1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * SMP initialisation and IPI support 4 * Based on arch/arm64/kernel/smp.c 5 * 6 * Copyright (C) 2012 ARM Ltd. 7 * Copyright (C) 2015 Regents of the University of California 8 * Copyright (C) 2017 SiFive 9 */ 10 11 #include <linux/acpi.h> 12 #include <linux/arch_topology.h> 13 #include <linux/module.h> 14 #include <linux/init.h> 15 #include <linux/kernel.h> 16 #include <linux/mm.h> 17 #include <linux/sched.h> 18 #include <linux/kernel_stat.h> 19 #include <linux/notifier.h> 20 #include <linux/cpu.h> 21 #include <linux/percpu.h> 22 #include <linux/delay.h> 23 #include <linux/err.h> 24 #include <linux/irq.h> 25 #include <linux/of.h> 26 #include <linux/sched/task_stack.h> 27 #include <linux/sched/mm.h> 28 29 #include <asm/cpufeature.h> 30 #include <asm/cpu_ops.h> 31 #include <asm/cpufeature.h> 32 #include <asm/irq.h> 33 #include <asm/mmu_context.h> 34 #include <asm/numa.h> 35 #include <asm/tlbflush.h> 36 #include <asm/sections.h> 37 #include <asm/smp.h> 38 #include <uapi/asm/hwcap.h> 39 #include <asm/vector.h> 40 41 #include "head.h" 42 43 static DECLARE_COMPLETION(cpu_running); 44 45 void __init smp_prepare_boot_cpu(void) 46 { 47 } 48 49 void __init smp_prepare_cpus(unsigned int max_cpus) 50 { 51 int cpuid; 52 unsigned int curr_cpuid; 53 54 init_cpu_topology(); 55 56 curr_cpuid = smp_processor_id(); 57 store_cpu_topology(curr_cpuid); 58 numa_store_cpu_info(curr_cpuid); 59 numa_add_cpu(curr_cpuid); 60 61 /* This covers non-smp usecase mandated by "nosmp" option */ 62 if (max_cpus == 0) 63 return; 64 65 for_each_possible_cpu(cpuid) { 66 if (cpuid == curr_cpuid) 67 continue; 68 set_cpu_present(cpuid, true); 69 numa_store_cpu_info(cpuid); 70 } 71 } 72 73 #ifdef CONFIG_ACPI 74 static unsigned int cpu_count = 1; 75 76 static int __init acpi_parse_rintc(union acpi_subtable_headers *header, const unsigned long end) 77 { 78 unsigned long hart; 79 static bool found_boot_cpu; 80 struct acpi_madt_rintc *processor = (struct acpi_madt_rintc *)header; 81 82 /* 83 * Each RINTC structure in MADT will have a flag. If ACPI_MADT_ENABLED 84 * bit in the flag is not enabled, it means OS should not try to enable 85 * the cpu to which RINTC belongs. 86 */ 87 if (!(processor->flags & ACPI_MADT_ENABLED)) 88 return 0; 89 90 if (BAD_MADT_ENTRY(processor, end)) 91 return -EINVAL; 92 93 acpi_table_print_madt_entry(&header->common); 94 95 hart = processor->hart_id; 96 if (hart == INVALID_HARTID) { 97 pr_warn("Invalid hartid\n"); 98 return 0; 99 } 100 101 if (hart == cpuid_to_hartid_map(0)) { 102 BUG_ON(found_boot_cpu); 103 found_boot_cpu = true; 104 early_map_cpu_to_node(0, acpi_numa_get_nid(cpu_count)); 105 return 0; 106 } 107 108 if (cpu_count >= NR_CPUS) { 109 pr_warn("NR_CPUS is too small for the number of ACPI tables.\n"); 110 return 0; 111 } 112 113 cpuid_to_hartid_map(cpu_count) = hart; 114 early_map_cpu_to_node(cpu_count, acpi_numa_get_nid(cpu_count)); 115 cpu_count++; 116 117 return 0; 118 } 119 120 static void __init acpi_parse_and_init_cpus(void) 121 { 122 acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_rintc, 0); 123 } 124 #else 125 #define acpi_parse_and_init_cpus(...) do { } while (0) 126 #endif 127 128 static void __init of_parse_and_init_cpus(void) 129 { 130 struct device_node *dn; 131 unsigned long hart; 132 bool found_boot_cpu = false; 133 int cpuid = 1; 134 int rc; 135 136 for_each_of_cpu_node(dn) { 137 rc = riscv_early_of_processor_hartid(dn, &hart); 138 if (rc < 0) 139 continue; 140 141 if (hart == cpuid_to_hartid_map(0)) { 142 BUG_ON(found_boot_cpu); 143 found_boot_cpu = 1; 144 early_map_cpu_to_node(0, of_node_to_nid(dn)); 145 continue; 146 } 147 if (cpuid >= NR_CPUS) { 148 pr_warn("Invalid cpuid [%d] for hartid [%lu]\n", 149 cpuid, hart); 150 continue; 151 } 152 153 cpuid_to_hartid_map(cpuid) = hart; 154 early_map_cpu_to_node(cpuid, of_node_to_nid(dn)); 155 cpuid++; 156 } 157 158 BUG_ON(!found_boot_cpu); 159 160 if (cpuid > nr_cpu_ids) 161 pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n", 162 cpuid, nr_cpu_ids); 163 } 164 165 void __init setup_smp(void) 166 { 167 int cpuid; 168 169 cpu_set_ops(); 170 171 if (acpi_disabled) 172 of_parse_and_init_cpus(); 173 else 174 acpi_parse_and_init_cpus(); 175 176 for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) 177 if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) 178 set_cpu_possible(cpuid, true); 179 } 180 181 static int start_secondary_cpu(int cpu, struct task_struct *tidle) 182 { 183 if (cpu_ops->cpu_start) 184 return cpu_ops->cpu_start(cpu, tidle); 185 186 return -EOPNOTSUPP; 187 } 188 189 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 190 { 191 int ret = 0; 192 tidle->thread_info.cpu = cpu; 193 194 ret = start_secondary_cpu(cpu, tidle); 195 if (!ret) { 196 wait_for_completion_timeout(&cpu_running, 197 msecs_to_jiffies(1000)); 198 199 if (!cpu_online(cpu)) { 200 pr_crit("CPU%u: failed to come online\n", cpu); 201 ret = -EIO; 202 } 203 } else { 204 pr_crit("CPU%u: failed to start\n", cpu); 205 } 206 207 return ret; 208 } 209 210 void __init smp_cpus_done(unsigned int max_cpus) 211 { 212 } 213 214 /* 215 * C entry point for a secondary processor. 216 */ 217 asmlinkage __visible void smp_callin(void) 218 { 219 struct mm_struct *mm = &init_mm; 220 unsigned int curr_cpuid = smp_processor_id(); 221 222 /* All kernel threads share the same mm context. */ 223 mmgrab(mm); 224 current->active_mm = mm; 225 226 store_cpu_topology(curr_cpuid); 227 notify_cpu_starting(curr_cpuid); 228 229 riscv_ipi_enable(); 230 231 numa_add_cpu(curr_cpuid); 232 set_cpu_online(curr_cpuid, 1); 233 234 if (has_vector()) { 235 if (riscv_v_setup_vsize()) 236 elf_hwcap &= ~COMPAT_HWCAP_ISA_V; 237 } 238 239 riscv_user_isa_enable(); 240 241 /* 242 * Remote TLB flushes are ignored while the CPU is offline, so emit 243 * a local TLB flush right now just in case. 244 */ 245 local_flush_tlb_all(); 246 complete(&cpu_running); 247 /* 248 * Disable preemption before enabling interrupts, so we don't try to 249 * schedule a CPU that hasn't actually started yet. 250 */ 251 local_irq_enable(); 252 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 253 } 254