arch/openrisc/kernel/smp.c

   1 /*
   2  * Copyright (C) 2014 Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
   3  * Copyright (C) 2017 Stafford Horne <shorne@gmail.com>
   4  *
   5  * Based on arm64 and arc implementations
   6  * Copyright (C) 2013 ARM Ltd.
   7  * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
   8  *
   9  * This file is licensed under the terms of the GNU General Public License
  10  * version 2.  This program is licensed "as is" without any warranty of any
  11  * kind, whether express or implied.
  12  */
  13
  14 #include <linux/smp.h>
  15 #include <linux/cpu.h>
  16 #include <linux/sched.h>
  17 #include <linux/irq.h>
  18 #include <asm/cpuinfo.h>
  19 #include <asm/mmu_context.h>
  20 #include <asm/tlbflush.h>
  21 #include <asm/cacheflush.h>
  22 #include <asm/time.h>
  23
  24 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
  25
  26 unsigned long secondary_release = -1;
  27 struct thread_info *secondary_thread_info;
  28
  29 enum ipi_msg_type {
  30         IPI_WAKEUP,
  31         IPI_RESCHEDULE,
  32         IPI_CALL_FUNC,
  33         IPI_CALL_FUNC_SINGLE,
  34 };
  35
  36 static DEFINE_SPINLOCK(boot_lock);
  37
  38 static void boot_secondary(unsigned int cpu, struct task_struct *idle)
  39 {
  40         /*
  41          * set synchronisation state between this boot processor
  42          * and the secondary one
  43          */
  44         spin_lock(&boot_lock);
  45
  46         secondary_release = cpu;
  47         smp_cross_call(cpumask_of(cpu), IPI_WAKEUP);
  48
  49         /*
  50          * now the secondary core is starting up let it run its
  51          * calibrations, then wait for it to finish
  52          */
  53         spin_unlock(&boot_lock);
  54 }
  55
  56 void __init smp_prepare_boot_cpu(void)
  57 {
  58 }
  59
  60 void __init smp_init_cpus(void)
  61 {
  62         int i;
  63
  64         for (i = 0; i < NR_CPUS; i++)
  65                 set_cpu_possible(i, true);
  66 }
  67
  68 void __init smp_prepare_cpus(unsigned int max_cpus)
  69 {
  70         int i;
  71
  72         /*
  73          * Initialise the present map, which describes the set of CPUs
  74          * actually populated at the present time.
  75          */
  76         for (i = 0; i < max_cpus; i++)
  77                 set_cpu_present(i, true);
  78 }
  79
  80 void __init smp_cpus_done(unsigned int max_cpus)
  81 {
  82 }
  83
  84 static DECLARE_COMPLETION(cpu_running);
  85
  86 int __cpu_up(unsigned int cpu, struct task_struct *idle)
  87 {
  88         if (smp_cross_call == NULL) {
  89                 pr_warn("CPU%u: failed to start, IPI controller missing",
  90                         cpu);
  91                 return -EIO;
  92         }
  93
  94         secondary_thread_info = task_thread_info(idle);
  95         current_pgd[cpu] = init_mm.pgd;
  96
  97         boot_secondary(cpu, idle);
  98         if (!wait_for_completion_timeout(&cpu_running,
  99                                         msecs_to_jiffies(1000))) {
 100                 pr_crit("CPU%u: failed to start\n", cpu);
 101                 return -EIO;
 102         }
 103         synchronise_count_master(cpu);
 104
 105         return 0;
 106 }
 107
 108 asmlinkage __init void secondary_start_kernel(void)
 109 {
 110         struct mm_struct *mm = &init_mm;
 111         unsigned int cpu = smp_processor_id();
 112         /*
 113          * All kernel threads share the same mm context; grab a
 114          * reference and switch to it.
 115          */
 116         atomic_inc(&mm->mm_count);
 117         current->active_mm = mm;
 118         cpumask_set_cpu(cpu, mm_cpumask(mm));
 119
 120         pr_info("CPU%u: Booted secondary processor\n", cpu);
 121
 122         setup_cpuinfo();
 123         openrisc_clockevent_init();
 124
 125         notify_cpu_starting(cpu);
 126
 127         /*
 128          * OK, now it's safe to let the boot CPU continue
 129          */
 130         complete(&cpu_running);
 131
 132         synchronise_count_slave(cpu);
 133         set_cpu_online(cpu, true);
 134
 135         local_irq_enable();
 136
 137         preempt_disable();
 138         /*
 139          * OK, it's off to the idle thread for us
 140          */
 141         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 142 }
 143
 144 void handle_IPI(unsigned int ipi_msg)
 145 {
 146         unsigned int cpu = smp_processor_id();
 147
 148         switch (ipi_msg) {
 149         case IPI_WAKEUP:
 150                 break;
 151
 152         case IPI_RESCHEDULE:
 153                 scheduler_ipi();
 154                 break;
 155
 156         case IPI_CALL_FUNC:
 157                 generic_smp_call_function_interrupt();
 158                 break;
 159
 160         case IPI_CALL_FUNC_SINGLE:
 161                 generic_smp_call_function_single_interrupt();
 162                 break;
 163
 164         default:
 165                 WARN(1, "CPU%u: Unknown IPI message 0x%x\n", cpu, ipi_msg);
 166                 break;
 167         }
 168 }
 169
 170 void smp_send_reschedule(int cpu)
 171 {
 172         smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 173 }
 174
 175 static void stop_this_cpu(void *dummy)
 176 {
 177         /* Remove this CPU */
 178         set_cpu_online(smp_processor_id(), false);
 179
 180         local_irq_disable();
 181         /* CPU Doze */
 182         if (mfspr(SPR_UPR) & SPR_UPR_PMP)
 183                 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
 184         /* If that didn't work, infinite loop */
 185         while (1)
 186                 ;
 187 }
 188
 189 void smp_send_stop(void)
 190 {
 191         smp_call_function(stop_this_cpu, NULL, 0);
 192 }
 193
 194 /* not supported, yet */
 195 int setup_profiling_timer(unsigned int multiplier)
 196 {
 197         return -EINVAL;
 198 }
 199
 200 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
 201 {
 202         smp_cross_call = fn;
 203 }
 204
 205 void arch_send_call_function_single_ipi(int cpu)
 206 {
 207         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
 208 }
 209
 210 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 211 {
 212         smp_cross_call(mask, IPI_CALL_FUNC);
 213 }
 214
 215 /* TLB flush operations - Performed on each CPU*/
 216 static inline void ipi_flush_tlb_all(void *ignored)
 217 {
 218         local_flush_tlb_all();
 219 }
 220
 221 void flush_tlb_all(void)
 222 {
 223         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 224 }
 225
 226 /*
 227  * FIXME: implement proper functionality instead of flush_tlb_all.
 228  * *But*, as things currently stands, the local_tlb_flush_* functions will
 229  * all boil down to local_tlb_flush_all anyway.
 230  */
 231 void flush_tlb_mm(struct mm_struct *mm)
 232 {
 233         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 234 }
 235
 236 void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
 237 {
 238         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 239 }
 240
 241 void flush_tlb_range(struct vm_area_struct *vma,
 242                      unsigned long start, unsigned long end)
 243 {
 244         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 245 }
 246
 247 /* Instruction cache invalidate - performed on each cpu */
 248 static void ipi_icache_page_inv(void *arg)
 249 {
 250         struct page *page = arg;
 251
 252         local_icache_page_inv(page);
 253 }
 254
 255 void smp_icache_page_inv(struct page *page)
 256 {
 257         on_each_cpu(ipi_icache_page_inv, page, 1);
 258 }
 259 EXPORT_SYMBOL(smp_icache_page_inv);