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838ba7733e
Logical destination mode of the local APIC is used for systems with up to 8 CPUs. It has an advantage over physical destination mode as it allows to target multiple CPUs at once with IPIs. That advantage was definitely worth it when systems with up to 8 CPUs were state of the art for servers and workstations, but that's history. Aside of that there are systems which fail to work with logical destination mode as the ACPI/DMI quirks show and there are AMD Zen1 systems out there which fail when interrupt remapping is enabled as reported by Rob and Christian. The latter problem can be cured by firmware updates, but not all OEMs distribute the required changes. Physical destination mode is guaranteed to work because it is the only way to get a CPU up and running via the INIT/INIT/STARTUP sequence. As the number of CPUs keeps increasing, logical destination mode becomes a less used code path so there is no real good reason to keep it around. Therefore remove logical destination mode support for 64-bit and default to physical destination mode. Reported-by: Rob Newcater <rob@durendal.co.uk> Reported-by: Christian Heusel <christian@heusel.eu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Borislav Petkov (AMD) <bp@alien8.de> Tested-by: Rob Newcater <rob@durendal.co.uk> Link: https://lore.kernel.org/all/877cd5u671.ffs@tglx
68 lines
1.6 KiB
C
68 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright 2004 James Cleverdon, IBM.
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*
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* Flat APIC subarch code.
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*
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* Hacked for x86-64 by James Cleverdon from i386 architecture code by
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* Martin Bligh, Andi Kleen, James Bottomley, John Stultz, and
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* James Cleverdon.
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*/
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#include <linux/export.h>
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#include <asm/apic.h>
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#include "local.h"
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static u32 physflat_get_apic_id(u32 x)
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{
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return (x >> 24) & 0xFF;
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}
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static int physflat_probe(void)
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{
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return 1;
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}
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static int physflat_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
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{
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return 1;
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}
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static struct apic apic_physflat __ro_after_init = {
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.name = "physical flat",
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.probe = physflat_probe,
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.acpi_madt_oem_check = physflat_acpi_madt_oem_check,
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.dest_mode_logical = false,
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.disable_esr = 0,
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.cpu_present_to_apicid = default_cpu_present_to_apicid,
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.max_apic_id = 0xFE,
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.get_apic_id = physflat_get_apic_id,
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.calc_dest_apicid = apic_default_calc_apicid,
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.send_IPI = default_send_IPI_single_phys,
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.send_IPI_mask = default_send_IPI_mask_sequence_phys,
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.send_IPI_mask_allbutself = default_send_IPI_mask_allbutself_phys,
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.send_IPI_allbutself = default_send_IPI_allbutself,
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.send_IPI_all = default_send_IPI_all,
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.send_IPI_self = default_send_IPI_self,
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.nmi_to_offline_cpu = true,
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.read = native_apic_mem_read,
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.write = native_apic_mem_write,
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.eoi = native_apic_mem_eoi,
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.icr_read = native_apic_icr_read,
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.icr_write = native_apic_icr_write,
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.wait_icr_idle = apic_mem_wait_icr_idle,
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.safe_wait_icr_idle = apic_mem_wait_icr_idle_timeout,
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};
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apic_driver(apic_physflat);
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struct apic *apic __ro_after_init = &apic_physflat;
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EXPORT_SYMBOL_GPL(apic);
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