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 #include <linux/cpumask.h> 13 14 #include <asm/apic.h> 15 16 static void noop_init_apic_ldr(void) { } 17 static void noop_send_IPI(int cpu, int vector) { } 18 static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { } 19 static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { } 20 static void noop_send_IPI_allbutself(int vector) { } 21 static void noop_send_IPI_all(int vector) { } 22 static void noop_send_IPI_self(int vector) { } 23 static void noop_apic_wait_icr_idle(void) { } 24 static void noop_apic_icr_write(u32 low, u32 id) { } 25 26 static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip) 27 { 28 return -1; 29 } 30 31 static u32 noop_safe_apic_wait_icr_idle(void) 32 { 33 return 0; 34 } 35 36 static u64 noop_apic_icr_read(void) 37 { 38 return 0; 39 } 40 41 static int noop_phys_pkg_id(int cpuid_apic, int index_msb) 42 { 43 return 0; 44 } 45 46 static unsigned int noop_get_apic_id(unsigned long x) 47 { 48 return 0; 49 } 50 51 static int noop_probe(void) 52 { 53 /* 54 * NOOP apic should not ever be 55 * enabled via probe routine 56 */ 57 return 0; 58 } 59 60 static int noop_apic_id_registered(void) 61 { 62 /* 63 * if we would be really "pedantic" 64 * we should pass read_apic_id() here 65 * but since NOOP suppose APIC ID = 0 66 * lets save a few cycles 67 */ 68 return physid_isset(0, phys_cpu_present_map); 69 } 70 71 static u32 noop_apic_read(u32 reg) 72 { 73 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic); 74 return 0; 75 } 76 77 static void noop_apic_write(u32 reg, u32 v) 78 { 79 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic); 80 } 81 82 #ifdef CONFIG_X86_32 83 static int noop_x86_32_early_logical_apicid(int cpu) 84 { 85 return BAD_APICID; 86 } 87 #endif 88 89 struct apic apic_noop __ro_after_init = { 90 .name = "noop", 91 .probe = noop_probe, 92 .acpi_madt_oem_check = NULL, 93 94 .apic_id_valid = default_apic_id_valid, 95 .apic_id_registered = noop_apic_id_registered, 96 97 .irq_delivery_mode = dest_Fixed, 98 /* logical delivery broadcast to all CPUs: */ 99 .irq_dest_mode = 1, 100 101 .disable_esr = 0, 102 .dest_logical = APIC_DEST_LOGICAL, 103 .check_apicid_used = default_check_apicid_used, 104 105 .init_apic_ldr = noop_init_apic_ldr, 106 107 .ioapic_phys_id_map = default_ioapic_phys_id_map, 108 .setup_apic_routing = NULL, 109 110 .cpu_present_to_apicid = default_cpu_present_to_apicid, 111 .apicid_to_cpu_present = physid_set_mask_of_physid, 112 113 .check_phys_apicid_present = default_check_phys_apicid_present, 114 115 .phys_pkg_id = noop_phys_pkg_id, 116 117 .get_apic_id = noop_get_apic_id, 118 .set_apic_id = NULL, 119 120 .calc_dest_apicid = apic_flat_calc_apicid, 121 122 .send_IPI = noop_send_IPI, 123 .send_IPI_mask = noop_send_IPI_mask, 124 .send_IPI_mask_allbutself = noop_send_IPI_mask_allbutself, 125 .send_IPI_allbutself = noop_send_IPI_allbutself, 126 .send_IPI_all = noop_send_IPI_all, 127 .send_IPI_self = noop_send_IPI_self, 128 129 .wakeup_secondary_cpu = noop_wakeup_secondary_cpu, 130 131 .inquire_remote_apic = NULL, 132 133 .read = noop_apic_read, 134 .write = noop_apic_write, 135 .eoi_write = noop_apic_write, 136 .icr_read = noop_apic_icr_read, 137 .icr_write = noop_apic_icr_write, 138 .wait_icr_idle = noop_apic_wait_icr_idle, 139 .safe_wait_icr_idle = noop_safe_apic_wait_icr_idle, 140 141 #ifdef CONFIG_X86_32 142 .x86_32_early_logical_apicid = noop_x86_32_early_logical_apicid, 143 #endif 144 }; 145