probe_32.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Default generic APIC driver. This handles up to 8 CPUs.
  4 *
  5 * Copyright 2003 Andi Kleen, SuSE Labs.
  6 *
  7 * Generic x86 APIC driver probe layer.
  8 */
  9#include <linux/export.h>
 10#include <linux/errno.h>
 11#include <linux/smp.h>
 12
 13#include <xen/xen.h>
 14
 15#include <asm/io_apic.h>
 16#include <asm/apic.h>
 17#include <asm/acpi.h>
 18
 19#include "local.h"
 20
 21static u32 default_get_apic_id(u32 x)
 22{
 23	unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
 24
 25	if (APIC_XAPIC(ver) || boot_cpu_has(X86_FEATURE_EXTD_APICID))
 26		return (x >> 24) & 0xFF;
 27	else
 28		return (x >> 24) & 0x0F;
 29}
 30
 31/* should be called last. */
 32static int probe_default(void)
 33{
 34	return 1;
 35}
 36
 37static struct apic apic_default __ro_after_init = {
 38
 39	.name				= "default",
 40	.probe				= probe_default,
 41
 42	.dest_mode_logical		= true,
 43
 44	.disable_esr			= 0,
 45
 46	.init_apic_ldr			= default_init_apic_ldr,
 47	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
 48
 49	.max_apic_id			= 0xFE,
 50	.get_apic_id			= default_get_apic_id,
 51
 52	.calc_dest_apicid		= apic_flat_calc_apicid,
 53
 54	.send_IPI			= default_send_IPI_single,
 55	.send_IPI_mask			= default_send_IPI_mask_logical,
 56	.send_IPI_mask_allbutself	= default_send_IPI_mask_allbutself_logical,
 57	.send_IPI_allbutself		= default_send_IPI_allbutself,
 58	.send_IPI_all			= default_send_IPI_all,
 59	.send_IPI_self			= default_send_IPI_self,
 60
 61	.read				= native_apic_mem_read,
 62	.write				= native_apic_mem_write,
 63	.eoi				= native_apic_mem_eoi,
 64	.icr_read			= native_apic_icr_read,
 65	.icr_write			= native_apic_icr_write,
 66	.wait_icr_idle			= apic_mem_wait_icr_idle,
 67	.safe_wait_icr_idle		= apic_mem_wait_icr_idle_timeout,
 68};
 69
 70apic_driver(apic_default);
 71
 72struct apic *apic __ro_after_init = &apic_default;
 73EXPORT_SYMBOL_GPL(apic);
 74
 75static int cmdline_apic __initdata;
 76static int __init parse_apic(char *arg)
 77{
 78	struct apic **drv;
 79
 80	if (!arg)
 81		return -EINVAL;
 82
 83	for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
 84		if (!strcmp((*drv)->name, arg)) {
 85			apic_install_driver(*drv);
 86			cmdline_apic = 1;
 87			return 0;
 88		}
 89	}
 90
 91	/* Parsed again by __setup for debug/verbose */
 92	return 0;
 93}
 94early_param("apic", parse_apic);
 95
 96void __init x86_32_probe_apic(void)
 97{
 98	if (!cmdline_apic) {
 99		struct apic **drv;
100
101		for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
102			if ((*drv)->probe()) {
103				apic_install_driver(*drv);
104				break;
105			}
106		}
107		/* Not visible without early console */
108		if (drv == __apicdrivers_end)
109			panic("Didn't find an APIC driver");
110	}
111}