arch/x86/kernel/apic/apic_noop.c

   1 /*
   2  * NOOP APIC driver.
   3  *
   4  * Does almost nothing and should be substituted by a real apic driver via
   5  * probe routine.
   6  *
   7  * Though in case if apic is disabled (for some reason) we try
   8  * to not uglify the caller's code and allow to call (some) apic routines
   9  * like self-ipi, etc...
  10  */
  11
  12 #include <linux/threads.h>
  13 #include <linux/cpumask.h>
  14 #include <linux/module.h>
  15 #include <linux/string.h>
  16 #include <linux/kernel.h>
  17 #include <linux/ctype.h>
  18 #include <linux/errno.h>
  19 #include <asm/fixmap.h>
  20 #include <asm/mpspec.h>
  21 #include <asm/apicdef.h>
  22 #include <asm/apic.h>
  23 #include <asm/setup.h>
  24
  25 #include <linux/smp.h>
  26 #include <asm/ipi.h>
  27
  28 #include <linux/interrupt.h>
  29 #include <asm/acpi.h>
  30 #include <asm/e820.h>
  31
  32 static void noop_init_apic_ldr(void) { }
  33 static void noop_send_IPI(int cpu, int vector) { }
  34 static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
  35 static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
  36 static void noop_send_IPI_allbutself(int vector) { }
  37 static void noop_send_IPI_all(int vector) { }
  38 static void noop_send_IPI_self(int vector) { }
  39 static void noop_apic_wait_icr_idle(void) { }
  40 static void noop_apic_icr_write(u32 low, u32 id) { }
  41
  42 static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
  43 {
  44         return -1;
  45 }
  46
  47 static u32 noop_safe_apic_wait_icr_idle(void)
  48 {
  49         return 0;
  50 }
  51
  52 static u64 noop_apic_icr_read(void)
  53 {
  54         return 0;
  55 }
  56
  57 static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
  58 {
  59         return 0;
  60 }
  61
  62 static unsigned int noop_get_apic_id(unsigned long x)
  63 {
  64         return 0;
  65 }
  66
  67 static int noop_probe(void)
  68 {
  69         /*
  70          * NOOP apic should not ever be
  71          * enabled via probe routine
  72          */
  73         return 0;
  74 }
  75
  76 static int noop_apic_id_registered(void)
  77 {
  78         /*
  79          * if we would be really "pedantic"
  80          * we should pass read_apic_id() here
  81          * but since NOOP suppose APIC ID = 0
  82          * lets save a few cycles
  83          */
  84         return physid_isset(0, phys_cpu_present_map);
  85 }
  86
  87 static const struct cpumask *noop_target_cpus(void)
  88 {
  89         /* only BSP here */
  90         return cpumask_of(0);
  91 }
  92
  93 static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask,
  94                                           const struct cpumask *mask)
  95 {
  96         if (cpu != 0)
  97                 pr_warning("APIC: Vector allocated for non-BSP cpu\n");
  98         cpumask_copy(retmask, cpumask_of(cpu));
  99 }
 100
 101 static u32 noop_apic_read(u32 reg)
 102 {
 103         WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
 104         return 0;
 105 }
 106
 107 static void noop_apic_write(u32 reg, u32 v)
 108 {
 109         WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
 110 }
 111
 112 struct apic apic_noop = {
 113         .name                           = "noop",
 114         .probe                          = noop_probe,
 115         .acpi_madt_oem_check            = NULL,
 116
 117         .apic_id_valid                  = default_apic_id_valid,
 118         .apic_id_registered             = noop_apic_id_registered,
 119
 120         .irq_delivery_mode              = dest_LowestPrio,
 121         /* logical delivery broadcast to all CPUs: */
 122         .irq_dest_mode                  = 1,
 123
 124         .target_cpus                    = noop_target_cpus,
 125         .disable_esr                    = 0,
 126         .dest_logical                   = APIC_DEST_LOGICAL,
 127         .check_apicid_used              = default_check_apicid_used,
 128
 129         .vector_allocation_domain       = noop_vector_allocation_domain,
 130         .init_apic_ldr                  = noop_init_apic_ldr,
 131
 132         .ioapic_phys_id_map             = default_ioapic_phys_id_map,
 133         .setup_apic_routing             = NULL,
 134
 135         .cpu_present_to_apicid          = default_cpu_present_to_apicid,
 136         .apicid_to_cpu_present          = physid_set_mask_of_physid,
 137
 138         .check_phys_apicid_present      = default_check_phys_apicid_present,
 139
 140         .phys_pkg_id                    = noop_phys_pkg_id,
 141
 142         .get_apic_id                    = noop_get_apic_id,
 143         .set_apic_id                    = NULL,
 144
 145         .cpu_mask_to_apicid_and         = flat_cpu_mask_to_apicid_and,
 146
 147         .send_IPI                       = noop_send_IPI,
 148         .send_IPI_mask                  = noop_send_IPI_mask,
 149         .send_IPI_mask_allbutself       = noop_send_IPI_mask_allbutself,
 150         .send_IPI_allbutself            = noop_send_IPI_allbutself,
 151         .send_IPI_all                   = noop_send_IPI_all,
 152         .send_IPI_self                  = noop_send_IPI_self,
 153
 154         .wakeup_secondary_cpu           = noop_wakeup_secondary_cpu,
 155
 156         .inquire_remote_apic            = NULL,
 157
 158         .read                           = noop_apic_read,
 159         .write                          = noop_apic_write,
 160         .eoi_write                      = noop_apic_write,
 161         .icr_read                       = noop_apic_icr_read,
 162         .icr_write                      = noop_apic_icr_write,
 163         .wait_icr_idle                  = noop_apic_wait_icr_idle,
 164         .safe_wait_icr_idle             = noop_safe_apic_wait_icr_idle,
 165
 166 #ifdef CONFIG_X86_32
 167         .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
 168 #endif
 169 };