1 // SPDX-License-Identifier: GPL-2.0 2 3 #include <linux/module.h> 4 #include <linux/init.h> 5 #include <linux/kernel.h> 6 #include <linux/mm.h> 7 #include <linux/sched.h> 8 #include <linux/kernel_stat.h> 9 #include <linux/notifier.h> 10 #include <linux/cpu.h> 11 #include <linux/percpu.h> 12 #include <linux/delay.h> 13 #include <linux/err.h> 14 #include <linux/irq.h> 15 #include <linux/irq_work.h> 16 #include <linux/irqdomain.h> 17 #include <linux/of.h> 18 #include <linux/seq_file.h> 19 #include <linux/sched/task_stack.h> 20 #include <linux/sched/mm.h> 21 #include <linux/sched/hotplug.h> 22 #include <asm/irq.h> 23 #include <asm/traps.h> 24 #include <asm/sections.h> 25 #include <asm/mmu_context.h> 26 #include <asm/pgalloc.h> 27 #ifdef CONFIG_CPU_HAS_FPU 28 #include <abi/fpu.h> 29 #endif 30 31 enum ipi_message_type { 32 IPI_EMPTY, 33 IPI_RESCHEDULE, 34 IPI_CALL_FUNC, 35 IPI_IRQ_WORK, 36 IPI_MAX 37 }; 38 39 struct ipi_data_struct { 40 unsigned long bits ____cacheline_aligned; 41 unsigned long stats[IPI_MAX] ____cacheline_aligned; 42 }; 43 static DEFINE_PER_CPU(struct ipi_data_struct, ipi_data); 44 45 static irqreturn_t handle_ipi(int irq, void *dev) 46 { 47 unsigned long *stats = this_cpu_ptr(&ipi_data)->stats; 48 49 while (true) { 50 unsigned long ops; 51 52 ops = xchg(&this_cpu_ptr(&ipi_data)->bits, 0); 53 if (ops == 0) 54 return IRQ_HANDLED; 55 56 if (ops & (1 << IPI_RESCHEDULE)) { 57 stats[IPI_RESCHEDULE]++; 58 scheduler_ipi(); 59 } 60 61 if (ops & (1 << IPI_CALL_FUNC)) { 62 stats[IPI_CALL_FUNC]++; 63 generic_smp_call_function_interrupt(); 64 } 65 66 if (ops & (1 << IPI_IRQ_WORK)) { 67 stats[IPI_IRQ_WORK]++; 68 irq_work_run(); 69 } 70 71 BUG_ON((ops >> IPI_MAX) != 0); 72 } 73 74 return IRQ_HANDLED; 75 } 76 77 static void (*send_arch_ipi)(const struct cpumask *mask); 78 79 static int ipi_irq; 80 void __init set_send_ipi(void (*func)(const struct cpumask *mask), int irq) 81 { 82 if (send_arch_ipi) 83 return; 84 85 send_arch_ipi = func; 86 ipi_irq = irq; 87 } 88 89 static void 90 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation) 91 { 92 int i; 93 94 for_each_cpu(i, to_whom) 95 set_bit(operation, &per_cpu_ptr(&ipi_data, i)->bits); 96 97 smp_mb(); 98 send_arch_ipi(to_whom); 99 } 100 101 static const char * const ipi_names[] = { 102 [IPI_EMPTY] = "Empty interrupts", 103 [IPI_RESCHEDULE] = "Rescheduling interrupts", 104 [IPI_CALL_FUNC] = "Function call interrupts", 105 [IPI_IRQ_WORK] = "Irq work interrupts", 106 }; 107 108 int arch_show_interrupts(struct seq_file *p, int prec) 109 { 110 unsigned int cpu, i; 111 112 for (i = 0; i < IPI_MAX; i++) { 113 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, 114 prec >= 4 ? " " : ""); 115 for_each_online_cpu(cpu) 116 seq_printf(p, "%10lu ", 117 per_cpu_ptr(&ipi_data, cpu)->stats[i]); 118 seq_printf(p, " %s\n", ipi_names[i]); 119 } 120 121 return 0; 122 } 123 124 void arch_send_call_function_ipi_mask(struct cpumask *mask) 125 { 126 send_ipi_message(mask, IPI_CALL_FUNC); 127 } 128 129 void arch_send_call_function_single_ipi(int cpu) 130 { 131 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC); 132 } 133 134 static void ipi_stop(void *unused) 135 { 136 while (1); 137 } 138 139 void smp_send_stop(void) 140 { 141 on_each_cpu(ipi_stop, NULL, 1); 142 } 143 144 void smp_send_reschedule(int cpu) 145 { 146 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE); 147 } 148 149 #ifdef CONFIG_IRQ_WORK 150 void arch_irq_work_raise(void) 151 { 152 send_ipi_message(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); 153 } 154 #endif 155 156 void __init smp_prepare_boot_cpu(void) 157 { 158 } 159 160 void __init smp_prepare_cpus(unsigned int max_cpus) 161 { 162 } 163 164 static int ipi_dummy_dev; 165 166 void __init setup_smp_ipi(void) 167 { 168 int rc; 169 170 if (ipi_irq == 0) 171 return; 172 173 rc = request_percpu_irq(ipi_irq, handle_ipi, "IPI Interrupt", 174 &ipi_dummy_dev); 175 if (rc) 176 panic("%s IRQ request failed\n", __func__); 177 178 enable_percpu_irq(ipi_irq, 0); 179 } 180 181 void __init setup_smp(void) 182 { 183 struct device_node *node = NULL; 184 int cpu; 185 186 for_each_of_cpu_node(node) { 187 if (!of_device_is_available(node)) 188 continue; 189 190 if (of_property_read_u32(node, "reg", &cpu)) 191 continue; 192 193 if (cpu >= NR_CPUS) 194 continue; 195 196 set_cpu_possible(cpu, true); 197 set_cpu_present(cpu, true); 198 } 199 } 200 201 extern void _start_smp_secondary(void); 202 203 volatile unsigned int secondary_hint; 204 volatile unsigned int secondary_hint2; 205 volatile unsigned int secondary_ccr; 206 volatile unsigned int secondary_stack; 207 208 unsigned long secondary_msa1; 209 210 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 211 { 212 unsigned long mask = 1 << cpu; 213 214 secondary_stack = 215 (unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8; 216 secondary_hint = mfcr("cr31"); 217 secondary_hint2 = mfcr("cr<21, 1>"); 218 secondary_ccr = mfcr("cr18"); 219 secondary_msa1 = read_mmu_msa1(); 220 221 /* 222 * Because other CPUs are in reset status, we must flush data 223 * from cache to out and secondary CPUs use them in 224 * csky_start_secondary(void) 225 */ 226 mtcr("cr17", 0x22); 227 228 if (mask & mfcr("cr<29, 0>")) { 229 send_arch_ipi(cpumask_of(cpu)); 230 } else { 231 /* Enable cpu in SMP reset ctrl reg */ 232 mask |= mfcr("cr<29, 0>"); 233 mtcr("cr<29, 0>", mask); 234 } 235 236 /* Wait for the cpu online */ 237 while (!cpu_online(cpu)); 238 239 secondary_stack = 0; 240 241 return 0; 242 } 243 244 void __init smp_cpus_done(unsigned int max_cpus) 245 { 246 } 247 248 int setup_profiling_timer(unsigned int multiplier) 249 { 250 return -EINVAL; 251 } 252 253 void csky_start_secondary(void) 254 { 255 struct mm_struct *mm = &init_mm; 256 unsigned int cpu = smp_processor_id(); 257 258 mtcr("cr31", secondary_hint); 259 mtcr("cr<21, 1>", secondary_hint2); 260 mtcr("cr18", secondary_ccr); 261 262 mtcr("vbr", vec_base); 263 264 flush_tlb_all(); 265 write_mmu_pagemask(0); 266 TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir); 267 TLBMISS_HANDLER_SETUP_PGD_KERNEL(swapper_pg_dir); 268 269 #ifdef CONFIG_CPU_HAS_FPU 270 init_fpu(); 271 #endif 272 273 enable_percpu_irq(ipi_irq, 0); 274 275 mmget(mm); 276 mmgrab(mm); 277 current->active_mm = mm; 278 cpumask_set_cpu(cpu, mm_cpumask(mm)); 279 280 notify_cpu_starting(cpu); 281 set_cpu_online(cpu, true); 282 283 pr_info("CPU%u Online: %s...\n", cpu, __func__); 284 285 local_irq_enable(); 286 preempt_disable(); 287 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 288 } 289 290 #ifdef CONFIG_HOTPLUG_CPU 291 int __cpu_disable(void) 292 { 293 unsigned int cpu = smp_processor_id(); 294 295 set_cpu_online(cpu, false); 296 297 irq_migrate_all_off_this_cpu(); 298 299 clear_tasks_mm_cpumask(cpu); 300 301 return 0; 302 } 303 304 void __cpu_die(unsigned int cpu) 305 { 306 if (!cpu_wait_death(cpu, 5)) { 307 pr_crit("CPU%u: shutdown failed\n", cpu); 308 return; 309 } 310 pr_notice("CPU%u: shutdown\n", cpu); 311 } 312 313 void arch_cpu_idle_dead(void) 314 { 315 idle_task_exit(); 316 317 cpu_report_death(); 318 319 while (!secondary_stack) 320 arch_cpu_idle(); 321 322 local_irq_disable(); 323 324 asm volatile( 325 "mov sp, %0\n" 326 "mov r8, %0\n" 327 "jmpi csky_start_secondary" 328 : 329 : "r" (secondary_stack)); 330 } 331 #endif 332