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/init.h>
  19 #include <linux/errno.h>
  20 #include <asm/fixmap.h>
  21 #include <asm/mpspec.h>
  22 #include <asm/apicdef.h>
  23 #include <asm/apic.h>
  24 #include <asm/setup.h>
  25
  26 #include <linux/smp.h>
  27 #include <asm/ipi.h>
  28
  29 #include <linux/interrupt.h>
  30 #include <asm/acpi.h>
  31 #include <asm/e820.h>
  32
  33 static void noop_init_apic_ldr(void) { }
  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 unsigned long noop_check_apicid_used(physid_mask_t *map, int apicid)
  94 {
  95         return physid_isset(apicid, *map);
  96 }
  97
  98 static unsigned long noop_check_apicid_present(int bit)
  99 {
 100         return physid_isset(bit, phys_cpu_present_map);
 101 }
 102
 103 static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask)
 104 {
 105         if (cpu != 0)
 106                 pr_warning("APIC: Vector allocated for non-BSP cpu\n");
 107         cpumask_clear(retmask);
 108         cpumask_set_cpu(cpu, retmask);
 109 }
 110
 111 static u32 noop_apic_read(u32 reg)
 112 {
 113         WARN_ON_ONCE((cpu_has_apic && !disable_apic));
 114         return 0;
 115 }
 116
 117 static void noop_apic_write(u32 reg, u32 v)
 118 {
 119         WARN_ON_ONCE(cpu_has_apic && !disable_apic);
 120 }
 121
 122 #ifdef CONFIG_X86_32
 123 static int noop_x86_32_numa_cpu_node(int cpu)
 124 {
 125         /* we're always on node 0 */
 126         return 0;
 127 }
 128 #endif
 129
 130 struct apic apic_noop = {
 131         .name                           = "noop",
 132         .probe                          = noop_probe,
 133         .acpi_madt_oem_check            = NULL,
 134
 135         .apic_id_registered             = noop_apic_id_registered,
 136
 137         .irq_delivery_mode              = dest_LowestPrio,
 138         /* logical delivery broadcast to all CPUs: */
 139         .irq_dest_mode                  = 1,
 140
 141         .target_cpus                    = noop_target_cpus,
 142         .disable_esr                    = 0,
 143         .dest_logical                   = APIC_DEST_LOGICAL,
 144         .check_apicid_used              = noop_check_apicid_used,
 145         .check_apicid_present           = noop_check_apicid_present,
 146
 147         .vector_allocation_domain       = noop_vector_allocation_domain,
 148         .init_apic_ldr                  = noop_init_apic_ldr,
 149
 150         .ioapic_phys_id_map             = default_ioapic_phys_id_map,
 151         .setup_apic_routing             = NULL,
 152         .multi_timer_check              = NULL,
 153
 154         .cpu_present_to_apicid          = default_cpu_present_to_apicid,
 155         .apicid_to_cpu_present          = physid_set_mask_of_physid,
 156
 157         .setup_portio_remap             = NULL,
 158         .check_phys_apicid_present      = default_check_phys_apicid_present,
 159         .enable_apic_mode               = NULL,
 160
 161         .phys_pkg_id                    = noop_phys_pkg_id,
 162
 163         .mps_oem_check                  = NULL,
 164
 165         .get_apic_id                    = noop_get_apic_id,
 166         .set_apic_id                    = NULL,
 167         .apic_id_mask                   = 0x0F << 24,
 168
 169         .cpu_mask_to_apicid             = default_cpu_mask_to_apicid,
 170         .cpu_mask_to_apicid_and         = default_cpu_mask_to_apicid_and,
 171
 172         .send_IPI_mask                  = noop_send_IPI_mask,
 173         .send_IPI_mask_allbutself       = noop_send_IPI_mask_allbutself,
 174         .send_IPI_allbutself            = noop_send_IPI_allbutself,
 175         .send_IPI_all                   = noop_send_IPI_all,
 176         .send_IPI_self                  = noop_send_IPI_self,
 177
 178         .wakeup_secondary_cpu           = noop_wakeup_secondary_cpu,
 179
 180         /* should be safe */
 181         .trampoline_phys_low            = DEFAULT_TRAMPOLINE_PHYS_LOW,
 182         .trampoline_phys_high           = DEFAULT_TRAMPOLINE_PHYS_HIGH,
 183
 184         .wait_for_init_deassert         = NULL,
 185
 186         .smp_callin_clear_local_apic    = NULL,
 187         .inquire_remote_apic            = NULL,
 188
 189         .read                           = noop_apic_read,
 190         .write                          = noop_apic_write,
 191         .icr_read                       = noop_apic_icr_read,
 192         .icr_write                      = noop_apic_icr_write,
 193         .wait_icr_idle                  = noop_apic_wait_icr_idle,
 194         .safe_wait_icr_idle             = noop_safe_apic_wait_icr_idle,
 195
 196 #ifdef CONFIG_X86_32
 197         .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
 198         .x86_32_numa_cpu_node           = noop_x86_32_numa_cpu_node,
 199 #endif
 200 };