void __init smp_prepare_cpus(unsigned int max_cpus) { int err; unsigned int cpu; unsigned int this_cpu; init_cpu_topology(); this_cpu = smp_processor_id(); store_cpu_topology(this_cpu); numa_store_cpu_info(this_cpu); /* * If UP is mandated by "nosmp" (which implies "maxcpus=0"), don't set * secondary CPUs present. */ if (max_cpus == 0) return; /* * Initialise the present map (which describes the set of CPUs * actually populated at the present time) and release the * secondaries from the bootloader. */ for_each_possible_cpu(cpu) { if (cpu == smp_processor_id()) continue; if (!cpu_ops[cpu]) continue; err = cpu_ops[cpu]->cpu_prepare(cpu); if (err) continue; set_cpu_present(cpu, true); numa_store_cpu_info(cpu); } }
static void __cpuinit smp_store_cpu_info(unsigned int cpuid) { store_cpu_topology(cpuid); }
/* * This is the secondary CPU boot entry. We're using this CPUs * idle thread stack, but a set of temporary page tables. */ asmlinkage void secondary_start_kernel(void) { struct mm_struct *mm = &init_mm; unsigned int cpu = smp_processor_id(); /* * All kernel threads share the same mm context; grab a * reference and switch to it. */ atomic_inc(&mm->mm_count); current->active_mm = mm; set_my_cpu_offset(per_cpu_offset(smp_processor_id())); /* * TTBR0 is only used for the identity mapping at this stage. Make it * point to zero page to avoid speculatively fetching new entries. */ cpu_uninstall_idmap(); preempt_disable(); trace_hardirqs_off(); /* * If the system has established the capabilities, make sure * this CPU ticks all of those. If it doesn't, the CPU will * fail to come online. */ verify_local_cpu_capabilities(); if (cpu_ops[cpu]->cpu_postboot) cpu_ops[cpu]->cpu_postboot(); /* * Log the CPU info before it is marked online and might get read. */ cpuinfo_store_cpu(); /* * Enable GIC and timers. */ notify_cpu_starting(cpu); store_cpu_topology(cpu); /* * OK, now it's safe to let the boot CPU continue. Wait for * the CPU migration code to notice that the CPU is online * before we continue. */ pr_info("CPU%u: Booted secondary processor [%08x]\n", cpu, read_cpuid_id()); update_cpu_boot_status(CPU_BOOT_SUCCESS); set_cpu_online(cpu, true); complete(&cpu_running); local_irq_enable(); local_async_enable(); /* * OK, it's off to the idle thread for us */ cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); }