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 static DECLARE_COMPLETION(cpu_running); 43 44 void __init smp_prepare_cpus(unsigned int max_cpus) 45 { 46 int cpuid; 47 unsigned int curr_cpuid; 48 49 init_cpu_topology(); 50 51 curr_cpuid = smp_processor_id(); 52 store_cpu_topology(curr_cpuid); 53 numa_store_cpu_info(curr_cpuid); 54 numa_add_cpu(curr_cpuid); 55 56 /* This covers non-smp usecase mandated by "nosmp" option */ 57 if (max_cpus == 0) 58 return; 59 60 for_each_possible_cpu(cpuid) { 61 if (cpuid == curr_cpuid) 62 continue; 63 set_cpu_present(cpuid, true); 64 numa_store_cpu_info(cpuid); 65 } 66 } 67 68 #ifdef CONFIG_ACPI 69 static unsigned int cpu_count = 1; 70 71 static int __init acpi_parse_rintc(union acpi_subtable_headers *header, const unsigned long end) 72 { 73 unsigned long hart; 74 static bool found_boot_cpu; 75 struct acpi_madt_rintc *processor = (struct acpi_madt_rintc *)header; 76 77 /* 78 * Each RINTC structure in MADT will have a flag. If ACPI_MADT_ENABLED 79 * bit in the flag is not enabled, it means OS should not try to enable 80 * the cpu to which RINTC belongs. 81 */ 82 if (!(processor->flags & ACPI_MADT_ENABLED)) 83 return 0; 84 85 if (BAD_MADT_ENTRY(processor, end)) 86 return -EINVAL; 87 88 acpi_table_print_madt_entry(&header->common); 89 90 hart = processor->hart_id; 91 if (hart == INVALID_HARTID) { 92 pr_warn("Invalid hartid\n"); 93 return 0; 94 } 95 96 if (hart == cpuid_to_hartid_map(0)) { 97 BUG_ON(found_boot_cpu); 98 found_boot_cpu = true; 99 return 0; 100 } 101 102 if (cpu_count >= NR_CPUS) { 103 pr_warn("NR_CPUS is too small for the number of ACPI tables.\n"); 104 return 0; 105 } 106 107 cpuid_to_hartid_map(cpu_count) = hart; 108 cpu_count++; 109 110 return 0; 111 } 112 113 static void __init acpi_parse_and_init_cpus(void) 114 { 115 acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_rintc, 0); 116 } 117 #else 118 #define acpi_parse_and_init_cpus(...) do { } while (0) 119 #endif 120 121 static void __init of_parse_and_init_cpus(void) 122 { 123 struct device_node *dn; 124 unsigned long hart; 125 bool found_boot_cpu = false; 126 int cpuid = 1; 127 int rc; 128 129 for_each_of_cpu_node(dn) { 130 rc = riscv_early_of_processor_hartid(dn, &hart); 131 if (rc < 0) 132 continue; 133 134 if (hart == cpuid_to_hartid_map(0)) { 135 BUG_ON(found_boot_cpu); 136 found_boot_cpu = 1; 137 early_map_cpu_to_node(0, of_node_to_nid(dn)); 138 continue; 139 } 140 if (cpuid >= NR_CPUS) { 141 pr_warn("Invalid cpuid [%d] for hartid [%lu]\n", 142 cpuid, hart); 143 continue; 144 } 145 146 cpuid_to_hartid_map(cpuid) = hart; 147 early_map_cpu_to_node(cpuid, of_node_to_nid(dn)); 148 cpuid++; 149 } 150 151 BUG_ON(!found_boot_cpu); 152 153 if (cpuid > nr_cpu_ids) 154 pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n", 155 cpuid, nr_cpu_ids); 156 } 157 158 void __init setup_smp(void) 159 { 160 int cpuid; 161 162 cpu_set_ops(); 163 164 if (acpi_disabled) 165 of_parse_and_init_cpus(); 166 else 167 acpi_parse_and_init_cpus(); 168 169 for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) 170 if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) 171 set_cpu_possible(cpuid, true); 172 } 173 174 static int start_secondary_cpu(int cpu, struct task_struct *tidle) 175 { 176 if (cpu_ops->cpu_start) 177 return cpu_ops->cpu_start(cpu, tidle); 178 179 return -EOPNOTSUPP; 180 } 181 182 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 183 { 184 int ret = 0; 185 tidle->thread_info.cpu = cpu; 186 187 ret = start_secondary_cpu(cpu, tidle); 188 if (!ret) { 189 wait_for_completion_timeout(&cpu_running, 190 msecs_to_jiffies(1000)); 191 192 if (!cpu_online(cpu)) { 193 pr_crit("CPU%u: failed to come online\n", cpu); 194 ret = -EIO; 195 } 196 } else { 197 pr_crit("CPU%u: failed to start\n", cpu); 198 } 199 200 return ret; 201 } 202 203 void __init smp_cpus_done(unsigned int max_cpus) 204 { 205 } 206 207 /* 208 * C entry point for a secondary processor. 209 */ 210 asmlinkage __visible void smp_callin(void) 211 { 212 struct mm_struct *mm = &init_mm; 213 unsigned int curr_cpuid = smp_processor_id(); 214 215 if (has_vector()) { 216 /* 217 * Return as early as possible so the hart with a mismatching 218 * vlen won't boot. 219 */ 220 if (riscv_v_setup_vsize()) 221 return; 222 } 223 224 /* All kernel threads share the same mm context. */ 225 mmgrab(mm); 226 current->active_mm = mm; 227 228 store_cpu_topology(curr_cpuid); 229 notify_cpu_starting(curr_cpuid); 230 231 riscv_ipi_enable(); 232 233 numa_add_cpu(curr_cpuid); 234 set_cpu_online(curr_cpuid, true); 235 236 riscv_user_isa_enable(); 237 238 /* 239 * Remote cache and TLB flushes are ignored while the CPU is offline, 240 * so flush them both right now just in case. 241 */ 242 local_flush_icache_all(); 243 local_flush_tlb_all(); 244 complete(&cpu_running); 245 /* 246 * Disable preemption before enabling interrupts, so we don't try to 247 * schedule a CPU that hasn't actually started yet. 248 */ 249 local_irq_enable(); 250 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 251 } 252