/* * x86 SMP booting functions * * (c) 1995 Alan Cox, Building #3 * (c) 1998, 1999, 2000, 2009 Ingo Molnar * Copyright 2001 Andi Kleen, SuSE Labs. * * Much of the core SMP work is based on previous work by Thomas Radke, to * whom a great many thanks are extended. * * Thanks to Intel for making available several different Pentium, * Pentium Pro and Pentium-II/Xeon MP machines. * Original development of Linux SMP code supported by Caldera. * * This code is released under the GNU General Public License version 2 or * later. * * Fixes * Felix Koop : NR_CPUS used properly * Jose Renau : Handle single CPU case. * Alan Cox : By repeated request 8) - Total BogoMIPS report. * Greg Wright : Fix for kernel stacks panic. * Erich Boleyn : MP v1.4 and additional changes. * Matthias Sattler : Changes for 2.1 kernel map. * Michel Lespinasse : Changes for 2.1 kernel map. * Michael Chastain : Change trampoline.S to gnu as. * Alan Cox : Dumb bug: 'B' step PPro's are fine * Ingo Molnar : Added APIC timers, based on code * from Jose Renau * Ingo Molnar : various cleanups and rewrites * Tigran Aivazian : fixed "0.00 in /proc/uptime on SMP" bug. * Maciej W. Rozycki : Bits for genuine 82489DX APICs * Andi Kleen : Changed for SMP boot into long mode. * Martin J. Bligh : Added support for multi-quad systems * Dave Jones : Report invalid combinations of Athlon CPUs. * Rusty Russell : Hacked into shape for new "hotplug" boot process. * Andi Kleen : Converted to new state machine. * Ashok Raj : CPU hotplug support * Glauber Costa : i386 and x86_64 integration */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* State of each CPU */ DEFINE_PER_CPU(int, cpu_state) = { 0 }; /* Store all idle threads, this can be reused instead of creating * a new thread. Also avoids complicated thread destroy functionality * for idle threads. */ #ifdef CONFIG_HOTPLUG_CPU /* * Needed only for CONFIG_HOTPLUG_CPU because __cpuinitdata is * removed after init for !CONFIG_HOTPLUG_CPU. */ static DEFINE_PER_CPU(struct task_struct *, idle_thread_array); #define get_idle_for_cpu(x) (per_cpu(idle_thread_array, x)) #define set_idle_for_cpu(x, p) (per_cpu(idle_thread_array, x) = (p)) /* * We need this for trampoline_base protection from concurrent accesses when * off- and onlining cores wildly. */ static DEFINE_MUTEX(x86_cpu_hotplug_driver_mutex); void cpu_hotplug_driver_lock(void) { mutex_lock(&x86_cpu_hotplug_driver_mutex); } void cpu_hotplug_driver_unlock(void) { mutex_unlock(&x86_cpu_hotplug_driver_mutex); } ssize_t arch_cpu_probe(const char *buf, size_t count) { return -1; } ssize_t arch_cpu_release(const char *buf, size_t count) { return -1; } #else static struct task_struct *idle_thread_array[NR_CPUS] __cpuinitdata ; #define get_idle_for_cpu(x) (idle_thread_array[(x)]) #define set_idle_for_cpu(x, p) (idle_thread_array[(x)] = (p)) #endif /* Number of siblings per CPU package */ int smp_num_siblings = 1; EXPORT_SYMBOL(smp_num_siblings); /* Last level cache ID of each logical CPU */ DEFINE_PER_CPU(u16, cpu_llc_id) = BAD_APICID; /* representing HT siblings of each logical CPU */ DEFINE_PER_CPU(cpumask_var_t, cpu_sibling_map); EXPORT_PER_CPU_SYMBOL(cpu_sibling_map); /* representing HT and core siblings of each logical CPU */ DEFINE_PER_CPU(cpumask_var_t, cpu_core_map); EXPORT_PER_CPU_SYMBOL(cpu_core_map); DEFINE_PER_CPU(cpumask_var_t, cpu_llc_shared_map); /* Per CPU bogomips and other parameters */ DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info); EXPORT_PER_CPU_SYMBOL(cpu_info); atomic_t init_deasserted; /* * Report back to the Boot Processor. * Running on AP. */ static void __cpuinit smp_callin(void) { int cpuid, phys_id; unsigned long timeout; /* * If waken up by an INIT in an 82489DX configuration * we may get here before an INIT-deassert IPI reaches * our local APIC. We have to wait for the IPI or we'll * lock up on an APIC access. */ if (apic->wait_for_init_deassert) apic->wait_for_init_deassert(&init_deasserted); /* * (This works even if the APIC is not enabled.) */ phys_id = read_apic_id(); cpuid = smp_processor_id(); if (cpumask_test_cpu(cpuid, cpu_callin_mask)) { panic("%s: phys CPU#%d, CPU#%d already present??\n", __func__, phys_id, cpuid); } pr_debug("CPU#%d (phys ID: %d) waiting for CALLOUT\n", cpuid, phys_id); /* * STARTUP IPIs are fragile beasts as they might sometimes * trigger some glue motherboard logic. Complete APIC bus * silence for 1 second, this overestimates the time the * boot CPU is spending to send the up to 2 STARTUP IPIs * by a factor of two. This should be enough. */ /* * Waiting 2s total for startup (udelay is not yet working) */ timeout = jiffies + 2*HZ; while (time_before(jiffies, timeout)) { /* * Has the boot CPU finished it's STARTUP sequence? */ if (cpumask_test_cpu(cpuid, cpu_callout_mask)) break; cpu_relax(); } if (!time_before(jiffies, timeout)) { panic("%s: CPU%d started up but did not get a callout!\n", __func__, cpuid); } /* * the boot CPU has finished the init stage and is spinning * on callin_map until we finish. We are free to set up this * CPU, first the APIC. (this is probably redundant on most * boards) */ pr_debug("CALLIN, before setup_local_APIC().\n"); if (apic->smp_callin_clear_local_apic) apic->smp_callin_clear_local_apic(); setup_local_APIC(); end_local_APIC_setup(); /* * Need to setup vector mappings before we enable interrupts. */ setup_vector_irq(smp_processor_id()); /* * Save our processor parameters. Note: this information * is needed for clock calibration. */ smp_store_cpu_info(cpuid); /* * Get our bogomips. * Update loops_per_jiffy in cpu_data. Previous call to * smp_store_cpu_info() stored a value that is close but not as * accurate as the value just calculated. * * Need to enable IRQs because it can take longer and then * the NMI watchdog might kill us. */ local_irq_enable(); calibrate_delay(); cpu_data(cpuid).loops_per_jiffy = loops_per_jiffy; local_irq_disable(); pr_debug("Stack at about %p\n", &cpuid); /* * This must be done before setting cpu_online_mask * or calling notify_cpu_starting. */ set_cpu_sibling_map(raw_smp_processor_id()); wmb(); notify_cpu_starting(cpuid); /* * Allow the master to continue. */ cpumask_set_cpu(cpuid, cpu_callin_mask); } /* * Activate a secondary processor. */ notrace static void __cpuinit start_secondary(void *unused) { /* * Don't put *anything* before cpu_init(), SMP booting is too * fragile that we want to limit the things done here to the * most necessary things. */ cpu_init(); preempt_disable(); smp_callin(); #ifdef CONFIG_X86_32 /* switch away from the initial page table */ load_cr3(swapper_pg_dir); __flush_tlb_all(); #endif /* otherwise gcc will move up smp_processor_id before the cpu_init */ barrier(); /* * Check TSC synchronization with the BP: */ check_tsc_sync_target(); /* * We need to hold call_lock, so there is no inconsistency * between the time smp_call_function() determines number of * IPI recipients, and the time when the determination is made * for which cpus receive the IPI. Holding this * lock helps us to not include this cpu in a currently in progress * smp_call_function(). * * We need to hold vector_lock so there the set of online cpus * does not change while we are assigning vectors to cpus. Holding * this lock ensures we don't half assign or remove an irq from a cpu. */ ipi_call_lock(); lock_vector_lock(); set_cpu_online(smp_processor_id(), true); unlock_vector_lock(); ipi_call_unlock(); per_cpu(cpu_state, smp_processor_id()) = CPU_ONLINE; x86_platform.nmi_init(); /* enable local interrupts */ local_irq_enable(); /* to prevent fake stack check failure in clock setup */ boot_init_stack_canary(); x86_cpuinit.setup_percpu_clockev(); wmb(); cpu_idle(); } /* * The bootstrap kernel entry code has set these up. Save them for * a given CPU */ void __cpuinit smp_store_cpu_info(int id) { struct cpuinfo_x86 *c = &cpu_data(id); *c = boot_cpu_data; c->cpu_index = id; if (id != 0) identify_secondary_cpu(c); } static void __cpuinit link_thread_siblings(int cpu1, int cpu2) { cpumask_set_cpu(cpu1, cpu_sibling_mask(cpu2)); cpumask_set_cpu(cpu2, cpu_sibling_mask(cpu1)); cpumask_set_cpu(cpu1, cpu_core_mask(cpu2)); cpumask_set_cpu(cpu2, cpu_core_mask(cpu1)); cpumask_set_cpu(cpu1, cpu_llc_shared_mask(cpu2)); cpumask_set_cpu(cpu2, cpu_llc_shared_mask(cpu1)); } void __cpuinit set_cpu_sibling_map(int cpu) { int i; struct cpuinfo_x86 *c = &cpu_data(cpu); cpumask_set_cpu(cpu, cpu_sibling_setup_mask); if (smp_num_siblings > 1) { for_each_cpu(i, cpu_sibling_setup_mask) { struct cpuinfo_x86 *o = &cpu_data(i); if (cpu_has(c, X86_FEATURE_TOPOEXT)) { if (c->phys_proc_id == o->phys_proc_id && per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i) && c->compute_unit_id == o->compute_unit_id) link_thread_siblings(cpu, i); } else if (c->phys_proc_id == o->phys_proc_id && c->cpu_core_id == o->cpu_core_id) { link_thread_siblings(cpu, i); } } } else { cpumask_set_cpu(cpu, cpu_sibling_mask(cpu)); } cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu)); if (__this_cpu_read(cpu_info.x86_max_cores) == 1) { cpumask_copy(cpu_core_mask(cpu), cpu_sibling_mask(cpu)); c->booted_cores = 1; return; } for_each_cpu(i, cpu_sibling_setup_mask) { if (per_cpu(cpu_llc_id, cpu) != BAD_APICID && per_cpu(cpu_llc_id, cpu) == per_cpu(cpu_llc_id, i)) { cpumask_set_cpu(i, cpu_llc_shared_mask(cpu)); cpumask_set_cpu(cpu, cpu_llc_shared_mask(i)); } if (c->phys_proc_id == cpu_data(i).phys_proc_id) { cpumask_set_cpu(i, cpu_core_mask(cpu)); cpumask_set_cpu(cpu, cpu_core_mask(i)); /* * Does this new cpu bringup a new core? */ if (cpumask_weight(cpu_sibling_mask(cpu)) == 1) { /* * for each core in package, increment * the booted_cores for this new cpu */ if (cpumask_first(cpu_sibling_mask(i)) == i) c->booted_cores++; /* * increment the core count for all * the other cpus in this package */ if (i != cpu) cpu_data(i).booted_cores++; } else if (i != cpu && !c->booted_cores) c->booted_cores = cpu_data(i).booted_cores; } } } /* maps the cpu to the sched domain representing multi-core */ const struct cpumask *cpu_coregroup_mask(int cpu) { struct cpuinfo_x86 *c = &cpu_data(cpu); /* * For perf, we return last level cache shared map. * And for power savings, we return cpu_core_map */ if ((sched_mc_power_savings || sched_smt_power_savings) && !(cpu_has(c, X86_FEATURE_AMD_DCM))) return cpu_core_mask(cpu); else return cpu_llc_shared_mask(cpu); } static void impress_friends(void) { int cpu; unsigned long bogosum = 0; /* * Allow the user to impress friends. */ pr_debug("Before bogomips.\n"); for_each_possible_cpu(cpu) if (cpumask_test_cpu(cpu, cpu_callout_mask)) bogosum += cpu_data(cpu).loops_per_jiffy; printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n", num_online_cpus(), bogosum/(500000/HZ), (bogosum/(5000/HZ))%100); pr_debug("Before bogocount - setting activated=1.\n"); } void __inquire_remote_apic(int apicid) { unsigned i, regs[] = { APIC_ID >> 4, APIC_LVR >> 4, APIC_SPIV >> 4 }; const char * const names[] = { "ID", "VERSION", "SPIV" }; int timeout; u32 status; printk(KERN_INFO "Inquiring remote APIC 0x%x...\n", apicid); for (i = 0; i < ARRAY_SIZE(regs); i++) { printk(KERN_INFO "... APIC 0x%x %s: ", apicid, names[i]); /* * Wait for idle. */ status = safe_apic_wait_icr_idle(); if (status) printk(KERN_CONT "a previous APIC delivery may have failed\n"); apic_icr_write(APIC_DM_REMRD | regs[i], apicid); timeout = 0; do { udelay(100); status = apic_read(APIC_ICR) & APIC_ICR_RR_MASK; } while (status == APIC_ICR_RR_INPROG && timeout++ < 1000); switch (status) { case APIC_ICR_RR_VALID: status = apic_read(APIC_RRR); printk(KERN_CONT "%08x\n", status); break; default: printk(KERN_CONT "failed\n"); } } } /* * Poke the other CPU in the eye via NMI to wake it up. Remember that the normal * INIT, INIT, STARTUP sequence will reset the chip hard for us, and this * won't ... remember to clear down the APIC, etc later. */ int __cpuinit wakeup_secondary_cpu_via_nmi(int logical_apicid, unsigned long start_eip) { unsigned long send_status, accept_status = 0; int maxlvt; /* Target chip */ /* Boot on the stack */ /* Kick the second */ apic_icr_write(APIC_DM_NMI | apic->dest_logical, logical_apicid); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); /* * Give the other CPU some time to accept the IPI. */ udelay(200); if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) { maxlvt = lapic_get_maxlvt(); if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); accept_status = (apic_read(APIC_ESR) & 0xEF); } pr_debug("NMI sent.\n"); if (send_status) printk(KERN_ERR "APIC never delivered???\n"); if (accept_status) printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status); return (send_status | accept_status); } static int __cpuinit wakeup_secondary_cpu_via_init(int phys_apicid, unsigned long start_eip) { unsigned long send_status, accept_status = 0; int maxlvt, num_starts, j; maxlvt = lapic_get_maxlvt(); /* * Be paranoid about clearing APIC errors. */ if (APIC_INTEGRATED(apic_version[phys_apicid])) { if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } pr_debug("Asserting INIT.\n"); /* * Turn INIT on target chip */ /* * Send IPI */ apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT, phys_apicid); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); mdelay(10); pr_debug("Deasserting INIT.\n"); /* Target chip */ /* Send IPI */ apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); mb(); atomic_set(&init_deasserted, 1); /* * Should we send STARTUP IPIs ? * * Determine this based on the APIC version. * If we don't have an integrated APIC, don't send the STARTUP IPIs. */ if (APIC_INTEGRATED(apic_version[phys_apicid])) num_starts = 2; else num_starts = 0; /* * Paravirt / VMI wants a startup IPI hook here to set up the * target processor state. */ startup_ipi_hook(phys_apicid, (unsigned long) start_secondary, stack_start); /* * Run STARTUP IPI loop. */ pr_debug("#startup loops: %d.\n", num_starts); for (j = 1; j <= num_starts; j++) { pr_debug("Sending STARTUP #%d.\n", j); if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); apic_read(APIC_ESR); pr_debug("After apic_write.\n"); /* * STARTUP IPI */ /* Target chip */ /* Boot on the stack */ /* Kick the second */ apic_icr_write(APIC_DM_STARTUP | (start_eip >> 12), phys_apicid); /* * Give the other CPU some time to accept the IPI. */ udelay(300); pr_debug("Startup point 1.\n"); pr_debug("Waiting for send to finish...\n"); send_status = safe_apic_wait_icr_idle(); /* * Give the other CPU some time to accept the IPI. */ udelay(200); if (maxlvt > 3) /* Due to the Pentium erratum 3AP. */ apic_write(APIC_ESR, 0); accept_status = (apic_read(APIC_ESR) & 0xEF); if (send_status || accept_status) break; } pr_debug("After Startup.\n"); if (send_status) printk(KERN_ERR "APIC never delivered???\n"); if (accept_status) printk(KERN_ERR "APIC delivery error (%lx).\n", accept_status); return (send_status | accept_status); } struct create_idle { struct work_struct work; struct task_struct *idle; struct completion done; int cpu; }; static void __cpuinit do_fork_idle(struct work_struct *work) { struct create_idle *c_idle = container_of(work, struct create_idle, work); c_idle->idle = fork_idle(c_idle->cpu); complete(&c_idle->done); } /* reduce the number of lines printed when booting a large cpu count system */ static void __cpuinit announce_cpu(int cpu, int apicid) { static int current_node = -1; int node = early_cpu_to_node(cpu); if (system_state == SYSTEM_BOOTING) { if (node != current_node) { if (current_node > (-1)) pr_cont(" Ok.\n"); current_node = node; pr_info("Booting Node %3d, Processors ", node); } pr_cont(" #%d%s", cpu, cpu == (nr_cpu_ids - 1) ? " Ok.\n" : ""); return; } else pr_info("Booting Node %d Processor %d APIC 0x%x\n", node, cpu, apicid); } /* * NOTE - on most systems this is a PHYSICAL apic ID, but on multiquad * (ie clustered apic addressing mode), this is a LOGICAL apic ID. * Returns zero if CPU booted OK, else error code from * ->wakeup_secondary_cpu. */ static int __cpuinit do_boot_cpu(int apicid, int cpu) { unsigned long boot_error = 0; unsigned long start_ip; int timeout; struct create_idle c_idle = { .cpu = cpu, .done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done), }; INIT_WORK_ONSTACK(&c_idle.work, do_fork_idle); alternatives_smp_switch(1); c_idle.idle = get_idle_for_cpu(cpu); /* * We can't use kernel_thread since we must avoid to * reschedule the child. */ if (c_idle.idle) { c_idle.idle->thread.sp = (unsigned long) (((struct pt_regs *) (THREAD_SIZE + task_stack_page(c_idle.idle))) - 1); init_idle(c_idle.idle, cpu); goto do_rest; } schedule_work(&c_idle.work); wait_for_completion(&c_idle.done); if (IS_ERR(c_idle.idle)) { printk("failed fork for CPU %d\n", cpu); destroy_work_on_stack(&c_idle.work); return PTR_ERR(c_idle.idle); } set_idle_for_cpu(cpu, c_idle.idle); do_rest: per_cpu(current_task, cpu) = c_idle.idle; #ifdef CONFIG_X86_32 /* Stack for startup_32 can be just as for start_secondary onwards */ irq_ctx_init(cpu); #else clear_tsk_thread_flag(c_idle.idle, TIF_FORK); initial_gs = per_cpu_offset(cpu); per_cpu(kernel_stack, cpu) = (unsigned long)task_stack_page(c_idle.idle) - KERNEL_STACK_OFFSET + THREAD_SIZE; #endif early_gdt_descr.address = (unsigned long)get_cpu_gdt_table(cpu); initial_code = (unsigned long)start_secondary; stack_start = c_idle.idle->thread.sp; /* start_ip had better be page-aligned! */ start_ip = trampoline_address(); /* So we see what's up */ announce_cpu(cpu, apicid); /* * This grunge runs the startup process for * the targeted processor. */ atomic_set(&init_deasserted, 0); if (get_uv_system_type() != UV_NON_UNIQUE_APIC) { pr_debug("Setting warm reset code and vector.\n"); smpboot_setup_warm_reset_vector(start_ip); /* * Be paranoid about clearing APIC errors. */ if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid])) { apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } } /* * Kick the secondary CPU. Use the method in the APIC driver * if it's defined - or use an INIT boot APIC message otherwise: */ if (apic->wakeup_secondary_cpu) boot_error = apic->wakeup_secondary_cpu(apicid, start_ip); else boot_error = wakeup_secondary_cpu_via_init(apicid, start_ip); if (!boot_error) { /* * allow APs to start initializing. */ pr_debug("Before Callout %d.\n", cpu); cpumask_set_cpu(cpu, cpu_callout_mask); pr_debug("After Callout %d.\n", cpu); /* * Wait 5s total for a response */ for (timeout = 0; timeout < 50000; timeout++) { if (cpumask_test_cpu(cpu, cpu_callin_mask)) break; /* It has booted */ udelay(100); /* * Allow other tasks to run while we wait for the * AP to come online. This also gives a chance * for the MTRR work(triggered by the AP coming online) * to be completed in the stop machine context. */ schedule(); } if (cpumask_test_cpu(cpu, cpu_callin_mask)) { print_cpu_msr(&cpu_data(cpu)); pr_debug("CPU%d: has booted.\n", cpu); } else { boot_error = 1; if (*(volatile u32 *)TRAMPOLINE_SYM(trampoline_status) == 0xA5A5A5A5) /* trampoline started but...? */ pr_err("CPU%d: Stuck ??\n", cpu); else /* trampoline code not run */ pr_err("CPU%d: Not responding.\n", cpu); if (apic->inquire_remote_apic) apic->inquire_remote_apic(apicid); } } if (boot_error) { /* Try to put things back the way they were before ... */ numa_remove_cpu(cpu); /* was set by numa_add_cpu */ /* was set by do_boot_cpu() */ cpumask_clear_cpu(cpu, cpu_callout_mask); /* was set by cpu_init() */ cpumask_clear_cpu(cpu, cpu_initialized_mask); set_cpu_present(cpu, false); per_cpu(x86_cpu_to_apicid, cpu) = BAD_APICID; } /* mark "stuck" area as not stuck */ *(volatile u32 *)TRAMPOLINE_SYM(trampoline_status) = 0; if (get_uv_system_type() != UV_NON_UNIQUE_APIC) { /* * Cleanup possible dangling ends... */ smpboot_restore_warm_reset_vector(); } destroy_work_on_stack(&c_idle.work); return boot_error; } int __cpuinit native_cpu_up(unsigned int cpu) { int apicid = apic->cpu_present_to_apicid(cpu); unsigned long flags; int err; WARN_ON(irqs_disabled()); pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu); if (apicid == BAD_APICID || apicid == boot_cpu_physical_apicid || !physid_isset(apicid, phys_cpu_present_map) || !apic->apic_id_valid(apicid)) { printk(KERN_ERR "%s: bad cpu %d\n", __func__, cpu); return -EINVAL; } /* * Already booted CPU? */ if (cpumask_test_cpu(cpu, cpu_callin_mask)) { pr_debug("do_boot_cpu %d Already started\n", cpu); return -ENOSYS; } /* * Save current MTRR state in case it was changed since early boot * (e.g. by the ACPI SMI) to initialize new CPUs with MTRRs in sync: */ mtrr_save_state(); per_cpu(cpu_state, cpu) = CPU_UP_PREPARE; err = do_boot_cpu(apicid, cpu); if (err) { pr_debug("do_boot_cpu failed %d\n", err); return -EIO; } /* * Check TSC synchronization with the AP (keep irqs disabled * while doing so): */ local_irq_save(flags); check_tsc_sync_source(cpu); local_irq_restore(flags); while (!cpu_online(cpu)) { cpu_relax(); touch_nmi_watchdog(); } return 0; } /** * arch_disable_smp_support() - disables SMP support for x86 at runtime */ void arch_disable_smp_support(void) { disable_ioapic_support(); } /* * Fall back to non SMP mode after errors. * * RED-PEN audit/test this more. I bet there is more state messed up here. */ static __init void disable_smp(void) { init_cpu_present(cpumask_of(0)); init_cpu_possible(cpumask_of(0)); smpboot_clear_io_apic_irqs(); if (smp_found_config) physid_set_mask_of_physid(boot_cpu_physical_apicid, &phys_cpu_present_map); else physid_set_mask_of_physid(0, &phys_cpu_present_map); cpumask_set_cpu(0, cpu_sibling_mask(0)); cpumask_set_cpu(0, cpu_core_mask(0)); } /* * Various sanity checks. */ static int __init smp_sanity_check(unsigned max_cpus) { preempt_disable(); #if !defined(CONFIG_X86_BIGSMP) && defined(CONFIG_X86_32) if (def_to_bigsmp && nr_cpu_ids > 8) { unsigned int cpu; unsigned nr; printk(KERN_WARNING "More than 8 CPUs detected - skipping them.\n" "Use CONFIG_X86_BIGSMP.\n"); nr = 0; for_each_present_cpu(cpu) { if (nr >= 8) set_cpu_present(cpu, false); nr++; } nr = 0; for_each_possible_cpu(cpu) { if (nr >= 8) set_cpu_possible(cpu, false); nr++; } nr_cpu_ids = 8; } #endif if (!physid_isset(hard_smp_processor_id(), phys_cpu_present_map)) { printk(KERN_WARNING "weird, boot CPU (#%d) not listed by the BIOS.\n", hard_smp_processor_id()); physid_set(hard_smp_processor_id(), phys_cpu_present_map); } /* * If we couldn't find an SMP configuration at boot time, * get out of here now! */ if (!smp_found_config && !acpi_lapic) { preempt_enable(); printk(KERN_NOTICE "SMP motherboard not detected.\n"); disable_smp(); if (APIC_init_uniprocessor()) printk(KERN_NOTICE "Local APIC not detected." " Using dummy APIC emulation.\n"); return -1; } /* * Should not be necessary because the MP table should list the boot * CPU too, but we do it for the sake of robustness anyway. */ if (!apic->check_phys_apicid_present(boot_cpu_physical_apicid)) { printk(KERN_NOTICE "weird, boot CPU (#%d) not listed by the BIOS.\n", boot_cpu_physical_apicid); physid_set(hard_smp_processor_id(), phys_cpu_present_map); } preempt_enable(); /* * If we couldn't find a local APIC, then get out of here now! */ if (APIC_INTEGRATED(apic_version[boot_cpu_physical_apicid]) && !cpu_has_apic) { if (!disable_apic) { pr_err("BIOS bug, local APIC #%d not detected!...\n", boot_cpu_physical_apicid); pr_err("... forcing use of dummy APIC emulation." "(tell your hw vendor)\n"); } smpboot_clear_io_apic(); disable_ioapic_support(); return -1; } verify_local_APIC(); /* * If SMP should be disabled, then really disable it! */ if (!max_cpus) { printk(KERN_INFO "SMP mode deactivated.\n"); smpboot_clear_io_apic(); connect_bsp_APIC(); setup_local_APIC(); bsp_end_local_APIC_setup(); return -1; } return 0; } static void __init smp_cpu_index_default(void) { int i; struct cpuinfo_x86 *c; for_each_possible_cpu(i) { c = &cpu_data(i); /* mark all to hotplug */ c->cpu_index = nr_cpu_ids; } } /* * Prepare for SMP bootup. The MP table or ACPI has been read * earlier. Just do some sanity checking here and enable APIC mode. */ void __init native_smp_prepare_cpus(unsigned int max_cpus) { unsigned int i; preempt_disable(); smp_cpu_index_default(); /* * Setup boot CPU information */ smp_store_cpu_info(0); /* Final full version of the data */ cpumask_copy(cpu_callin_mask, cpumask_of(0)); mb(); current_thread_info()->cpu = 0; /* needed? */ for_each_possible_cpu(i) { zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL); zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL); zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL); } set_cpu_sibling_map(0); if (smp_sanity_check(max_cpus) < 0) { printk(KERN_INFO "SMP disabled\n"); disable_smp(); goto out; } default_setup_apic_routing(); preempt_disable(); if (read_apic_id() != boot_cpu_physical_apicid) { panic("Boot APIC ID in local APIC unexpected (%d vs %d)", read_apic_id(), boot_cpu_physical_apicid); /* Or can we switch back to PIC here? */ } preempt_enable(); connect_bsp_APIC(); /* * Switch from PIC to APIC mode. */ setup_local_APIC(); /* * Enable IO APIC before setting up error vector */ if (!skip_ioapic_setup && nr_ioapics) enable_IO_APIC(); bsp_end_local_APIC_setup(); if (apic->setup_portio_remap) apic->setup_portio_remap(); smpboot_setup_io_apic(); /* * Set up local APIC timer on boot CPU. */ printk(KERN_INFO "CPU%d: ", 0); print_cpu_info(&cpu_data(0)); x86_init.timers.setup_percpu_clockev(); if (is_uv_system()) uv_system_init(); set_mtrr_aps_delayed_init(); out: preempt_enable(); } void arch_disable_nonboot_cpus_begin(void) { /* * Avoid the smp alternatives switch during the disable_nonboot_cpus(). * In the suspend path, we will be back in the SMP mode shortly anyways. */ skip_smp_alternatives = true; } void arch_disable_nonboot_cpus_end(void) { skip_smp_alternatives = false; } void arch_enable_nonboot_cpus_begin(void) { set_mtrr_aps_delayed_init(); } void arch_enable_nonboot_cpus_end(void) { mtrr_aps_init(); } /* * Early setup to make printk work. */ void __init native_smp_prepare_boot_cpu(void) { int me = smp_processor_id(); switch_to_new_gdt(me); /* already set me in cpu_online_mask in boot_cpu_init() */ cpumask_set_cpu(me, cpu_callout_mask); per_cpu(cpu_state, me) = CPU_ONLINE; } void __init native_smp_cpus_done(unsigned int max_cpus) { pr_debug("Boot done.\n"); nmi_selftest(); impress_friends(); #ifdef CONFIG_X86_IO_APIC setup_ioapic_dest(); #endif mtrr_aps_init(); } static int __initdata setup_possible_cpus = -1; static int __init _setup_possible_cpus(char *str) { get_option(&str, &setup_possible_cpus); return 0; } early_param("possible_cpus", _setup_possible_cpus); /* * cpu_possible_mask should be static, it cannot change as cpu's * are onlined, or offlined. The reason is per-cpu data-structures * are allocated by some modules at init time, and dont expect to * do this dynamically on cpu arrival/departure. * cpu_present_mask on the other hand can change dynamically. * In case when cpu_hotplug is not compiled, then we resort to current * behaviour, which is cpu_possible == cpu_present. * - Ashok Raj * * Three ways to find out the number of additional hotplug CPUs: * - If the BIOS specified disabled CPUs in ACPI/mptables use that. * - The user can overwrite it with possible_cpus=NUM * - Otherwise don't reserve additional CPUs. * We do this because additional CPUs waste a lot of memory. * -AK */ __init void prefill_possible_map(void) { int i, possible; /* no processor from mptable or madt */ if (!num_processors) num_processors = 1; i = setup_max_cpus ?: 1; if (setup_possible_cpus == -1) { possible = num_processors; #ifdef CONFIG_HOTPLUG_CPU if (setup_max_cpus) possible += disabled_cpus; #else if (possible > i) possible = i; #endif } else possible = setup_possible_cpus; total_cpus = max_t(int, possible, num_processors + disabled_cpus); /* nr_cpu_ids could be reduced via nr_cpus= */ if (possible > nr_cpu_ids) { printk(KERN_WARNING "%d Processors exceeds NR_CPUS limit of %d\n", possible, nr_cpu_ids); possible = nr_cpu_ids; } #ifdef CONFIG_HOTPLUG_CPU if (!setup_max_cpus) #endif if (possible > i) { printk(KERN_WARNING "%d Processors exceeds max_cpus limit of %u\n", possible, setup_max_cpus); possible = i; } printk(KERN_INFO "SMP: Allowing %d CPUs, %d hotplug CPUs\n", possible, max_t(int, possible - num_processors, 0)); for (i = 0; i < possible; i++) set_cpu_possible(i, true); for (; i < NR_CPUS; i++) set_cpu_possible(i, false); nr_cpu_ids = possible; } #ifdef CONFIG_HOTPLUG_CPU static void remove_siblinginfo(int cpu) { int sibling; struct cpuinfo_x86 *c = &cpu_data(cpu); for_each_cpu(sibling, cpu_core_mask(cpu)) { cpumask_clear_cpu(cpu, cpu_core_mask(sibling)); /*/ * last thread sibling in this cpu core going down */ if (cpumask_weight(cpu_sibling_mask(cpu)) == 1) cpu_data(sibling).booted_cores--; } for_each_cpu(sibling, cpu_sibling_mask(cpu)) cpumask_clear_cpu(cpu, cpu_sibling_mask(sibling)); cpumask_clear(cpu_sibling_mask(cpu)); cpumask_clear(cpu_core_mask(cpu)); c->phys_proc_id = 0; c->cpu_core_id = 0; cpumask_clear_cpu(cpu, cpu_sibling_setup_mask); } static void __ref remove_cpu_from_maps(int cpu) { set_cpu_online(cpu, false); cpumask_clear_cpu(cpu, cpu_callout_mask); cpumask_clear_cpu(cpu, cpu_callin_mask); /* was set by cpu_init() */ cpumask_clear_cpu(cpu, cpu_initialized_mask); numa_remove_cpu(cpu); } void cpu_disable_common(void) { int cpu = smp_processor_id(); remove_siblinginfo(cpu); /* It's now safe to remove this processor from the online map */ lock_vector_lock(); remove_cpu_from_maps(cpu); unlock_vector_lock(); fixup_irqs(); } int native_cpu_disable(void) { int cpu = smp_processor_id(); /* * Perhaps use cpufreq to drop frequency, but that could go * into generic code. * * We won't take down the boot processor on i386 due to some * interrupts only being able to be serviced by the BSP. * Especially so if we're not using an IOAPIC -zwane */ if (cpu == 0) return -EBUSY; clear_local_APIC(); cpu_disable_common(); return 0; } void native_cpu_die(unsigned int cpu) { /* We don't do anything here: idle task is faking death itself. */ unsigned int i; for (i = 0; i < 10; i++) { /* They ack this in play_dead by setting CPU_DEAD */ if (per_cpu(cpu_state, cpu) == CPU_DEAD) { if (system_state == SYSTEM_RUNNING) pr_info("CPU %u is now offline\n", cpu); if (1 == num_online_cpus()) alternatives_smp_switch(0); return; } msleep(100); } pr_err("CPU %u didn't die...\n", cpu); } void play_dead_common(void) { idle_task_exit(); reset_lazy_tlbstate(); amd_e400_remove_cpu(raw_smp_processor_id()); mb(); /* Ack it */ __this_cpu_write(cpu_state, CPU_DEAD); /* * With physical CPU hotplug, we should halt the cpu */ local_irq_disable(); } /* * We need to flush the caches before going to sleep, lest we have * dirty data in our caches when we come back up. */ static inline void mwait_play_dead(void) { unsigned int eax, ebx, ecx, edx; unsigned int highest_cstate = 0; unsigned int highest_subcstate = 0; int i; void *mwait_ptr; struct cpuinfo_x86 *c = __this_cpu_ptr(&cpu_info); if (!(this_cpu_has(X86_FEATURE_MWAIT) && mwait_usable(c))) return; if (!this_cpu_has(X86_FEATURE_CLFLSH)) return; if (__this_cpu_read(cpu_info.cpuid_level) < CPUID_MWAIT_LEAF) return; eax = CPUID_MWAIT_LEAF; ecx = 0; native_cpuid(&eax, &ebx, &ecx, &edx); /* * eax will be 0 if EDX enumeration is not valid. * Initialized below to cstate, sub_cstate value when EDX is valid. */ if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED)) { eax = 0; } else { edx >>= MWAIT_SUBSTATE_SIZE; for (i = 0; i < 7 && edx; i++, edx >>= MWAIT_SUBSTATE_SIZE) { if (edx & MWAIT_SUBSTATE_MASK) { highest_cstate = i; highest_subcstate = edx & MWAIT_SUBSTATE_MASK; } } eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) | (highest_subcstate - 1); } /* * This should be a memory location in a cache line which is * unlikely to be touched by other processors. The actual * content is immaterial as it is not actually modified in any way. */ mwait_ptr = ¤t_thread_info()->flags; wbinvd(); while (1) { /* * The CLFLUSH is a workaround for erratum AAI65 for * the Xeon 7400 series. It's not clear it is actually * needed, but it should be harmless in either case. * The WBINVD is insufficient due to the spurious-wakeup * case where we return around the loop. */ clflush(mwait_ptr); __monitor(mwait_ptr, 0, 0); mb(); __mwait(eax, 0); } } static inline void hlt_play_dead(void) { if (__this_cpu_read(cpu_info.x86) >= 4) wbinvd(); while (1) { native_halt(); } } void native_play_dead(void) { play_dead_common(); tboot_shutdown(TB_SHUTDOWN_WFS); mwait_play_dead(); /* Only returns on failure */ hlt_play_dead(); } #else /* ... !CONFIG_HOTPLUG_CPU */ int native_cpu_disable(void) { return -ENOSYS; } void native_cpu_die(unsigned int cpu) { /* We said "no" in __cpu_disable */ BUG(); } void native_play_dead(void) { BUG(); } #endif