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/sched/mm.h>
  18 #include <linux/irq.h>
  19 #include <asm/cpuinfo.h>
  20 #include <asm/mmu_context.h>
  21 #include <asm/tlbflush.h>
  22 #include <asm/cacheflush.h>
  23 #include <asm/time.h>
  24
  25 static void (*smp_cross_call)(const struct cpumask *, unsigned int);
  26
  27 unsigned long secondary_release = -1;
  28 struct thread_info *secondary_thread_info;
  29
  30 enum ipi_msg_type {
  31         IPI_WAKEUP,
  32         IPI_RESCHEDULE,
  33         IPI_CALL_FUNC,
  34         IPI_CALL_FUNC_SINGLE,
  35 };
  36
  37 static DEFINE_SPINLOCK(boot_lock);
  38
  39 static void boot_secondary(unsigned int cpu, struct task_struct *idle)
  40 {
  41         /*
  42          * set synchronisation state between this boot processor
  43          * and the secondary one
  44          */
  45         spin_lock(&boot_lock);
  46
  47         secondary_release = cpu;
  48         smp_cross_call(cpumask_of(cpu), IPI_WAKEUP);
  49
  50         /*
  51          * now the secondary core is starting up let it run its
  52          * calibrations, then wait for it to finish
  53          */
  54         spin_unlock(&boot_lock);
  55 }
  56
  57 void __init smp_prepare_boot_cpu(void)
  58 {
  59 }
  60
  61 void __init smp_init_cpus(void)
  62 {
  63         int i;
  64
  65         for (i = 0; i < NR_CPUS; i++)
  66                 set_cpu_possible(i, true);
  67 }
  68
  69 void __init smp_prepare_cpus(unsigned int max_cpus)
  70 {
  71         int i;
  72
  73         /*
  74          * Initialise the present map, which describes the set of CPUs
  75          * actually populated at the present time.
  76          */
  77         for (i = 0; i < max_cpus; i++)
  78                 set_cpu_present(i, true);
  79 }
  80
  81 void __init smp_cpus_done(unsigned int max_cpus)
  82 {
  83 }
  84
  85 static DECLARE_COMPLETION(cpu_running);
  86
  87 int __cpu_up(unsigned int cpu, struct task_struct *idle)
  88 {
  89         if (smp_cross_call == NULL) {
  90                 pr_warn("CPU%u: failed to start, IPI controller missing",
  91                         cpu);
  92                 return -EIO;
  93         }
  94
  95         secondary_thread_info = task_thread_info(idle);
  96         current_pgd[cpu] = init_mm.pgd;
  97
  98         boot_secondary(cpu, idle);
  99         if (!wait_for_completion_timeout(&cpu_running,
 100                                         msecs_to_jiffies(1000))) {
 101                 pr_crit("CPU%u: failed to start\n", cpu);
 102                 return -EIO;
 103         }
 104         synchronise_count_master(cpu);
 105
 106         return 0;
 107 }
 108
 109 asmlinkage __init void secondary_start_kernel(void)
 110 {
 111         struct mm_struct *mm = &init_mm;
 112         unsigned int cpu = smp_processor_id();
 113         /*
 114          * All kernel threads share the same mm context; grab a
 115          * reference and switch to it.
 116          */
 117         mmgrab(mm);
 118         current->active_mm = mm;
 119         cpumask_set_cpu(cpu, mm_cpumask(mm));
 120
 121         pr_info("CPU%u: Booted secondary processor\n", cpu);
 122
 123         setup_cpuinfo();
 124         openrisc_clockevent_init();
 125
 126         notify_cpu_starting(cpu);
 127
 128         /*
 129          * OK, now it's safe to let the boot CPU continue
 130          */
 131         complete(&cpu_running);
 132
 133         synchronise_count_slave(cpu);
 134         set_cpu_online(cpu, true);
 135
 136         local_irq_enable();
 137
 138         preempt_disable();
 139         /*
 140          * OK, it's off to the idle thread for us
 141          */
 142         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
 143 }
 144
 145 void handle_IPI(unsigned int ipi_msg)
 146 {
 147         unsigned int cpu = smp_processor_id();
 148
 149         switch (ipi_msg) {
 150         case IPI_WAKEUP:
 151                 break;
 152
 153         case IPI_RESCHEDULE:
 154                 scheduler_ipi();
 155                 break;
 156
 157         case IPI_CALL_FUNC:
 158                 generic_smp_call_function_interrupt();
 159                 break;
 160
 161         case IPI_CALL_FUNC_SINGLE:
 162                 generic_smp_call_function_single_interrupt();
 163                 break;
 164
 165         default:
 166                 WARN(1, "CPU%u: Unknown IPI message 0x%x\n", cpu, ipi_msg);
 167                 break;
 168         }
 169 }
 170
 171 void smp_send_reschedule(int cpu)
 172 {
 173         smp_cross_call(cpumask_of(cpu), IPI_RESCHEDULE);
 174 }
 175
 176 static void stop_this_cpu(void *dummy)
 177 {
 178         /* Remove this CPU */
 179         set_cpu_online(smp_processor_id(), false);
 180
 181         local_irq_disable();
 182         /* CPU Doze */
 183         if (mfspr(SPR_UPR) & SPR_UPR_PMP)
 184                 mtspr(SPR_PMR, mfspr(SPR_PMR) | SPR_PMR_DME);
 185         /* If that didn't work, infinite loop */
 186         while (1)
 187                 ;
 188 }
 189
 190 void smp_send_stop(void)
 191 {
 192         smp_call_function(stop_this_cpu, NULL, 0);
 193 }
 194
 195 /* not supported, yet */
 196 int setup_profiling_timer(unsigned int multiplier)
 197 {
 198         return -EINVAL;
 199 }
 200
 201 void __init set_smp_cross_call(void (*fn)(const struct cpumask *, unsigned int))
 202 {
 203         smp_cross_call = fn;
 204 }
 205
 206 void arch_send_call_function_single_ipi(int cpu)
 207 {
 208         smp_cross_call(cpumask_of(cpu), IPI_CALL_FUNC_SINGLE);
 209 }
 210
 211 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
 212 {
 213         smp_cross_call(mask, IPI_CALL_FUNC);
 214 }
 215
 216 /* TLB flush operations - Performed on each CPU*/
 217 static inline void ipi_flush_tlb_all(void *ignored)
 218 {
 219         local_flush_tlb_all();
 220 }
 221
 222 void flush_tlb_all(void)
 223 {
 224         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 225 }
 226
 227 /*
 228  * FIXME: implement proper functionality instead of flush_tlb_all.
 229  * *But*, as things currently stands, the local_tlb_flush_* functions will
 230  * all boil down to local_tlb_flush_all anyway.
 231  */
 232 void flush_tlb_mm(struct mm_struct *mm)
 233 {
 234         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 235 }
 236
 237 void flush_tlb_page(struct vm_area_struct *vma, unsigned long uaddr)
 238 {
 239         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 240 }
 241
 242 void flush_tlb_range(struct vm_area_struct *vma,
 243                      unsigned long start, unsigned long end)
 244 {
 245         on_each_cpu(ipi_flush_tlb_all, NULL, 1);
 246 }
 247
 248 /* Instruction cache invalidate - performed on each cpu */
 249 static void ipi_icache_page_inv(void *arg)
 250 {
 251         struct page *page = arg;
 252
 253         local_icache_page_inv(page);
 254 }
 255
 256 void smp_icache_page_inv(struct page *page)
 257 {
 258         on_each_cpu(ipi_icache_page_inv, page, 1);
 259 }
 260 EXPORT_SYMBOL(smp_icache_page_inv);