #else
  163. #define unmap_cpu_to_logical_apicid(cpu) do {} while (0)
  164. #define map_cpu_to_logical_apicid() do {} while (0)
  165. #endif
  166. /*
  167. * Report back to the Boot Processor.
  168. * Running on AP.
  169. */
  170. static void __cpuinit smp_callin(void)
  171. {
  172. int cpuid, phys_id;
  173. unsigned long timeout;
  174. /*
  175. * If waken up by an INIT in an 82489DX configuration
  176. * we may get here before an INIT-deassert IPI reaches
  177. * our local APIC. We have to wait for the IPI or we'll
  178. * lock up on an APIC access.
  179. */
  180. wait_for_init_deassert(&init_deasserted);
  181. /*
  182. * (This works even if the APIC is not enabled.)
  183. */
  184. phys_id = GET_APIC_ID(read_apic_id());
  185. cpuid = smp_processor_id();
  186. if (cpu_isset(cpuid, cpu_callin_map)) {
  187. panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__,
  188. phys_id, cpuid);
  189. }
  190. Dprintk("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);
  191. /*
  192. * STARTUP IPIs are fragile beasts as they might sometimes
  193. * trigger some glue motherboard logic. Complete APIC bus
  194. * silence for 1 second, this overestimates the time the
  195. * boot CPU is spending to send the up to 2 STARTUP IPIs
  196. * by a factor of two. This should be enough.
  197. */
  198. /*
  199. * Waiting 2s total for startup (udelay is not yet working)
  200. */
  201. timeout = jiffies + 2*HZ;
  202. while (time_before(jiffies, timeout)) {
  203. /*
  204. * Has the boot CPU finished it's STARTUP sequence?
  205. */
  206. if (cpu_isset(cpuid, cpu_callout_map))
  207. break;
  208. cpu_relax();
  209. }
  210. if (!time_before(jiffies, timeout)) {
  211. panic("%s: CPU%d started up but did not get a callout!\n",
  212. __func__, cpuid);
  213. }
  214. /*
  215. * the boot CPU has finished the init stage and is spinning
  216. * on callin_map until we finish. We are free to set up this
  217. * CPU, first the APIC. (this is probably redundant on most
  218. * boards)
  219. */
  220. Dprintk("CALLIN, before setup_local_APIC().\n");
  221. smp_callin_clear_local_apic();
  222. setup_local_APIC();
  223. end_local_APIC_setup();
  224. map_cpu_to_logical_apicid();
  225. /*
  226. * Get our bogomips.
  227. *
  228. * Need to enable IRQs because it can take longer and then
  229. * the NMI watchdog might kill us.
  230. */
  231. local_irq_enable();
  232. calibrate_delay();
  233. local_irq_disable();
  234. Dprintk("Stack at about %p\n", &cpuid);
  235. /*
  236. * Save our processor parameters
  237. */
  238. smp_store_cpu_info(cpuid);
  239. /*
  240. * Allow the master to continue.
  241. */
  242. cpu_set(cpuid, cpu_callin_map);
  243. }
  244. /*
  245. * Activate a secondary processor.
  246. */
  247. static void __cpuinit start_secondary(void *unused)
  248. {
  249. /*
  250. * Don't put *anything* before cpu_init(), SMP booting is too
  251. * fragile that we want to limit the things done here to the
  252. * most necessary things.
  253. */
  254. #ifdef CONFIG_VMI
  255. vmi_bringup();
  256. #endif
  257. cpu_init();
  258. preempt_disable();
  259. smp_callin();
  260. /* otherwise gcc will move up smp_processor_id before the cpu_init */
  261. barrier();
  262. /*
  263. * Check TSC synchronization with the BP:
  264. */
  265. check_tsc_sync_target();
  266. if (nmi_watchdog == NMI_IO_APIC) {
  267. disable_8259A_irq(0);
  268. enable_NMI_through_LVT0();
  269. enable_8259A_irq(0);
  270. }
  271. #ifdef CONFIG_X86_32
  272. while (low_mappings)
  273. cpu_relax();
  274. __flush_tlb_all();
  275. #endif
  276. /* This must be done before setting cpu_online_map */
  277. set_cpu_sibling_map(raw_smp_processor_id());
  278. wmb();
  279. /*
  280. * We need to hold call_lock, so there is no inconsistency
  281. * between the time smp_call_function() determines number of
  282. * IPI recipients, and the time when the determination is made
  283. * for which cpus receive the IPI. Holding this
  284. * lock helps us to not include this cpu in a currently in progress
  285. * smp_call_function().
  286. */
  287. lock_ipi_call_lock();
  288. #ifdef CONFIG_X86_64
  289. spin_lock(&vector_lock);
  290. /* Setup the per cpu irq handling data structures */
  291. __setup_vector_irq(smp_processor_id());
  292. /*
  293. * Allow the master to continue.
  294. */
  295. spin_unlock(&vector_lock);
  296. #endif
  297. cpu_set(smp_processor_id(), cpu_online_map);
  298. unlock_ipi_call_lock();
  299. per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
  300. setup_secondary_clock();
  301. wmb();
  302. cpu_idle();
  303. }
  304. static void __cpuinit smp_apply_quirks(struct cpuinfo_x86 *c)
  305. {
  306. #ifdef CONFIG_X86_32
  307. /*
  308. * Mask B, Pentium, but not Pentium MMX
  309. */
  310. if (c->x86_vendor == X86_VENDOR_INTEL &&
  311. c->x86 == 5 &&
  312. c->x86_mask >= 1 && c->x86_mask <= 4 &&
  313. c->x86_model <= 3)
  314. /*
  315. * Remember we have B step Pentia with bugs
  316. */
  317. smp_b_stepping = 1;
  318. /*
  319. * Certain Athlons might work (for various values of 'work') in SMP
  320. * but they are not certified as MP capable.
  321. */
  322. if ((c->x86_vendor == X86_VENDOR_AMD) && (c->x86 == 6)) {
  323. if (num_possible_cpus() == 1)
  324. goto valid_k7;
  325. /* Athlon 660/661 is valid. */
  326. if ((c->x86_model == 6) && ((c->x86_mask == 0) ||
  327. (c->x86_mask == 1)))
  328. goto valid_k7;
  329. /* Duron 670 is valid */
  330. if ((c->x86_model == 7) && (c->x86_mask == 0))
  331. goto valid_k7;
  332. /*
  333. * Athlon 662, Duron 671, and Athlon >model 7 have capability
  334. * bit. It's worth noting that the A5 stepping (662) of some
  335. * Athlon XP's have the MP bit set.
  336. * See http://www.heise.de/newsticker/data/jow-18.10.01-000 for
  337. * more.
  338. */
  339. if (((c->x86_model == 6) && (c->x86_mask >= 2)) ||
  340. ((c->x86_model == 7) && (c->x86_mask >= 1)) ||
  341. (c->x86_model > 7))
  342. if (cpu_has_mp)
  343. goto valid_k7;
  344. /* If we get here, not a certified SMP capable AMD system. */
  345. add_taint(TAINT_UNSAFE_SMP);
  346. }
  347. valid_k7:
  348. ;
  349. #endif
  350. }
  351. static void __cpuinit smp_checks(void)
  352. {
  353. if (smp_b_stepping)
  354. printk(KERN_WARNING "WARNING: SMP operation may be unreliable"
  355. "with B stepping processors.\n");
  356. /*
  357. * Don't taint if we are running SMP kernel on a single non-MP
  358. * approved Athlon
  359. */
  360. if (tainted & TAINT_UNSAFE_SMP) {
  361. if (num_online_cpus())
  362. printk(KERN_INFO "WARNING: This combination of AMD"
  363. "processors is not suitable for SMP.\n");
  364. else
  365. tainted &= ~TAINT_UNSAFE_SMP;
  366. }
  367. }
  368. /*
  369. * The bootstrap kernel entry code has set these up. Save them for
  370. * a given CPU
  371. */
  372. void __cpuinit smp_store_cpu_info(int id)
  373. {
  374. struct cpuinfo_x86 *c = &cpu_data(id);
  375. *c = boot_cpu_data;
  376. c->cpu_index = id;
  377. if (id != 0)
  378. identify_secondary_cpu(c);
  379. smp_apply_quirks(c);
  380. }
  381. void __cpuinit set_cpu_sibling_map(int cpu)
  382. {
  383. int i;
  384. struct cpuinfo_x86 *c = &cpu_data(cpu);
  385. cpu_set(cpu, cpu_sibling_setup_map);
  386. if (smp_num_siblings > 1) {
  387. for_each_cpu_mask(i, cpu_sibling_setup_map) {
  388. if (c->phys_proc_id == cpu_data(i).phys_proc_id &&
  389. c->cpu_core_id == cpu_data(i).cpu_core_id) {
  390. cpu_set(i, per_cpu(cpu_sibling_map, cpu));
  391. cpu_set(cpu, per_cpu(cpu_sibling_map, i));
  392. cpu_set(i, per_cpu(cpu_core_map, cpu));
  393. cpu_set(cpu, per_cpu(cpu_core_map, i));
  394. cpu_set(i, c->llc_shared_map);
  395. cpu_set(cpu, cpu_data(i).llc_shared_map);
  396. }
  397. }
  398. } else {
  399. cpu_set(cpu, per_cpu(cpu_sibling_map, cpu));
  400. }
  401. cpu_set(cpu, c->llc_shared_map);
  402. if (current_cpu_data.x86_max_cores == 1) {
  403. per_cpu(cpu_core_map, cpu) = per_cpu(cpu_sibling_map, cpu);
  404. c->booted_cores = 1;
  405. return;
  406. }
  407. for_each_cpu_mask(i, cpu_sibling_setup_map) {
  408. if (per_cpu(cpu_llc_id, cpu) != BAD_APICID &&
  409. per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i)) {
  410. cpu_set(i, c->llc_shared_map);
  411. cpu_set(cpu, cpu_data(i).llc_shared_map);
  412. }
  413. if (c->phys_proc_id == cpu_data(i).phys_proc_id) {
  414. cpu_set(i, per_cpu(cpu_core_map, cpu));
  415. cpu_set(cpu, per_cpu(cpu_core_map, i));
  416. /*
  417. * Does this new cpu bringup a new core?
  418. */
  419. if (cpus_weight(per_cpu(cpu_sibling_map, cpu)) == 1) {
  420. /*
  421. * for each core in package, increment
  422. * the booted_cores for this new cpu
  423. */
  424. if (first_cpu(per_cpu(cpu_sibling_map, i)) == i)
  425. c->booted_cores++;
  426. /*
  427. * increment the core count for all
  428. * the other cpus in this package
  429. */
  430. if (i != cpu)
  431. cpu_data(i).booted_cores++;
  432. } else if (i != cpu && !c->booted_cores)
  433. c->booted_cores = cpu_data(i).booted_cores;
  434. }
  435. }
  436. }
  437. /* maps the cpu to the sched domain representing multi-core */
  438. cpumask_t cpu_coregroup_map(int cpu)
  439. {
  440. struct cpuinfo_x86 *c = &cpu_data(cpu);
  441. /*
  442. * For perf, we return last level cache shared map.
  443. * And for power savings, we return cpu_core_map
  444. */
  445. if (sched_mc_power_savings || sched_smt_power_savings)
  446. return per_cpu(cpu_core_map, cpu);
  447. else
  448. return c->llc_shared_map;
  449. }
  450. static void impress_friends(void)
  451. {
  452. int cpu;
  453. unsigned long bogosum = 0;
  454. /*
  455. * Allow the user to impress friends.
  456. */
  457. Dprintk("Before bogomips.\n");
  458. for_each_possible_cpu(cpu)
  459. if (cpu_isset(cpu, cpu_callout_map))
  460. bogosum += cpu_data(cpu).loops_per_jiffy;
  461. printk(KERN_INFO
  462. "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
  463. num_online_cpus(),
  464. bogosum/(500000/HZ),
  465. (bogosum/(5000/HZ))%100);
  466. Dprintk("Before bogocount - setting activated=1.\n");
  467. }
  468. static inline void __inquire_remote_apic(int apicid)
  469. {
  470. unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
  471. char *names[] = { "ID", "VERSION", "SPIV" };
  472. int timeout;
  473. u32 status;
  474. printk(KERN_INFO "Inquiring remote APIC #%d...\n", apicid);
  475. for (i = 0; i < ARRAY_SIZE(regs); i++) {
  476. printk(KERN_INFO "... APIC #%d %s: ", apicid, names[i]);
  477. /*
  478. * Wait for idle.
  479. */
  480. status = safe_apic_wait_icr_idle();
  481. if (status)
  482. printk(KERN_CONT
  483. "a previous APIC delivery may have failed\n");
  484. apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(apicid));
  485. apic_write_around(APIC_ICR, APIC_DM_REMRD | regs[i]);
  486. timeout = 0;
  487. do {
  488. udelay(100);
  489. status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
  490. } while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
  491. switch (status) {
  492. case APIC_ICR_RR_VALID:
  493. status = apic_read(APIC_RRR);
  494. printk(KERN_CONT "%08x\n", status);
  495. break;
  496. default:
  497. printk(KERN_CONT "failed\n");
  498. }
  499. }
  500. }
  501. #ifdef WAKE_SECONDARY_VIA_NMI
  502. /*
  503. * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
  504. * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
  505. * won't ... remember to clear down the APIC, etc later.
  506. */
  507. static int __devinit
  508. wakeup_secondary_cpu(int logical_apicid, unsigned long start_eip)
  509. {
  510. unsigned long send_status, accept_status = 0;
  511. int maxlvt;
  512. /* Target chip */
  513. apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(logical_apicid));
  514. /* Boot on the stack */
  515. /* Kick the second */
  516. apic_write_around(APIC_ICR, APIC_DM_NMI | APIC_DEST_LOGICAL);
  517. Dprintk("Waiting for send to finish...\n");
  518. send_status = safe_apic_wait_icr_idle();
  519. /*
  520. * Give the other CPU some time to accept the IPI.
  521. */
  522. udelay(200);
  523. /*
  524. * Due to the Pentium erratum 3AP.
  525. */
  526. maxlvt = lapic_get_maxlvt();
  527. if (maxlvt > 3) {
  528. apic_read_around(APIC_SPIV);
  529. apic_write(APIC_ESR, 0);
  530. }
  531. accept_status = (apic_read(APIC_ESR) & 0xEF);
  532. Dprintk("NMI sent.\n");
  533. if (send_status)
  534. printk(KERN_ERR "APIC never delivered???\n");
  535. if (accept_status)
  536. printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
  537. return (send_status | accept_status);
  538. }
  539. #endif /* WAKE_SECONDARY_VIA_NMI */
  540. #ifdef WAKE_SECONDARY_VIA_INIT
  541. static int __devinit
  542. wakeup_secondary_cpu(int phys_apicid, unsigned long start_eip)
  543. {
  544. unsigned long send_status, accept_status = 0;
  545. int maxlvt, num_starts, j;
  546. if (get_uv_system_type() == UV_NON_UNIQUE_APIC) {
  547. send_status = uv_wakeup_secondary(phys_apicid, start_eip);
  548. atomic_set(&init_deasserted, 1);
  549. return send_status;
  550. }
  551. /*
  552. * Be paranoid about clearing APIC errors.
  553. */
  554. if (APIC_INTEGRATED(apic_version[phys_apicid])) {
  555. apic_read_around(APIC_SPIV);
  556. apic_write(APIC_ESR, 0);
  557. apic_read(APIC_ESR);
  558. }
  559. Dprintk("Asserting INIT.\n");
  560. /*
  561. * Turn INIT on target chip
  562. */
  563. apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));
  564. /*
  565. * Send IPI
  566. */
  567. apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_INT_ASSERT
  568. | APIC_DM_INIT);
  569. Dprintk("Waiting for send to finish...\n");
  570. send_status = safe_apic_wait_icr_idle();
  571. mdelay(10);
  572. Dprintk("Deasserting INIT.\n");
  573. /* Target chip */
  574. apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));
  575. /* Send IPI */
  576. apic_write_around(APIC_ICR, APIC_INT_LEVELTRIG | APIC_DM_INIT);
  577. Dprintk("Waiting for send to finish...\n");
  578. send_status = safe_apic_wait_icr_idle();
  579. mb();
  580. atomic_set(&init_deasserted, 1);
  581. /*
  582. * Should we send STARTUP IPIs ?
  583. *
  584. * Determine this based on the APIC version.
  585. * If we don't have an integrated APIC, don't send the STARTUP IPIs.
  586. */
  587. if (APIC_INTEGRATED(apic_version[phys_apicid]))
  588. num_starts = 2;
  589. else
  590. num_starts = 0;
  591. /*
  592. * Paravirt / VMI wants a startup IPI hook here to set up the
  593. * target processor state.
  594. */
  595. startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
  596. (unsigned long)stack_start.sp);
  597. /*
  598. * Run STARTUP IPI loop.
  599. */
  600. Dprintk("#startup loops: %d.\n", num_starts);
  601. maxlvt = lapic_get_maxlvt();
  602. for (j = 1; j <= num_starts; j++) {
  603. Dprintk("Sending STARTUP #%d.\n", j);
  604. apic_read_around(APIC_SPIV);
  605. apic_write(APIC_ESR, 0);
  606. apic_read(APIC_ESR);
  607. Dprintk("After apic_write.\n");
  608. /*
  609. * STARTUP IPI
  610. */
  611. /* Target chip */
  612. apic_write_around(APIC_ICR2, SET_APIC_DEST_FIELD(phys_apicid));
  613. /* Boot on the stack */
  614. /* Kick the second */
  615. apic_write_around(APIC_ICR, APIC_DM_STARTUP
  616. | (start_eip >> 12));
  617. /*
  618. * Give the other CPU some time to accept the IPI.
  619. */
  620. udelay(300);
  621. Dprintk("Startup point 1.\n");
  622. Dprintk("Waiting for send to finish...\n");
  623. send_status = safe_apic_wait_icr_idle();
  624. /*
  625. * Give the other CPU some time to accept the IPI.
  626. */
  627. udelay(200);
  628. /*
  629. * Due to the Pentium erratum 3AP.
  630. */
  631. if (maxlvt > 3) {
  632. apic_read_around(APIC_SPIV);
  633. apic_write(APIC_ESR, 0);
  634. }
  635. accept_status = (apic_read(APIC_ESR) & 0xEF);
  636. if (send_status || accept_status)
  637. break;
  638. }
  639. Dprintk("After Startup.\n");
  640. if (send_status)
  641. printk(KERN_ERR "APIC never delivered???\n");
  642. if (accept_status)
  643. printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
  644. return (send_status | accept_status);
  645. }
  646. #endif /* WAKE_SECONDARY_VIA_INIT */
  647. struct create_idle {
  648. struct work_struct work;
  649. struct task_struct *idle;
  650. struct completion done;
  651. int cpu;
  652. };
  653. static void __cpuinit do_fork_idle(struct work_struct *work)
  654. {
  655. struct create_idle *c_idle =
  656. container_of(work, struct create_idle, work);
  657. c_idle->idle = fork_idle(c_idle->cpu);
  658. complete(&c_idle->done);
  659. }
  660. #ifdef CONFIG_X86_64
  661. /*
  662. * Allocate node local memory for the AP pda.
  663. *
  664. * Must be called after the _cpu_pda pointer table is initialized.
  665. */
  666. static int __cpuinit get_local_pda(int cpu)
  667. {
  668. struct x8664_pda *oldpda, *newpda;
  669. unsigned long size = sizeof(struct x8664_pda);
  670. int node = cpu_to_node(cpu);
  671. if (cpu_pda(cpu) && !cpu_pda(cpu)->in_bootmem)
  672. return 0;
  673. oldpda = cpu_pda(cpu);
  674. newpda = kmalloc_node(size, GFP_ATOMIC, node);
  675. if (!newpda) {
  676. printk(KERN_ERR "Could not allocate node local PDA "
  677. "for CPU %d on node %d\n", cpu, node);
  678. if (oldpda)
  679. return 0; /* have a usable pda */
  680. else
  681. return -1;
  682. }
  683. if (oldpda) {
  684. memcpy(newpda, oldpda, size);
  685. if (!after_bootmem)
  686. free_bootmem((unsigned long)oldpda, size);
  687. }
  688. newpda->in_bootmem = 0;
  689. cpu_pda(cpu) = newpda;
  690. return 0;
  691. }
  692. #endif /* CONFIG_X86_64 */
  693. static int __cpuinit do_boot_cpu(int apicid, int cpu)
  694. /*
  695. * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
  696. * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
  697. * Returns zero if CPU booted OK, else error code from wakeup_secondary_cpu.
  698. */
  699. {
  700. unsigned long boot_error = 0;
  701. int timeout;
  702. unsigned long start_ip;
  703. unsigned short nmi_high = 0, nmi_low = 0;
  704. struct create_idle c_idle = {
  705. .cpu = cpu,
  706. .done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
  707. };
  708. INIT_WORK(&c_idle.work, do_fork_idle);
  709. #ifdef CONFIG_X86_64
  710. /* Allocate node local memory for AP pdas */
  711. if (cpu > 0) {
  712. boot_error = get_local_pda(cpu);
  713. if (boot_error)
  714. goto restore_state;
  715. /* if can't get pda memory, can't start cpu */
  716. }
  717. #endif
  718. alternatives_smp_switch(1);
  719. c_idle.idle = get_idle_for_cpu(cpu);
  720. /*
  721. * We can't use kernel_thread since we must avoid to
  722. * reschedule the child.
  723. */
  724. if (c_idle.idle) {
  725. c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)
  726. (THREAD_SIZE + task_stack_page(c_idle.idle))) - 1);
  727. init_idle(c_idle.idle, cpu);
  728. goto do_rest;
  729. }
  730. if (!keventd_up() || current_is_keventd())
  731. c_idle.work.func(&c_idle.work);
  732. else {
  733. schedule_work(&c_idle.work);
  734. wait_for_completion(&c_idle.done);
  735. }
  736. if (IS_ERR(c_idle.idle)) {
  737. printk("failed fork for CPU %d\n", cpu);
  738. return PTR_ERR(c_idle.idle);
  739. }
  740. set_idle_for_cpu(cpu, c_idle.idle);
  741. do_rest:
  742. #ifdef CONFIG_X86_32
  743. per_cpu(current_task, cpu) = c_idle.idle;
  744. init_gdt(cpu);
  745. /* Stack for startup_32 can be just as for start_secondary onwards */
  746. irq_ctx_init(cpu);
  747. #else
  748. cpu_pda(cpu)->pcurrent = c_idle.idle;
  749. load_sp0(&per_cpu(init_tss, cpu), &c_idle.idle->thread);
  750. clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
  751. #endif
  752. early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
  753. initial_code = (unsigned long)start_secondary;
  754. stack_start.sp = (void *) c_idle.idle->thread.sp;
  755. /* start_ip had better be page-aligned! */
  756. start_ip = setup_trampoline();
  757. /* So we see what's up */
  758. printk(KERN_INFO "Booting processor %d/%d ip %lx\n",
  759. cpu, apicid, start_ip);
  760. /*
  761. * This grunge runs the startup process for
  762. * the targeted processor.
  763. */
  764. atomic_set(&init_deasserted, 0);
  765. if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
  766. Dprintk("Setting warm reset code and vector.\n");
  767. store_NMI_vector(&nmi_high, &nmi_low);
  768. smpboot_setup_warm_reset_vector(start_ip);
  769. /*
  770. * Be paranoid about clearing APIC errors.
  771. */
  772. apic_write(APIC_ESR, 0);
  773. apic_read(APIC_ESR);
  774. }
  775. /*
  776. * Starting actual IPI sequence...
  777. */
  778. boot_error = wakeup_secondary_cpu(apicid, start_ip);
  779. if (!boot_error) {
  780. /*
  781. * allow APs to start initializing.
  782. */
  783. Dprintk("Before Callout %d.\n", cpu);
  784. cpu_set(cpu, cpu_callout_map);
  785. Dprintk("After Callout %d.\n", cpu);
  786. /*
  787. * Wait 5s total for a response
  788. */
  789. for (timeout = 0; timeout < 50000; timeout++) {
  790. if (cpu_isset(cpu, cpu_callin_map))
  791. break; /* It has booted */
  792. udelay(100);
  793. }
  794. if (cpu_isset(cpu, cpu_callin_map)) {
  795. /* number CPUs logically, starting from 1 (BSP is 0) */
  796. Dprintk("OK.\n");
  797. printk(KERN_INFO "CPU%d: ", cpu);
  798. print_cpu_info(&cpu_data(cpu));
  799. Dprintk("CPU has booted.\n");
  800. } else {
  801. boot_error = 1;
  802. if (*((volatile unsigned char *)trampoline_base)
  803. == 0xA5)
  804. /* trampoline started but...? */
  805. printk(KERN_ERR "Stuck ??\n");
  806. else
  807. /* trampoline code not run */
  808. printk(KERN_ERR "Not responding.\n");
  809. if (get_uv_system_type() != UV_NON_UNIQUE_APIC)
  810. inquire_remote_apic(apicid);
  811. }
  812. }
  813. restore_state:
  814. if (boot_error) {
  815. /* Try to put things back the way they were before ... */
  816. unmap_cpu_to_logical_apicid(cpu);
  817. #ifdef CONFIG_X86_64
  818. numa_remove_cpu(cpu); /* was set by numa_add_cpu */
  819. #endif
  820. cpu_clear(cpu, cpu_callout_map); /* was set by do_boot_cpu() */
  821. cpu_clear(cpu, cpu_initialized); /* was set by cpu_init() */
  822. cpu_clear(cpu, cpu_present_map);
  823. per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
  824. }
  825. /* mark "stuck" area as not stuck */
  826. *((volatile unsigned long *)trampoline_base) = 0;
  827. /*
  828. * Cleanup possible dangling ends...
  829. */
  830. smpboot_restore_warm_reset_vector();
  831. return boot_error;
  832. }
  833. int __cpuinit native_cpu_up(unsigned int cpu)
  834. {
  835. int apicid = cpu_present_to_apicid(cpu);
  836. unsigned long flags;
  837. int err;
  838. WARN_ON(irqs_disabled());
  839. Dprintk("++++++++++++++++++++=_---CPU UP %u\n", cpu);
  840. if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid ||
  841. !physid_isset(apicid, phys_cpu_present_map)) {
  842. printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu);
  843. return -EINVAL;
  844. }
  845. /*
  846. * Already booted CPU?
  847. */
  848. if (cpu_isset(cpu, cpu_callin_map)) {
  849. Dprintk("do_boot_cpu %d Already started\n", cpu);
  850. return -ENOSYS;
  851. }
  852. /*
  853. * Save current MTRR state in case it was changed since early boot
  854. * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
  855. */
  856. mtrr_save_state();
  857. per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
  858. #ifdef CONFIG_X86_32
  859. /* init low mem mapping */
  860. clone_pgd_range(swapper_pg_dir, swapper_pg_dir + KERNEL_PGD_BOUNDARY,
  861. min_t(unsigned long, KERNEL_PGD_PTRS, KERNEL_PGD_BOUNDARY));
  862. flush_tlb_all();
  863. low_mappings = 1;
  864. err = do_boot_cpu(apicid, cpu);
  865. zap_low_mappings();
  866. low_mappings = 0;
  867. #else
  868. err = do_boot_cpu(apicid, cpu);
  869. #endif
  870. if (err) {
  871. Dprintk("do_boot_cpu failed %d\n", err);
  872. return -EIO;
  873. }
  874. /*
  875. * Check TSC synchronization with the AP (keep irqs disabled
  876. * while doing so):
  877. */
  878. local_irq_save(flags);
  879. check_tsc_sync_source(cpu);
  880. local_irq_restore(flags);
  881. while (!cpu_online(cpu)) {
  882. cpu_relax();
  883. touch_nmi_watchdog();
  884. }
  885. return 0;
  886. }
  887. /*
  888. * Fall back to non SMP mode after errors.
  889. *
  890. * RED-PEN audit/test this more. I bet there is more state messed up here.
  891. */
  892. static __init void disable_smp(void)
  893. {
  894. cpu_present_map = cpumask_of_cpu(0);
  895. cpu_possible_map = cpumask_of_cpu(0);
  896. #ifdef CONFIG_X86_32
  897. smpboot_clear_io_apic_irqs();
  898. #endif
  899. if (smp_found_config)
  900. physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
  901. else
  902. physid_set_mask_of_physid(0, &phys_cpu_present_map);
  903. map_cpu_to_logical_apicid();
  904. cpu_set(0, per_cpu(cpu_sibling_map, 0));
  905. cpu_set(0, per_cpu(cpu_core_map, 0));
  906. }
  907. /*
  908. * Various sanity checks.
  909. */
  910. static int __init smp_sanity_check(unsigned max_cpus)
  911. {
  912. preempt_disable();
  913. if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
  914. printk(KERN_WARNING "weird, boot CPU (#%d) not listed"
  915. "by the BIOS.\n", hard_smp_processor_id());
  916. physid_set(hard_smp_processor_id(), phys_cpu_present_map);
  917. }
  918. /*
  919. * If we couldn't find an SMP configuration at boot time,
  920. * get out of here now!
  921. */
  922. if (!smp_found_config && !acpi_lapic) {
  923. preempt_enable();
  924. printk(KERN_NOTICE "SMP motherboard not detected.\n");
  925. disable_smp();
  926. if (APIC_init_uniprocessor())
  927. printk(KERN_NOTICE "Local APIC not detected."
  928. " Using dummy APIC emulation.\n");
  929. return -1;
  930. }
  931. /*
  932. * Should not be necessary because the MP table should list the boot
  933. * CPU too, but we do it for the sake of robustness anyway.
  934. */
  935. if (!check_phys_apicid_present(boot_cpu_physical_apicid)) {
  936. printk(KERN_NOTICE
  937. "weird, boot CPU (#%d) not listed by the BIOS.\n",
  938. boot_cpu_physical_apicid);
  939. physid_set(hard_smp_processor_id(), phys_cpu_present_map);
  940. }
  941. preempt_enable();
  942. /*
  943. * If we couldn't find a local APIC, then get out of here now!
  944. */
  945. if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
  946. !cpu_has_apic) {
  947. printk(KERN_ERR "BIOS bug, local APIC #%d not detected!...\n",
  948. boot_cpu_physical_apicid);
  949. printk(KERN_ERR "... forcing use of dummy APIC emulation."
  950. "(tell your hw vendor)\n");
  951. smpboot_clear_io_apic();
  952. return -1;
  953. }
  954. verify_local_APIC();
  955. /*
  956. * If SMP should be disabled, then really disable it!
  957. */
  958. if (!max_cpus) {
  959. printk(KERN_INFO "SMP mode deactivated.\n");
  960. smpboot_clear_io_apic();
  961. localise_nmi_watchdog();
  962. #ifdef CONFIG_X86_32
  963. connect_bsp_APIC();
  964. #endif
  965. setup_local_APIC();
  966. end_local_APIC_setup();
  967. return -1;
  968. }
  969. return 0;
  970. }
  971. static void __init smp_cpu_index_default(void)
  972. {
  973. int i;
  974. struct cpuinfo_x86 *c;
  975. for_each_possible_cpu(i) {
  976. c = &cpu_data(i);
  977. /* mark all to hotplug */
  978. c->cpu_index = NR_CPUS;
  979. }
  980. }
  981. /*
  982. * Prepare for SMP bootup. The MP table or ACPI has been read
  983. * earlier. Just do some sanity checking here and enable APIC mode.
  984. */
  985. void __init native_smp_prepare_cpus(unsigned int max_cpus)
  986. {
  987. preempt_disable();
  988. nmi_watchdog_default();
  989. smp_cpu_index_default();
  990. current_cpu_data = boot_cpu_data;
  991. cpu_callin_map = cpumask_of_cpu(0);
  992. mb();
  993. /*
  994. * Setup boot CPU information
  995. */
  996. smp_store_cpu_info(0); /* Final full version of the data */
  997. boot_cpu_logical_apicid = logical_smp_processor_id();
  998. current_thread_info()->cpu = 0; /* needed? */
  999. set_cpu_sibling_map(0);
  1000. if (smp_sanity_check(max_cpus) < 0) {
  1001. printk(KERN_INFO "SMP disabled\n");
  1002. disable_smp();
  1003. goto out;
  1004. }
  1005. preempt_disable();
  1006. if (GET_APIC_ID(read_apic_id()) != boot_cpu_physical_apicid) {
  1007. panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
  1008. GET_APIC_ID(read_apic_id()), boot_cpu_physical_apicid);
  1009. /* Or can we switch back to PIC here? */
  1010. }
  1011. preempt_enable();
  1012. #ifdef CONFIG_X86_32
  1013. connect_bsp_APIC();
  1014. #endif
  1015. /*
  1016. * Switch from PIC to APIC mode.
  1017. */
  1018. setup_local_APIC();
  1019. #ifdef CONFIG_X86_64
  1020. /*
  1021. * Enable IO APIC before setting up error vector
  1022. */
  1023. if (!skip_ioapic_setup && nr_ioapics)
  1024. enable_IO_APIC();
  1025. #endif
  1026. end_local_APIC_setup();
  1027. map_cpu_to_logical_apicid();
  1028. setup_portio_remap();
  1029. smpboot_setup_io_apic();
  1030. /*
  1031. * Set up local APIC timer on boot CPU.
  1032. */
  1033. printk(KERN_INFO "CPU%d: ", 0);
  1034. print_cpu_info(&cpu_data(0));
  1035. setup_boot_clock();
  1036. out:
  1037. preempt_enable();
  1038. }
  1039. /*
  1040. * Early setup to make printk work.
  1041. */
  1042. void __init native_smp_prepare_boot_cpu(void)
  1043. {
  1044. int me = smp_processor_id();
  1045. #ifdef CONFIG_X86_32
  1046. init_gdt(me);
  1047. #endif
  1048. switch_to_new_gdt();
  1049. /* already set me in cpu_online_map in boot_cpu_init() */
  1050. cpu_set(me, cpu_callout_map);
  1051. per_cpu(cpu_state, me) = CPU_ONLINE;
  1052. }
  1053. void __init native_smp_cpus_done(unsigned int max_cpus)
  1054. {
  1055. Dprintk("Boot done.\n");
  1056. impress_friends();
  1057. smp_checks();
  1058. #ifdef CONFIG_X86_IO_APIC
  1059. setup_ioapic_dest();
  1060. #endif
  1061. check_nmi_watchdog();
  1062. }
  1063. #ifdef CONFIG_HOTPLUG_CPU
  1064. # ifdef CONFIG_X86_32
  1065. void cpu_exit_clear(void)
  1066. {
  1067. int cpu = raw_smp_processor_id();
  1068. idle_task_exit();
  1069. cpu_uninit();
  1070. irq_ctx_exit(cpu);
  1071. cpu_clear(cpu, cpu_callout_map);
  1072. cpu_clear(cpu, cpu_callin_map);
  1073. unmap_cpu_to_logical_apicid(cpu);
  1074. }
  1075. # endif /* CONFIG_X86_32 */
  1076. static void remove_siblinginfo(int cpu)
  1077. {
  1078. int sibling;
  1079. struct cpuinfo_x86 *c = &cpu_data(cpu);
  1080. for_each_cpu_mask(sibling, per_cpu(cpu_core_map, cpu)) {
  1081. cpu_clear(cpu, per_cpu(cpu_core_map, sibling));
  1082. /*/
  1083. * last thread sibling in this cpu core going down
  1084. */
  1085. if (cpus_weight(per_cpu(cpu_sibling_map, cpu)) == 1)
  1086. cpu_data(sibling).booted_cores--;
  1087. }
  1088. for_each_cpu_mask(sibling, per_cpu(cpu_sibling_map, cpu))
  1089. cpu_clear(cpu, per_cpu(cpu_sibling_map, sibling));
  1090. cpus_clear(per_cpu(cpu_sibling_map, cpu));
  1091. cpus_clear(per_cpu(cpu_core_map, cpu));
  1092. c->phys_proc_id = 0;
  1093. c->cpu_core_id = 0;
  1094. cpu_clear(cpu, cpu_sibling_setup_map);
  1095. }
  1096. static int additional_cpus __initdata = -1;
  1097. static __init int setup_additional_cpus(char *s)
  1098. {
  1099. return s && get_option(&s, &additional_cpus) ? 0 : -EINVAL;
  1100. }
  1101. early_param("additional_cpus", setup_additional_cpus);
  1102. /*
  1103. * cpu_possible_map should be static, it cannot change as cpu's
  1104. * are onlined, or offlined. The reason is per-cpu data-structures
  1105. * are allocated by some modules at init time, and dont expect to
  1106. * do this dynamically on cpu arrival/departure.
  1107. * cpu_present_map on the other hand can change dynamically.
  1108. * In case when cpu_hotplug is not compiled, then we resort to current
  1109. * behaviour, which is cpu_possible == cpu_present.
  1110. * - Ashok Raj
  1111. *
  1112. * Three ways to find out the number of additional hotplug CPUs:
  1113. * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
  1114. * - The user can overwrite it with additional_cpus=NUM
  1115. * - Otherwise don't reserve additional CPUs.
  1116. * We do this because additional CPUs waste a lot of memory.
  1117. * -AK
  1118. */
  1119. __init void prefill_possible_map(void)
  1120. {
  1121. int i;
  1122. int possible;
  1123. if (additional_cpus == -1) {
  1124. if (disabled_cpus > 0)
  1125. additional_cpus = disabled_cpus;
  1126. else
  1127. additional_cpus = 0;
  1128. }
  1129. possible = num_processors + additional_cpus;
  1130. if (possible > NR_CPUS)
  1131. possible = NR_CPUS;
  1132. printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
  1133. possible, max_t(int, possible - num_processors, 0));
  1134. for (i = 0; i < possible; i++)
  1135. cpu_set(i, cpu_possible_map);
  1136. nr_cpu_ids = possible;
  1137. }
  1138. static void __ref remove_cpu_from_maps(int cpu)
  1139. {
  1140. cpu_clear(cpu, cpu_online_map);
  1141. #ifdef CONFIG_X86_64
  1142. cpu_clear(cpu, cpu_callout_map);
  1143. cpu_clear(cpu, cpu_callin_map);
  1144. /* was set by cpu_init() */
  1145. clear_bit(cpu, (unsigned long *)&cpu_initialized);
  1146. numa_remove_cpu(cpu);
  1147. #endif
  1148. }
  1149. int __cpu_disable(void)
  1150. {
  1151. int cpu = smp_processor_id();
  1152. /*
  1153. * Perhaps use cpufreq to drop frequency, but that could go
  1154. * into generic code.
  1155. *
  1156. * We won't take down the boot processor on i386 due to some
  1157. * interrupts only being able to be serviced by the BSP.
  1158. * Especially so if we're not using an IOAPIC -zwane
  1159. */
  1160. if (cpu == 0)
  1161. return -EBUSY;
  1162. if (nmi_watchdog == NMI_LOCAL_APIC)
  1163. stop_apic_nmi_watchdog(NULL);
  1164. clear_local_APIC();
  1165. /*
  1166. * HACK:
  1167. * Allow any queued timer interrupts to get serviced
  1168. * This is only a temporary solution until we cleanup
  1169. * fixup_irqs as we do for IA64.
  1170. */
  1171. local_irq_enable();
  1172. mdelay(1);
  1173. local_irq_disable();
  1174. remove_siblinginfo(cpu);
  1175. /* It's now safe to remove this processor from the online map */
  1176. remove_cpu_from_maps(cpu);
  1177. fixup_irqs(cpu_online_map);
  1178. return 0;
  1179. }
  1180. void __cpu_die(unsigned int cpu)
  1181. {
  1182. /* We don't do anything here: idle task is faking death itself. */
  1183. unsigned int i;
  1184. for (i = 0; i < 10; i++) {
  1185. /* They ack this in play_dead by setting CPU_DEAD */
  1186. if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
  1187. printk(KERN_INFO "CPU %d is now offline\n", cpu);
  1188. if (1 == num_online_cpus())
  1189. alternatives_smp_switch(0);
  1190. return;
  1191. }
  1192. msleep(100);
  1193. }
  1194. printk(KERN_ERR "CPU %u didn't die...\n", cpu);
  1195. }
  1196. #else /* ... !CONFIG_HOTPLUG_CPU */
  1197. int __cpu_disable(void)
  1198. {
  1199. return -ENOSYS;
  1200. }
  1201. void __cpu_die(unsigned int cpu)
  1202. {
  1203. /* We said "no" in __cpu_disable */
  1204. BUG();
  1205. }
  1206. #endif
  1207. /*
  1208. * If the BIOS enumerates physical processors before logical,
  1209. * maxcpus=N at enumeration-time can be used to disable HT.
  1210. */
  1211. static int __init parse_maxcpus(char *arg)
  1212. {
  1213. extern unsigned int maxcpus;
  1214. maxcpus = simple_strtoul(arg, NULL, 0);
  1215. return 0;
  1216. }
  1217. early_param("maxcpus", parse_maxcpus);