arch/csky/kernel/smp.c

   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