1 // SPDX-License-Identifier: GPL-2.0-only
3 * Default generic APIC driver. This handles up to 8 CPUs.
5 * Copyright 2003 Andi Kleen, SuSE Labs.
7 * Generic x86 APIC driver probe layer.
9 #include <linux/export.h>
10 #include <linux/errno.h>
11 #include <linux/smp.h>
13 #include <asm/io_apic.h>
19 static int default_x86_32_early_logical_apicid(int cpu)
24 static void setup_apic_flat_routing(void)
26 #ifdef CONFIG_X86_IO_APIC
28 "Enabling APIC mode: Flat. Using %d I/O APICs\n",
33 static int default_apic_id_registered(void)
35 return physid_isset(read_apic_id(), phys_cpu_present_map);
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).
43 static void default_init_apic_ldr(void)
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);
53 static int default_phys_pkg_id(int cpuid_apic, int index_msb)
55 return cpuid_apic >> index_msb;
58 /* should be called last. */
59 static int probe_default(void)
64 static struct apic apic_default __ro_after_init = {
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,
72 .delivery_mode = APIC_DELIVERY_MODE_FIXED,
73 .dest_mode_logical = true,
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,
86 .get_apic_id = default_get_apic_id,
89 .calc_dest_apicid = apic_flat_calc_apicid,
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,
98 .inquire_remote_apic = default_inquire_remote_apic,
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,
108 .x86_32_early_logical_apicid = default_x86_32_early_logical_apicid,
111 apic_driver(apic_default);
113 struct apic *apic __ro_after_init = &apic_default;
114 EXPORT_SYMBOL_GPL(apic);
116 static int cmdline_apic __initdata;
117 static int __init parse_apic(char *arg)
124 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
125 if (!strcmp((*drv)->name, arg)) {
132 /* Parsed again by __setup for debug/verbose */
135 early_param("apic", parse_apic);
137 void __init default_setup_apic_routing(void)
139 int version = boot_cpu_apic_version;
141 if (num_possible_cpus() > 8) {
142 switch (boot_cpu_data.x86_vendor) {
143 case X86_VENDOR_INTEL:
144 if (!APIC_XAPIC(version)) {
150 case X86_VENDOR_HYGON:
156 #ifdef CONFIG_X86_BIGSMP
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
164 if (!cmdline_apic && apic == &apic_default)
165 generic_bigsmp_probe();
168 if (apic->setup_apic_routing)
169 apic->setup_apic_routing();
172 void __init generic_apic_probe(void)
177 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
178 if ((*drv)->probe()) {
183 /* Not visible without early console */
184 if (drv == __apicdrivers_end)
185 panic("Didn't find an APIC driver");
187 printk(KERN_INFO "Using APIC driver %s\n", apic->name);
190 /* This function can switch the APIC even after the initial ->probe() */
191 int __init default_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
195 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
196 if (!(*drv)->acpi_madt_oem_check)
198 if (!(*drv)->acpi_madt_oem_check(oem_id, oem_table_id))
203 printk(KERN_INFO "Switched to APIC driver `%s'.\n",