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 #ifdef CONFIG_CPU_HAS_FPU 27 #include <abi/fpu.h> 28 #endif 29 30 enum ipi_message_type { 31 IPI_EMPTY, 32 IPI_RESCHEDULE, 33 IPI_CALL_FUNC, 34 IPI_IRQ_WORK, 35 IPI_MAX 36 }; 37 38 struct ipi_data_struct { 39 unsigned long bits ____cacheline_aligned; 40 unsigned long stats[IPI_MAX] ____cacheline_aligned; 41 }; 42 static DEFINE_PER_CPU(struct ipi_data_struct, ipi_data); 43 44 static irqreturn_t handle_ipi(int irq, void *dev) 45 { 46 unsigned long *stats = this_cpu_ptr(&ipi_data)->stats; 47 48 while (true) { 49 unsigned long ops; 50 51 ops = xchg(&this_cpu_ptr(&ipi_data)->bits, 0); 52 if (ops == 0) 53 return IRQ_HANDLED; 54 55 if (ops & (1 << IPI_RESCHEDULE)) { 56 stats[IPI_RESCHEDULE]++; 57 scheduler_ipi(); 58 } 59 60 if (ops & (1 << IPI_CALL_FUNC)) { 61 stats[IPI_CALL_FUNC]++; 62 generic_smp_call_function_interrupt(); 63 } 64 65 if (ops & (1 << IPI_IRQ_WORK)) { 66 stats[IPI_IRQ_WORK]++; 67 irq_work_run(); 68 } 69 70 BUG_ON((ops >> IPI_MAX) != 0); 71 } 72 73 return IRQ_HANDLED; 74 } 75 76 static void (*send_arch_ipi)(const struct cpumask *mask); 77 78 static int ipi_irq; 79 void __init set_send_ipi(void (*func)(const struct cpumask *mask), int irq) 80 { 81 if (send_arch_ipi) 82 return; 83 84 send_arch_ipi = func; 85 ipi_irq = irq; 86 } 87 88 static void 89 send_ipi_message(const struct cpumask *to_whom, enum ipi_message_type operation) 90 { 91 int i; 92 93 for_each_cpu(i, to_whom) 94 set_bit(operation, &per_cpu_ptr(&ipi_data, i)->bits); 95 96 smp_mb(); 97 send_arch_ipi(to_whom); 98 } 99 100 static const char * const ipi_names[] = { 101 [IPI_EMPTY] = "Empty interrupts", 102 [IPI_RESCHEDULE] = "Rescheduling interrupts", 103 [IPI_CALL_FUNC] = "Function call interrupts", 104 [IPI_IRQ_WORK] = "Irq work interrupts", 105 }; 106 107 int arch_show_interrupts(struct seq_file *p, int prec) 108 { 109 unsigned int cpu, i; 110 111 for (i = 0; i < IPI_MAX; i++) { 112 seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, 113 prec >= 4 ? " " : ""); 114 for_each_online_cpu(cpu) 115 seq_printf(p, "%10lu ", 116 per_cpu_ptr(&ipi_data, cpu)->stats[i]); 117 seq_printf(p, " %s\n", ipi_names[i]); 118 } 119 120 return 0; 121 } 122 123 void arch_send_call_function_ipi_mask(struct cpumask *mask) 124 { 125 send_ipi_message(mask, IPI_CALL_FUNC); 126 } 127 128 void arch_send_call_function_single_ipi(int cpu) 129 { 130 send_ipi_message(cpumask_of(cpu), IPI_CALL_FUNC); 131 } 132 133 static void ipi_stop(void *unused) 134 { 135 while (1); 136 } 137 138 void smp_send_stop(void) 139 { 140 on_each_cpu(ipi_stop, NULL, 1); 141 } 142 143 void smp_send_reschedule(int cpu) 144 { 145 send_ipi_message(cpumask_of(cpu), IPI_RESCHEDULE); 146 } 147 148 #ifdef CONFIG_IRQ_WORK 149 void arch_irq_work_raise(void) 150 { 151 send_ipi_message(cpumask_of(smp_processor_id()), IPI_IRQ_WORK); 152 } 153 #endif 154 155 void __init smp_prepare_boot_cpu(void) 156 { 157 } 158 159 void __init smp_prepare_cpus(unsigned int max_cpus) 160 { 161 } 162 163 static int ipi_dummy_dev; 164 165 void __init setup_smp_ipi(void) 166 { 167 int rc; 168 169 if (ipi_irq == 0) 170 return; 171 172 rc = request_percpu_irq(ipi_irq, handle_ipi, "IPI Interrupt", 173 &ipi_dummy_dev); 174 if (rc) 175 panic("%s IRQ request failed\n", __func__); 176 177 enable_percpu_irq(ipi_irq, 0); 178 } 179 180 void __init setup_smp(void) 181 { 182 struct device_node *node = NULL; 183 int cpu; 184 185 for_each_of_cpu_node(node) { 186 if (!of_device_is_available(node)) 187 continue; 188 189 if (of_property_read_u32(node, "reg", &cpu)) 190 continue; 191 192 if (cpu >= NR_CPUS) 193 continue; 194 195 set_cpu_possible(cpu, true); 196 set_cpu_present(cpu, true); 197 } 198 } 199 200 extern void _start_smp_secondary(void); 201 202 volatile unsigned int secondary_hint; 203 volatile unsigned int secondary_hint2; 204 volatile unsigned int secondary_ccr; 205 volatile unsigned int secondary_stack; 206 volatile unsigned int secondary_msa1; 207 volatile unsigned int secondary_pgd; 208 209 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 210 { 211 unsigned long mask = 1 << cpu; 212 213 secondary_stack = 214 (unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8; 215 secondary_hint = mfcr("cr31"); 216 secondary_hint2 = mfcr("cr<21, 1>"); 217 secondary_ccr = mfcr("cr18"); 218 secondary_msa1 = read_mmu_msa1(); 219 secondary_pgd = mfcr("cr<29, 15>"); 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); 266 267 #ifdef CONFIG_CPU_HAS_FPU 268 init_fpu(); 269 #endif 270 271 enable_percpu_irq(ipi_irq, 0); 272 273 mmget(mm); 274 mmgrab(mm); 275 current->active_mm = mm; 276 cpumask_set_cpu(cpu, mm_cpumask(mm)); 277 278 notify_cpu_starting(cpu); 279 set_cpu_online(cpu, true); 280 281 pr_info("CPU%u Online: %s...\n", cpu, __func__); 282 283 local_irq_enable(); 284 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 285 } 286 287 #ifdef CONFIG_HOTPLUG_CPU 288 int __cpu_disable(void) 289 { 290 unsigned int cpu = smp_processor_id(); 291 292 set_cpu_online(cpu, false); 293 294 irq_migrate_all_off_this_cpu(); 295 296 clear_tasks_mm_cpumask(cpu); 297 298 return 0; 299 } 300 301 void __cpu_die(unsigned int cpu) 302 { 303 if (!cpu_wait_death(cpu, 5)) { 304 pr_crit("CPU%u: shutdown failed\n", cpu); 305 return; 306 } 307 pr_notice("CPU%u: shutdown\n", cpu); 308 } 309 310 void arch_cpu_idle_dead(void) 311 { 312 idle_task_exit(); 313 314 cpu_report_death(); 315 316 while (!secondary_stack) 317 arch_cpu_idle(); 318 319 local_irq_disable(); 320 321 asm volatile( 322 "mov sp, %0\n" 323 "mov r8, %0\n" 324 "jmpi csky_start_secondary" 325 : 326 : "r" (secondary_stack)); 327 } 328 #endif 329