smpboot.c 35 KB

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  1. /*
  2. * x86 SMP booting functions
  3. *
  4. * (c) 1995 Alan Cox, Building #3 <alan@lxorguk.ukuu.org.uk>
  5. * (c) 1998, 1999, 2000, 2009 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 <linux/tboot.h>
  50. #include <linux/stackprotector.h>
  51. #include <linux/gfp.h>
  52. #include <asm/acpi.h>
  53. #include <asm/desc.h>
  54. #include <asm/nmi.h>
  55. #include <asm/irq.h>
  56. #include <asm/idle.h>
  57. #include <asm/trampoline.h>
  58. #include <asm/cpu.h>
  59. #include <asm/numa.h>
  60. #include <asm/pgtable.h>
  61. #include <asm/tlbflush.h>
  62. #include <asm/mtrr.h>
  63. #include <asm/mwait.h>
  64. #include <asm/apic.h>
  65. #include <asm/io_apic.h>
  66. #include <asm/setup.h>
  67. #include <asm/uv/uv.h>
  68. #include <linux/mc146818rtc.h>
  69. #include <asm/smpboot_hooks.h>
  70. #include <asm/i8259.h>
  71. /* State of each CPU */
  72. DEFINE_PER_CPU(int, cpu_state) = { 0 };
  73. /* Store all idle threads, this can be reused instead of creating
  74. * a new thread. Also avoids complicated thread destroy functionality
  75. * for idle threads.
  76. */
  77. #ifdef CONFIG_HOTPLUG_CPU
  78. /*
  79. * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is
  80. * removed after init for !CONFIG_HOTPLUG_CPU.
  81. */
  82. static DEFINE_PER_CPU(struct task_struct *, idle_thread_array);
  83. #define get_idle_for_cpu(x) (per_cpu(idle_thread_array, x))
  84. #define set_idle_for_cpu(x, p) (per_cpu(idle_thread_array, x) = (p))
  85. /*
  86. * We need this for trampoline_base protection from concurrent accesses when
  87. * off- and onlining cores wildly.
  88. */
  89. static DEFINE_MUTEX(x86_cpu_hotplug_driver_mutex);
  90. void cpu_hotplug_driver_lock(void)
  91. {
  92. mutex_lock(&x86_cpu_hotplug_driver_mutex);
  93. }
  94. void cpu_hotplug_driver_unlock(void)
  95. {
  96. mutex_unlock(&x86_cpu_hotplug_driver_mutex);
  97. }
  98. ssize_t arch_cpu_probe(const char *buf, size_t count) { return -1; }
  99. ssize_t arch_cpu_release(const char *buf, size_t count) { return -1; }
  100. #else
  101. static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ;
  102. #define get_idle_for_cpu(x) (idle_thread_array[(x)])
  103. #define set_idle_for_cpu(x, p) (idle_thread_array[(x)] = (p))
  104. #endif
  105. /* Number of siblings per CPU package */
  106. int smp_num_siblings = 1;
  107. EXPORT_SYMBOL(smp_num_siblings);
  108. /* Last level cache ID of each logical CPU */
  109. DEFINE_PER_CPU(u16, cpu_llc_id) = BAD_APICID;
  110. /* representing HT siblings of each logical CPU */
  111. DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map);
  112. EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
  113. /* representing HT and core siblings of each logical CPU */
  114. DEFINE_PER_CPU(cpumask_var_t, cpu_core_map);
  115. EXPORT_PER_CPU_SYMBOL(cpu_core_map);
  116. DEFINE_PER_CPU(cpumask_var_t, cpu_llc_shared_map);
  117. /* Per CPU bogomips and other parameters */
  118. DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
  119. EXPORT_PER_CPU_SYMBOL(cpu_info);
  120. atomic_t init_deasserted;
  121. /*
  122. * Report back to the Boot Processor.
  123. * Running on AP.
  124. */
  125. static void __cpuinit smp_callin(void)
  126. {
  127. int cpuid, phys_id;
  128. unsigned long timeout;
  129. /*
  130. * If waken up by an INIT in an 82489DX configuration
  131. * we may get here before an INIT-deassert IPI reaches
  132. * our local APIC. We have to wait for the IPI or we'll
  133. * lock up on an APIC access.
  134. */
  135. if (apic->wait_for_init_deassert)
  136. apic->wait_for_init_deassert(&init_deasserted);
  137. /*
  138. * (This works even if the APIC is not enabled.)
  139. */
  140. phys_id = read_apic_id();
  141. cpuid = smp_processor_id();
  142. if (cpumask_test_cpu(cpuid, cpu_callin_mask)) {
  143. panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__,
  144. phys_id, cpuid);
  145. }
  146. pr_debug("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id);
  147. /*
  148. * STARTUP IPIs are fragile beasts as they might sometimes
  149. * trigger some glue motherboard logic. Complete APIC bus
  150. * silence for 1 second, this overestimates the time the
  151. * boot CPU is spending to send the up to 2 STARTUP IPIs
  152. * by a factor of two. This should be enough.
  153. */
  154. /*
  155. * Waiting 2s total for startup (udelay is not yet working)
  156. */
  157. timeout = jiffies + 2*HZ;
  158. while (time_before(jiffies, timeout)) {
  159. /*
  160. * Has the boot CPU finished it's STARTUP sequence?
  161. */
  162. if (cpumask_test_cpu(cpuid, cpu_callout_mask))
  163. break;
  164. cpu_relax();
  165. }
  166. if (!time_before(jiffies, timeout)) {
  167. panic("%s: CPU%d started up but did not get a callout!\n",
  168. __func__, cpuid);
  169. }
  170. /*
  171. * the boot CPU has finished the init stage and is spinning
  172. * on callin_map until we finish. We are free to set up this
  173. * CPU, first the APIC. (this is probably redundant on most
  174. * boards)
  175. */
  176. pr_debug("CALLIN, before setup_local_APIC().\n");
  177. if (apic->smp_callin_clear_local_apic)
  178. apic->smp_callin_clear_local_apic();
  179. setup_local_APIC();
  180. end_local_APIC_setup();
  181. /*
  182. * Need to setup vector mappings before we enable interrupts.
  183. */
  184. setup_vector_irq(smp_processor_id());
  185. /*
  186. * Get our bogomips.
  187. *
  188. * Need to enable IRQs because it can take longer and then
  189. * the NMI watchdog might kill us.
  190. */
  191. local_irq_enable();
  192. calibrate_delay();
  193. local_irq_disable();
  194. pr_debug("Stack at about %p\n", &cpuid);
  195. /*
  196. * Save our processor parameters
  197. */
  198. smp_store_cpu_info(cpuid);
  199. /*
  200. * This must be done before setting cpu_online_mask
  201. * or calling notify_cpu_starting.
  202. */
  203. set_cpu_sibling_map(raw_smp_processor_id());
  204. wmb();
  205. notify_cpu_starting(cpuid);
  206. /*
  207. * Allow the master to continue.
  208. */
  209. cpumask_set_cpu(cpuid, cpu_callin_mask);
  210. }
  211. /*
  212. * Activate a secondary processor.
  213. */
  214. notrace static void __cpuinit start_secondary(void *unused)
  215. {
  216. /*
  217. * Don't put *anything* before cpu_init(), SMP booting is too
  218. * fragile that we want to limit the things done here to the
  219. * most necessary things.
  220. */
  221. cpu_init();
  222. preempt_disable();
  223. smp_callin();
  224. #ifdef CONFIG_X86_32
  225. /* switch away from the initial page table */
  226. load_cr3(swapper_pg_dir);
  227. __flush_tlb_all();
  228. #endif
  229. /* otherwise gcc will move up smp_processor_id before the cpu_init */
  230. barrier();
  231. /*
  232. * Check TSC synchronization with the BP:
  233. */
  234. check_tsc_sync_target();
  235. /*
  236. * We need to hold call_lock, so there is no inconsistency
  237. * between the time smp_call_function() determines number of
  238. * IPI recipients, and the time when the determination is made
  239. * for which cpus receive the IPI. Holding this
  240. * lock helps us to not include this cpu in a currently in progress
  241. * smp_call_function().
  242. *
  243. * We need to hold vector_lock so there the set of online cpus
  244. * does not change while we are assigning vectors to cpus. Holding
  245. * this lock ensures we don't half assign or remove an irq from a cpu.
  246. */
  247. ipi_call_lock();
  248. lock_vector_lock();
  249. set_cpu_online(smp_processor_id(), true);
  250. unlock_vector_lock();
  251. ipi_call_unlock();
  252. per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE;
  253. x86_platform.nmi_init();
  254. /* enable local interrupts */
  255. local_irq_enable();
  256. /* to prevent fake stack check failure in clock setup */
  257. boot_init_stack_canary();
  258. x86_cpuinit.setup_percpu_clockev();
  259. wmb();
  260. cpu_idle();
  261. }
  262. /*
  263. * The bootstrap kernel entry code has set these up. Save them for
  264. * a given CPU
  265. */
  266. void __cpuinit smp_store_cpu_info(int id)
  267. {
  268. struct cpuinfo_x86 *c = &cpu_data(id);
  269. *c = boot_cpu_data;
  270. c->cpu_index = id;
  271. if (id != 0)
  272. identify_secondary_cpu(c);
  273. }
  274. static void __cpuinit check_cpu_siblings_on_same_node(int cpu1, int cpu2)
  275. {
  276. int node1 = early_cpu_to_node(cpu1);
  277. int node2 = early_cpu_to_node(cpu2);
  278. /*
  279. * Our CPU scheduler assumes all logical cpus in the same physical cpu
  280. * share the same node. But, buggy ACPI or NUMA emulation might assign
  281. * them to different node. Fix it.
  282. */
  283. if (node1 != node2) {
  284. pr_warning("CPU %d in node %d and CPU %d in node %d are in the same physical CPU. forcing same node %d\n",
  285. cpu1, node1, cpu2, node2, node2);
  286. numa_remove_cpu(cpu1);
  287. numa_set_node(cpu1, node2);
  288. numa_add_cpu(cpu1);
  289. }
  290. }
  291. static void __cpuinit link_thread_siblings(int cpu1, int cpu2)
  292. {
  293. cpumask_set_cpu(cpu1, cpu_sibling_mask(cpu2));
  294. cpumask_set_cpu(cpu2, cpu_sibling_mask(cpu1));
  295. cpumask_set_cpu(cpu1, cpu_core_mask(cpu2));
  296. cpumask_set_cpu(cpu2, cpu_core_mask(cpu1));
  297. cpumask_set_cpu(cpu1, cpu_llc_shared_mask(cpu2));
  298. cpumask_set_cpu(cpu2, cpu_llc_shared_mask(cpu1));
  299. check_cpu_siblings_on_same_node(cpu1, cpu2);
  300. }
  301. void __cpuinit set_cpu_sibling_map(int cpu)
  302. {
  303. int i;
  304. struct cpuinfo_x86 *c = &cpu_data(cpu);
  305. cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
  306. if (smp_num_siblings > 1) {
  307. for_each_cpu(i, cpu_sibling_setup_mask) {
  308. struct cpuinfo_x86 *o = &cpu_data(i);
  309. if (cpu_has(c, X86_FEATURE_TOPOEXT)) {
  310. if (c->phys_proc_id == o->phys_proc_id &&
  311. per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i) &&
  312. c->compute_unit_id == o->compute_unit_id)
  313. link_thread_siblings(cpu, i);
  314. } else if (c->phys_proc_id == o->phys_proc_id &&
  315. c->cpu_core_id == o->cpu_core_id) {
  316. link_thread_siblings(cpu, i);
  317. }
  318. }
  319. } else {
  320. cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
  321. }
  322. cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
  323. if (__this_cpu_read(cpu_info.x86_max_cores) == 1) {
  324. cpumask_copy(cpu_core_mask(cpu), cpu_sibling_mask(cpu));
  325. c->booted_cores = 1;
  326. return;
  327. }
  328. for_each_cpu(i, cpu_sibling_setup_mask) {
  329. if (per_cpu(cpu_llc_id, cpu) != BAD_APICID &&
  330. per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i)) {
  331. cpumask_set_cpu(i, cpu_llc_shared_mask(cpu));
  332. cpumask_set_cpu(cpu, cpu_llc_shared_mask(i));
  333. check_cpu_siblings_on_same_node(cpu, i);
  334. }
  335. if (c->phys_proc_id == cpu_data(i).phys_proc_id) {
  336. cpumask_set_cpu(i, cpu_core_mask(cpu));
  337. cpumask_set_cpu(cpu, cpu_core_mask(i));
  338. check_cpu_siblings_on_same_node(cpu, i);
  339. /*
  340. * Does this new cpu bringup a new core?
  341. */
  342. if (cpumask_weight(cpu_sibling_mask(cpu)) == 1) {
  343. /*
  344. * for each core in package, increment
  345. * the booted_cores for this new cpu
  346. */
  347. if (cpumask_first(cpu_sibling_mask(i)) == i)
  348. c->booted_cores++;
  349. /*
  350. * increment the core count for all
  351. * the other cpus in this package
  352. */
  353. if (i != cpu)
  354. cpu_data(i).booted_cores++;
  355. } else if (i != cpu && !c->booted_cores)
  356. c->booted_cores = cpu_data(i).booted_cores;
  357. }
  358. }
  359. }
  360. /* maps the cpu to the sched domain representing multi-core */
  361. const struct cpumask *cpu_coregroup_mask(int cpu)
  362. {
  363. struct cpuinfo_x86 *c = &cpu_data(cpu);
  364. /*
  365. * For perf, we return last level cache shared map.
  366. * And for power savings, we return cpu_core_map
  367. */
  368. if ((sched_mc_power_savings || sched_smt_power_savings) &&
  369. !(cpu_has(c, X86_FEATURE_AMD_DCM)))
  370. return cpu_core_mask(cpu);
  371. else
  372. return cpu_llc_shared_mask(cpu);
  373. }
  374. static void impress_friends(void)
  375. {
  376. int cpu;
  377. unsigned long bogosum = 0;
  378. /*
  379. * Allow the user to impress friends.
  380. */
  381. pr_debug("Before bogomips.\n");
  382. for_each_possible_cpu(cpu)
  383. if (cpumask_test_cpu(cpu, cpu_callout_mask))
  384. bogosum += cpu_data(cpu).loops_per_jiffy;
  385. printk(KERN_INFO
  386. "Total of %d processors activated (%lu.%02lu BogoMIPS).\n",
  387. num_online_cpus(),
  388. bogosum/(500000/HZ),
  389. (bogosum/(5000/HZ))%100);
  390. pr_debug("Before bogocount - setting activated=1.\n");
  391. }
  392. void __inquire_remote_apic(int apicid)
  393. {
  394. unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
  395. char *names[] = { "ID", "VERSION", "SPIV" };
  396. int timeout;
  397. u32 status;
  398. printk(KERN_INFO "Inquiring remote APIC 0x%x...\n", apicid);
  399. for (i = 0; i < ARRAY_SIZE(regs); i++) {
  400. printk(KERN_INFO "... APIC 0x%x %s: ", apicid, names[i]);
  401. /*
  402. * Wait for idle.
  403. */
  404. status = safe_apic_wait_icr_idle();
  405. if (status)
  406. printk(KERN_CONT
  407. "a previous APIC delivery may have failed\n");
  408. apic_icr_write(APIC_DM_REMRD | regs[i], apicid);
  409. timeout = 0;
  410. do {
  411. udelay(100);
  412. status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
  413. } while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
  414. switch (status) {
  415. case APIC_ICR_RR_VALID:
  416. status = apic_read(APIC_RRR);
  417. printk(KERN_CONT "%08x\n", status);
  418. break;
  419. default:
  420. printk(KERN_CONT "failed\n");
  421. }
  422. }
  423. }
  424. /*
  425. * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
  426. * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
  427. * won't ... remember to clear down the APIC, etc later.
  428. */
  429. int __cpuinit
  430. wakeup_secondary_cpu_via_nmi(int logical_apicid, unsigned long start_eip)
  431. {
  432. unsigned long send_status, accept_status = 0;
  433. int maxlvt;
  434. /* Target chip */
  435. /* Boot on the stack */
  436. /* Kick the second */
  437. apic_icr_write(APIC_DM_NMI | apic->dest_logical, logical_apicid);
  438. pr_debug("Waiting for send to finish...\n");
  439. send_status = safe_apic_wait_icr_idle();
  440. /*
  441. * Give the other CPU some time to accept the IPI.
  442. */
  443. udelay(200);
  444. if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
  445. maxlvt = lapic_get_maxlvt();
  446. if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
  447. apic_write(APIC_ESR, 0);
  448. accept_status = (apic_read(APIC_ESR) & 0xEF);
  449. }
  450. pr_debug("NMI sent.\n");
  451. if (send_status)
  452. printk(KERN_ERR "APIC never delivered???\n");
  453. if (accept_status)
  454. printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
  455. return (send_status | accept_status);
  456. }
  457. static int __cpuinit
  458. wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
  459. {
  460. unsigned long send_status, accept_status = 0;
  461. int maxlvt, num_starts, j;
  462. maxlvt = lapic_get_maxlvt();
  463. /*
  464. * Be paranoid about clearing APIC errors.
  465. */
  466. if (APIC_INTEGRATED(apic_version[phys_apicid])) {
  467. if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
  468. apic_write(APIC_ESR, 0);
  469. apic_read(APIC_ESR);
  470. }
  471. pr_debug("Asserting INIT.\n");
  472. /*
  473. * Turn INIT on target chip
  474. */
  475. /*
  476. * Send IPI
  477. */
  478. apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
  479. phys_apicid);
  480. pr_debug("Waiting for send to finish...\n");
  481. send_status = safe_apic_wait_icr_idle();
  482. mdelay(10);
  483. pr_debug("Deasserting INIT.\n");
  484. /* Target chip */
  485. /* Send IPI */
  486. apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
  487. pr_debug("Waiting for send to finish...\n");
  488. send_status = safe_apic_wait_icr_idle();
  489. mb();
  490. atomic_set(&init_deasserted, 1);
  491. /*
  492. * Should we send STARTUP IPIs ?
  493. *
  494. * Determine this based on the APIC version.
  495. * If we don't have an integrated APIC, don't send the STARTUP IPIs.
  496. */
  497. if (APIC_INTEGRATED(apic_version[phys_apicid]))
  498. num_starts = 2;
  499. else
  500. num_starts = 0;
  501. /*
  502. * Paravirt / VMI wants a startup IPI hook here to set up the
  503. * target processor state.
  504. */
  505. startup_ipi_hook(phys_apicid, (unsigned long) start_secondary,
  506. stack_start);
  507. /*
  508. * Run STARTUP IPI loop.
  509. */
  510. pr_debug("#startup loops: %d.\n", num_starts);
  511. for (j = 1; j <= num_starts; j++) {
  512. pr_debug("Sending STARTUP #%d.\n", j);
  513. if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
  514. apic_write(APIC_ESR, 0);
  515. apic_read(APIC_ESR);
  516. pr_debug("After apic_write.\n");
  517. /*
  518. * STARTUP IPI
  519. */
  520. /* Target chip */
  521. /* Boot on the stack */
  522. /* Kick the second */
  523. apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
  524. phys_apicid);
  525. /*
  526. * Give the other CPU some time to accept the IPI.
  527. */
  528. udelay(300);
  529. pr_debug("Startup point 1.\n");
  530. pr_debug("Waiting for send to finish...\n");
  531. send_status = safe_apic_wait_icr_idle();
  532. /*
  533. * Give the other CPU some time to accept the IPI.
  534. */
  535. udelay(200);
  536. if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
  537. apic_write(APIC_ESR, 0);
  538. accept_status = (apic_read(APIC_ESR) & 0xEF);
  539. if (send_status || accept_status)
  540. break;
  541. }
  542. pr_debug("After Startup.\n");
  543. if (send_status)
  544. printk(KERN_ERR "APIC never delivered???\n");
  545. if (accept_status)
  546. printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status);
  547. return (send_status | accept_status);
  548. }
  549. struct create_idle {
  550. struct work_struct work;
  551. struct task_struct *idle;
  552. struct completion done;
  553. int cpu;
  554. };
  555. static void __cpuinit do_fork_idle(struct work_struct *work)
  556. {
  557. struct create_idle *c_idle =
  558. container_of(work, struct create_idle, work);
  559. c_idle->idle = fork_idle(c_idle->cpu);
  560. complete(&c_idle->done);
  561. }
  562. /* reduce the number of lines printed when booting a large cpu count system */
  563. static void __cpuinit announce_cpu(int cpu, int apicid)
  564. {
  565. static int current_node = -1;
  566. int node = early_cpu_to_node(cpu);
  567. if (system_state == SYSTEM_BOOTING) {
  568. if (node != current_node) {
  569. if (current_node > (-1))
  570. pr_cont(" Ok.\n");
  571. current_node = node;
  572. pr_info("Booting Node %3d, Processors ", node);
  573. }
  574. pr_cont(" #%d%s", cpu, cpu == (nr_cpu_ids - 1) ? " Ok.\n" : "");
  575. return;
  576. } else
  577. pr_info("Booting Node %d Processor %d APIC 0x%x\n",
  578. node, cpu, apicid);
  579. }
  580. /*
  581. * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
  582. * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
  583. * Returns zero if CPU booted OK, else error code from
  584. * ->wakeup_secondary_cpu.
  585. */
  586. static int __cpuinit do_boot_cpu(int apicid, int cpu)
  587. {
  588. unsigned long boot_error = 0;
  589. unsigned long start_ip;
  590. int timeout;
  591. struct create_idle c_idle = {
  592. .cpu = cpu,
  593. .done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done),
  594. };
  595. INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle);
  596. alternatives_smp_switch(1);
  597. c_idle.idle = get_idle_for_cpu(cpu);
  598. /*
  599. * We can't use kernel_thread since we must avoid to
  600. * reschedule the child.
  601. */
  602. if (c_idle.idle) {
  603. c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *)
  604. (THREAD_SIZE + task_stack_page(c_idle.idle))) - 1);
  605. init_idle(c_idle.idle, cpu);
  606. goto do_rest;
  607. }
  608. schedule_work(&c_idle.work);
  609. wait_for_completion(&c_idle.done);
  610. if (IS_ERR(c_idle.idle)) {
  611. printk("failed fork for CPU %d\n", cpu);
  612. destroy_work_on_stack(&c_idle.work);
  613. return PTR_ERR(c_idle.idle);
  614. }
  615. set_idle_for_cpu(cpu, c_idle.idle);
  616. do_rest:
  617. per_cpu(current_task, cpu) = c_idle.idle;
  618. #ifdef CONFIG_X86_32
  619. /* Stack for startup_32 can be just as for start_secondary onwards */
  620. irq_ctx_init(cpu);
  621. #else
  622. clear_tsk_thread_flag(c_idle.idle, TIF_FORK);
  623. initial_gs = per_cpu_offset(cpu);
  624. per_cpu(kernel_stack, cpu) =
  625. (unsigned long)task_stack_page(c_idle.idle) -
  626. KERNEL_STACK_OFFSET + THREAD_SIZE;
  627. #endif
  628. early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu);
  629. initial_code = (unsigned long)start_secondary;
  630. stack_start = c_idle.idle->thread.sp;
  631. /* start_ip had better be page-aligned! */
  632. start_ip = trampoline_address();
  633. /* So we see what's up */
  634. announce_cpu(cpu, apicid);
  635. /*
  636. * This grunge runs the startup process for
  637. * the targeted processor.
  638. */
  639. printk(KERN_DEBUG "smpboot cpu %d: start_ip = %lx\n", cpu, start_ip);
  640. atomic_set(&init_deasserted, 0);
  641. if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
  642. pr_debug("Setting warm reset code and vector.\n");
  643. smpboot_setup_warm_reset_vector(start_ip);
  644. /*
  645. * Be paranoid about clearing APIC errors.
  646. */
  647. if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) {
  648. apic_write(APIC_ESR, 0);
  649. apic_read(APIC_ESR);
  650. }
  651. }
  652. /*
  653. * Kick the secondary CPU. Use the method in the APIC driver
  654. * if it's defined - or use an INIT boot APIC message otherwise:
  655. */
  656. if (apic->wakeup_secondary_cpu)
  657. boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
  658. else
  659. boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
  660. if (!boot_error) {
  661. /*
  662. * allow APs to start initializing.
  663. */
  664. pr_debug("Before Callout %d.\n", cpu);
  665. cpumask_set_cpu(cpu, cpu_callout_mask);
  666. pr_debug("After Callout %d.\n", cpu);
  667. /*
  668. * Wait 5s total for a response
  669. */
  670. for (timeout = 0; timeout < 50000; timeout++) {
  671. if (cpumask_test_cpu(cpu, cpu_callin_mask))
  672. break; /* It has booted */
  673. udelay(100);
  674. /*
  675. * Allow other tasks to run while we wait for the
  676. * AP to come online. This also gives a chance
  677. * for the MTRR work(triggered by the AP coming online)
  678. * to be completed in the stop machine context.
  679. */
  680. schedule();
  681. }
  682. if (cpumask_test_cpu(cpu, cpu_callin_mask))
  683. pr_debug("CPU%d: has booted.\n", cpu);
  684. else {
  685. boot_error = 1;
  686. if (*(volatile u32 *)TRAMPOLINE_SYM(trampoline_status)
  687. == 0xA5A5A5A5)
  688. /* trampoline started but...? */
  689. pr_err("CPU%d: Stuck ??\n", cpu);
  690. else
  691. /* trampoline code not run */
  692. pr_err("CPU%d: Not responding.\n", cpu);
  693. if (apic->inquire_remote_apic)
  694. apic->inquire_remote_apic(apicid);
  695. }
  696. }
  697. if (boot_error) {
  698. /* Try to put things back the way they were before ... */
  699. numa_remove_cpu(cpu); /* was set by numa_add_cpu */
  700. /* was set by do_boot_cpu() */
  701. cpumask_clear_cpu(cpu, cpu_callout_mask);
  702. /* was set by cpu_init() */
  703. cpumask_clear_cpu(cpu, cpu_initialized_mask);
  704. set_cpu_present(cpu, false);
  705. per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID;
  706. }
  707. /* mark "stuck" area as not stuck */
  708. *(volatile u32 *)TRAMPOLINE_SYM(trampoline_status) = 0;
  709. if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
  710. /*
  711. * Cleanup possible dangling ends...
  712. */
  713. smpboot_restore_warm_reset_vector();
  714. }
  715. destroy_work_on_stack(&c_idle.work);
  716. return boot_error;
  717. }
  718. int __cpuinit native_cpu_up(unsigned int cpu)
  719. {
  720. int apicid = apic->cpu_present_to_apicid(cpu);
  721. unsigned long flags;
  722. int err;
  723. WARN_ON(irqs_disabled());
  724. pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu);
  725. if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid ||
  726. !physid_isset(apicid, phys_cpu_present_map)) {
  727. printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu);
  728. return -EINVAL;
  729. }
  730. /*
  731. * Already booted CPU?
  732. */
  733. if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
  734. pr_debug("do_boot_cpu %d Already started\n", cpu);
  735. return -ENOSYS;
  736. }
  737. /*
  738. * Save current MTRR state in case it was changed since early boot
  739. * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
  740. */
  741. mtrr_save_state();
  742. per_cpu(cpu_state, cpu) = CPU_UP_PREPARE;
  743. err = do_boot_cpu(apicid, cpu);
  744. if (err) {
  745. pr_debug("do_boot_cpu failed %d\n", err);
  746. return -EIO;
  747. }
  748. /*
  749. * Check TSC synchronization with the AP (keep irqs disabled
  750. * while doing so):
  751. */
  752. local_irq_save(flags);
  753. check_tsc_sync_source(cpu);
  754. local_irq_restore(flags);
  755. while (!cpu_online(cpu)) {
  756. cpu_relax();
  757. touch_nmi_watchdog();
  758. }
  759. return 0;
  760. }
  761. /**
  762. * arch_disable_smp_support() - disables SMP support for x86 at runtime
  763. */
  764. void arch_disable_smp_support(void)
  765. {
  766. disable_ioapic_support();
  767. }
  768. /*
  769. * Fall back to non SMP mode after errors.
  770. *
  771. * RED-PEN audit/test this more. I bet there is more state messed up here.
  772. */
  773. static __init void disable_smp(void)
  774. {
  775. init_cpu_present(cpumask_of(0));
  776. init_cpu_possible(cpumask_of(0));
  777. smpboot_clear_io_apic_irqs();
  778. if (smp_found_config)
  779. physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
  780. else
  781. physid_set_mask_of_physid(0, &phys_cpu_present_map);
  782. cpumask_set_cpu(0, cpu_sibling_mask(0));
  783. cpumask_set_cpu(0, cpu_core_mask(0));
  784. }
  785. /*
  786. * Various sanity checks.
  787. */
  788. static int __init smp_sanity_check(unsigned max_cpus)
  789. {
  790. preempt_disable();
  791. #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
  792. if (def_to_bigsmp && nr_cpu_ids > 8) {
  793. unsigned int cpu;
  794. unsigned nr;
  795. printk(KERN_WARNING
  796. "More than 8 CPUs detected - skipping them.\n"
  797. "Use CONFIG_X86_BIGSMP.\n");
  798. nr = 0;
  799. for_each_present_cpu(cpu) {
  800. if (nr >= 8)
  801. set_cpu_present(cpu, false);
  802. nr++;
  803. }
  804. nr = 0;
  805. for_each_possible_cpu(cpu) {
  806. if (nr >= 8)
  807. set_cpu_possible(cpu, false);
  808. nr++;
  809. }
  810. nr_cpu_ids = 8;
  811. }
  812. #endif
  813. if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
  814. printk(KERN_WARNING
  815. "weird, boot CPU (#%d) not listed by the BIOS.\n",
  816. hard_smp_processor_id());
  817. physid_set(hard_smp_processor_id(), phys_cpu_present_map);
  818. }
  819. /*
  820. * If we couldn't find an SMP configuration at boot time,
  821. * get out of here now!
  822. */
  823. if (!smp_found_config && !acpi_lapic) {
  824. preempt_enable();
  825. printk(KERN_NOTICE "SMP motherboard not detected.\n");
  826. disable_smp();
  827. if (APIC_init_uniprocessor())
  828. printk(KERN_NOTICE "Local APIC not detected."
  829. " Using dummy APIC emulation.\n");
  830. return -1;
  831. }
  832. /*
  833. * Should not be necessary because the MP table should list the boot
  834. * CPU too, but we do it for the sake of robustness anyway.
  835. */
  836. if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
  837. printk(KERN_NOTICE
  838. "weird, boot CPU (#%d) not listed by the BIOS.\n",
  839. boot_cpu_physical_apicid);
  840. physid_set(hard_smp_processor_id(), phys_cpu_present_map);
  841. }
  842. preempt_enable();
  843. /*
  844. * If we couldn't find a local APIC, then get out of here now!
  845. */
  846. if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) &&
  847. !cpu_has_apic) {
  848. if (!disable_apic) {
  849. pr_err("BIOS bug, local APIC #%d not detected!...\n",
  850. boot_cpu_physical_apicid);
  851. pr_err("... forcing use of dummy APIC emulation."
  852. "(tell your hw vendor)\n");
  853. }
  854. smpboot_clear_io_apic();
  855. disable_ioapic_support();
  856. return -1;
  857. }
  858. verify_local_APIC();
  859. /*
  860. * If SMP should be disabled, then really disable it!
  861. */
  862. if (!max_cpus) {
  863. printk(KERN_INFO "SMP mode deactivated.\n");
  864. smpboot_clear_io_apic();
  865. connect_bsp_APIC();
  866. setup_local_APIC();
  867. bsp_end_local_APIC_setup();
  868. return -1;
  869. }
  870. return 0;
  871. }
  872. static void __init smp_cpu_index_default(void)
  873. {
  874. int i;
  875. struct cpuinfo_x86 *c;
  876. for_each_possible_cpu(i) {
  877. c = &cpu_data(i);
  878. /* mark all to hotplug */
  879. c->cpu_index = nr_cpu_ids;
  880. }
  881. }
  882. /*
  883. * Prepare for SMP bootup. The MP table or ACPI has been read
  884. * earlier. Just do some sanity checking here and enable APIC mode.
  885. */
  886. void __init native_smp_prepare_cpus(unsigned int max_cpus)
  887. {
  888. unsigned int i;
  889. preempt_disable();
  890. smp_cpu_index_default();
  891. /*
  892. * Setup boot CPU information
  893. */
  894. smp_store_cpu_info(0); /* Final full version of the data */
  895. cpumask_copy(cpu_callin_mask, cpumask_of(0));
  896. mb();
  897. current_thread_info()->cpu = 0; /* needed? */
  898. for_each_possible_cpu(i) {
  899. zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
  900. zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
  901. zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
  902. }
  903. set_cpu_sibling_map(0);
  904. if (smp_sanity_check(max_cpus) < 0) {
  905. printk(KERN_INFO "SMP disabled\n");
  906. disable_smp();
  907. goto out;
  908. }
  909. default_setup_apic_routing();
  910. preempt_disable();
  911. if (read_apic_id() != boot_cpu_physical_apicid) {
  912. panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
  913. read_apic_id(), boot_cpu_physical_apicid);
  914. /* Or can we switch back to PIC here? */
  915. }
  916. preempt_enable();
  917. connect_bsp_APIC();
  918. /*
  919. * Switch from PIC to APIC mode.
  920. */
  921. setup_local_APIC();
  922. /*
  923. * Enable IO APIC before setting up error vector
  924. */
  925. if (!skip_ioapic_setup && nr_ioapics)
  926. enable_IO_APIC();
  927. bsp_end_local_APIC_setup();
  928. if (apic->setup_portio_remap)
  929. apic->setup_portio_remap();
  930. smpboot_setup_io_apic();
  931. /*
  932. * Set up local APIC timer on boot CPU.
  933. */
  934. printk(KERN_INFO "CPU%d: ", 0);
  935. print_cpu_info(&cpu_data(0));
  936. x86_init.timers.setup_percpu_clockev();
  937. if (is_uv_system())
  938. uv_system_init();
  939. set_mtrr_aps_delayed_init();
  940. out:
  941. preempt_enable();
  942. }
  943. void arch_disable_nonboot_cpus_begin(void)
  944. {
  945. /*
  946. * Avoid the smp alternatives switch during the disable_nonboot_cpus().
  947. * In the suspend path, we will be back in the SMP mode shortly anyways.
  948. */
  949. skip_smp_alternatives = true;
  950. }
  951. void arch_disable_nonboot_cpus_end(void)
  952. {
  953. skip_smp_alternatives = false;
  954. }
  955. void arch_enable_nonboot_cpus_begin(void)
  956. {
  957. set_mtrr_aps_delayed_init();
  958. }
  959. void arch_enable_nonboot_cpus_end(void)
  960. {
  961. mtrr_aps_init();
  962. }
  963. /*
  964. * Early setup to make printk work.
  965. */
  966. void __init native_smp_prepare_boot_cpu(void)
  967. {
  968. int me = smp_processor_id();
  969. switch_to_new_gdt(me);
  970. /* already set me in cpu_online_mask in boot_cpu_init() */
  971. cpumask_set_cpu(me, cpu_callout_mask);
  972. per_cpu(cpu_state, me) = CPU_ONLINE;
  973. }
  974. void __init native_smp_cpus_done(unsigned int max_cpus)
  975. {
  976. pr_debug("Boot done.\n");
  977. impress_friends();
  978. #ifdef CONFIG_X86_IO_APIC
  979. setup_ioapic_dest();
  980. #endif
  981. mtrr_aps_init();
  982. }
  983. static int __initdata setup_possible_cpus = -1;
  984. static int __init _setup_possible_cpus(char *str)
  985. {
  986. get_option(&str, &setup_possible_cpus);
  987. return 0;
  988. }
  989. early_param("possible_cpus", _setup_possible_cpus);
  990. /*
  991. * cpu_possible_mask should be static, it cannot change as cpu's
  992. * are onlined, or offlined. The reason is per-cpu data-structures
  993. * are allocated by some modules at init time, and dont expect to
  994. * do this dynamically on cpu arrival/departure.
  995. * cpu_present_mask on the other hand can change dynamically.
  996. * In case when cpu_hotplug is not compiled, then we resort to current
  997. * behaviour, which is cpu_possible == cpu_present.
  998. * - Ashok Raj
  999. *
  1000. * Three ways to find out the number of additional hotplug CPUs:
  1001. * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
  1002. * - The user can overwrite it with possible_cpus=NUM
  1003. * - Otherwise don't reserve additional CPUs.
  1004. * We do this because additional CPUs waste a lot of memory.
  1005. * -AK
  1006. */
  1007. __init void prefill_possible_map(void)
  1008. {
  1009. int i, possible;
  1010. /* no processor from mptable or madt */
  1011. if (!num_processors)
  1012. num_processors = 1;
  1013. i = setup_max_cpus ?: 1;
  1014. if (setup_possible_cpus == -1) {
  1015. possible = num_processors;
  1016. #ifdef CONFIG_HOTPLUG_CPU
  1017. if (setup_max_cpus)
  1018. possible += disabled_cpus;
  1019. #else
  1020. if (possible > i)
  1021. possible = i;
  1022. #endif
  1023. } else
  1024. possible = setup_possible_cpus;
  1025. total_cpus = max_t(int, possible, num_processors + disabled_cpus);
  1026. /* nr_cpu_ids could be reduced via nr_cpus= */
  1027. if (possible > nr_cpu_ids) {
  1028. printk(KERN_WARNING
  1029. "%d Processors exceeds NR_CPUS limit of %d\n",
  1030. possible, nr_cpu_ids);
  1031. possible = nr_cpu_ids;
  1032. }
  1033. #ifdef CONFIG_HOTPLUG_CPU
  1034. if (!setup_max_cpus)
  1035. #endif
  1036. if (possible > i) {
  1037. printk(KERN_WARNING
  1038. "%d Processors exceeds max_cpus limit of %u\n",
  1039. possible, setup_max_cpus);
  1040. possible = i;
  1041. }
  1042. printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n",
  1043. possible, max_t(int, possible - num_processors, 0));
  1044. for (i = 0; i < possible; i++)
  1045. set_cpu_possible(i, true);
  1046. for (; i < NR_CPUS; i++)
  1047. set_cpu_possible(i, false);
  1048. nr_cpu_ids = possible;
  1049. }
  1050. #ifdef CONFIG_HOTPLUG_CPU
  1051. static void remove_siblinginfo(int cpu)
  1052. {
  1053. int sibling;
  1054. struct cpuinfo_x86 *c = &cpu_data(cpu);
  1055. for_each_cpu(sibling, cpu_core_mask(cpu)) {
  1056. cpumask_clear_cpu(cpu, cpu_core_mask(sibling));
  1057. /*/
  1058. * last thread sibling in this cpu core going down
  1059. */
  1060. if (cpumask_weight(cpu_sibling_mask(cpu)) == 1)
  1061. cpu_data(sibling).booted_cores--;
  1062. }
  1063. for_each_cpu(sibling, cpu_sibling_mask(cpu))
  1064. cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling));
  1065. cpumask_clear(cpu_sibling_mask(cpu));
  1066. cpumask_clear(cpu_core_mask(cpu));
  1067. c->phys_proc_id = 0;
  1068. c->cpu_core_id = 0;
  1069. cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
  1070. }
  1071. static void __ref remove_cpu_from_maps(int cpu)
  1072. {
  1073. set_cpu_online(cpu, false);
  1074. cpumask_clear_cpu(cpu, cpu_callout_mask);
  1075. cpumask_clear_cpu(cpu, cpu_callin_mask);
  1076. /* was set by cpu_init() */
  1077. cpumask_clear_cpu(cpu, cpu_initialized_mask);
  1078. numa_remove_cpu(cpu);
  1079. }
  1080. void cpu_disable_common(void)
  1081. {
  1082. int cpu = smp_processor_id();
  1083. remove_siblinginfo(cpu);
  1084. /* It's now safe to remove this processor from the online map */
  1085. lock_vector_lock();
  1086. remove_cpu_from_maps(cpu);
  1087. unlock_vector_lock();
  1088. fixup_irqs();
  1089. }
  1090. int native_cpu_disable(void)
  1091. {
  1092. int cpu = smp_processor_id();
  1093. /*
  1094. * Perhaps use cpufreq to drop frequency, but that could go
  1095. * into generic code.
  1096. *
  1097. * We won't take down the boot processor on i386 due to some
  1098. * interrupts only being able to be serviced by the BSP.
  1099. * Especially so if we're not using an IOAPIC -zwane
  1100. */
  1101. if (cpu == 0)
  1102. return -EBUSY;
  1103. clear_local_APIC();
  1104. cpu_disable_common();
  1105. return 0;
  1106. }
  1107. void native_cpu_die(unsigned int cpu)
  1108. {
  1109. /* We don't do anything here: idle task is faking death itself. */
  1110. unsigned int i;
  1111. for (i = 0; i < 10; i++) {
  1112. /* They ack this in play_dead by setting CPU_DEAD */
  1113. if (per_cpu(cpu_state, cpu) == CPU_DEAD) {
  1114. if (system_state == SYSTEM_RUNNING)
  1115. pr_info("CPU %u is now offline\n", cpu);
  1116. if (1 == num_online_cpus())
  1117. alternatives_smp_switch(0);
  1118. return;
  1119. }
  1120. msleep(100);
  1121. }
  1122. pr_err("CPU %u didn't die...\n", cpu);
  1123. }
  1124. void play_dead_common(void)
  1125. {
  1126. idle_task_exit();
  1127. reset_lazy_tlbstate();
  1128. c1e_remove_cpu(raw_smp_processor_id());
  1129. mb();
  1130. /* Ack it */
  1131. __this_cpu_write(cpu_state, CPU_DEAD);
  1132. /*
  1133. * With physical CPU hotplug, we should halt the cpu
  1134. */
  1135. local_irq_disable();
  1136. }
  1137. /*
  1138. * We need to flush the caches before going to sleep, lest we have
  1139. * dirty data in our caches when we come back up.
  1140. */
  1141. static inline void mwait_play_dead(void)
  1142. {
  1143. unsigned int eax, ebx, ecx, edx;
  1144. unsigned int highest_cstate = 0;
  1145. unsigned int highest_subcstate = 0;
  1146. int i;
  1147. void *mwait_ptr;
  1148. struct cpuinfo_x86 *c = __this_cpu_ptr(&cpu_info);
  1149. if (!(cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)))
  1150. return;
  1151. if (!cpu_has(__this_cpu_ptr(&cpu_info), X86_FEATURE_CLFLSH))
  1152. return;
  1153. if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
  1154. return;
  1155. eax = CPUID_MWAIT_LEAF;
  1156. ecx = 0;
  1157. native_cpuid(&eax, &ebx, &ecx, &edx);
  1158. /*
  1159. * eax will be 0 if EDX enumeration is not valid.
  1160. * Initialized below to cstate, sub_cstate value when EDX is valid.
  1161. */
  1162. if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) {
  1163. eax = 0;
  1164. } else {
  1165. edx >>= MWAIT_SUBSTATE_SIZE;
  1166. for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
  1167. if (edx & MWAIT_SUBSTATE_MASK) {
  1168. highest_cstate = i;
  1169. highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
  1170. }
  1171. }
  1172. eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
  1173. (highest_subcstate - 1);
  1174. }
  1175. /*
  1176. * This should be a memory location in a cache line which is
  1177. * unlikely to be touched by other processors. The actual
  1178. * content is immaterial as it is not actually modified in any way.
  1179. */
  1180. mwait_ptr = &current_thread_info()->flags;
  1181. wbinvd();
  1182. while (1) {
  1183. /*
  1184. * The CLFLUSH is a workaround for erratum AAI65 for
  1185. * the Xeon 7400 series. It's not clear it is actually
  1186. * needed, but it should be harmless in either case.
  1187. * The WBINVD is insufficient due to the spurious-wakeup
  1188. * case where we return around the loop.
  1189. */
  1190. clflush(mwait_ptr);
  1191. __monitor(mwait_ptr, 0, 0);
  1192. mb();
  1193. __mwait(eax, 0);
  1194. }
  1195. }
  1196. static inline void hlt_play_dead(void)
  1197. {
  1198. if (__this_cpu_read(cpu_info.x86) >= 4)
  1199. wbinvd();
  1200. while (1) {
  1201. native_halt();
  1202. }
  1203. }
  1204. void native_play_dead(void)
  1205. {
  1206. play_dead_common();
  1207. tboot_shutdown(TB_SHUTDOWN_WFS);
  1208. mwait_play_dead(); /* Only returns on failure */
  1209. hlt_play_dead();
  1210. }
  1211. #else /* ... !CONFIG_HOTPLUG_CPU */
  1212. int native_cpu_disable(void)
  1213. {
  1214. return -ENOSYS;
  1215. }
  1216. void native_cpu_die(unsigned int cpu)
  1217. {
  1218. /* We said "no" in __cpu_disable */
  1219. BUG();
  1220. }
  1221. void native_play_dead(void)
  1222. {
  1223. BUG();
  1224. }
  1225. #endif