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/cpu.h> 12 #include <linux/sched/hotplug.h> 13 #include <asm/irq.h> 14 #include <asm/cpu_ops.h> 15 #include <asm/numa.h> 16 #include <asm/smp.h> 17 18 bool cpu_has_hotplug(unsigned int cpu) 19 { 20 if (cpu_ops[cpu]->cpu_stop) 21 return true; 22 23 return false; 24 } 25 26 /* 27 * __cpu_disable runs on the processor to be shutdown. 28 */ 29 int __cpu_disable(void) 30 { 31 int ret = 0; 32 unsigned int cpu = smp_processor_id(); 33 34 if (!cpu_ops[cpu] || !cpu_ops[cpu]->cpu_stop) 35 return -EOPNOTSUPP; 36 37 if (cpu_ops[cpu]->cpu_disable) 38 ret = cpu_ops[cpu]->cpu_disable(cpu); 39 40 if (ret) 41 return ret; 42 43 remove_cpu_topology(cpu); 44 numa_remove_cpu(cpu); 45 set_cpu_online(cpu, false); 46 riscv_ipi_disable(); 47 irq_migrate_all_off_this_cpu(); 48 49 return ret; 50 } 51 52 /* 53 * Called on the thread which is asking for a CPU to be shutdown. 54 */ 55 void __cpu_die(unsigned int cpu) 56 { 57 int ret = 0; 58 59 if (!cpu_wait_death(cpu, 5)) { 60 pr_err("CPU %u: didn't die\n", cpu); 61 return; 62 } 63 pr_notice("CPU%u: off\n", cpu); 64 65 /* Verify from the firmware if the cpu is really stopped*/ 66 if (cpu_ops[cpu]->cpu_is_stopped) 67 ret = cpu_ops[cpu]->cpu_is_stopped(cpu); 68 if (ret) 69 pr_warn("CPU%d may not have stopped: %d\n", cpu, ret); 70 } 71 72 /* 73 * Called from the idle thread for the CPU which has been shutdown. 74 */ 75 void __noreturn arch_cpu_idle_dead(void) 76 { 77 idle_task_exit(); 78 79 (void)cpu_report_death(); 80 81 cpu_ops[smp_processor_id()]->cpu_stop(); 82 /* It should never reach here */ 83 BUG(); 84 } 85