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_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 unsigned int cpu = smp_processor_id(); 33 34 if (!cpu_ops->cpu_stop) 35 return -EOPNOTSUPP; 36 37 remove_cpu_topology(cpu); 38 numa_remove_cpu(cpu); 39 set_cpu_online(cpu, false); 40 riscv_ipi_disable(); 41 irq_migrate_all_off_this_cpu(); 42 43 return 0; 44 } 45 46 #ifdef CONFIG_HOTPLUG_CPU 47 /* 48 * Called on the thread which is asking for a CPU to be shutdown, if the 49 * CPU reported dead to the hotplug core. 50 */ 51 void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) 52 { 53 int ret = 0; 54 55 pr_notice("CPU%u: off\n", cpu); 56 57 /* Verify from the firmware if the cpu is really stopped*/ 58 if (cpu_ops->cpu_is_stopped) 59 ret = cpu_ops->cpu_is_stopped(cpu); 60 if (ret) 61 pr_warn("CPU%d may not have stopped: %d\n", cpu, ret); 62 } 63 64 /* 65 * Called from the idle thread for the CPU which has been shutdown. 66 */ 67 void __noreturn arch_cpu_idle_dead(void) 68 { 69 idle_task_exit(); 70 71 cpuhp_ap_report_dead(); 72 73 cpu_ops->cpu_stop(); 74 /* It should never reach here */ 75 BUG(); 76 } 77 #endif 78