apic_noop.c

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/*
 * NOOP APIC driver.
 *
 * Does almost nothing and should be substituted by a real apic driver via
 * probe routine.
 *
 * Though in case if apic is disabled (for some reason) we try
 * to not uglify the caller's code and allow to call (some) apic routines
 * like self-ipi, etc...
 */

#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/kernel.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <asm/fixmap.h>
#include <asm/mpspec.h>
#include <asm/apicdef.h>
#include <asm/apic.h>
#include <asm/setup.h>

#include <linux/smp.h>
#include <asm/ipi.h>

#include <linux/interrupt.h>
#include <asm/acpi.h>
#include <asm/e820.h>

static void noop_init_apic_ldr(void) { }
static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
static void noop_send_IPI_allbutself(int vector) { }
static void noop_send_IPI_all(int vector) { }
static void noop_send_IPI_self(int vector) { }
static void noop_apic_wait_icr_idle(void) { }
static void noop_apic_icr_write(u32 low, u32 id) { }

static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
{
    return -1;
}

static u32 noop_safe_apic_wait_icr_idle(void)
{
    return 0;
}

static u64 noop_apic_icr_read(void)
{
    return 0;
}

static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
{
    return 0;
}

static unsigned int noop_get_apic_id(unsigned long x)
{
    return 0;
}

static int noop_probe(void)
{
    /*
     * NOOP apic should not ever be
     * enabled via probe routine
     */
    return 0;
}

static int noop_apic_id_registered(void)
{
    /*
     * if we would be really "pedantic"
     * we should pass read_apic_id() here
     * but since NOOP suppose APIC ID = 0
     * lets save a few cycles
     */
    return physid_isset(0, phys_cpu_present_map);
}

static const struct cpumask *noop_target_cpus(void)
{
    /* only BSP here */
    return cpumask_of(0);
}

static unsigned long noop_check_apicid_used(physid_mask_t *map, int apicid)
{
    return physid_isset(apicid, *map);
}

static unsigned long noop_check_apicid_present(int bit)
{
    return physid_isset(bit, phys_cpu_present_map);
}

static void noop_vector_allocation_domain(int cpu, struct cpumask *retmask,
                      const struct cpumask *mask)
{
    if (cpu != 0)
        pr_warning("APIC: Vector allocated for non-BSP cpu\n");
    cpumask_copy(retmask, cpumask_of(cpu));
}

static u32 noop_apic_read(u32 reg)
{
    WARN_ON_ONCE((cpu_has_apic && !disable_apic));
    return 0;
}

static void noop_apic_write(u32 reg, u32 v)
{
    WARN_ON_ONCE(cpu_has_apic && !disable_apic);
}

struct apic apic_noop = {
    .name               = "noop",
    .probe              = noop_probe,
    .acpi_madt_oem_check        = NULL,

    .apic_id_valid          = default_apic_id_valid,
    .apic_id_registered     = noop_apic_id_registered,

    .irq_delivery_mode      = dest_LowestPrio,
    /* logical delivery broadcast to all CPUs: */
    .irq_dest_mode          = 1,

    .target_cpus            = noop_target_cpus,
    .disable_esr            = 0,
    .dest_logical           = APIC_DEST_LOGICAL,
    .check_apicid_used      = noop_check_apicid_used,
    .check_apicid_present       = noop_check_apicid_present,

    .vector_allocation_domain   = noop_vector_allocation_domain,
    .init_apic_ldr          = noop_init_apic_ldr,

    .ioapic_phys_id_map     = default_ioapic_phys_id_map,
    .setup_apic_routing     = NULL,
    .multi_timer_check      = NULL,

    .cpu_present_to_apicid      = default_cpu_present_to_apicid,
    .apicid_to_cpu_present      = physid_set_mask_of_physid,

    .setup_portio_remap     = NULL,
    .check_phys_apicid_present  = default_check_phys_apicid_present,
    .enable_apic_mode       = NULL,

    .phys_pkg_id            = noop_phys_pkg_id,

    .mps_oem_check          = NULL,

    .get_apic_id            = noop_get_apic_id,
    .set_apic_id            = NULL,
    .apic_id_mask           = 0x0F << 24,

    .cpu_mask_to_apicid_and     = flat_cpu_mask_to_apicid_and,

    .send_IPI_mask          = noop_send_IPI_mask,
    .send_IPI_mask_allbutself   = noop_send_IPI_mask_allbutself,
    .send_IPI_allbutself        = noop_send_IPI_allbutself,
    .send_IPI_all           = noop_send_IPI_all,
    .send_IPI_self          = noop_send_IPI_self,

    .wakeup_secondary_cpu       = noop_wakeup_secondary_cpu,

    /* should be safe */
    .trampoline_phys_low        = DEFAULT_TRAMPOLINE_PHYS_LOW,
    .trampoline_phys_high       = DEFAULT_TRAMPOLINE_PHYS_HIGH,

    .wait_for_init_deassert     = NULL,

    .smp_callin_clear_local_apic    = NULL,
    .inquire_remote_apic        = NULL,

    .read               = noop_apic_read,
    .write              = noop_apic_write,
    .eoi_write          = noop_apic_write,
    .icr_read           = noop_apic_icr_read,
    .icr_write          = noop_apic_icr_write,
    .wait_icr_idle          = noop_apic_wait_icr_idle,
    .safe_wait_icr_idle     = noop_safe_apic_wait_icr_idle,

#ifdef CONFIG_X86_32
    .x86_32_early_logical_apicid    = noop_x86_32_early_logical_apicid,
#endif
};