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/string.h>
  15 #include <linux/kernel.h>
  16 #include <linux/ctype.h>
  17 #include <linux/errno.h>
  18 #include <asm/fixmap.h>
  19 #include <asm/mpspec.h>
  20 #include <asm/apicdef.h>
  21 #include <asm/apic.h>
  22 #include <asm/setup.h>
  23
  24 #include <linux/smp.h>
  25 #include <asm/ipi.h>
  26
  27 #include <linux/interrupt.h>
  28 #include <asm/acpi.h>
  29 #include <asm/e820.h>
  30
  31 static void noop_init_apic_ldr(void) { }
  32 static void noop_send_IPI(int cpu, int vector) { }
  33 static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
  34 static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
  35 static void noop_send_IPI_allbutself(int vector) { }
  36 static void noop_send_IPI_all(int vector) { }
  37 static void noop_send_IPI_self(int vector) { }
  38 static void noop_apic_wait_icr_idle(void) { }
  39 static void noop_apic_icr_write(u32 low, u32 id) { }
  40
  41 static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
  42 {
  43         return -1;
  44 }
  45
  46 static u32 noop_safe_apic_wait_icr_idle(void)
  47 {
  48         return 0;
  49 }
  50
  51 static u64 noop_apic_icr_read(void)
  52 {
  53         return 0;
  54 }
  55
  56 static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
  57 {
  58         return 0;
  59 }
  60
  61 static unsigned int noop_get_apic_id(unsigned long x)
  62 {
  63         return 0;
  64 }
  65
  66 static int noop_probe(void)
  67 {
  68         /*
  69          * NOOP apic should not ever be
  70          * enabled via probe routine
  71          */
  72         return 0;
  73 }
  74
  75 static int noop_apic_id_registered(void)
  76 {
  77         /*
  78          * if we would be really "pedantic"
  79          * we should pass read_apic_id() here
  80          * but since NOOP suppose APIC ID = 0
  81          * lets save a few cycles
  82          */
  83         return physid_isset(0, phys_cpu_present_map);
  84 }
  85
  86 static const struct cpumask *noop_target_cpus(void)
  87 {
  88         /* only BSP here */
  89         return cpumask_of(0);
  90 }
  91
  92 static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask,
  93                                           const struct cpumask *mask)
  94 {
  95         if (cpu != 0)
  96                 pr_warning("APIC: Vector allocated for non-BSP cpu\n");
  97         cpumask_copy(retmask, cpumask_of(cpu));
  98 }
  99
 100 static u32 noop_apic_read(u32 reg)
 101 {
 102         WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
 103         return 0;
 104 }
 105
 106 static void noop_apic_write(u32 reg, u32 v)
 107 {
 108         WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
 109 }
 110
 111 struct apic apic_noop __ro_after_init = {
 112         .name                           = "noop",
 113         .probe                          = noop_probe,
 114         .acpi_madt_oem_check            = NULL,
 115
 116         .apic_id_valid                  = default_apic_id_valid,
 117         .apic_id_registered             = noop_apic_id_registered,
 118
 119         .irq_delivery_mode              = dest_LowestPrio,
 120         /* logical delivery broadcast to all CPUs: */
 121         .irq_dest_mode                  = 1,
 122
 123         .target_cpus                    = noop_target_cpus,
 124         .disable_esr                    = 0,
 125         .dest_logical                   = APIC_DEST_LOGICAL,
 126         .check_apicid_used              = default_check_apicid_used,
 127
 128         .vector_allocation_domain       = noop_vector_allocation_domain,
 129         .init_apic_ldr                  = noop_init_apic_ldr,
 130
 131         .ioapic_phys_id_map             = default_ioapic_phys_id_map,
 132         .setup_apic_routing             = NULL,
 133
 134         .cpu_present_to_apicid          = default_cpu_present_to_apicid,
 135         .apicid_to_cpu_present          = physid_set_mask_of_physid,
 136
 137         .check_phys_apicid_present      = default_check_phys_apicid_present,
 138
 139         .phys_pkg_id                    = noop_phys_pkg_id,
 140
 141         .get_apic_id                    = noop_get_apic_id,
 142         .set_apic_id                    = NULL,
 143
 144         .cpu_mask_to_apicid_and         = flat_cpu_mask_to_apicid_and,
 145
 146         .send_IPI                       = noop_send_IPI,
 147         .send_IPI_mask                  = noop_send_IPI_mask,
 148         .send_IPI_mask_allbutself       = noop_send_IPI_mask_allbutself,
 149         .send_IPI_allbutself            = noop_send_IPI_allbutself,
 150         .send_IPI_all                   = noop_send_IPI_all,
 151         .send_IPI_self                  = noop_send_IPI_self,
 152
 153         .wakeup_secondary_cpu           = noop_wakeup_secondary_cpu,
 154
 155         .inquire_remote_apic            = NULL,
 156
 157         .read                           = noop_apic_read,
 158         .write                          = noop_apic_write,
 159         .eoi_write                      = noop_apic_write,
 160         .icr_read                       = noop_apic_icr_read,
 161         .icr_write                      = noop_apic_icr_write,
 162         .wait_icr_idle                  = noop_apic_wait_icr_idle,
 163         .safe_wait_icr_idle             = noop_safe_apic_wait_icr_idle,
 164
 165 #ifdef CONFIG_X86_32
 166         .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
 167 #endif
 168 };