// SPDX-License-Identifier: GPL-2.0-or-later /* * 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. * * 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 */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* representing HT siblings of each logical CPU */ DEFINE_PER_CPU_READ_MOSTLY(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_READ_MOSTLY(cpumask_var_t, cpu_core_map); EXPORT_PER_CPU_SYMBOL(cpu_core_map); /* representing HT, core, and die siblings of each logical CPU */ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_die_map); EXPORT_PER_CPU_SYMBOL(cpu_die_map); /* CPUs which are the primary SMT threads */ struct cpumask __cpu_primary_thread_mask __read_mostly; /* Representing CPUs for which sibling maps can be computed */ static cpumask_var_t cpu_sibling_setup_mask; struct mwait_cpu_dead { unsigned int control; unsigned int status; }; #define CPUDEAD_MWAIT_WAIT 0xDEADBEEF #define CPUDEAD_MWAIT_KEXEC_HLT 0x4A17DEAD /* * Cache line aligned data for mwait_play_dead(). Separate on purpose so * that it's unlikely to be touched by other CPUs. */ static DEFINE_PER_CPU_ALIGNED(struct mwait_cpu_dead, mwait_cpu_dead); /* Maximum number of SMT threads on any online core */ int __read_mostly __max_smt_threads = 1; /* Flag to indicate if a complete sched domain rebuild is required */ bool x86_topology_update; int arch_update_cpu_topology(void) { int retval = x86_topology_update; x86_topology_update = false; return retval; } static unsigned int smpboot_warm_reset_vector_count; static inline void smpboot_setup_warm_reset_vector(unsigned long start_eip) { unsigned long flags; spin_lock_irqsave(&rtc_lock, flags); if (!smpboot_warm_reset_vector_count++) { CMOS_WRITE(0xa, 0xf); *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_HIGH)) = start_eip >> 4; *((volatile unsigned short *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = start_eip & 0xf; } spin_unlock_irqrestore(&rtc_lock, flags); } static inline void smpboot_restore_warm_reset_vector(void) { unsigned long flags; /* * Paranoid: Set warm reset code and vector here back * to default values. */ spin_lock_irqsave(&rtc_lock, flags); if (!--smpboot_warm_reset_vector_count) { CMOS_WRITE(0, 0xf); *((volatile u32 *)phys_to_virt(TRAMPOLINE_PHYS_LOW)) = 0; } spin_unlock_irqrestore(&rtc_lock, flags); } /* Run the next set of setup steps for the upcoming CPU */ static void ap_starting(void) { int cpuid = smp_processor_id(); /* Mop up eventual mwait_play_dead() wreckage */ this_cpu_write(mwait_cpu_dead.status, 0); this_cpu_write(mwait_cpu_dead.control, 0); /* * If woken up by an INIT in an 82489DX configuration the alive * synchronization guarantees that the CPU does not reach this * point before an INIT_deassert IPI reaches the local APIC, so it * is now safe to touch the local APIC. * * Set up this CPU, first the APIC, which is probably redundant on * most boards. */ apic_ap_setup(); /* Save the processor parameters. */ smp_store_cpu_info(cpuid); /* * The topology information must be up to date before * notify_cpu_starting(). */ set_cpu_sibling_map(cpuid); ap_init_aperfmperf(); pr_debug("Stack at about %p\n", &cpuid); wmb(); /* * This runs the AP through all the cpuhp states to its target * state CPUHP_ONLINE. */ notify_cpu_starting(cpuid); } static void ap_calibrate_delay(void) { /* * Calibrate the delay loop and update loops_per_jiffy in cpu_data. * smp_store_cpu_info() stored a value that is close but not as * accurate as the value just calculated. * * As this is invoked after the TSC synchronization check, * calibrate_delay_is_known() will skip the calibration routine * when TSC is synchronized across sockets. */ calibrate_delay(); cpu_data(smp_processor_id()).loops_per_jiffy = loops_per_jiffy; } /* * Activate a secondary processor. */ static void notrace start_secondary(void *unused) { /* * Don't put *anything* except direct CPU state initialization * before cpu_init(), SMP booting is too fragile that we want to * limit the things done here to the most necessary things. */ cr4_init(); /* * 32-bit specific. 64-bit reaches this code with the correct page * table established. Yet another historical divergence. */ if (IS_ENABLED(CONFIG_X86_32)) { /* switch away from the initial page table */ load_cr3(swapper_pg_dir); __flush_tlb_all(); } cpu_init_exception_handling(); /* * Load the microcode before reaching the AP alive synchronization * point below so it is not part of the full per CPU serialized * bringup part when "parallel" bringup is enabled. * * That's even safe when hyperthreading is enabled in the CPU as * the core code starts the primary threads first and leaves the * secondary threads waiting for SIPI. Loading microcode on * physical cores concurrently is a safe operation. * * This covers both the Intel specific issue that concurrent * microcode loading on SMT siblings must be prohibited and the * vendor independent issue`that microcode loading which changes * CPUID, MSRs etc. must be strictly serialized to maintain * software state correctness. */ load_ucode_ap(); /* * Synchronization point with the hotplug core. Sets this CPUs * synchronization state to ALIVE and spin-waits for the control CPU to * release this CPU for further bringup. */ cpuhp_ap_sync_alive(); cpu_init(); fpu__init_cpu(); rcutree_report_cpu_starting(raw_smp_processor_id()); x86_cpuinit.early_percpu_clock_init(); ap_starting(); /* Check TSC synchronization with the control CPU. */ check_tsc_sync_target(); /* * Calibrate the delay loop after the TSC synchronization check. * This allows to skip the calibration when TSC is synchronized * across sockets. */ ap_calibrate_delay(); speculative_store_bypass_ht_init(); /* * Lock vector_lock, set CPU online and bring the vector * allocator online. Online must be set with vector_lock held * to prevent a concurrent irq setup/teardown from seeing a * half valid vector space. */ lock_vector_lock(); set_cpu_online(smp_processor_id(), true); lapic_online(); unlock_vector_lock(); x86_platform.nmi_init(); /* enable local interrupts */ local_irq_enable(); x86_cpuinit.setup_percpu_clockev(); wmb(); cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); } /* * The bootstrap kernel entry code has set these up. Save them for * a given CPU */ void smp_store_cpu_info(int id) { struct cpuinfo_x86 *c = &cpu_data(id); /* Copy boot_cpu_data only on the first bringup */ if (!c->initialized) *c = boot_cpu_data; c->cpu_index = id; /* * During boot time, CPU0 has this setup already. Save the info when * bringing up an AP. */ identify_secondary_cpu(c); c->initialized = true; } static bool topology_same_node(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; return (cpu_to_node(cpu1) == cpu_to_node(cpu2)); } static bool topology_sane(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o, const char *name) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; return !WARN_ONCE(!topology_same_node(c, o), "sched: CPU #%d's %s-sibling CPU #%d is not on the same node! " "[node: %d != %d]. Ignoring dependency.\n", cpu1, name, cpu2, cpu_to_node(cpu1), cpu_to_node(cpu2)); } #define link_mask(mfunc, c1, c2) \ do { \ cpumask_set_cpu((c1), mfunc(c2)); \ cpumask_set_cpu((c2), mfunc(c1)); \ } while (0) static bool match_smt(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { if (boot_cpu_has(X86_FEATURE_TOPOEXT)) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; if (c->topo.pkg_id == o->topo.pkg_id && c->topo.die_id == o->topo.die_id && c->topo.amd_node_id == o->topo.amd_node_id && per_cpu_llc_id(cpu1) == per_cpu_llc_id(cpu2)) { if (c->topo.core_id == o->topo.core_id) return topology_sane(c, o, "smt"); if ((c->topo.cu_id != 0xff) && (o->topo.cu_id != 0xff) && (c->topo.cu_id == o->topo.cu_id)) return topology_sane(c, o, "smt"); } } else if (c->topo.pkg_id == o->topo.pkg_id && c->topo.die_id == o->topo.die_id && c->topo.core_id == o->topo.core_id) { return topology_sane(c, o, "smt"); } return false; } static bool match_die(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { if (c->topo.pkg_id != o->topo.pkg_id || c->topo.die_id != o->topo.die_id) return false; if (cpu_feature_enabled(X86_FEATURE_TOPOEXT) && topology_amd_nodes_per_pkg() > 1) return c->topo.amd_node_id == o->topo.amd_node_id; return true; } static bool match_l2c(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { int cpu1 = c->cpu_index, cpu2 = o->cpu_index; /* If the arch didn't set up l2c_id, fall back to SMT */ if (per_cpu_l2c_id(cpu1) == BAD_APICID) return match_smt(c, o); /* Do not match if L2 cache id does not match: */ if (per_cpu_l2c_id(cpu1) != per_cpu_l2c_id(cpu2)) return false; return topology_sane(c, o, "l2c"); } /* * Unlike the other levels, we do not enforce keeping a * multicore group inside a NUMA node. If this happens, we will * discard the MC level of the topology later. */ static bool match_pkg(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { if (c->topo.pkg_id == o->topo.pkg_id) return true; return false; } /* * Define intel_cod_cpu[] for Intel COD (Cluster-on-Die) CPUs. * * Any Intel CPU that has multiple nodes per package and does not * match intel_cod_cpu[] has the SNC (Sub-NUMA Cluster) topology. * * When in SNC mode, these CPUs enumerate an LLC that is shared * by multiple NUMA nodes. The LLC is shared for off-package data * access but private to the NUMA node (half of the package) for * on-package access. CPUID (the source of the information about * the LLC) can only enumerate the cache as shared or unshared, * but not this particular configuration. */ static const struct x86_cpu_id intel_cod_cpu[] = { X86_MATCH_INTEL_FAM6_MODEL(HASWELL_X, 0), /* COD */ X86_MATCH_INTEL_FAM6_MODEL(BROADWELL_X, 0), /* COD */ X86_MATCH_INTEL_FAM6_MODEL(ANY, 1), /* SNC */ {} }; static bool match_llc(struct cpuinfo_x86 *c, struct cpuinfo_x86 *o) { const struct x86_cpu_id *id = x86_match_cpu(intel_cod_cpu); int cpu1 = c->cpu_index, cpu2 = o->cpu_index; bool intel_snc = id && id->driver_data; /* Do not match if we do not have a valid APICID for cpu: */ if (per_cpu_llc_id(cpu1) == BAD_APICID) return false; /* Do not match if LLC id does not match: */ if (per_cpu_llc_id(cpu1) != per_cpu_llc_id(cpu2)) return false; /* * Allow the SNC topology without warning. Return of false * means 'c' does not share the LLC of 'o'. This will be * reflected to userspace. */ if (match_pkg(c, o) && !topology_same_node(c, o) && intel_snc) return false; return topology_sane(c, o, "llc"); } static inline int x86_sched_itmt_flags(void) { return sysctl_sched_itmt_enabled ? SD_ASYM_PACKING : 0; } #ifdef CONFIG_SCHED_MC static int x86_core_flags(void) { return cpu_core_flags() | x86_sched_itmt_flags(); } #endif #ifdef CONFIG_SCHED_SMT static int x86_smt_flags(void) { return cpu_smt_flags(); } #endif #ifdef CONFIG_SCHED_CLUSTER static int x86_cluster_flags(void) { return cpu_cluster_flags() | x86_sched_itmt_flags(); } #endif static int x86_die_flags(void) { if (cpu_feature_enabled(X86_FEATURE_HYBRID_CPU)) return x86_sched_itmt_flags(); return 0; } /* * Set if a package/die has multiple NUMA nodes inside. * AMD Magny-Cours, Intel Cluster-on-Die, and Intel * Sub-NUMA Clustering have this. */ static bool x86_has_numa_in_package; static struct sched_domain_topology_level x86_topology[6]; static void __init build_sched_topology(void) { int i = 0; #ifdef CONFIG_SCHED_SMT x86_topology[i++] = (struct sched_domain_topology_level){ cpu_smt_mask, x86_smt_flags, SD_INIT_NAME(SMT) }; #endif #ifdef CONFIG_SCHED_CLUSTER x86_topology[i++] = (struct sched_domain_topology_level){ cpu_clustergroup_mask, x86_cluster_flags, SD_INIT_NAME(CLS) }; #endif #ifdef CONFIG_SCHED_MC x86_topology[i++] = (struct sched_domain_topology_level){ cpu_coregroup_mask, x86_core_flags, SD_INIT_NAME(MC) }; #endif /* * When there is NUMA topology inside the package skip the PKG domain * since the NUMA domains will auto-magically create the right spanning * domains based on the SLIT. */ if (!x86_has_numa_in_package) { x86_topology[i++] = (struct sched_domain_topology_level){ cpu_cpu_mask, x86_die_flags, SD_INIT_NAME(PKG) }; } /* * There must be one trailing NULL entry left. */ BUG_ON(i >= ARRAY_SIZE(x86_topology)-1); set_sched_topology(x86_topology); } void set_cpu_sibling_map(int cpu) { bool has_smt = __max_threads_per_core > 1; bool has_mp = has_smt || topology_num_cores_per_package() > 1; struct cpuinfo_x86 *c = &cpu_data(cpu); struct cpuinfo_x86 *o; int i, threads; cpumask_set_cpu(cpu, cpu_sibling_setup_mask); if (!has_mp) { cpumask_set_cpu(cpu, topology_sibling_cpumask(cpu)); cpumask_set_cpu(cpu, cpu_llc_shared_mask(cpu)); cpumask_set_cpu(cpu, cpu_l2c_shared_mask(cpu)); cpumask_set_cpu(cpu, topology_core_cpumask(cpu)); cpumask_set_cpu(cpu, topology_die_cpumask(cpu)); c->booted_cores = 1; return; } for_each_cpu(i, cpu_sibling_setup_mask) { o = &cpu_data(i); if (match_pkg(c, o) && !topology_same_node(c, o)) x86_has_numa_in_package = true; if ((i == cpu) || (has_smt && match_smt(c, o))) link_mask(topology_sibling_cpumask, cpu, i); if ((i == cpu) || (has_mp && match_llc(c, o))) link_mask(cpu_llc_shared_mask, cpu, i); if ((i == cpu) || (has_mp && match_l2c(c, o))) link_mask(cpu_l2c_shared_mask, cpu, i); if ((i == cpu) || (has_mp && match_die(c, o))) link_mask(topology_die_cpumask, cpu, i); } threads = cpumask_weight(topology_sibling_cpumask(cpu)); if (threads > __max_smt_threads) __max_smt_threads = threads; for_each_cpu(i, topology_sibling_cpumask(cpu)) cpu_data(i).smt_active = threads > 1; /* * This needs a separate iteration over the cpus because we rely on all * topology_sibling_cpumask links to be set-up. */ for_each_cpu(i, cpu_sibling_setup_mask) { o = &cpu_data(i); if ((i == cpu) || (has_mp && match_pkg(c, o))) { link_mask(topology_core_cpumask, cpu, i); /* * Does this new cpu bringup a new core? */ if (threads == 1) { /* * for each core in package, increment * the booted_cores for this new cpu */ if (cpumask_first( topology_sibling_cpumask(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) { return cpu_llc_shared_mask(cpu); } const struct cpumask *cpu_clustergroup_mask(int cpu) { return cpu_l2c_shared_mask(cpu); } EXPORT_SYMBOL_GPL(cpu_clustergroup_mask); static void impress_friends(void) { int cpu; unsigned long bogosum = 0; /* * Allow the user to impress friends. */ pr_debug("Before bogomips\n"); for_each_online_cpu(cpu) bogosum += cpu_data(cpu).loops_per_jiffy; pr_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"); } /* * The Multiprocessor Specification 1.4 (1997) example code suggests * that there should be a 10ms delay between the BSP asserting INIT * and de-asserting INIT, when starting a remote processor. * But that slows boot and resume on modern processors, which include * many cores and don't require that delay. * * Cmdline "init_cpu_udelay=" is available to over-ride this delay. * Modern processor families are quirked to remove the delay entirely. */ #define UDELAY_10MS_DEFAULT 10000 static unsigned int init_udelay = UINT_MAX; static int __init cpu_init_udelay(char *str) { get_option(&str, &init_udelay); return 0; } early_param("cpu_init_udelay", cpu_init_udelay); static void __init smp_quirk_init_udelay(void) { /* if cmdline changed it from default, leave it alone */ if (init_udelay != UINT_MAX) return; /* if modern processor, use no delay */ if (((boot_cpu_data.x86_vendor == X86_VENDOR_INTEL) && (boot_cpu_data.x86 == 6)) || ((boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) && (boot_cpu_data.x86 >= 0x18)) || ((boot_cpu_data.x86_vendor == X86_VENDOR_AMD) && (boot_cpu_data.x86 >= 0xF))) { init_udelay = 0; return; } /* else, use legacy delay */ init_udelay = UDELAY_10MS_DEFAULT; } /* * Wake up AP by INIT, INIT, STARTUP sequence. */ static void send_init_sequence(u32 phys_apicid) { int maxlvt = lapic_get_maxlvt(); /* Be paranoid about clearing APIC errors. */ if (APIC_INTEGRATED(boot_cpu_apic_version)) { /* Due to the Pentium erratum 3AP. */ if (maxlvt > 3) apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } /* Assert INIT on the target CPU */ apic_icr_write(APIC_INT_LEVELTRIG | APIC_INT_ASSERT | APIC_DM_INIT, phys_apicid); safe_apic_wait_icr_idle(); udelay(init_udelay); /* Deassert INIT on the target CPU */ apic_icr_write(APIC_INT_LEVELTRIG | APIC_DM_INIT, phys_apicid); safe_apic_wait_icr_idle(); } /* * Wake up AP by INIT, INIT, STARTUP sequence. */ static int wakeup_secondary_cpu_via_init(u32 phys_apicid, unsigned long start_eip) { unsigned long send_status = 0, accept_status = 0; int num_starts, j, maxlvt; preempt_disable(); maxlvt = lapic_get_maxlvt(); send_init_sequence(phys_apicid); mb(); /* * 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(boot_cpu_apic_version)) num_starts = 2; else num_starts = 0; /* * 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. */ if (init_udelay == 0) udelay(10); else 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. */ if (init_udelay == 0) udelay(10); else 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) pr_err("APIC never delivered???\n"); if (accept_status) pr_err("APIC delivery error (%lx)\n", accept_status); preempt_enable(); return (send_status | accept_status); } /* reduce the number of lines printed when booting a large cpu count system */ static void announce_cpu(int cpu, int apicid) { static int width, node_width, first = 1; static int current_node = NUMA_NO_NODE; int node = early_cpu_to_node(cpu); if (!width) width = num_digits(num_possible_cpus()) + 1; /* + '#' sign */ if (!node_width) node_width = num_digits(num_possible_nodes()) + 1; /* + '#' */ if (system_state < SYSTEM_RUNNING) { if (first) pr_info("x86: Booting SMP configuration:\n"); if (node != current_node) { if (current_node > (-1)) pr_cont("\n"); current_node = node; printk(KERN_INFO ".... node %*s#%d, CPUs: ", node_width - num_digits(node), " ", node); } /* Add padding for the BSP */ if (first) pr_cont("%*s", width + 1, " "); first = 0; pr_cont("%*s#%d", width - num_digits(cpu), " ", cpu); } else pr_info("Booting Node %d Processor %d APIC 0x%x\n", node, cpu, apicid); } int common_cpu_up(unsigned int cpu, struct task_struct *idle) { int ret; /* Just in case we booted with a single CPU. */ alternatives_enable_smp(); per_cpu(pcpu_hot.current_task, cpu) = idle; cpu_init_stack_canary(cpu, idle); /* Initialize the interrupt stack(s) */ ret = irq_init_percpu_irqstack(cpu); if (ret) return ret; #ifdef CONFIG_X86_32 /* Stack for startup_32 can be just as for start_secondary onwards */ per_cpu(pcpu_hot.top_of_stack, cpu) = task_top_of_stack(idle); #endif return 0; } /* * 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 startup was successfully sent, else error code from * ->wakeup_secondary_cpu. */ static int do_boot_cpu(u32 apicid, int cpu, struct task_struct *idle) { unsigned long start_ip = real_mode_header->trampoline_start; int ret; #ifdef CONFIG_X86_64 /* If 64-bit wakeup method exists, use the 64-bit mode trampoline IP */ if (apic->wakeup_secondary_cpu_64) start_ip = real_mode_header->trampoline_start64; #endif idle->thread.sp = (unsigned long)task_pt_regs(idle); initial_code = (unsigned long)start_secondary; if (IS_ENABLED(CONFIG_X86_32)) { early_gdt_descr.address = (unsigned long)get_cpu_gdt_rw(cpu); initial_stack = idle->thread.sp; } else if (!(smpboot_control & STARTUP_PARALLEL_MASK)) { smpboot_control = cpu; } /* Enable the espfix hack for this CPU */ init_espfix_ap(cpu); /* So we see what's up */ announce_cpu(cpu, apicid); /* * This grunge runs the startup process for * the targeted processor. */ if (x86_platform.legacy.warm_reset) { 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(boot_cpu_apic_version)) { apic_write(APIC_ESR, 0); apic_read(APIC_ESR); } } smp_mb(); /* * Wake up a CPU in difference cases: * - Use a method from the APIC driver if one defined, with wakeup * straight to 64-bit mode preferred over wakeup to RM. * Otherwise, * - Use an INIT boot APIC message */ if (apic->wakeup_secondary_cpu_64) ret = apic->wakeup_secondary_cpu_64(apicid, start_ip); else if (apic->wakeup_secondary_cpu) ret = apic->wakeup_secondary_cpu(apicid, start_ip); else ret = wakeup_secondary_cpu_via_init(apicid, start_ip); /* If the wakeup mechanism failed, cleanup the warm reset vector */ if (ret) arch_cpuhp_cleanup_kick_cpu(cpu); return ret; } int native_kick_ap(unsigned int cpu, struct task_struct *tidle) { u32 apicid = apic->cpu_present_to_apicid(cpu); int err; lockdep_assert_irqs_enabled(); pr_debug("++++++++++++++++++++=_---CPU UP %u\n", cpu); if (apicid == BAD_APICID || !apic_id_valid(apicid)) { pr_err("CPU %u has invalid APIC ID %x. Aborting bringup\n", cpu, apicid); return -EINVAL; } if (!test_bit(apicid, phys_cpu_present_map)) { pr_err("CPU %u APIC ID %x is not present. Aborting bringup\n", cpu, apicid); return -EINVAL; } /* * 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(); /* the FPU context is blank, nobody can own it */ per_cpu(fpu_fpregs_owner_ctx, cpu) = NULL; err = common_cpu_up(cpu, tidle); if (err) return err; err = do_boot_cpu(apicid, cpu, tidle); if (err) pr_err("do_boot_cpu failed(%d) to wakeup CPU#%u\n", err, cpu); return err; } int arch_cpuhp_kick_ap_alive(unsigned int cpu, struct task_struct *tidle) { return smp_ops.kick_ap_alive(cpu, tidle); } void arch_cpuhp_cleanup_kick_cpu(unsigned int cpu) { /* Cleanup possible dangling ends... */ if (smp_ops.kick_ap_alive == native_kick_ap && x86_platform.legacy.warm_reset) smpboot_restore_warm_reset_vector(); } void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) { if (smp_ops.cleanup_dead_cpu) smp_ops.cleanup_dead_cpu(cpu); if (system_state == SYSTEM_RUNNING) pr_info("CPU %u is now offline\n", cpu); } void arch_cpuhp_sync_state_poll(void) { if (smp_ops.poll_sync_state) smp_ops.poll_sync_state(); } /** * arch_disable_smp_support() - Disables SMP support for x86 at boottime */ void __init 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) { pr_info("SMP disabled\n"); disable_ioapic_support(); topology_reset_possible_cpus_up(); cpumask_set_cpu(0, topology_sibling_cpumask(0)); cpumask_set_cpu(0, topology_core_cpumask(0)); cpumask_set_cpu(0, topology_die_cpumask(0)); } void __init smp_prepare_cpus_common(void) { unsigned int i; /* Mark all except the boot CPU as hotpluggable */ for_each_possible_cpu(i) { if (i) per_cpu(cpu_info.cpu_index, i) = nr_cpu_ids; } 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_die_map, i), GFP_KERNEL); zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL); zalloc_cpumask_var(&per_cpu(cpu_l2c_shared_map, i), GFP_KERNEL); } set_cpu_sibling_map(0); } void __init smp_prepare_boot_cpu(void) { smp_ops.smp_prepare_boot_cpu(); } #ifdef CONFIG_X86_64 /* Establish whether parallel bringup can be supported. */ bool __init arch_cpuhp_init_parallel_bringup(void) { if (!x86_cpuinit.parallel_bringup) { pr_info("Parallel CPU startup disabled by the platform\n"); return false; } smpboot_control = STARTUP_READ_APICID; pr_debug("Parallel CPU startup enabled: 0x%08x\n", smpboot_control); return true; } #endif /* * Prepare for SMP bootup. * @max_cpus: configured maximum number of CPUs, It is a legacy parameter * for common interface support. */ void __init native_smp_prepare_cpus(unsigned int max_cpus) { smp_prepare_cpus_common(); switch (apic_intr_mode) { case APIC_PIC: case APIC_VIRTUAL_WIRE_NO_CONFIG: disable_smp(); return; case APIC_SYMMETRIC_IO_NO_ROUTING: disable_smp(); /* Setup local timer */ x86_init.timers.setup_percpu_clockev(); return; case APIC_VIRTUAL_WIRE: case APIC_SYMMETRIC_IO: break; } /* Setup local timer */ x86_init.timers.setup_percpu_clockev(); pr_info("CPU0: "); print_cpu_info(&cpu_data(0)); uv_system_init(); smp_quirk_init_udelay(); speculative_store_bypass_ht_init(); snp_set_wakeup_secondary_cpu(); } void arch_thaw_secondary_cpus_begin(void) { set_cache_aps_delayed_init(true); } void arch_thaw_secondary_cpus_end(void) { cache_aps_init(); } /* * Early setup to make printk work. */ void __init native_smp_prepare_boot_cpu(void) { int me = smp_processor_id(); /* SMP handles this from setup_per_cpu_areas() */ if (!IS_ENABLED(CONFIG_SMP)) switch_gdt_and_percpu_base(me); native_pv_lock_init(); } void __init native_smp_cpus_done(unsigned int max_cpus) { pr_debug("Boot done\n"); build_sched_topology(); nmi_selftest(); impress_friends(); cache_aps_init(); } /* correctly size the local cpu masks */ void __init setup_cpu_local_masks(void) { alloc_bootmem_cpumask_var(&cpu_sibling_setup_mask); } #ifdef CONFIG_HOTPLUG_CPU /* Recompute SMT state for all CPUs on offline */ static void recompute_smt_state(void) { int max_threads, cpu; max_threads = 0; for_each_online_cpu (cpu) { int threads = cpumask_weight(topology_sibling_cpumask(cpu)); if (threads > max_threads) max_threads = threads; } __max_smt_threads = max_threads; } static void remove_siblinginfo(int cpu) { int sibling; struct cpuinfo_x86 *c = &cpu_data(cpu); for_each_cpu(sibling, topology_core_cpumask(cpu)) { cpumask_clear_cpu(cpu, topology_core_cpumask(sibling)); /*/ * last thread sibling in this cpu core going down */ if (cpumask_weight(topology_sibling_cpumask(cpu)) == 1) cpu_data(sibling).booted_cores--; } for_each_cpu(sibling, topology_die_cpumask(cpu)) cpumask_clear_cpu(cpu, topology_die_cpumask(sibling)); for_each_cpu(sibling, topology_sibling_cpumask(cpu)) { cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling)); if (cpumask_weight(topology_sibling_cpumask(sibling)) == 1) cpu_data(sibling).smt_active = false; } for_each_cpu(sibling, cpu_llc_shared_mask(cpu)) cpumask_clear_cpu(cpu, cpu_llc_shared_mask(sibling)); for_each_cpu(sibling, cpu_l2c_shared_mask(cpu)) cpumask_clear_cpu(cpu, cpu_l2c_shared_mask(sibling)); cpumask_clear(cpu_llc_shared_mask(cpu)); cpumask_clear(cpu_l2c_shared_mask(cpu)); cpumask_clear(topology_sibling_cpumask(cpu)); cpumask_clear(topology_core_cpumask(cpu)); cpumask_clear(topology_die_cpumask(cpu)); c->topo.core_id = 0; c->booted_cores = 0; cpumask_clear_cpu(cpu, cpu_sibling_setup_mask); recompute_smt_state(); } static void remove_cpu_from_maps(int cpu) { set_cpu_online(cpu, false); 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(); lapic_offline(); } int native_cpu_disable(void) { int ret; ret = lapic_can_unplug_cpu(); if (ret) return ret; cpu_disable_common(); /* * Disable the local APIC. Otherwise IPI broadcasts will reach * it. It still responds normally to INIT, NMI, SMI, and SIPI * messages. * * Disabling the APIC must happen after cpu_disable_common() * which invokes fixup_irqs(). * * Disabling the APIC preserves already set bits in IRR, but * an interrupt arriving after disabling the local APIC does not * set the corresponding IRR bit. * * fixup_irqs() scans IRR for set bits so it can raise a not * yet handled interrupt on the new destination CPU via an IPI * but obviously it can't do so for IRR bits which are not set. * IOW, interrupts arriving after disabling the local APIC will * be lost. */ apic_soft_disable(); return 0; } void play_dead_common(void) { idle_task_exit(); cpuhp_ap_report_dead(); 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) { struct mwait_cpu_dead *md = this_cpu_ptr(&mwait_cpu_dead); unsigned int eax, ebx, ecx, edx; unsigned int highest_cstate = 0; unsigned int highest_subcstate = 0; int i; if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD || boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) return; if (!this_cpu_has(X86_FEATURE_MWAIT)) return; if (!this_cpu_has(X86_FEATURE_CLFLUSH)) 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); } /* Set up state for the kexec() hack below */ md->status = CPUDEAD_MWAIT_WAIT; md->control = CPUDEAD_MWAIT_WAIT; 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. */ mb(); clflush(md); mb(); __monitor(md, 0, 0); mb(); __mwait(eax, 0); if (READ_ONCE(md->control) == CPUDEAD_MWAIT_KEXEC_HLT) { /* * Kexec is about to happen. Don't go back into mwait() as * the kexec kernel might overwrite text and data including * page tables and stack. So mwait() would resume when the * monitor cache line is written to and then the CPU goes * south due to overwritten text, page tables and stack. * * Note: This does _NOT_ protect against a stray MCE, NMI, * SMI. They will resume execution at the instruction * following the HLT instruction and run into the problem * which this is trying to prevent. */ WRITE_ONCE(md->status, CPUDEAD_MWAIT_KEXEC_HLT); while(1) native_halt(); } } } /* * Kick all "offline" CPUs out of mwait on kexec(). See comment in * mwait_play_dead(). */ void smp_kick_mwait_play_dead(void) { u32 newstate = CPUDEAD_MWAIT_KEXEC_HLT; struct mwait_cpu_dead *md; unsigned int cpu, i; for_each_cpu_andnot(cpu, cpu_present_mask, cpu_online_mask) { md = per_cpu_ptr(&mwait_cpu_dead, cpu); /* Does it sit in mwait_play_dead() ? */ if (READ_ONCE(md->status) != CPUDEAD_MWAIT_WAIT) continue; /* Wait up to 5ms */ for (i = 0; READ_ONCE(md->status) != newstate && i < 1000; i++) { /* Bring it out of mwait */ WRITE_ONCE(md->control, newstate); udelay(5); } if (READ_ONCE(md->status) != newstate) pr_err_once("CPU%u is stuck in mwait_play_dead()\n", cpu); } } void __noreturn hlt_play_dead(void) { if (__this_cpu_read(cpu_info.x86) >= 4) wbinvd(); while (1) native_halt(); } /* * native_play_dead() is essentially a __noreturn function, but it can't * be marked as such as the compiler may complain about it. */ void native_play_dead(void) { if (cpu_feature_enabled(X86_FEATURE_KERNEL_IBRS)) __update_spec_ctrl(0); play_dead_common(); tboot_shutdown(TB_SHUTDOWN_WFS); mwait_play_dead(); if (cpuidle_play_dead()) hlt_play_dead(); } #else /* ... !CONFIG_HOTPLUG_CPU */ int native_cpu_disable(void) { return -ENOSYS; } void native_play_dead(void) { BUG(); } #endif