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 21 static 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. */ 32 static int probe_default(void) 33 { 34 return 1; 35 } 36 37 static struct apic apic_default __ro_after_init = { 38 39 .name = "default", 40 .probe = probe_default, 41 .apic_id_registered = default_apic_id_registered, 42 43 .dest_mode_logical = true, 44 45 .disable_esr = 0, 46 47 .check_apicid_used = default_check_apicid_used, 48 .init_apic_ldr = default_init_apic_ldr, 49 .ioapic_phys_id_map = default_ioapic_phys_id_map, 50 .cpu_present_to_apicid = default_cpu_present_to_apicid, 51 52 .max_apic_id = 0xFE, 53 .get_apic_id = default_get_apic_id, 54 55 .calc_dest_apicid = apic_flat_calc_apicid, 56 57 .send_IPI = default_send_IPI_single, 58 .send_IPI_mask = default_send_IPI_mask_logical, 59 .send_IPI_mask_allbutself = default_send_IPI_mask_allbutself_logical, 60 .send_IPI_allbutself = default_send_IPI_allbutself, 61 .send_IPI_all = default_send_IPI_all, 62 .send_IPI_self = default_send_IPI_self, 63 64 .read = native_apic_mem_read, 65 .write = native_apic_mem_write, 66 .eoi = native_apic_mem_eoi, 67 .icr_read = native_apic_icr_read, 68 .icr_write = native_apic_icr_write, 69 .wait_icr_idle = apic_mem_wait_icr_idle, 70 .safe_wait_icr_idle = apic_mem_wait_icr_idle_timeout, 71 }; 72 73 apic_driver(apic_default); 74 75 struct apic *apic __ro_after_init = &apic_default; 76 EXPORT_SYMBOL_GPL(apic); 77 78 static int cmdline_apic __initdata; 79 static int __init parse_apic(char *arg) 80 { 81 struct apic **drv; 82 83 if (!arg) 84 return -EINVAL; 85 86 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) { 87 if (!strcmp((*drv)->name, arg)) { 88 apic_install_driver(*drv); 89 cmdline_apic = 1; 90 return 0; 91 } 92 } 93 94 /* Parsed again by __setup for debug/verbose */ 95 return 0; 96 } 97 early_param("apic", parse_apic); 98 99 void __init x86_32_probe_bigsmp_early(void) 100 { 101 if (nr_cpu_ids <= 8 || xen_pv_domain()) 102 return; 103 104 if (IS_ENABLED(CONFIG_X86_BIGSMP)) { 105 switch (boot_cpu_data.x86_vendor) { 106 case X86_VENDOR_INTEL: 107 if (!APIC_XAPIC(boot_cpu_apic_version)) 108 break; 109 /* P4 and above */ 110 fallthrough; 111 case X86_VENDOR_HYGON: 112 case X86_VENDOR_AMD: 113 if (apic_bigsmp_possible(cmdline_apic)) 114 return; 115 break; 116 } 117 } 118 pr_info("Limiting to 8 possible CPUs\n"); 119 set_nr_cpu_ids(8); 120 } 121 122 void __init x86_32_install_bigsmp(void) 123 { 124 if (nr_cpu_ids > 8 && !xen_pv_domain()) 125 apic_bigsmp_force(); 126 } 127 128 void __init x86_32_probe_apic(void) 129 { 130 if (!cmdline_apic) { 131 struct apic **drv; 132 133 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) { 134 if ((*drv)->probe()) { 135 apic_install_driver(*drv); 136 break; 137 } 138 } 139 /* Not visible without early console */ 140 if (drv == __apicdrivers_end) 141 panic("Didn't find an APIC driver"); 142 } 143 } 144