1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * NOOP APIC driver. 4 * 5 * Does almost nothing and should be substituted by a real apic driver via 6 * probe routine. 7 * 8 * Though in case if apic is disabled (for some reason) we try 9 * to not uglify the caller's code and allow to call (some) apic routines 10 * like self-ipi, etc... 11 */ 12 13 #include <linux/threads.h> 14 #include <linux/cpumask.h> 15 #include <linux/string.h> 16 #include <linux/kernel.h> 17 #include <linux/ctype.h> 18 #include <linux/errno.h> 19 #include <asm/fixmap.h> 20 #include <asm/mpspec.h> 21 #include <asm/apicdef.h> 22 #include <asm/apic.h> 23 #include <asm/setup.h> 24 25 #include <linux/smp.h> 26 #include <asm/ipi.h> 27 28 #include <linux/interrupt.h> 29 #include <asm/acpi.h> 30 #include <asm/e820/api.h> 31 32 static void noop_init_apic_ldr(void) { } 33 static void noop_send_IPI(int cpu, int vector) { } 34 static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { } 35 static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { } 36 static void noop_send_IPI_allbutself(int vector) { } 37 static void noop_send_IPI_all(int vector) { } 38 static void noop_send_IPI_self(int vector) { } 39 static void noop_apic_wait_icr_idle(void) { } 40 static void noop_apic_icr_write(u32 low, u32 id) { } 41 42 static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip) 43 { 44 return -1; 45 } 46 47 static u32 noop_safe_apic_wait_icr_idle(void) 48 { 49 return 0; 50 } 51 52 static u64 noop_apic_icr_read(void) 53 { 54 return 0; 55 } 56 57 static int noop_phys_pkg_id(int cpuid_apic, int index_msb) 58 { 59 return 0; 60 } 61 62 static unsigned int noop_get_apic_id(unsigned long x) 63 { 64 return 0; 65 } 66 67 static int noop_probe(void) 68 { 69 /* 70 * NOOP apic should not ever be 71 * enabled via probe routine 72 */ 73 return 0; 74 } 75 76 static int noop_apic_id_registered(void) 77 { 78 /* 79 * if we would be really "pedantic" 80 * we should pass read_apic_id() here 81 * but since NOOP suppose APIC ID = 0 82 * lets save a few cycles 83 */ 84 return physid_isset(0, phys_cpu_present_map); 85 } 86 87 static u32 noop_apic_read(u32 reg) 88 { 89 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic); 90 return 0; 91 } 92 93 static void noop_apic_write(u32 reg, u32 v) 94 { 95 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic); 96 } 97 98 #ifdef CONFIG_X86_32 99 static int noop_x86_32_early_logical_apicid(int cpu) 100 { 101 return BAD_APICID; 102 } 103 #endif 104 105 struct apic apic_noop __ro_after_init = { 106 .name = "noop", 107 .probe = noop_probe, 108 .acpi_madt_oem_check = NULL, 109 110 .apic_id_valid = default_apic_id_valid, 111 .apic_id_registered = noop_apic_id_registered, 112 113 .irq_delivery_mode = dest_Fixed, 114 /* logical delivery broadcast to all CPUs: */ 115 .irq_dest_mode = 1, 116 117 .disable_esr = 0, 118 .dest_logical = APIC_DEST_LOGICAL, 119 .check_apicid_used = default_check_apicid_used, 120 121 .init_apic_ldr = noop_init_apic_ldr, 122 123 .ioapic_phys_id_map = default_ioapic_phys_id_map, 124 .setup_apic_routing = NULL, 125 126 .cpu_present_to_apicid = default_cpu_present_to_apicid, 127 .apicid_to_cpu_present = physid_set_mask_of_physid, 128 129 .check_phys_apicid_present = default_check_phys_apicid_present, 130 131 .phys_pkg_id = noop_phys_pkg_id, 132 133 .get_apic_id = noop_get_apic_id, 134 .set_apic_id = NULL, 135 136 .calc_dest_apicid = apic_flat_calc_apicid, 137 138 .send_IPI = noop_send_IPI, 139 .send_IPI_mask = noop_send_IPI_mask, 140 .send_IPI_mask_allbutself = noop_send_IPI_mask_allbutself, 141 .send_IPI_allbutself = noop_send_IPI_allbutself, 142 .send_IPI_all = noop_send_IPI_all, 143 .send_IPI_self = noop_send_IPI_self, 144 145 .wakeup_secondary_cpu = noop_wakeup_secondary_cpu, 146 147 .inquire_remote_apic = NULL, 148 149 .read = noop_apic_read, 150 .write = noop_apic_write, 151 .eoi_write = noop_apic_write, 152 .icr_read = noop_apic_icr_read, 153 .icr_write = noop_apic_icr_write, 154 .wait_icr_idle = noop_apic_wait_icr_idle, 155 .safe_wait_icr_idle = noop_safe_apic_wait_icr_idle, 156 157 #ifdef CONFIG_X86_32 158 .x86_32_early_logical_apicid = noop_x86_32_early_logical_apicid, 159 #endif 160 }; 161