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
noop_init_apic_ldr(void)17 static void noop_init_apic_ldr(void) { }
noop_send_IPI(int cpu,int vector)18 static void noop_send_IPI(int cpu, int vector) { }
noop_send_IPI_mask(const struct cpumask * cpumask,int vector)19 static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
noop_send_IPI_mask_allbutself(const struct cpumask * cpumask,int vector)20 static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
noop_send_IPI_allbutself(int vector)21 static void noop_send_IPI_allbutself(int vector) { }
noop_send_IPI_all(int vector)22 static void noop_send_IPI_all(int vector) { }
noop_send_IPI_self(int vector)23 static void noop_send_IPI_self(int vector) { }
noop_apic_wait_icr_idle(void)24 static void noop_apic_wait_icr_idle(void) { }
noop_apic_icr_write(u32 low,u32 id)25 static void noop_apic_icr_write(u32 low, u32 id) { }
26
noop_wakeup_secondary_cpu(int apicid,unsigned long start_eip)27 static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip)
28 {
29 return -1;
30 }
31
noop_safe_apic_wait_icr_idle(void)32 static u32 noop_safe_apic_wait_icr_idle(void)
33 {
34 return 0;
35 }
36
noop_apic_icr_read(void)37 static u64 noop_apic_icr_read(void)
38 {
39 return 0;
40 }
41
noop_phys_pkg_id(int cpuid_apic,int index_msb)42 static int noop_phys_pkg_id(int cpuid_apic, int index_msb)
43 {
44 return 0;
45 }
46
noop_get_apic_id(unsigned long x)47 static unsigned int noop_get_apic_id(unsigned long x)
48 {
49 return 0;
50 }
51
noop_probe(void)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
noop_apic_id_registered(void)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
noop_apic_read(u32 reg)72 static u32 noop_apic_read(u32 reg)
73 {
74 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
75 return 0;
76 }
77
noop_apic_write(u32 reg,u32 v)78 static void noop_apic_write(u32 reg, u32 v)
79 {
80 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !disable_apic);
81 }
82
83 #ifdef CONFIG_X86_32
noop_x86_32_early_logical_apicid(int cpu)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