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