apic_noop.c
// SPDX-License-Identifier: GPL-2.0
/*
* 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/cpumask.h>
#include <linux/thread_info.h>
#include <asm/apic.h>
static void noop_init_apic_ldr(void) { }
static void noop_send_IPI(int cpu, int vector) { }
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 u32 noop_apic_read(u32 reg)
{
WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
return 0;
}
static void noop_apic_write(u32 reg, u32 v)
{
WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
}
#ifdef CONFIG_X86_32
static int noop_x86_32_early_logical_apicid(int cpu)
{
return BAD_APICID;
}
#endif
struct apic apic_noop __ro_after_init = {
.name = "noop",
.probe = noop_probe,
.acpi_madt_oem_check = NULL,
.apic_id_valid = default_apic_id_valid,
.apic_id_registered = noop_apic_id_registered,
.delivery_mode = APIC_DELIVERY_MODE_FIXED,
.dest_mode_logical = true,
.disable_esr = 0,
.check_apicid_used = default_check_apicid_used,
.init_apic_ldr = noop_init_apic_ldr,
.ioapic_phys_id_map = default_ioapic_phys_id_map,
.setup_apic_routing = NULL,
.cpu_present_to_apicid = default_cpu_present_to_apicid,
.apicid_to_cpu_present = physid_set_mask_of_physid,
.check_phys_apicid_present = default_check_phys_apicid_present,
.phys_pkg_id = noop_phys_pkg_id,
.get_apic_id = noop_get_apic_id,
.set_apic_id = NULL,
.calc_dest_apicid = apic_flat_calc_apicid,
.send_IPI = noop_send_IPI,
.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,
.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
};