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/cacheflush.h> 30 #include <asm/cpu_ops.h> 31 #include <asm/irq.h> 32 #include <asm/mmu_context.h> 33 #include <asm/numa.h> 34 #include <asm/tlbflush.h> 35 #include <asm/sections.h> 36 #include <asm/smp.h> 37 #include <uapi/asm/hwcap.h> 38 #include <asm/vector.h> 39 40 #include "head.h" 41 42 #ifndef CONFIG_HOTPLUG_PARALLEL 43 static DECLARE_COMPLETION(cpu_running); 44 #endif 45 46 void __init smp_prepare_cpus(unsigned int max_cpus) 47 { 48 int cpuid; 49 unsigned int curr_cpuid; 50 51 init_cpu_topology(); 52 53 curr_cpuid = smp_processor_id(); 54 store_cpu_topology(curr_cpuid); 55 numa_store_cpu_info(curr_cpuid); 56 numa_add_cpu(curr_cpuid); 57 58 /* This covers non-smp usecase mandated by "nosmp" option */ 59 if (max_cpus == 0) 60 return; 61 62 for_each_possible_cpu(cpuid) { 63 if (cpuid == curr_cpuid) 64 continue; 65 set_cpu_present(cpuid, true); 66 numa_store_cpu_info(cpuid); 67 } 68 } 69 70 #ifdef CONFIG_ACPI 71 static unsigned int cpu_count = 1; 72 73 static int __init acpi_parse_rintc(union acpi_subtable_headers *header, const unsigned long end) 74 { 75 unsigned long hart; 76 static bool found_boot_cpu; 77 struct acpi_madt_rintc *processor = (struct acpi_madt_rintc *)header; 78 79 /* 80 * Each RINTC structure in MADT will have a flag. If ACPI_MADT_ENABLED 81 * bit in the flag is not enabled, it means OS should not try to enable 82 * the cpu to which RINTC belongs. 83 */ 84 if (!(processor->flags & ACPI_MADT_ENABLED)) 85 return 0; 86 87 if (BAD_MADT_ENTRY(processor, end)) 88 return -EINVAL; 89 90 acpi_table_print_madt_entry(&header->common); 91 92 hart = processor->hart_id; 93 if (hart == INVALID_HARTID) { 94 pr_warn("Invalid hartid\n"); 95 return 0; 96 } 97 98 if (hart == cpuid_to_hartid_map(0)) { 99 BUG_ON(found_boot_cpu); 100 found_boot_cpu = true; 101 return 0; 102 } 103 104 if (cpu_count >= NR_CPUS) { 105 pr_warn("NR_CPUS is too small for the number of ACPI tables.\n"); 106 return 0; 107 } 108 109 cpuid_to_hartid_map(cpu_count) = hart; 110 cpu_count++; 111 112 return 0; 113 } 114 115 static void __init acpi_parse_and_init_cpus(void) 116 { 117 acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_rintc, 0); 118 } 119 #else 120 #define acpi_parse_and_init_cpus(...) do { } while (0) 121 #endif 122 123 static void __init of_parse_and_init_cpus(void) 124 { 125 struct device_node *dn; 126 unsigned long hart; 127 bool found_boot_cpu = false; 128 int cpuid = 1; 129 int rc; 130 131 for_each_of_cpu_node(dn) { 132 rc = riscv_early_of_processor_hartid(dn, &hart); 133 if (rc < 0) 134 continue; 135 136 if (hart == cpuid_to_hartid_map(0)) { 137 BUG_ON(found_boot_cpu); 138 found_boot_cpu = 1; 139 early_map_cpu_to_node(0, of_node_to_nid(dn)); 140 continue; 141 } 142 if (cpuid >= NR_CPUS) { 143 pr_warn("Invalid cpuid [%d] for hartid [%lu]\n", 144 cpuid, hart); 145 continue; 146 } 147 148 cpuid_to_hartid_map(cpuid) = hart; 149 early_map_cpu_to_node(cpuid, of_node_to_nid(dn)); 150 cpuid++; 151 } 152 153 BUG_ON(!found_boot_cpu); 154 155 if (cpuid > nr_cpu_ids) 156 pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n", 157 cpuid, nr_cpu_ids); 158 } 159 160 void __init setup_smp(void) 161 { 162 int cpuid; 163 164 cpu_set_ops(); 165 166 if (acpi_disabled) 167 of_parse_and_init_cpus(); 168 else 169 acpi_parse_and_init_cpus(); 170 171 for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) 172 if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) 173 set_cpu_possible(cpuid, true); 174 } 175 176 static int start_secondary_cpu(int cpu, struct task_struct *tidle) 177 { 178 if (cpu_ops->cpu_start) 179 return cpu_ops->cpu_start(cpu, tidle); 180 181 return -EOPNOTSUPP; 182 } 183 184 #ifdef CONFIG_HOTPLUG_PARALLEL 185 int arch_cpuhp_kick_ap_alive(unsigned int cpu, struct task_struct *tidle) 186 { 187 return start_secondary_cpu(cpu, tidle); 188 } 189 #else 190 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 191 { 192 int ret; 193 tidle->thread_info.cpu = cpu; 194 195 ret = start_secondary_cpu(cpu, tidle); 196 if (!ret) { 197 wait_for_completion_timeout(&cpu_running, secs_to_jiffies(1)); 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 #endif 210 211 void __init smp_cpus_done(unsigned int max_cpus) 212 { 213 } 214 215 /* 216 * C entry point for a secondary processor. 217 */ 218 asmlinkage __visible void smp_callin(void) 219 { 220 struct mm_struct *mm = &init_mm; 221 unsigned int curr_cpuid = smp_processor_id(); 222 223 if (has_vector()) { 224 /* 225 * Return as early as possible so the hart with a mismatching 226 * vlen won't boot. 227 */ 228 if (riscv_v_setup_vsize()) 229 return; 230 } 231 232 /* All kernel threads share the same mm context. */ 233 mmgrab(mm); 234 current->active_mm = mm; 235 236 #ifdef CONFIG_HOTPLUG_PARALLEL 237 cpuhp_ap_sync_alive(); 238 #endif 239 240 store_cpu_topology(curr_cpuid); 241 notify_cpu_starting(curr_cpuid); 242 243 riscv_ipi_enable(); 244 245 numa_add_cpu(curr_cpuid); 246 247 pr_debug("CPU%u: Booted secondary hartid %lu\n", curr_cpuid, 248 cpuid_to_hartid_map(curr_cpuid)); 249 250 set_cpu_online(curr_cpuid, true); 251 252 /* 253 * Remote instruction cache and TLB flushes are ignored while the CPU 254 * is offline, so flush them both right now just in case. 255 */ 256 local_flush_icache_all(); 257 local_flush_tlb_all(); 258 #ifndef CONFIG_HOTPLUG_PARALLEL 259 complete(&cpu_running); 260 #endif 261 local_irq_enable(); 262 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 263 } 264