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 <asm/io_apic.h>
14#include <asm/apic.h>
15#include <asm/acpi.h>
16
17#include "local.h"
18
19static int default_x86_32_early_logical_apicid(int cpu)
20{
21	return 1 << cpu;
22}
23
24static void setup_apic_flat_routing(void)
25{
26#ifdef CONFIG_X86_IO_APIC
27	printk(KERN_INFO
28		"Enabling APIC mode:  Flat.  Using %d I/O APICs\n",
29		nr_ioapics);
30#endif
31}
32
33static int default_apic_id_registered(void)
34{
35	return physid_isset(read_apic_id(), phys_cpu_present_map);
36}
37
38/*
39 * Set up the logical destination ID.  Intel recommends to set DFR, LDR and
40 * TPR before enabling an APIC.  See e.g. "AP-388 82489DX User's Manual"
41 * (Intel document number 292116).
42 */
43static void default_init_apic_ldr(void)
44{
45	unsigned long val;
46
47	apic_write(APIC_DFR, APIC_DFR_VALUE);
48	val = apic_read(APIC_LDR) & ~APIC_LDR_MASK;
49	val |= SET_APIC_LOGICAL_ID(1UL << smp_processor_id());
50	apic_write(APIC_LDR, val);
51}
52
53static int default_phys_pkg_id(int cpuid_apic, int index_msb)
54{
55	return cpuid_apic >> index_msb;
56}
57
58/* should be called last. */
59static int probe_default(void)
60{
61	return 1;
62}
63
64static struct apic apic_default __ro_after_init = {
65
66	.name				= "default",
67	.probe				= probe_default,
68	.acpi_madt_oem_check		= NULL,
69	.apic_id_valid			= default_apic_id_valid,
70	.apic_id_registered		= default_apic_id_registered,
71
72	.irq_delivery_mode		= dest_Fixed,
73	/* logical delivery broadcast to all CPUs: */
74	.irq_dest_mode			= 1,
75
76	.disable_esr			= 0,
77	.dest_logical			= APIC_DEST_LOGICAL,
78	.check_apicid_used		= default_check_apicid_used,
79
80	.init_apic_ldr			= default_init_apic_ldr,
81
82	.ioapic_phys_id_map		= default_ioapic_phys_id_map,
83	.setup_apic_routing		= setup_apic_flat_routing,
84	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
85	.apicid_to_cpu_present		= physid_set_mask_of_physid,
86	.check_phys_apicid_present	= default_check_phys_apicid_present,
87	.phys_pkg_id			= default_phys_pkg_id,
88
89	.get_apic_id			= default_get_apic_id,
90	.set_apic_id			= NULL,
91
92	.calc_dest_apicid		= apic_flat_calc_apicid,
93
94	.send_IPI			= default_send_IPI_single,
95	.send_IPI_mask			= default_send_IPI_mask_logical,
96	.send_IPI_mask_allbutself	= default_send_IPI_mask_allbutself_logical,
97	.send_IPI_allbutself		= default_send_IPI_allbutself,
98	.send_IPI_all			= default_send_IPI_all,
99	.send_IPI_self			= default_send_IPI_self,
100
101	.inquire_remote_apic		= default_inquire_remote_apic,
102
103	.read				= native_apic_mem_read,
104	.write				= native_apic_mem_write,
105	.eoi_write			= native_apic_mem_write,
106	.icr_read			= native_apic_icr_read,
107	.icr_write			= native_apic_icr_write,
108	.wait_icr_idle			= native_apic_wait_icr_idle,
109	.safe_wait_icr_idle		= native_safe_apic_wait_icr_idle,
110
111	.x86_32_early_logical_apicid	= default_x86_32_early_logical_apicid,
112};
113
114apic_driver(apic_default);
115
116struct apic *apic __ro_after_init = &apic_default;
117EXPORT_SYMBOL_GPL(apic);
118
119static int cmdline_apic __initdata;
120static int __init parse_apic(char *arg)
121{
122	struct apic **drv;
123
124	if (!arg)
125		return -EINVAL;
126
127	for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
128		if (!strcmp((*drv)->name, arg)) {
129			apic = *drv;
130			cmdline_apic = 1;
131			return 0;
132		}
133	}
134
135	/* Parsed again by __setup for debug/verbose */
136	return 0;
137}
138early_param("apic", parse_apic);
139
140void __init default_setup_apic_routing(void)
141{
142	int version = boot_cpu_apic_version;
143
144	if (num_possible_cpus() > 8) {
145		switch (boot_cpu_data.x86_vendor) {
146		case X86_VENDOR_INTEL:
147			if (!APIC_XAPIC(version)) {
148				def_to_bigsmp = 0;
149				break;
150			}
151			/* P4 and above */
152			fallthrough;
153		case X86_VENDOR_HYGON:
154		case X86_VENDOR_AMD:
155			def_to_bigsmp = 1;
156		}
157	}
158
159#ifdef CONFIG_X86_BIGSMP
160	/*
161	 * This is used to switch to bigsmp mode when
162	 * - There is no apic= option specified by the user
163	 * - generic_apic_probe() has chosen apic_default as the sub_arch
164	 * - we find more than 8 CPUs in acpi LAPIC listing with xAPIC support
165	 */
166
167	if (!cmdline_apic && apic == &apic_default)
168		generic_bigsmp_probe();
169#endif
170
171	if (apic->setup_apic_routing)
172		apic->setup_apic_routing();
173}
174
175void __init generic_apic_probe(void)
176{
177	if (!cmdline_apic) {
178		struct apic **drv;
179
180		for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
181			if ((*drv)->probe()) {
182				apic = *drv;
183				break;
184			}
185		}
186		/* Not visible without early console */
187		if (drv == __apicdrivers_end)
188			panic("Didn't find an APIC driver");
189	}
190	printk(KERN_INFO "Using APIC driver %s\n", apic->name);
191}
192
193/* This function can switch the APIC even after the initial ->probe() */
194int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
195{
196	struct apic **drv;
197
198	for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
199		if (!(*drv)->acpi_madt_oem_check)
200			continue;
201		if (!(*drv)->acpi_madt_oem_check(oem_id, oem_table_id))
202			continue;
203
204		if (!cmdline_apic) {
205			apic = *drv;
206			printk(KERN_INFO "Switched to APIC driver `%s'.\n",
207			       apic->name);
208		}
209		return 1;
210	}
211	return 0;
212}
213