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