LXR linux/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 */
  24unsigned long paravirt_smp_sp[NR_CPUS];
  25unsigned long paravirt_smp_gp[NR_CPUS];
  26
  27static int numcpus = 1;
  28
  29static 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        }
  39bad:
  40        return -EINVAL;
  41}
  42early_param("numcpus", set_numcpus);
  43
  44
  45static 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
  69void irq_mbox_ipi(int cpu, unsigned int actions);
  70static void paravirt_send_ipi_single(int cpu, unsigned int action)
  71{
  72        irq_mbox_ipi(cpu, action);
  73}
  74
  75static 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
  83static 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
  96static 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
 103static 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
 111static irqreturn_t paravirt_reched_interrupt(int irq, void *dev_id)
 112{
 113        scheduler_ipi();
 114        return IRQ_HANDLED;
 115}
 116
 117static irqreturn_t paravirt_function_interrupt(int irq, void *dev_id)
 118{
 119        generic_smp_call_function_interrupt();
 120        return IRQ_HANDLED;
 121}
 122
 123static 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
 137const 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};
 146