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#include <linux/thread_info.h>
  14
  15#include <asm/apic.h>
  16
  17static void noop_init_apic_ldr(void) { }
  18static void noop_send_IPI(int cpu, int vector) { }
  19static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
  20static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
  21static void noop_send_IPI_allbutself(int vector) { }
  22static void noop_send_IPI_all(int vector) { }
  23static void noop_send_IPI_self(int vector) { }
  24static void noop_apic_wait_icr_idle(void) { }
  25static void noop_apic_icr_write(u32 low, u32 id) { }
  26
  27static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
  28{
  29        return -1;
  30}
  31
  32static u32 noop_safe_apic_wait_icr_idle(void)
  33{
  34        return 0;
  35}
  36
  37static u64 noop_apic_icr_read(void)
  38{
  39        return 0;
  40}
  41
  42static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
  43{
  44        return 0;
  45}
  46
  47static unsigned int noop_get_apic_id(unsigned long x)
  48{
  49        return 0;
  50}
  51
  52static int noop_probe(void)
  53{
  54        /*
  55         * NOOP apic should not ever be
  56         * enabled via probe routine
  57         */
  58        return 0;
  59}
  60
  61static int noop_apic_id_registered(void)
  62{
  63        /*
  64         * if we would be really "pedantic"
  65         * we should pass read_apic_id() here
  66         * but since NOOP suppose APIC ID = 0
  67         * lets save a few cycles
  68         */
  69        return physid_isset(0, phys_cpu_present_map);
  70}
  71
  72static u32 noop_apic_read(u32 reg)
  73{
  74        WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
  75        return 0;
  76}
  77
  78static void noop_apic_write(u32 reg, u32 v)
  79{
  80        WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
  81}
  82
  83#ifdef CONFIG_X86_32
  84static int noop_x86_32_early_logical_apicid(int cpu)
  85{
  86        return BAD_APICID;
  87}
  88#endif
  89
  90struct apic apic_noop __ro_after_init = {
  91        .name                           = "noop",
  92        .probe                          = noop_probe,
  93        .acpi_madt_oem_check            = NULL,
  94
  95        .apic_id_valid                  = default_apic_id_valid,
  96        .apic_id_registered             = noop_apic_id_registered,
  97
  98        .delivery_mode                  = APIC_DELIVERY_MODE_FIXED,
  99        .dest_mode_logical              = true,
 100
 101        .disable_esr                    = 0,
 102
 103        .check_apicid_used              = default_check_apicid_used,
 104        .init_apic_ldr                  = noop_init_apic_ldr,
 105        .ioapic_phys_id_map             = default_ioapic_phys_id_map,
 106        .setup_apic_routing             = NULL,
 107        .cpu_present_to_apicid          = default_cpu_present_to_apicid,
 108        .apicid_to_cpu_present          = physid_set_mask_of_physid,
 109
 110        .check_phys_apicid_present      = default_check_phys_apicid_present,
 111
 112        .phys_pkg_id                    = noop_phys_pkg_id,
 113
 114        .get_apic_id                    = noop_get_apic_id,
 115        .set_apic_id                    = NULL,
 116
 117        .calc_dest_apicid               = apic_flat_calc_apicid,
 118
 119        .send_IPI                       = noop_send_IPI,
 120        .send_IPI_mask                  = noop_send_IPI_mask,
 121        .send_IPI_mask_allbutself       = noop_send_IPI_mask_allbutself,
 122        .send_IPI_allbutself            = noop_send_IPI_allbutself,
 123        .send_IPI_all                   = noop_send_IPI_all,
 124        .send_IPI_self                  = noop_send_IPI_self,
 125
 126        .wakeup_secondary_cpu           = noop_wakeup_secondary_cpu,
 127
 128        .inquire_remote_apic            = NULL,
 129
 130        .read                           = noop_apic_read,
 131        .write                          = noop_apic_write,
 132        .eoi_write                      = noop_apic_write,
 133        .icr_read                       = noop_apic_icr_read,
 134        .icr_write                      = noop_apic_icr_write,
 135        .wait_icr_idle                  = noop_apic_wait_icr_idle,
 136        .safe_wait_icr_idle             = noop_safe_apic_wait_icr_idle,
 137
 138#ifdef CONFIG_X86_32
 139        .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
 140#endif
 141};
 142