arch/mips/paravirt/paravirt-smp.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2013 Cavium, Inc.
   7  */
   8
   9 #include <linux/interrupt.h>
  10 #include <linux/cpumask.h>
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/sched/task_stack.h>
  14
  15 #include <asm/mipsregs.h>
  16 #include <asm/setup.h>
  17 #include <asm/time.h>
  18 #include <asm/smp.h>
  19
  20 /*
  21  * Writing the sp releases the CPU, so writes must be ordered, gp
  22  * first, then sp.
  23  */
  24 unsigned long paravirt_smp_sp[NR_CPUS];
  25 unsigned long paravirt_smp_gp[NR_CPUS];
  26
  27 static int numcpus = 1;
  28
  29 static int __init set_numcpus(char *str)
  30 {
  31         int newval;
  32
  33         if (get_option(&str, &newval)) {
  34                 if (newval < 1 || newval >= NR_CPUS)
  35                         goto bad;
  36                 numcpus = newval;
  37                 return 0;
  38         }
  39 bad:
  40         return -EINVAL;
  41 }
  42 early_param("numcpus", set_numcpus);
  43
  44
  45 static void paravirt_smp_setup(void)
  46 {
  47         int id;
  48         unsigned int cpunum = get_ebase_cpunum();
  49
  50         if (WARN_ON(cpunum >= NR_CPUS))
  51                 return;
  52
  53         /* The present CPUs are initially just the boot cpu (CPU 0). */
  54         for (id = 0; id < NR_CPUS; id++) {
  55                 set_cpu_possible(id, id == 0);
  56                 set_cpu_present(id, id == 0);
  57         }
  58         __cpu_number_map[cpunum] = 0;
  59         __cpu_logical_map[0] = cpunum;
  60
  61         for (id = 0; id < numcpus; id++) {
  62                 set_cpu_possible(id, true);
  63                 set_cpu_present(id, true);
  64                 __cpu_number_map[id] = id;
  65                 __cpu_logical_map[id] = id;
  66         }
  67 }
  68
  69 void irq_mbox_ipi(int cpu, unsigned int actions);
  70 static void paravirt_send_ipi_single(int cpu, unsigned int action)
  71 {
  72         irq_mbox_ipi(cpu, action);
  73 }
  74
  75 static void paravirt_send_ipi_mask(const struct cpumask *mask, unsigned int action)
  76 {
  77         unsigned int cpu;
  78
  79         for_each_cpu(cpu, mask)
  80                 paravirt_send_ipi_single(cpu, action);
  81 }
  82
  83 static void paravirt_init_secondary(void)
  84 {
  85         unsigned int sr;
  86
  87         sr = set_c0_status(ST0_BEV);
  88         write_c0_ebase((u32)ebase);
  89
  90         sr |= STATUSF_IP2; /* Interrupt controller on IP2 */
  91         write_c0_status(sr);
  92
  93         irq_cpu_online();
  94 }
  95
  96 static void paravirt_smp_finish(void)
  97 {
  98         /* to generate the first CPU timer interrupt */
  99         write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);
 100         local_irq_enable();
 101 }
 102
 103 static int paravirt_boot_secondary(int cpu, struct task_struct *idle)
 104 {
 105         paravirt_smp_gp[cpu] = (unsigned long)task_thread_info(idle);
 106         smp_wmb();
 107         paravirt_smp_sp[cpu] = __KSTK_TOS(idle);
 108         return 0;
 109 }
 110
 111 static irqreturn_t paravirt_reched_interrupt(int irq, void *dev_id)
 112 {
 113         scheduler_ipi();
 114         return IRQ_HANDLED;
 115 }
 116
 117 static irqreturn_t paravirt_function_interrupt(int irq, void *dev_id)
 118 {
 119         generic_smp_call_function_interrupt();
 120         return IRQ_HANDLED;
 121 }
 122
 123 static void paravirt_prepare_cpus(unsigned int max_cpus)
 124 {
 125         if (request_irq(MIPS_IRQ_MBOX0, paravirt_reched_interrupt,
 126                         IRQF_PERCPU | IRQF_NO_THREAD, "Scheduler",
 127                         paravirt_reched_interrupt)) {
 128                 panic("Cannot request_irq for SchedulerIPI");
 129         }
 130         if (request_irq(MIPS_IRQ_MBOX1, paravirt_function_interrupt,
 131                         IRQF_PERCPU | IRQF_NO_THREAD, "SMP-Call",
 132                         paravirt_function_interrupt)) {
 133                 panic("Cannot request_irq for SMP-Call");
 134         }
 135 }
 136
 137 const struct plat_smp_ops paravirt_smp_ops = {
 138         .send_ipi_single        = paravirt_send_ipi_single,
 139         .send_ipi_mask          = paravirt_send_ipi_mask,
 140         .init_secondary         = paravirt_init_secondary,
 141         .smp_finish             = paravirt_smp_finish,
 142         .boot_secondary         = paravirt_boot_secondary,
 143         .smp_setup              = paravirt_smp_setup,
 144         .prepare_cpus           = paravirt_prepare_cpus,
 145 };