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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/x86/kernel/apic/init.c
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// SPDX-License-Identifier: GPL-2.0-only

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#define pr_fmt(fmt) "APIC: " fmt

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#include <asm/apic.h>

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#include "local.h"

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/*

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 * Use DEFINE_STATIC_CALL_NULL() to avoid having to provide stub functions

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 * for each callback. The callbacks are setup during boot and all except

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 * wait_icr_idle() must be initialized before usage. The IPI wrappers

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 * use static_call() and not static_call_cond() to catch any fails.

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 */

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#define DEFINE_APIC_CALL(__cb)						\

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	DEFINE_STATIC_CALL_NULL(apic_call_##__cb, *apic->__cb)

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DEFINE_APIC_CALL(eoi);

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DEFINE_APIC_CALL(native_eoi);

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DEFINE_APIC_CALL(icr_read);

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DEFINE_APIC_CALL(icr_write);

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DEFINE_APIC_CALL(read);

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DEFINE_APIC_CALL(send_IPI);

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DEFINE_APIC_CALL(send_IPI_mask);

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DEFINE_APIC_CALL(send_IPI_mask_allbutself);

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DEFINE_APIC_CALL(send_IPI_allbutself);

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DEFINE_APIC_CALL(send_IPI_all);

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DEFINE_APIC_CALL(send_IPI_self);

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DEFINE_APIC_CALL(wait_icr_idle);

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DEFINE_APIC_CALL(wakeup_secondary_cpu);

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DEFINE_APIC_CALL(wakeup_secondary_cpu_64);

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DEFINE_APIC_CALL(write);

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EXPORT_STATIC_CALL_TRAMP_GPL(apic_call_send_IPI_mask);

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EXPORT_STATIC_CALL_TRAMP_GPL(apic_call_send_IPI_self);

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/* The container for function call overrides */

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struct apic_override __x86_apic_override __initdata;

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#define apply_override(__cb)					\

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	if (__x86_apic_override.__cb)				\

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		apic->__cb = __x86_apic_override.__cb

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static __init void restore_override_callbacks(void)

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{

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	apply_override(eoi);

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	apply_override(native_eoi);

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	apply_override(write);

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	apply_override(read);

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	apply_override(send_IPI);

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	apply_override(send_IPI_mask);

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	apply_override(send_IPI_mask_allbutself);

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	apply_override(send_IPI_allbutself);

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	apply_override(send_IPI_all);

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	apply_override(send_IPI_self);

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	apply_override(icr_read);

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	apply_override(icr_write);

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	apply_override(wakeup_secondary_cpu);

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	apply_override(wakeup_secondary_cpu_64);

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}

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#define update_call(__cb)					\

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	static_call_update(apic_call_##__cb, *apic->__cb)

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static __init void update_static_calls(void)

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{

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	update_call(eoi);

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	update_call(native_eoi);

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	update_call(write);

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	update_call(read);

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	update_call(send_IPI);

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	update_call(send_IPI_mask);

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	update_call(send_IPI_mask_allbutself);

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	update_call(send_IPI_allbutself);

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	update_call(send_IPI_all);

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	update_call(send_IPI_self);

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	update_call(icr_read);

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	update_call(icr_write);

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	update_call(wait_icr_idle);

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	update_call(wakeup_secondary_cpu);

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	update_call(wakeup_secondary_cpu_64);

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}

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void __init apic_setup_apic_calls(void)

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{

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	/* Ensure that the default APIC has native_eoi populated */

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	apic->native_eoi = apic->eoi;

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	update_static_calls();

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	pr_info("Static calls initialized\n");

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}

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void __init apic_install_driver(struct apic *driver)

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{

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	if (apic == driver)

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		return;

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	apic = driver;

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	if (IS_ENABLED(CONFIG_X86_X2APIC) && apic->x2apic_set_max_apicid)

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		apic->max_apic_id = x2apic_max_apicid;

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	/* Copy the original eoi() callback as KVM/HyperV might overwrite it */

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	if (!apic->native_eoi)

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		apic->native_eoi = apic->eoi;

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	/* Apply any already installed callback overrides */

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	restore_override_callbacks();

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	update_static_calls();

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	pr_info("Switched APIC routing to: %s\n", driver->name);

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}

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