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_phys_pkg_id(u32 cpuid_apic, int index_msb) 22 { 23 return cpuid_apic >> index_msb; 24 } 25 26 static u32 default_get_apic_id(u32 x) 27 { 28 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR)); 29 30 if (APIC_XAPIC(ver) || boot_cpu_has(X86_FEATURE_EXTD_APICID)) 31 return (x >> 24) & 0xFF; 32 else 33 return (x >> 24) & 0x0F; 34 } 35 36 /* should be called last. */ 37 static int probe_default(void) 38 { 39 return 1; 40 } 41 42 static struct apic apic_default __ro_after_init = { 43 44 .name = "default", 45 .probe = probe_default, 46 .apic_id_registered = default_apic_id_registered, 47 48 .dest_mode_logical = true, 49 50 .disable_esr = 0, 51 52 .check_apicid_used = default_check_apicid_used, 53 .init_apic_ldr = default_init_apic_ldr, 54 .ioapic_phys_id_map = default_ioapic_phys_id_map, 55 .cpu_present_to_apicid = default_cpu_present_to_apicid, 56 .phys_pkg_id = default_phys_pkg_id, 57 58 .max_apic_id = 0xFE, 59 .get_apic_id = default_get_apic_id, 60 61 .calc_dest_apicid = apic_flat_calc_apicid, 62 63 .send_IPI = default_send_IPI_single, 64 .send_IPI_mask = default_send_IPI_mask_logical, 65 .send_IPI_mask_allbutself = default_send_IPI_mask_allbutself_logical, 66 .send_IPI_allbutself = default_send_IPI_allbutself, 67 .send_IPI_all = default_send_IPI_all, 68 .send_IPI_self = default_send_IPI_self, 69 70 .read = native_apic_mem_read, 71 .write = native_apic_mem_write, 72 .eoi = native_apic_mem_eoi, 73 .icr_read = native_apic_icr_read, 74 .icr_write = native_apic_icr_write, 75 .wait_icr_idle = apic_mem_wait_icr_idle, 76 .safe_wait_icr_idle = apic_mem_wait_icr_idle_timeout, 77 }; 78 79 apic_driver(apic_default); 80 81 struct apic *apic __ro_after_init = &apic_default; 82 EXPORT_SYMBOL_GPL(apic); 83 84 static int cmdline_apic __initdata; 85 static int __init parse_apic(char *arg) 86 { 87 struct apic **drv; 88 89 if (!arg) 90 return -EINVAL; 91 92 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) { 93 if (!strcmp((*drv)->name, arg)) { 94 apic_install_driver(*drv); 95 cmdline_apic = 1; 96 return 0; 97 } 98 } 99 100 /* Parsed again by __setup for debug/verbose */ 101 return 0; 102 } 103 early_param("apic", parse_apic); 104 105 void __init x86_32_probe_bigsmp_early(void) 106 { 107 if (nr_cpu_ids <= 8 || xen_pv_domain()) 108 return; 109 110 if (IS_ENABLED(CONFIG_X86_BIGSMP)) { 111 switch (boot_cpu_data.x86_vendor) { 112 case X86_VENDOR_INTEL: 113 if (!APIC_XAPIC(boot_cpu_apic_version)) 114 break; 115 /* P4 and above */ 116 fallthrough; 117 case X86_VENDOR_HYGON: 118 case X86_VENDOR_AMD: 119 if (apic_bigsmp_possible(cmdline_apic)) 120 return; 121 break; 122 } 123 } 124 pr_info("Limiting to 8 possible CPUs\n"); 125 set_nr_cpu_ids(8); 126 } 127 128 void __init x86_32_install_bigsmp(void) 129 { 130 if (nr_cpu_ids > 8 && !xen_pv_domain()) 131 apic_bigsmp_force(); 132 } 133 134 void __init x86_32_probe_apic(void) 135 { 136 if (!cmdline_apic) { 137 struct apic **drv; 138 139 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) { 140 if ((*drv)->probe()) { 141 apic_install_driver(*drv); 142 break; 143 } 144 } 145 /* Not visible without early console */ 146 if (drv == __apicdrivers_end) 147 panic("Didn't find an APIC driver"); 148 } 149 } 150