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Diffstat (limited to 'arch/riscv/kernel/smpboot.c')
| -rw-r--r-- | arch/riscv/kernel/smpboot.c | 184 |
1 files changed, 184 insertions, 0 deletions
diff --git a/arch/riscv/kernel/smpboot.c b/arch/riscv/kernel/smpboot.c new file mode 100644 index 000000000..ddb2afba6 --- /dev/null +++ b/arch/riscv/kernel/smpboot.c @@ -0,0 +1,184 @@ +// 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 "head.h" + +static DECLARE_COMPLETION(cpu_running); + +void __init smp_prepare_boot_cpu(void) +{ +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + int cpuid; + int ret; + unsigned int curr_cpuid; + + init_cpu_topology(); + + curr_cpuid = smp_processor_id(); + store_cpu_topology(curr_cpuid); + 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; + unsigned long hart; + bool found_boot_cpu = false; + int cpuid = 1; + int rc; + + cpu_set_ops(0); + + for_each_of_cpu_node(dn) { + rc = riscv_of_processor_hartid(dn, &hart); + if (rc < 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 [%lu]\n", + cpuid, hart); + continue; + } + + 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; + + store_cpu_topology(curr_cpuid); + notify_cpu_starting(curr_cpuid); + numa_add_cpu(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. + */ + local_irq_enable(); + cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); +} |