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 arch_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_cpus(unsigned int max_cpus) 156 { 157 } 158 159 static int ipi_dummy_dev; 160 161 void __init setup_smp_ipi(void) 162 { 163 int rc; 164 165 if (ipi_irq == 0) 166 return; 167 168 rc = request_percpu_irq(ipi_irq, handle_ipi, "IPI Interrupt", 169 &ipi_dummy_dev); 170 if (rc) 171 panic("%s IRQ request failed\n", __func__); 172 173 enable_percpu_irq(ipi_irq, 0); 174 } 175 176 void __init setup_smp(void) 177 { 178 struct device_node *node = NULL; 179 unsigned int cpu; 180 181 for_each_of_cpu_node(node) { 182 if (!of_device_is_available(node)) 183 continue; 184 185 cpu = of_get_cpu_hwid(node, 0); 186 if (cpu >= NR_CPUS) 187 continue; 188 189 set_cpu_possible(cpu, true); 190 set_cpu_present(cpu, true); 191 } 192 } 193 194 extern void _start_smp_secondary(void); 195 196 volatile unsigned int secondary_hint; 197 volatile unsigned int secondary_hint2; 198 volatile unsigned int secondary_ccr; 199 volatile unsigned int secondary_stack; 200 volatile unsigned int secondary_msa1; 201 volatile unsigned int secondary_pgd; 202 203 int __cpu_up(unsigned int cpu, struct task_struct *tidle) 204 { 205 unsigned long mask = 1 << cpu; 206 207 secondary_stack = 208 (unsigned int) task_stack_page(tidle) + THREAD_SIZE - 8; 209 secondary_hint = mfcr("cr31"); 210 secondary_hint2 = mfcr("cr<21, 1>"); 211 secondary_ccr = mfcr("cr18"); 212 secondary_msa1 = read_mmu_msa1(); 213 secondary_pgd = mfcr("cr<29, 15>"); 214 215 /* 216 * Because other CPUs are in reset status, we must flush data 217 * from cache to out and secondary CPUs use them in 218 * csky_start_secondary(void) 219 */ 220 mtcr("cr17", 0x22); 221 222 if (mask & mfcr("cr<29, 0>")) { 223 send_arch_ipi(cpumask_of(cpu)); 224 } else { 225 /* Enable cpu in SMP reset ctrl reg */ 226 mask |= mfcr("cr<29, 0>"); 227 mtcr("cr<29, 0>", mask); 228 } 229 230 /* Wait for the cpu online */ 231 while (!cpu_online(cpu)); 232 233 secondary_stack = 0; 234 235 return 0; 236 } 237 238 void __init smp_cpus_done(unsigned int max_cpus) 239 { 240 } 241 242 void csky_start_secondary(void) 243 { 244 struct mm_struct *mm = &init_mm; 245 unsigned int cpu = smp_processor_id(); 246 247 mtcr("cr31", secondary_hint); 248 mtcr("cr<21, 1>", secondary_hint2); 249 mtcr("cr18", secondary_ccr); 250 251 mtcr("vbr", vec_base); 252 253 flush_tlb_all(); 254 write_mmu_pagemask(0); 255 256 #ifdef CONFIG_CPU_HAS_FPU 257 init_fpu(); 258 #endif 259 260 enable_percpu_irq(ipi_irq, 0); 261 262 mmget(mm); 263 mmgrab(mm); 264 current->active_mm = mm; 265 cpumask_set_cpu(cpu, mm_cpumask(mm)); 266 267 notify_cpu_starting(cpu); 268 set_cpu_online(cpu, true); 269 270 pr_info("CPU%u Online: %s...\n", cpu, __func__); 271 272 local_irq_enable(); 273 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE); 274 } 275 276 #ifdef CONFIG_HOTPLUG_CPU 277 int __cpu_disable(void) 278 { 279 unsigned int cpu = smp_processor_id(); 280 281 set_cpu_online(cpu, false); 282 283 irq_migrate_all_off_this_cpu(); 284 285 clear_tasks_mm_cpumask(cpu); 286 287 return 0; 288 } 289 290 void arch_cpuhp_cleanup_dead_cpu(unsigned int cpu) 291 { 292 pr_notice("CPU%u: shutdown\n", cpu); 293 } 294 295 void __noreturn arch_cpu_idle_dead(void) 296 { 297 idle_task_exit(); 298 299 cpuhp_ap_report_dead(); 300 301 while (!secondary_stack) 302 arch_cpu_idle(); 303 304 raw_local_irq_disable(); 305 306 asm volatile( 307 "mov sp, %0\n" 308 "mov r8, %0\n" 309 "jmpi csky_start_secondary" 310 : 311 : "r" (secondary_stack)); 312 313 BUG(); 314 } 315 #endif 316