1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 2020 Western Digital Corporation or its affiliates. 4 */ 5 6 #include <linux/kernel.h> 7 #include <linux/mm.h> 8 #include <linux/sched.h> 9 #include <linux/err.h> 10 #include <linux/irq.h> 11 #include <linux/cpuhotplug.h> 12 #include <linux/cpu.h> 13 #include <linux/sched/hotplug.h> 14 #include <asm/irq.h> 15 #include <asm/cpu_ops.h> 16 #include <asm/numa.h> 17 #include <asm/smp.h> 18 19 bool cpu_has_hotplug(unsigned int cpu) 20 { 21 if (cpu_ops[cpu]->cpu_stop) 22 return true; 23 24 return false; 25 } 26 27 /* 28 * __cpu_disable runs on the processor to be shutdown. 29 */ 30 int __cpu_disable(void) 31 { 32 int ret = 0; 33 unsigned int cpu = smp_processor_id(); 34 35 if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop) 36 return -EOPNOTSUPP; 37 38 if (cpu_ops[cpu]->cpu_disable) 39 ret = cpu_ops[cpu]->cpu_disable(cpu); 40 41 if (ret) 42 return ret; 43 44 remove_cpu_topology(cpu); 45 numa_remove_cpu(cpu); 46 set_cpu_online(cpu, false); 47 riscv_ipi_disable(); 48 irq_migrate_all_off_this_cpu(); 49 50 return ret; 51 } 52 53 #ifdef CONFIG_HOTPLUG_CPU 54 /* 55 * Called on the thread which is asking for a CPU to be shutdown, if the 56 * CPU reported dead to the hotplug core. 57 */ 58 void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) 59 { 60 int ret = 0; 61 62 pr_notice("CPU%u: off\n", cpu); 63 64 /* Verify from the firmware if the cpu is really stopped*/ 65 if (cpu_ops[cpu]->cpu_is_stopped) 66 ret = cpu_ops[cpu]->cpu_is_stopped(cpu); 67 if (ret) 68 pr_warn("CPU%u may not have stopped: %d\n", cpu, ret); 69 } 70 71 /* 72 * Called from the idle thread for the CPU which has been shutdown. 73 */ 74 void __noreturn arch_cpu_idle_dead(void) 75 { 76 idle_task_exit(); 77 78 cpuhp_ap_report_dead(); 79 80 cpu_ops[smp_processor_id()]->cpu_stop(); 81 /* It should never reach here */ 82 BUG(); 83 } 84 #endif 85