2 * x86 SMP booting functions
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.
8 * Much of the core SMP work is based on previous work by Thomas Radke, to
9 * whom a great many thanks are extended.
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.
15 * This code is released under the GNU General Public License version 2 or
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
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
42 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
44 #include <linux/init.h>
45 #include <linux/smp.h>
46 #include <linux/export.h>
47 #include <linux/sched.h>
48 #include <linux/sched/topology.h>
49 #include <linux/sched/hotplug.h>
50 #include <linux/sched/task_stack.h>
51 #include <linux/percpu.h>
52 #include <linux/bootmem.h>
53 #include <linux/err.h>
54 #include <linux/nmi.h>
55 #include <linux/tboot.h>
56 #include <linux/stackprotector.h>
57 #include <linux/gfp.h>
58 #include <linux/cpuidle.h>
64 #include <asm/realmode.h>
67 #include <asm/pgtable.h>
68 #include <asm/tlbflush.h>
70 #include <asm/mwait.h>
72 #include <asm/io_apic.h>
73 #include <asm/fpu/internal.h>
74 #include <asm/setup.h>
75 #include <asm/uv/uv.h>
76 #include <linux/mc146818rtc.h>
77 #include <asm/i8259.h>
78 #include <asm/realmode.h>
81 /* Number of siblings per CPU package */
82 int smp_num_siblings = 1;
83 EXPORT_SYMBOL(smp_num_siblings);
85 /* Last level cache ID of each logical CPU */
86 DEFINE_PER_CPU_READ_MOSTLY(u16, cpu_llc_id) = BAD_APICID;
88 /* representing HT siblings of each logical CPU */
89 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_sibling_map);
90 EXPORT_PER_CPU_SYMBOL(cpu_sibling_map);
92 /* representing HT and core siblings of each logical CPU */
93 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_core_map);
94 EXPORT_PER_CPU_SYMBOL(cpu_core_map);
96 DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map);
98 /* Per CPU bogomips and other parameters */
99 DEFINE_PER_CPU_READ_MOSTLY(struct cpuinfo_x86, cpu_info);
100 EXPORT_PER_CPU_SYMBOL(cpu_info);
102 /* Logical package management. We might want to allocate that dynamically */
103 static int *physical_to_logical_pkg __read_mostly;
104 static unsigned long *physical_package_map __read_mostly;;
105 static unsigned int max_physical_pkg_id __read_mostly;
106 unsigned int __max_logical_packages __read_mostly;
107 EXPORT_SYMBOL(__max_logical_packages);
108 static unsigned int logical_packages __read_mostly;
110 /* Maximum number of SMT threads on any online core */
111 int __max_smt_threads __read_mostly;
113 /* Flag to indicate if a complete sched domain rebuild is required */
114 bool x86_topology_update;
116 int arch_update_cpu_topology(void)
118 int retval = x86_topology_update;
120 x86_topology_update = false;
124 static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip)
128 spin_lock_irqsave(&rtc_lock, flags);
129 CMOS_WRITE(0xa, 0xf);
130 spin_unlock_irqrestore(&rtc_lock, flags);
133 *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) =
136 *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) =
141 static inline void smpboot_restore_warm_reset_vector(void)
146 * Install writable page 0 entry to set BIOS data area.
151 * Paranoid: Set warm reset code and vector here back
154 spin_lock_irqsave(&rtc_lock, flags);
156 spin_unlock_irqrestore(&rtc_lock, flags);
158 *((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0;
162 * Report back to the Boot Processor during boot time or to the caller processor
165 static void smp_callin(void)
170 * If waken up by an INIT in an 82489DX configuration
171 * cpu_callout_mask guarantees we don't get here before
172 * an INIT_deassert IPI reaches our local APIC, so it is
173 * now safe to touch our local APIC.
175 cpuid = smp_processor_id();
178 * (This works even if the APIC is not enabled.)
180 phys_id = read_apic_id();
183 * the boot CPU has finished the init stage and is spinning
184 * on callin_map until we finish. We are free to set up this
185 * CPU, first the APIC. (this is probably redundant on most
191 * Save our processor parameters. Note: this information
192 * is needed for clock calibration.
194 smp_store_cpu_info(cpuid);
197 * The topology information must be up to date before
198 * calibrate_delay() and notify_cpu_starting().
200 set_cpu_sibling_map(raw_smp_processor_id());
204 * Update loops_per_jiffy in cpu_data. Previous call to
205 * smp_store_cpu_info() stored a value that is close but not as
206 * accurate as the value just calculated.
209 cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy;
210 pr_debug("Stack at about %p\n", &cpuid);
214 notify_cpu_starting(cpuid);
217 * Allow the master to continue.
219 cpumask_set_cpu(cpuid, cpu_callin_mask);
222 static int cpu0_logical_apicid;
223 static int enable_start_cpu0;
225 * Activate a secondary processor.
227 static void notrace start_secondary(void *unused)
230 * Don't put *anything* except direct CPU state initialization
231 * before cpu_init(), SMP booting is too fragile that we want to
232 * limit the things done here to the most necessary things.
234 if (boot_cpu_has(X86_FEATURE_PCID))
235 __write_cr4(__read_cr4() | X86_CR4_PCIDE);
238 /* switch away from the initial page table */
239 load_cr3(swapper_pg_dir);
244 x86_cpuinit.early_percpu_clock_init();
248 enable_start_cpu0 = 0;
250 /* otherwise gcc will move up smp_processor_id before the cpu_init */
253 * Check TSC synchronization with the BP:
255 check_tsc_sync_target();
258 * Lock vector_lock and initialize the vectors on this cpu
259 * before setting the cpu online. We must set it online with
260 * vector_lock held to prevent a concurrent setup/teardown
261 * from seeing a half valid vector space.
264 setup_vector_irq(smp_processor_id());
265 set_cpu_online(smp_processor_id(), true);
266 unlock_vector_lock();
267 cpu_set_state_online(smp_processor_id());
268 x86_platform.nmi_init();
270 /* enable local interrupts */
273 /* to prevent fake stack check failure in clock setup */
274 boot_init_stack_canary();
276 x86_cpuinit.setup_percpu_clockev();
279 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
283 * topology_update_package_map - Update the physical to logical package map
284 * @pkg: The physical package id as retrieved via CPUID
285 * @cpu: The cpu for which this is updated
287 int topology_update_package_map(unsigned int pkg, unsigned int cpu)
291 /* Called from early boot ? */
292 if (!physical_package_map)
295 if (pkg >= max_physical_pkg_id)
298 /* Set the logical package id */
299 if (test_and_set_bit(pkg, physical_package_map))
302 if (logical_packages >= __max_logical_packages) {
303 pr_warn("Package %u of CPU %u exceeds BIOS package data %u.\n",
304 logical_packages, cpu, __max_logical_packages);
308 new = logical_packages++;
310 pr_info("CPU %u Converting physical %u to logical package %u\n",
313 physical_to_logical_pkg[pkg] = new;
316 cpu_data(cpu).logical_proc_id = physical_to_logical_pkg[pkg];
321 * topology_phys_to_logical_pkg - Map a physical package id to a logical
323 * Returns logical package id or -1 if not found
325 int topology_phys_to_logical_pkg(unsigned int phys_pkg)
327 if (phys_pkg >= max_physical_pkg_id)
329 return physical_to_logical_pkg[phys_pkg];
331 EXPORT_SYMBOL(topology_phys_to_logical_pkg);
333 static void __init smp_init_package_map(struct cpuinfo_x86 *c, unsigned int cpu)
339 * Today neither Intel nor AMD support heterogenous systems. That
340 * might change in the future....
342 * While ideally we'd want '* smp_num_siblings' in the below @ncpus
343 * computation, this won't actually work since some Intel BIOSes
344 * report inconsistent HT data when they disable HT.
346 * In particular, they reduce the APIC-IDs to only include the cores,
347 * but leave the CPUID topology to say there are (2) siblings.
348 * This means we don't know how many threads there will be until
349 * after the APIC enumeration.
351 * By not including this we'll sometimes over-estimate the number of
352 * logical packages by the amount of !present siblings, but this is
353 * still better than MAX_LOCAL_APIC.
355 * We use total_cpus not nr_cpu_ids because nr_cpu_ids can be limited
356 * on the command line leading to a similar issue as the HT disable
357 * problem because the hyperthreads are usually enumerated after the
360 ncpus = boot_cpu_data.x86_max_cores;
362 pr_warn("x86_max_cores == zero !?!?");
366 __max_logical_packages = DIV_ROUND_UP(total_cpus, ncpus);
367 logical_packages = 0;
370 * Possibly larger than what we need as the number of apic ids per
371 * package can be smaller than the actual used apic ids.
373 max_physical_pkg_id = DIV_ROUND_UP(MAX_LOCAL_APIC, ncpus);
374 size = max_physical_pkg_id * sizeof(unsigned int);
375 physical_to_logical_pkg = kmalloc(size, GFP_KERNEL);
376 memset(physical_to_logical_pkg, 0xff, size);
377 size = BITS_TO_LONGS(max_physical_pkg_id) * sizeof(unsigned long);
378 physical_package_map = kzalloc(size, GFP_KERNEL);
380 pr_info("Max logical packages: %u\n", __max_logical_packages);
382 topology_update_package_map(c->phys_proc_id, cpu);
385 void __init smp_store_boot_cpu_info(void)
387 int id = 0; /* CPU 0 */
388 struct cpuinfo_x86 *c = &cpu_data(id);
392 smp_init_package_map(c, id);
396 * The bootstrap kernel entry code has set these up. Save them for
399 void smp_store_cpu_info(int id)
401 struct cpuinfo_x86 *c = &cpu_data(id);
406 * During boot time, CPU0 has this setup already. Save the info when
407 * bringing up AP or offlined CPU0.
409 identify_secondary_cpu(c);
413 topology_same_node(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
415 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
417 return (cpu_to_node(cpu1) == cpu_to_node(cpu2));
421 topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name)
423 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
425 return !WARN_ONCE(!topology_same_node(c, o),
426 "sched: CPU #%d's %s-sibling CPU #%d is not on the same node! "
427 "[node: %d != %d]. Ignoring dependency.\n",
428 cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2));
431 #define link_mask(mfunc, c1, c2) \
433 cpumask_set_cpu((c1), mfunc(c2)); \
434 cpumask_set_cpu((c2), mfunc(c1)); \
437 static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
439 if (boot_cpu_has(X86_FEATURE_TOPOEXT)) {
440 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
442 if (c->phys_proc_id == o->phys_proc_id &&
443 per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2)) {
444 if (c->cpu_core_id == o->cpu_core_id)
445 return topology_sane(c, o, "smt");
447 if ((c->cu_id != 0xff) &&
448 (o->cu_id != 0xff) &&
449 (c->cu_id == o->cu_id))
450 return topology_sane(c, o, "smt");
453 } else if (c->phys_proc_id == o->phys_proc_id &&
454 c->cpu_core_id == o->cpu_core_id) {
455 return topology_sane(c, o, "smt");
461 static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
463 int cpu1 = c->cpu_index, cpu2 = o->cpu_index;
465 if (per_cpu(cpu_llc_id, cpu1) != BAD_APICID &&
466 per_cpu(cpu_llc_id, cpu1) == per_cpu(cpu_llc_id, cpu2))
467 return topology_sane(c, o, "llc");
473 * Unlike the other levels, we do not enforce keeping a
474 * multicore group inside a NUMA node. If this happens, we will
475 * discard the MC level of the topology later.
477 static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o)
479 if (c->phys_proc_id == o->phys_proc_id)
484 #if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC)
485 static inline int x86_sched_itmt_flags(void)
487 return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0;
490 #ifdef CONFIG_SCHED_MC
491 static int x86_core_flags(void)
493 return cpu_core_flags() | x86_sched_itmt_flags();
496 #ifdef CONFIG_SCHED_SMT
497 static int x86_smt_flags(void)
499 return cpu_smt_flags() | x86_sched_itmt_flags();
504 static struct sched_domain_topology_level x86_numa_in_package_topology[] = {
505 #ifdef CONFIG_SCHED_SMT
506 { cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
508 #ifdef CONFIG_SCHED_MC
509 { cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
514 static struct sched_domain_topology_level x86_topology[] = {
515 #ifdef CONFIG_SCHED_SMT
516 { cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) },
518 #ifdef CONFIG_SCHED_MC
519 { cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) },
521 { cpu_cpu_mask, SD_INIT_NAME(DIE) },
526 * Set if a package/die has multiple NUMA nodes inside.
527 * AMD Magny-Cours and Intel Cluster-on-Die have this.
529 static bool x86_has_numa_in_package;
531 void set_cpu_sibling_map(int cpu)
533 bool has_smt = smp_num_siblings > 1;
534 bool has_mp = has_smt || boot_cpu_data.x86_max_cores > 1;
535 struct cpuinfo_x86 *c = &cpu_data(cpu);
536 struct cpuinfo_x86 *o;
539 cpumask_set_cpu(cpu, cpu_sibling_setup_mask);
542 cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu));
543 cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu));
544 cpumask_set_cpu(cpu, topology_core_cpumask(cpu));
549 for_each_cpu(i, cpu_sibling_setup_mask) {
552 if ((i == cpu) || (has_smt && match_smt(c, o)))
553 link_mask(topology_sibling_cpumask, cpu, i);
555 if ((i == cpu) || (has_mp && match_llc(c, o)))
556 link_mask(cpu_llc_shared_mask, cpu, i);
561 * This needs a separate iteration over the cpus because we rely on all
562 * topology_sibling_cpumask links to be set-up.
564 for_each_cpu(i, cpu_sibling_setup_mask) {
567 if ((i == cpu) || (has_mp && match_die(c, o))) {
568 link_mask(topology_core_cpumask, cpu, i);
571 * Does this new cpu bringup a new core?
574 topology_sibling_cpumask(cpu)) == 1) {
576 * for each core in package, increment
577 * the booted_cores for this new cpu
580 topology_sibling_cpumask(i)) == i)
583 * increment the core count for all
584 * the other cpus in this package
587 cpu_data(i).booted_cores++;
588 } else if (i != cpu && !c->booted_cores)
589 c->booted_cores = cpu_data(i).booted_cores;
591 if (match_die(c, o) && !topology_same_node(c, o))
592 x86_has_numa_in_package = true;
595 threads = cpumask_weight(topology_sibling_cpumask(cpu));
596 if (threads > __max_smt_threads)
597 __max_smt_threads = threads;
600 /* maps the cpu to the sched domain representing multi-core */
601 const struct cpumask *cpu_coregroup_mask(int cpu)
603 return cpu_llc_shared_mask(cpu);
606 static void impress_friends(void)
609 unsigned long bogosum = 0;
611 * Allow the user to impress friends.
613 pr_debug("Before bogomips\n");
614 for_each_possible_cpu(cpu)
615 if (cpumask_test_cpu(cpu, cpu_callout_mask))
616 bogosum += cpu_data(cpu).loops_per_jiffy;
617 pr_info("Total of %d processors activated (%lu.%02lu BogoMIPS)\n",
620 (bogosum/(5000/HZ))%100);
622 pr_debug("Before bogocount - setting activated=1\n");
625 void __inquire_remote_apic(int apicid)
627 unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 };
628 const char * const names[] = { "ID", "VERSION", "SPIV" };
632 pr_info("Inquiring remote APIC 0x%x...\n", apicid);
634 for (i = 0; i < ARRAY_SIZE(regs); i++) {
635 pr_info("... APIC 0x%x %s: ", apicid, names[i]);
640 status = safe_apic_wait_icr_idle();
642 pr_cont("a previous APIC delivery may have failed\n");
644 apic_icr_write(APIC_DM_REMRD | regs[i], apicid);
649 status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK;
650 } while (status == APIC_ICR_RR_INPROG && timeout++ < 1000);
653 case APIC_ICR_RR_VALID:
654 status = apic_read(APIC_RRR);
655 pr_cont("%08x\n", status);
664 * The Multiprocessor Specification 1.4 (1997) example code suggests
665 * that there should be a 10ms delay between the BSP asserting INIT
666 * and de-asserting INIT, when starting a remote processor.
667 * But that slows boot and resume on modern processors, which include
668 * many cores and don't require that delay.
670 * Cmdline "init_cpu_udelay=" is available to over-ride this delay.
671 * Modern processor families are quirked to remove the delay entirely.
673 #define UDELAY_10MS_DEFAULT 10000
675 static unsigned int init_udelay = UINT_MAX;
677 static int __init cpu_init_udelay(char *str)
679 get_option(&str, &init_udelay);
683 early_param("cpu_init_udelay", cpu_init_udelay);
685 static void __init smp_quirk_init_udelay(void)
687 /* if cmdline changed it from default, leave it alone */
688 if (init_udelay != UINT_MAX)
691 /* if modern processor, use no delay */
692 if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) ||
693 ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) {
697 /* else, use legacy delay */
698 init_udelay = UDELAY_10MS_DEFAULT;
702 * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal
703 * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this
704 * won't ... remember to clear down the APIC, etc later.
707 wakeup_secondary_cpu_via_nmi(int apicid, unsigned long start_eip)
709 unsigned long send_status, accept_status = 0;
713 /* Boot on the stack */
714 /* Kick the second */
715 apic_icr_write(APIC_DM_NMI | apic->dest_logical, apicid);
717 pr_debug("Waiting for send to finish...\n");
718 send_status = safe_apic_wait_icr_idle();
721 * Give the other CPU some time to accept the IPI.
724 if (APIC_INTEGRATED(boot_cpu_apic_version)) {
725 maxlvt = lapic_get_maxlvt();
726 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
727 apic_write(APIC_ESR, 0);
728 accept_status = (apic_read(APIC_ESR) & 0xEF);
730 pr_debug("NMI sent\n");
733 pr_err("APIC never delivered???\n");
735 pr_err("APIC delivery error (%lx)\n", accept_status);
737 return (send_status | accept_status);
741 wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip)
743 unsigned long send_status = 0, accept_status = 0;
744 int maxlvt, num_starts, j;
746 maxlvt = lapic_get_maxlvt();
749 * Be paranoid about clearing APIC errors.
751 if (APIC_INTEGRATED(boot_cpu_apic_version)) {
752 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
753 apic_write(APIC_ESR, 0);
757 pr_debug("Asserting INIT\n");
760 * Turn INIT on target chip
765 apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT,
768 pr_debug("Waiting for send to finish...\n");
769 send_status = safe_apic_wait_icr_idle();
773 pr_debug("Deasserting INIT\n");
777 apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid);
779 pr_debug("Waiting for send to finish...\n");
780 send_status = safe_apic_wait_icr_idle();
785 * Should we send STARTUP IPIs ?
787 * Determine this based on the APIC version.
788 * If we don't have an integrated APIC, don't send the STARTUP IPIs.
790 if (APIC_INTEGRATED(boot_cpu_apic_version))
796 * Run STARTUP IPI loop.
798 pr_debug("#startup loops: %d\n", num_starts);
800 for (j = 1; j <= num_starts; j++) {
801 pr_debug("Sending STARTUP #%d\n", j);
802 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
803 apic_write(APIC_ESR, 0);
805 pr_debug("After apic_write\n");
812 /* Boot on the stack */
813 /* Kick the second */
814 apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12),
818 * Give the other CPU some time to accept the IPI.
820 if (init_udelay == 0)
825 pr_debug("Startup point 1\n");
827 pr_debug("Waiting for send to finish...\n");
828 send_status = safe_apic_wait_icr_idle();
831 * Give the other CPU some time to accept the IPI.
833 if (init_udelay == 0)
838 if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */
839 apic_write(APIC_ESR, 0);
840 accept_status = (apic_read(APIC_ESR) & 0xEF);
841 if (send_status || accept_status)
844 pr_debug("After Startup\n");
847 pr_err("APIC never delivered???\n");
849 pr_err("APIC delivery error (%lx)\n", accept_status);
851 return (send_status | accept_status);
854 /* reduce the number of lines printed when booting a large cpu count system */
855 static void announce_cpu(int cpu, int apicid)
857 static int current_node = -1;
858 int node = early_cpu_to_node(cpu);
859 static int width, node_width;
862 width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */
865 node_width = num_digits(num_possible_nodes()) + 1; /* + '#' */
868 printk(KERN_INFO "x86: Booting SMP configuration:\n");
870 if (system_state < SYSTEM_RUNNING) {
871 if (node != current_node) {
872 if (current_node > (-1))
876 printk(KERN_INFO ".... node %*s#%d, CPUs: ",
877 node_width - num_digits(node), " ", node);
880 /* Add padding for the BSP */
882 pr_cont("%*s", width + 1, " ");
884 pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu);
887 pr_info("Booting Node %d Processor %d APIC 0x%x\n",
891 static int wakeup_cpu0_nmi(unsigned int cmd, struct pt_regs *regs)
895 cpu = smp_processor_id();
896 if (cpu == 0 && !cpu_online(cpu) && enable_start_cpu0)
903 * Wake up AP by INIT, INIT, STARTUP sequence.
905 * Instead of waiting for STARTUP after INITs, BSP will execute the BIOS
906 * boot-strap code which is not a desired behavior for waking up BSP. To
907 * void the boot-strap code, wake up CPU0 by NMI instead.
909 * This works to wake up soft offlined CPU0 only. If CPU0 is hard offlined
910 * (i.e. physically hot removed and then hot added), NMI won't wake it up.
911 * We'll change this code in the future to wake up hard offlined CPU0 if
912 * real platform and request are available.
915 wakeup_cpu_via_init_nmi(int cpu, unsigned long start_ip, int apicid,
916 int *cpu0_nmi_registered)
924 * Wake up AP by INIT, INIT, STARTUP sequence.
927 boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip);
932 * Wake up BSP by nmi.
934 * Register a NMI handler to help wake up CPU0.
936 boot_error = register_nmi_handler(NMI_LOCAL,
937 wakeup_cpu0_nmi, 0, "wake_cpu0");
940 enable_start_cpu0 = 1;
941 *cpu0_nmi_registered = 1;
942 if (apic->dest_logical == APIC_DEST_LOGICAL)
943 id = cpu0_logical_apicid;
946 boot_error = wakeup_secondary_cpu_via_nmi(id, start_ip);
955 void common_cpu_up(unsigned int cpu, struct task_struct *idle)
957 /* Just in case we booted with a single CPU. */
958 alternatives_enable_smp();
960 per_cpu(current_task, cpu) = idle;
963 /* Stack for startup_32 can be just as for start_secondary onwards */
965 per_cpu(cpu_current_top_of_stack, cpu) = task_top_of_stack(idle);
967 initial_gs = per_cpu_offset(cpu);
972 * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad
973 * (ie clustered apic addressing mode), this is a LOGICAL apic ID.
974 * Returns zero if CPU booted OK, else error code from
975 * ->wakeup_secondary_cpu.
977 static int do_boot_cpu(int apicid, int cpu, struct task_struct *idle,
978 int *cpu0_nmi_registered)
980 volatile u32 *trampoline_status =
981 (volatile u32 *) __va(real_mode_header->trampoline_status);
982 /* start_ip had better be page-aligned! */
983 unsigned long start_ip = real_mode_header->trampoline_start;
985 unsigned long boot_error = 0;
986 unsigned long timeout;
988 idle->thread.sp = (unsigned long)task_pt_regs(idle);
989 early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu);
990 initial_code = (unsigned long)start_secondary;
991 initial_stack = idle->thread.sp;
994 * Enable the espfix hack for this CPU
996 #ifdef CONFIG_X86_ESPFIX64
1000 /* So we see what's up */
1001 announce_cpu(cpu, apicid);
1004 * This grunge runs the startup process for
1005 * the targeted processor.
1008 if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
1010 pr_debug("Setting warm reset code and vector.\n");
1012 smpboot_setup_warm_reset_vector(start_ip);
1014 * Be paranoid about clearing APIC errors.
1016 if (APIC_INTEGRATED(boot_cpu_apic_version)) {
1017 apic_write(APIC_ESR, 0);
1018 apic_read(APIC_ESR);
1023 * AP might wait on cpu_callout_mask in cpu_init() with
1024 * cpu_initialized_mask set if previous attempt to online
1025 * it timed-out. Clear cpu_initialized_mask so that after
1026 * INIT/SIPI it could start with a clean state.
1028 cpumask_clear_cpu(cpu, cpu_initialized_mask);
1032 * Wake up a CPU in difference cases:
1033 * - Use the method in the APIC driver if it's defined
1035 * - Use an INIT boot APIC message for APs or NMI for BSP.
1037 if (apic->wakeup_secondary_cpu)
1038 boot_error = apic->wakeup_secondary_cpu(apicid, start_ip);
1040 boot_error = wakeup_cpu_via_init_nmi(cpu, start_ip, apicid,
1041 cpu0_nmi_registered);
1045 * Wait 10s total for first sign of life from AP
1048 timeout = jiffies + 10*HZ;
1049 while (time_before(jiffies, timeout)) {
1050 if (cpumask_test_cpu(cpu, cpu_initialized_mask)) {
1052 * Tell AP to proceed with initialization
1054 cpumask_set_cpu(cpu, cpu_callout_mask);
1064 * Wait till AP completes initial initialization
1066 while (!cpumask_test_cpu(cpu, cpu_callin_mask)) {
1068 * Allow other tasks to run while we wait for the
1069 * AP to come online. This also gives a chance
1070 * for the MTRR work(triggered by the AP coming online)
1071 * to be completed in the stop machine context.
1077 /* mark "stuck" area as not stuck */
1078 *trampoline_status = 0;
1080 if (get_uv_system_type() != UV_NON_UNIQUE_APIC) {
1082 * Cleanup possible dangling ends...
1084 smpboot_restore_warm_reset_vector();
1090 int native_cpu_up(unsigned int cpu, struct task_struct *tidle)
1092 int apicid = apic->cpu_present_to_apicid(cpu);
1093 int cpu0_nmi_registered = 0;
1094 unsigned long flags;
1097 WARN_ON(irqs_disabled());
1099 pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu);
1101 if (apicid == BAD_APICID ||
1102 !physid_isset(apicid, phys_cpu_present_map) ||
1103 !apic->apic_id_valid(apicid)) {
1104 pr_err("%s: bad cpu %d\n", __func__, cpu);
1109 * Already booted CPU?
1111 if (cpumask_test_cpu(cpu, cpu_callin_mask)) {
1112 pr_debug("do_boot_cpu %d Already started\n", cpu);
1117 * Save current MTRR state in case it was changed since early boot
1118 * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync:
1122 /* x86 CPUs take themselves offline, so delayed offline is OK. */
1123 err = cpu_check_up_prepare(cpu);
1124 if (err && err != -EBUSY)
1127 /* the FPU context is blank, nobody can own it */
1128 per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL;
1130 common_cpu_up(cpu, tidle);
1132 err = do_boot_cpu(apicid, cpu, tidle, &cpu0_nmi_registered);
1134 pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu);
1140 * Check TSC synchronization with the AP (keep irqs disabled
1143 local_irq_save(flags);
1144 check_tsc_sync_source(cpu);
1145 local_irq_restore(flags);
1147 while (!cpu_online(cpu)) {
1149 touch_nmi_watchdog();
1154 * Clean up the nmi handler. Do this after the callin and callout sync
1155 * to avoid impact of possible long unregister time.
1157 if (cpu0_nmi_registered)
1158 unregister_nmi_handler(NMI_LOCAL, "wake_cpu0");
1164 * arch_disable_smp_support() - disables SMP support for x86 at runtime
1166 void arch_disable_smp_support(void)
1168 disable_ioapic_support();
1172 * Fall back to non SMP mode after errors.
1174 * RED-PEN audit/test this more. I bet there is more state messed up here.
1176 static __init void disable_smp(void)
1178 pr_info("SMP disabled\n");
1180 disable_ioapic_support();
1182 init_cpu_present(cpumask_of(0));
1183 init_cpu_possible(cpumask_of(0));
1185 if (smp_found_config)
1186 physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map);
1188 physid_set_mask_of_physid(0, &phys_cpu_present_map);
1189 cpumask_set_cpu(0, topology_sibling_cpumask(0));
1190 cpumask_set_cpu(0, topology_core_cpumask(0));
1201 * Various sanity checks.
1203 static int __init smp_sanity_check(unsigned max_cpus)
1207 #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32)
1208 if (def_to_bigsmp && nr_cpu_ids > 8) {
1212 pr_warn("More than 8 CPUs detected - skipping them\n"
1213 "Use CONFIG_X86_BIGSMP\n");
1216 for_each_present_cpu(cpu) {
1218 set_cpu_present(cpu, false);
1223 for_each_possible_cpu(cpu) {
1225 set_cpu_possible(cpu, false);
1233 if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) {
1234 pr_warn("weird, boot CPU (#%d) not listed by the BIOS\n",
1235 hard_smp_processor_id());
1237 physid_set(hard_smp_processor_id(), phys_cpu_present_map);
1241 * If we couldn't find an SMP configuration at boot time,
1242 * get out of here now!
1244 if (!smp_found_config && !acpi_lapic) {
1246 pr_notice("SMP motherboard not detected\n");
1247 return SMP_NO_CONFIG;
1251 * Should not be necessary because the MP table should list the boot
1252 * CPU too, but we do it for the sake of robustness anyway.
1254 if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) {
1255 pr_notice("weird, boot CPU (#%d) not listed by the BIOS\n",
1256 boot_cpu_physical_apicid);
1257 physid_set(hard_smp_processor_id(), phys_cpu_present_map);
1262 * If we couldn't find a local APIC, then get out of here now!
1264 if (APIC_INTEGRATED(boot_cpu_apic_version) &&
1265 !boot_cpu_has(X86_FEATURE_APIC)) {
1266 if (!disable_apic) {
1267 pr_err("BIOS bug, local APIC #%d not detected!...\n",
1268 boot_cpu_physical_apicid);
1269 pr_err("... forcing use of dummy APIC emulation (tell your hw vendor)\n");
1275 * If SMP should be disabled, then really disable it!
1278 pr_info("SMP mode deactivated\n");
1279 return SMP_FORCE_UP;
1285 static void __init smp_cpu_index_default(void)
1288 struct cpuinfo_x86 *c;
1290 for_each_possible_cpu(i) {
1292 /* mark all to hotplug */
1293 c->cpu_index = nr_cpu_ids;
1298 * Prepare for SMP bootup. The MP table or ACPI has been read
1299 * earlier. Just do some sanity checking here and enable APIC mode.
1301 void __init native_smp_prepare_cpus(unsigned int max_cpus)
1305 smp_cpu_index_default();
1308 * Setup boot CPU information
1310 smp_store_boot_cpu_info(); /* Final full version of the data */
1311 cpumask_copy(cpu_callin_mask, cpumask_of(0));
1314 for_each_possible_cpu(i) {
1315 zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
1316 zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
1317 zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
1321 * Set 'default' x86 topology, this matches default_topology() in that
1322 * it has NUMA nodes as a topology level. See also
1323 * native_smp_cpus_done().
1325 * Must be done before set_cpus_sibling_map() is ran.
1327 set_sched_topology(x86_topology);
1329 set_cpu_sibling_map(0);
1331 switch (smp_sanity_check(max_cpus)) {
1334 if (APIC_init_uniprocessor())
1335 pr_notice("Local APIC not detected. Using dummy APIC emulation.\n");
1342 apic_bsp_setup(false);
1348 if (read_apic_id() != boot_cpu_physical_apicid) {
1349 panic("Boot APIC ID in local APIC unexpected (%d vs %d)",
1350 read_apic_id(), boot_cpu_physical_apicid);
1351 /* Or can we switch back to PIC here? */
1354 default_setup_apic_routing();
1355 cpu0_logical_apicid = apic_bsp_setup(false);
1358 print_cpu_info(&cpu_data(0));
1362 set_mtrr_aps_delayed_init();
1364 smp_quirk_init_udelay();
1367 void arch_enable_nonboot_cpus_begin(void)
1369 set_mtrr_aps_delayed_init();
1372 void arch_enable_nonboot_cpus_end(void)
1378 * Early setup to make printk work.
1380 void __init native_smp_prepare_boot_cpu(void)
1382 int me = smp_processor_id();
1383 switch_to_new_gdt(me);
1384 /* already set me in cpu_online_mask in boot_cpu_init() */
1385 cpumask_set_cpu(me, cpu_callout_mask);
1386 cpu_set_state_online(me);
1389 void __init native_smp_cpus_done(unsigned int max_cpus)
1391 pr_debug("Boot done\n");
1393 if (x86_has_numa_in_package)
1394 set_sched_topology(x86_numa_in_package_topology);
1398 setup_ioapic_dest();
1402 static int __initdata setup_possible_cpus = -1;
1403 static int __init _setup_possible_cpus(char *str)
1405 get_option(&str, &setup_possible_cpus);
1408 early_param("possible_cpus", _setup_possible_cpus);
1412 * cpu_possible_mask should be static, it cannot change as cpu's
1413 * are onlined, or offlined. The reason is per-cpu data-structures
1414 * are allocated by some modules at init time, and dont expect to
1415 * do this dynamically on cpu arrival/departure.
1416 * cpu_present_mask on the other hand can change dynamically.
1417 * In case when cpu_hotplug is not compiled, then we resort to current
1418 * behaviour, which is cpu_possible == cpu_present.
1421 * Three ways to find out the number of additional hotplug CPUs:
1422 * - If the BIOS specified disabled CPUs in ACPI/mptables use that.
1423 * - The user can overwrite it with possible_cpus=NUM
1424 * - Otherwise don't reserve additional CPUs.
1425 * We do this because additional CPUs waste a lot of memory.
1428 __init void prefill_possible_map(void)
1432 /* No boot processor was found in mptable or ACPI MADT */
1433 if (!num_processors) {
1434 if (boot_cpu_has(X86_FEATURE_APIC)) {
1435 int apicid = boot_cpu_physical_apicid;
1436 int cpu = hard_smp_processor_id();
1438 pr_warn("Boot CPU (id %d) not listed by BIOS\n", cpu);
1440 /* Make sure boot cpu is enumerated */
1441 if (apic->cpu_present_to_apicid(0) == BAD_APICID &&
1442 apic->apic_id_valid(apicid))
1443 generic_processor_info(apicid, boot_cpu_apic_version);
1446 if (!num_processors)
1450 i = setup_max_cpus ?: 1;
1451 if (setup_possible_cpus == -1) {
1452 possible = num_processors;
1453 #ifdef CONFIG_HOTPLUG_CPU
1455 possible += disabled_cpus;
1461 possible = setup_possible_cpus;
1463 total_cpus = max_t(int, possible, num_processors + disabled_cpus);
1465 /* nr_cpu_ids could be reduced via nr_cpus= */
1466 if (possible > nr_cpu_ids) {
1467 pr_warn("%d Processors exceeds NR_CPUS limit of %u\n",
1468 possible, nr_cpu_ids);
1469 possible = nr_cpu_ids;
1472 #ifdef CONFIG_HOTPLUG_CPU
1473 if (!setup_max_cpus)
1476 pr_warn("%d Processors exceeds max_cpus limit of %u\n",
1477 possible, setup_max_cpus);
1481 nr_cpu_ids = possible;
1483 pr_info("Allowing %d CPUs, %d hotplug CPUs\n",
1484 possible, max_t(int, possible - num_processors, 0));
1486 reset_cpu_possible_mask();
1488 for (i = 0; i < possible; i++)
1489 set_cpu_possible(i, true);
1492 #ifdef CONFIG_HOTPLUG_CPU
1494 /* Recompute SMT state for all CPUs on offline */
1495 static void recompute_smt_state(void)
1497 int max_threads, cpu;
1500 for_each_online_cpu (cpu) {
1501 int threads = cpumask_weight(topology_sibling_cpumask(cpu));
1503 if (threads > max_threads)
1504 max_threads = threads;
1506 __max_smt_threads = max_threads;
1509 static void remove_siblinginfo(int cpu)
1512 struct cpuinfo_x86 *c = &cpu_data(cpu);
1514 for_each_cpu(sibling, topology_core_cpumask(cpu)) {
1515 cpumask_clear_cpu(cpu, topology_core_cpumask(sibling));
1517 * last thread sibling in this cpu core going down
1519 if (cpumask_weight(topology_sibling_cpumask(cpu)) == 1)
1520 cpu_data(sibling).booted_cores--;
1523 for_each_cpu(sibling, topology_sibling_cpumask(cpu))
1524 cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
1525 for_each_cpu(sibling, cpu_llc_shared_mask(cpu))
1526 cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling));
1527 cpumask_clear(cpu_llc_shared_mask(cpu));
1528 cpumask_clear(topology_sibling_cpumask(cpu));
1529 cpumask_clear(topology_core_cpumask(cpu));
1530 c->phys_proc_id = 0;
1532 cpumask_clear_cpu(cpu, cpu_sibling_setup_mask);
1533 recompute_smt_state();
1536 static void remove_cpu_from_maps(int cpu)
1538 set_cpu_online(cpu, false);
1539 cpumask_clear_cpu(cpu, cpu_callout_mask);
1540 cpumask_clear_cpu(cpu, cpu_callin_mask);
1541 /* was set by cpu_init() */
1542 cpumask_clear_cpu(cpu, cpu_initialized_mask);
1543 numa_remove_cpu(cpu);
1546 void cpu_disable_common(void)
1548 int cpu = smp_processor_id();
1550 remove_siblinginfo(cpu);
1552 /* It's now safe to remove this processor from the online map */
1554 remove_cpu_from_maps(cpu);
1555 unlock_vector_lock();
1559 int native_cpu_disable(void)
1563 ret = check_irq_vectors_for_cpu_disable();
1568 cpu_disable_common();
1573 int common_cpu_die(unsigned int cpu)
1577 /* We don't do anything here: idle task is faking death itself. */
1579 /* They ack this in play_dead() by setting CPU_DEAD */
1580 if (cpu_wait_death(cpu, 5)) {
1581 if (system_state == SYSTEM_RUNNING)
1582 pr_info("CPU %u is now offline\n", cpu);
1584 pr_err("CPU %u didn't die...\n", cpu);
1591 void native_cpu_die(unsigned int cpu)
1593 common_cpu_die(cpu);
1596 void play_dead_common(void)
1601 (void)cpu_report_death();
1604 * With physical CPU hotplug, we should halt the cpu
1606 local_irq_disable();
1609 static bool wakeup_cpu0(void)
1611 if (smp_processor_id() == 0 && enable_start_cpu0)
1618 * We need to flush the caches before going to sleep, lest we have
1619 * dirty data in our caches when we come back up.
1621 static inline void mwait_play_dead(void)
1623 unsigned int eax, ebx, ecx, edx;
1624 unsigned int highest_cstate = 0;
1625 unsigned int highest_subcstate = 0;
1629 if (!this_cpu_has(X86_FEATURE_MWAIT))
1631 if (!this_cpu_has(X86_FEATURE_CLFLUSH))
1633 if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF)
1636 eax = CPUID_MWAIT_LEAF;
1638 native_cpuid(&eax, &ebx, &ecx, &edx);
1641 * eax will be 0 if EDX enumeration is not valid.
1642 * Initialized below to cstate, sub_cstate value when EDX is valid.
1644 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) {
1647 edx >>= MWAIT_SUBSTATE_SIZE;
1648 for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) {
1649 if (edx & MWAIT_SUBSTATE_MASK) {
1651 highest_subcstate = edx & MWAIT_SUBSTATE_MASK;
1654 eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
1655 (highest_subcstate - 1);
1659 * This should be a memory location in a cache line which is
1660 * unlikely to be touched by other processors. The actual
1661 * content is immaterial as it is not actually modified in any way.
1663 mwait_ptr = ¤t_thread_info()->flags;
1669 * The CLFLUSH is a workaround for erratum AAI65 for
1670 * the Xeon 7400 series. It's not clear it is actually
1671 * needed, but it should be harmless in either case.
1672 * The WBINVD is insufficient due to the spurious-wakeup
1673 * case where we return around the loop.
1678 __monitor(mwait_ptr, 0, 0);
1682 * If NMI wants to wake up CPU0, start CPU0.
1689 void hlt_play_dead(void)
1691 if (__this_cpu_read(cpu_info.x86) >= 4)
1697 * If NMI wants to wake up CPU0, start CPU0.
1704 void native_play_dead(void)
1707 tboot_shutdown(TB_SHUTDOWN_WFS);
1709 mwait_play_dead(); /* Only returns on failure */
1710 if (cpuidle_play_dead())
1714 #else /* ... !CONFIG_HOTPLUG_CPU */
1715 int native_cpu_disable(void)
1720 void native_cpu_die(unsigned int cpu)
1722 /* We said "no" in __cpu_disable */
1726 void native_play_dead(void)