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 
default_x86_32_early_logical_apicid(int cpu)19 static int default_x86_32_early_logical_apicid(int cpu)
20 {
21 	return 1 << cpu;
22 }
23 
setup_apic_flat_routing(void)24 static 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 
default_apic_id_registered(void)33 static 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  */
default_init_apic_ldr(void)43 static 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 
default_phys_pkg_id(int cpuid_apic,int index_msb)53 static 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. */
probe_default(void)59 static int probe_default(void)
60 {
61 	return 1;
62 }
63 
64 static 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 	.delivery_mode			= APIC_DELIVERY_MODE_FIXED,
73 	.dest_mode_logical		= true,
74 
75 	.disable_esr			= 0,
76 
77 	.check_apicid_used		= default_check_apicid_used,
78 	.init_apic_ldr			= default_init_apic_ldr,
79 	.ioapic_phys_id_map		= default_ioapic_phys_id_map,
80 	.setup_apic_routing		= setup_apic_flat_routing,
81 	.cpu_present_to_apicid		= default_cpu_present_to_apicid,
82 	.apicid_to_cpu_present		= physid_set_mask_of_physid,
83 	.check_phys_apicid_present	= default_check_phys_apicid_present,
84 	.phys_pkg_id			= default_phys_pkg_id,
85 
86 	.get_apic_id			= default_get_apic_id,
87 	.set_apic_id			= NULL,
88 
89 	.calc_dest_apicid		= apic_flat_calc_apicid,
90 
91 	.send_IPI			= default_send_IPI_single,
92 	.send_IPI_mask			= default_send_IPI_mask_logical,
93 	.send_IPI_mask_allbutself	= default_send_IPI_mask_allbutself_logical,
94 	.send_IPI_allbutself		= default_send_IPI_allbutself,
95 	.send_IPI_all			= default_send_IPI_all,
96 	.send_IPI_self			= default_send_IPI_self,
97 
98 	.inquire_remote_apic		= default_inquire_remote_apic,
99 
100 	.read				= native_apic_mem_read,
101 	.write				= native_apic_mem_write,
102 	.eoi_write			= native_apic_mem_write,
103 	.icr_read			= native_apic_icr_read,
104 	.icr_write			= native_apic_icr_write,
105 	.wait_icr_idle			= native_apic_wait_icr_idle,
106 	.safe_wait_icr_idle		= native_safe_apic_wait_icr_idle,
107 
108 	.x86_32_early_logical_apicid	= default_x86_32_early_logical_apicid,
109 };
110 
111 apic_driver(apic_default);
112 
113 struct apic *apic __ro_after_init = &apic_default;
114 EXPORT_SYMBOL_GPL(apic);
115 
116 static int cmdline_apic __initdata;
parse_apic(char * arg)117 static int __init parse_apic(char *arg)
118 {
119 	struct apic **drv;
120 
121 	if (!arg)
122 		return -EINVAL;
123 
124 	for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
125 		if (!strcmp((*drv)->name, arg)) {
126 			apic = *drv;
127 			cmdline_apic = 1;
128 			return 0;
129 		}
130 	}
131 
132 	/* Parsed again by __setup for debug/verbose */
133 	return 0;
134 }
135 early_param("apic", parse_apic);
136 
default_setup_apic_routing(void)137 void __init default_setup_apic_routing(void)
138 {
139 	int version = boot_cpu_apic_version;
140 
141 	if (num_possible_cpus() > 8) {
142 		switch (boot_cpu_data.x86_vendor) {
143 		case X86_VENDOR_INTEL:
144 			if (!APIC_XAPIC(version)) {
145 				def_to_bigsmp = 0;
146 				break;
147 			}
148 			/* P4 and above */
149 			fallthrough;
150 		case X86_VENDOR_HYGON:
151 		case X86_VENDOR_AMD:
152 			def_to_bigsmp = 1;
153 		}
154 	}
155 
156 #ifdef CONFIG_X86_BIGSMP
157 	/*
158 	 * This is used to switch to bigsmp mode when
159 	 * - There is no apic= option specified by the user
160 	 * - generic_apic_probe() has chosen apic_default as the sub_arch
161 	 * - we find more than 8 CPUs in acpi LAPIC listing with xAPIC support
162 	 */
163 
164 	if (!cmdline_apic && apic == &apic_default)
165 		generic_bigsmp_probe();
166 #endif
167 
168 	if (apic->setup_apic_routing)
169 		apic->setup_apic_routing();
170 }
171 
generic_apic_probe(void)172 void __init generic_apic_probe(void)
173 {
174 	if (!cmdline_apic) {
175 		struct apic **drv;
176 
177 		for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
178 			if ((*drv)->probe()) {
179 				apic = *drv;
180 				break;
181 			}
182 		}
183 		/* Not visible without early console */
184 		if (drv == __apicdrivers_end)
185 			panic("Didn't find an APIC driver");
186 	}
187 	printk(KERN_INFO "Using APIC driver %s\n", apic->name);
188 }
189 
190 /* This function can switch the APIC even after the initial ->probe() */
default_acpi_madt_oem_check(char * oem_id,char * oem_table_id)191 int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
192 {
193 	struct apic **drv;
194 
195 	for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
196 		if (!(*drv)->acpi_madt_oem_check)
197 			continue;
198 		if (!(*drv)->acpi_madt_oem_check(oem_id, oem_table_id))
199 			continue;
200 
201 		if (!cmdline_apic) {
202 			apic = *drv;
203 			printk(KERN_INFO "Switched to APIC driver `%s'.\n",
204 			       apic->name);
205 		}
206 		return 1;
207 	}
208 	return 0;
209 }
210