| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * SMP initialisation and IPI support |
| * Based on arch/arm64/kernel/smp.c |
| * |
| * Copyright (C) 2012 ARM Ltd. |
| * Copyright (C) 2015 Regents of the University of California |
| * Copyright (C) 2017 SiFive |
| */ |
| |
| #include <linux/arch_topology.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/kernel.h> |
| #include <linux/mm.h> |
| #include <linux/sched.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/notifier.h> |
| #include <linux/cpu.h> |
| #include <linux/percpu.h> |
| #include <linux/delay.h> |
| #include <linux/err.h> |
| #include <linux/irq.h> |
| #include <linux/of.h> |
| #include <linux/sched/task_stack.h> |
| #include <linux/sched/mm.h> |
| #include <asm/cpu_ops.h> |
| #include <asm/irq.h> |
| #include <asm/mmu_context.h> |
| #include <asm/numa.h> |
| #include <asm/tlbflush.h> |
| #include <asm/sections.h> |
| #include <asm/sbi.h> |
| #include <asm/smp.h> |
| #include <asm/alternative.h> |
| |
| #include "head.h" |
| |
| static DECLARE_COMPLETION(cpu_running); |
| |
| void __init smp_prepare_boot_cpu(void) |
| { |
| init_cpu_topology(); |
| #ifdef CONFIG_RISCV_ERRATA_ALTERNATIVE |
| apply_boot_alternatives(); |
| #endif |
| } |
| |
| void __init smp_prepare_cpus(unsigned int max_cpus) |
| { |
| int cpuid; |
| int ret; |
| unsigned int curr_cpuid; |
| |
| curr_cpuid = smp_processor_id(); |
| numa_store_cpu_info(curr_cpuid); |
| numa_add_cpu(curr_cpuid); |
| |
| /* This covers non-smp usecase mandated by "nosmp" option */ |
| if (max_cpus == 0) |
| return; |
| |
| for_each_possible_cpu(cpuid) { |
| if (cpuid == curr_cpuid) |
| continue; |
| if (cpu_ops[cpuid]->cpu_prepare) { |
| ret = cpu_ops[cpuid]->cpu_prepare(cpuid); |
| if (ret) |
| continue; |
| } |
| set_cpu_present(cpuid, true); |
| numa_store_cpu_info(cpuid); |
| } |
| } |
| |
| void __init setup_smp(void) |
| { |
| struct device_node *dn; |
| int hart; |
| bool found_boot_cpu = false; |
| int cpuid = 1; |
| |
| cpu_set_ops(0); |
| |
| for_each_of_cpu_node(dn) { |
| hart = riscv_of_processor_hartid(dn); |
| if (hart < 0) |
| continue; |
| |
| if (hart == cpuid_to_hartid_map(0)) { |
| BUG_ON(found_boot_cpu); |
| found_boot_cpu = 1; |
| early_map_cpu_to_node(0, of_node_to_nid(dn)); |
| continue; |
| } |
| if (cpuid >= NR_CPUS) { |
| pr_warn("Invalid cpuid [%d] for hartid [%d]\n", |
| cpuid, hart); |
| break; |
| } |
| |
| cpuid_to_hartid_map(cpuid) = hart; |
| early_map_cpu_to_node(cpuid, of_node_to_nid(dn)); |
| cpuid++; |
| } |
| |
| BUG_ON(!found_boot_cpu); |
| |
| if (cpuid > nr_cpu_ids) |
| pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n", |
| cpuid, nr_cpu_ids); |
| |
| for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) { |
| if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) { |
| cpu_set_ops(cpuid); |
| set_cpu_possible(cpuid, true); |
| } |
| } |
| } |
| |
| static int start_secondary_cpu(int cpu, struct task_struct *tidle) |
| { |
| if (cpu_ops[cpu]->cpu_start) |
| return cpu_ops[cpu]->cpu_start(cpu, tidle); |
| |
| return -EOPNOTSUPP; |
| } |
| |
| int __cpu_up(unsigned int cpu, struct task_struct *tidle) |
| { |
| int ret = 0; |
| tidle->thread_info.cpu = cpu; |
| |
| ret = start_secondary_cpu(cpu, tidle); |
| if (!ret) { |
| wait_for_completion_timeout(&cpu_running, |
| msecs_to_jiffies(1000)); |
| |
| if (!cpu_online(cpu)) { |
| pr_crit("CPU%u: failed to come online\n", cpu); |
| ret = -EIO; |
| } |
| } else { |
| pr_crit("CPU%u: failed to start\n", cpu); |
| } |
| |
| return ret; |
| } |
| |
| void __init smp_cpus_done(unsigned int max_cpus) |
| { |
| } |
| |
| /* |
| * C entry point for a secondary processor. |
| */ |
| asmlinkage __visible void smp_callin(void) |
| { |
| struct mm_struct *mm = &init_mm; |
| unsigned int curr_cpuid = smp_processor_id(); |
| |
| riscv_clear_ipi(); |
| |
| /* All kernel threads share the same mm context. */ |
| mmgrab(mm); |
| current->active_mm = mm; |
| |
| notify_cpu_starting(curr_cpuid); |
| numa_add_cpu(curr_cpuid); |
| update_siblings_masks(curr_cpuid); |
| set_cpu_online(curr_cpuid, 1); |
| |
| /* |
| * Remote TLB flushes are ignored while the CPU is offline, so emit |
| * a local TLB flush right now just in case. |
| */ |
| local_flush_tlb_all(); |
| complete(&cpu_running); |
| /* |
| * Disable preemption before enabling interrupts, so we don't try to |
| * schedule a CPU that hasn't actually started yet. |
| */ |
| preempt_disable(); |
| local_irq_enable(); |
| cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); |
| } |