4a5f72a4a3
Paranoia is not wrong, but having an APIC callback which is in most implementations a complete NOOP and in one actually looking whether the APICID of an upcoming CPU has been registered. The same APICID which was used to bring the CPU out of wait for startup. That's paranoia for the paranoia sake. Remove the voodoo. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Michael Kelley <mhklinux@outlook.com> Tested-by: Sohil Mehta <sohil.mehta@intel.com> Link: https://lore.kernel.org/r/20240212154640.116510935@linutronix.de
140 lines
3 KiB
C
140 lines
3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Default generic APIC driver. This handles up to 8 CPUs.
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*
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* Copyright 2003 Andi Kleen, SuSE Labs.
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*
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* Generic x86 APIC driver probe layer.
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*/
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#include <linux/export.h>
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#include <linux/errno.h>
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#include <linux/smp.h>
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#include <xen/xen.h>
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#include <asm/io_apic.h>
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#include <asm/apic.h>
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#include <asm/acpi.h>
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#include "local.h"
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static u32 default_get_apic_id(u32 x)
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{
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unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
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if (APIC_XAPIC(ver) || boot_cpu_has(X86_FEATURE_EXTD_APICID))
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return (x >> 24) & 0xFF;
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else
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return (x >> 24) & 0x0F;
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}
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/* should be called last. */
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static int probe_default(void)
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{
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return 1;
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}
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static struct apic apic_default __ro_after_init = {
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.name = "default",
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.probe = probe_default,
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.dest_mode_logical = true,
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.disable_esr = 0,
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.init_apic_ldr = default_init_apic_ldr,
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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 = default_get_apic_id,
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.calc_dest_apicid = apic_flat_calc_apicid,
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.send_IPI = default_send_IPI_single,
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.send_IPI_mask = default_send_IPI_mask_logical,
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.send_IPI_mask_allbutself = default_send_IPI_mask_allbutself_logical,
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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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.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_default);
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struct apic *apic __ro_after_init = &apic_default;
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EXPORT_SYMBOL_GPL(apic);
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static int cmdline_apic __initdata;
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static int __init parse_apic(char *arg)
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{
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struct apic **drv;
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if (!arg)
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return -EINVAL;
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for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
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if (!strcmp((*drv)->name, arg)) {
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apic_install_driver(*drv);
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cmdline_apic = 1;
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return 0;
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}
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}
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/* Parsed again by __setup for debug/verbose */
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return 0;
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}
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early_param("apic", parse_apic);
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void __init x86_32_probe_bigsmp_early(void)
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{
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if (nr_cpu_ids <= 8 || xen_pv_domain())
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return;
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if (IS_ENABLED(CONFIG_X86_BIGSMP)) {
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switch (boot_cpu_data.x86_vendor) {
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case X86_VENDOR_INTEL:
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if (!APIC_XAPIC(boot_cpu_apic_version))
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break;
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/* P4 and above */
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fallthrough;
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case X86_VENDOR_HYGON:
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case X86_VENDOR_AMD:
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if (apic_bigsmp_possible(cmdline_apic))
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return;
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break;
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}
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}
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pr_info("Limiting to 8 possible CPUs\n");
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set_nr_cpu_ids(8);
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}
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void __init x86_32_install_bigsmp(void)
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{
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if (nr_cpu_ids > 8 && !xen_pv_domain())
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apic_bigsmp_force();
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}
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void __init x86_32_probe_apic(void)
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{
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if (!cmdline_apic) {
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struct apic **drv;
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for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
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if ((*drv)->probe()) {
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apic_install_driver(*drv);
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break;
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}
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}
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/* Not visible without early console */
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if (drv == __apicdrivers_end)
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panic("Didn't find an APIC driver");
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}
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}
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