LXR linux/arch/x86/kernel/apic/apic

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * NOOP APIC driver.
   4 *
   5 * Does almost nothing and should be substituted by a real apic driver via
   6 * probe routine.
   7 *
   8 * Though in case if apic is disabled (for some reason) we try
   9 * to not uglify the caller's code and allow to call (some) apic routines
  10 * like self-ipi, etc...
  11 */
  12#include <linux/cpumask.h>
  13
  14#include <asm/apic.h>
  15
  16static void noop_init_apic_ldr(void) { }
  17static void noop_send_IPI(int cpu, int vector) { }
  18static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
  19static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
  20static void noop_send_IPI_allbutself(int vector) { }
  21static void noop_send_IPI_all(int vector) { }
  22static void noop_send_IPI_self(int vector) { }
  23static void noop_apic_wait_icr_idle(void) { }
  24static void noop_apic_icr_write(u32 low, u32 id) { }
  25
  26static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
  27{
  28        return -1;
  29}
  30
  31static u32 noop_safe_apic_wait_icr_idle(void)
  32{
  33        return 0;
  34}
  35
  36static u64 noop_apic_icr_read(void)
  37{
  38        return 0;
  39}
  40
  41static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
  42{
  43        return 0;
  44}
  45
  46static unsigned int noop_get_apic_id(unsigned long x)
  47{
  48        return 0;
  49}
  50
  51static int noop_probe(void)
  52{
  53        /*
  54         * NOOP apic should not ever be
  55         * enabled via probe routine
  56         */
  57        return 0;
  58}
  59
  60static int noop_apic_id_registered(void)
  61{
  62        /*
  63         * if we would be really "pedantic"
  64         * we should pass read_apic_id() here
  65         * but since NOOP suppose APIC ID = 0
  66         * lets save a few cycles
  67         */
  68        return physid_isset(0, phys_cpu_present_map);
  69}
  70
  71static u32 noop_apic_read(u32 reg)
  72{
  73        WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
  74        return 0;
  75}
  76
  77static void noop_apic_write(u32 reg, u32 v)
  78{
  79        WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
  80}
  81
  82#ifdef CONFIG_X86_32
  83static int noop_x86_32_early_logical_apicid(int cpu)
  84{
  85        return BAD_APICID;
  86}
  87#endif
  88
  89struct apic apic_noop __ro_after_init = {
  90        .name                           = "noop",
  91        .probe                          = noop_probe,
  92        .acpi_madt_oem_check            = NULL,
  93
  94        .apic_id_valid                  = default_apic_id_valid,
  95        .apic_id_registered             = noop_apic_id_registered,
  96
  97        .irq_delivery_mode              = dest_Fixed,
  98        /* logical delivery broadcast to all CPUs: */
  99        .irq_dest_mode                  = 1,
 100
 101        .disable_esr                    = 0,
 102        .dest_logical                   = APIC_DEST_LOGICAL,
 103        .check_apicid_used              = default_check_apicid_used,
 104
 105        .init_apic_ldr                  = noop_init_apic_ldr,
 106
 107        .ioapic_phys_id_map             = default_ioapic_phys_id_map,
 108        .setup_apic_routing             = NULL,
 109
 110        .cpu_present_to_apicid          = default_cpu_present_to_apicid,
 111        .apicid_to_cpu_present          = physid_set_mask_of_physid,
 112
 113        .check_phys_apicid_present      = default_check_phys_apicid_present,
 114
 115        .phys_pkg_id                    = noop_phys_pkg_id,
 116
 117        .get_apic_id                    = noop_get_apic_id,
 118        .set_apic_id                    = NULL,
 119
 120        .calc_dest_apicid               = apic_flat_calc_apicid,
 121
 122        .send_IPI                       = noop_send_IPI,
 123        .send_IPI_mask                  = noop_send_IPI_mask,
 124        .send_IPI_mask_allbutself       = noop_send_IPI_mask_allbutself,
 125        .send_IPI_allbutself            = noop_send_IPI_allbutself,
 126        .send_IPI_all                   = noop_send_IPI_all,
 127        .send_IPI_self                  = noop_send_IPI_self,
 128
 129        .wakeup_secondary_cpu           = noop_wakeup_secondary_cpu,
 130
 131        .inquire_remote_apic            = NULL,
 132
 133        .read                           = noop_apic_read,
 134        .write                          = noop_apic_write,
 135        .eoi_write                      = noop_apic_write,
 136        .icr_read                       = noop_apic_icr_read,
 137        .icr_write                      = noop_apic_icr_write,
 138        .wait_icr_idle                  = noop_apic_wait_icr_idle,
 139        .safe_wait_icr_idle             = noop_safe_apic_wait_icr_idle,
 140
 141#ifdef CONFIG_X86_32
 142        .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
 143#endif
 144};
 145