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 #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
 207 unsigned long secondary_msa1;
 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
 220         /*
 221          * Because other CPUs are in reset status, we must flush data
 222          * from cache to out and secondary CPUs use them in
 223          * csky_start_secondary(void)
 224          */
 225         mtcr("cr17", 0x22);
 226
 227         if (mask & mfcr("cr<29, 0>")) {
 228                 send_arch_ipi(cpumask_of(cpu));
 229         } else {
 230                 /* Enable cpu in SMP reset ctrl reg */
 231                 mask |= mfcr("cr<29, 0>");
 232                 mtcr("cr<29, 0>", mask);
 233         }
 234
 235         /* Wait for the cpu online */
 236         while (!cpu_online(cpu));
 237
 238         secondary_stack = 0;
 239
 240         return 0;
 241 }
 242
 243 void __init smp_cpus_done(unsigned int max_cpus)
 244 {
 245 }
 246
 247 int setup_profiling_timer(unsigned int multiplier)
 248 {
 249         return -EINVAL;
 250 }
 251
 252 void csky_start_secondary(void)
 253 {
 254         struct mm_struct *mm = &init_mm;
 255         unsigned int cpu = smp_processor_id();
 256
 257         mtcr("cr31", secondary_hint);
 258         mtcr("cr<21, 1>", secondary_hint2);
 259         mtcr("cr18", secondary_ccr);
 260
 261         mtcr("vbr", vec_base);
 262
 263         flush_tlb_all();
 264         write_mmu_pagemask(0);
 265         TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir);
 266         TLBMISS_HANDLER_SETUP_PGD_KERNEL(swapper_pg_dir);
 267
 268 #ifdef CONFIG_CPU_HAS_FPU
 269         init_fpu();
 270 #endif
 271
 272         enable_percpu_irq(ipi_irq, 0);
 273
 274         mmget(mm);
 275         mmgrab(mm);
 276         current->active_mm = mm;
 277         cpumask_set_cpu(cpu, mm_cpumask(mm));
 278
 279         notify_cpu_starting(cpu);
 280         set_cpu_online(cpu, true);
 281
 282         pr_info("CPU%u Online: %s...\n", cpu, __func__);
 283
 284         local_irq_enable();
 285         preempt_disable();
 286         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 287 }
 288
 289 #ifdef CONFIG_HOTPLUG_CPU
 290 int __cpu_disable(void)
 291 {
 292         unsigned int cpu = smp_processor_id();
 293
 294         set_cpu_online(cpu, false);
 295
 296         irq_migrate_all_off_this_cpu();
 297
 298         clear_tasks_mm_cpumask(cpu);
 299
 300         return 0;
 301 }
 302
 303 void __cpu_die(unsigned int cpu)
 304 {
 305         if (!cpu_wait_death(cpu, 5)) {
 306                 pr_crit("CPU%u: shutdown failed\n", cpu);
 307                 return;
 308         }
 309         pr_notice("CPU%u: shutdown\n", cpu);
 310 }
 311
 312 void arch_cpu_idle_dead(void)
 313 {
 314         idle_task_exit();
 315
 316         cpu_report_death();
 317
 318         while (!secondary_stack)
 319                 arch_cpu_idle();
 320
 321         local_irq_disable();
 322
 323         asm volatile(
 324                 "mov    sp, %0\n"
 325                 "mov    r8, %0\n"
 326                 "jmpi   csky_start_secondary"
 327                 :
 328                 : "r" (secondary_stack));
 329 }
 330 #endif