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 * FIXME: Remove this gunk. The above argument which was intentionally left
13 * in place is silly to begin with because none of the callbacks except for
14 * APIC::read/write() have a WARN_ON_ONCE() in them. Sigh...
15 */
16 #include <linux/cpumask.h>
17 #include <linux/thread_info.h>
18
19 #include <asm/apic.h>
20
noop_send_IPI(int cpu,int vector)21 static void noop_send_IPI(int cpu, int vector) { }
noop_send_IPI_mask(const struct cpumask * cpumask,int vector)22 static void noop_send_IPI_mask(const struct cpumask *cpumask, int vector) { }
noop_send_IPI_mask_allbutself(const struct cpumask * cpumask,int vector)23 static void noop_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) { }
noop_send_IPI_allbutself(int vector)24 static void noop_send_IPI_allbutself(int vector) { }
noop_send_IPI_all(int vector)25 static void noop_send_IPI_all(int vector) { }
noop_send_IPI_self(int vector)26 static void noop_send_IPI_self(int vector) { }
noop_apic_icr_write(u32 low,u32 id)27 static void noop_apic_icr_write(u32 low, u32 id) { }
noop_wakeup_secondary_cpu(int apicid,unsigned long start_eip)28 static int noop_wakeup_secondary_cpu(int apicid, unsigned long start_eip) { return -1; }
noop_apic_icr_read(void)29 static u64 noop_apic_icr_read(void) { return 0; }
noop_phys_pkg_id(int cpuid_apic,int index_msb)30 static int noop_phys_pkg_id(int cpuid_apic, int index_msb) { return 0; }
noop_get_apic_id(unsigned long x)31 static unsigned int noop_get_apic_id(unsigned long x) { return 0; }
noop_apic_eoi(void)32 static void noop_apic_eoi(void) { }
33
noop_apic_read(u32 reg)34 static u32 noop_apic_read(u32 reg)
35 {
36 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !apic_is_disabled);
37 return 0;
38 }
39
noop_apic_write(u32 reg,u32 val)40 static void noop_apic_write(u32 reg, u32 val)
41 {
42 WARN_ON_ONCE(boot_cpu_has(X86_FEATURE_APIC) && !apic_is_disabled);
43 }
44
45 struct apic apic_noop __ro_after_init = {
46 .name = "noop",
47
48 .delivery_mode = APIC_DELIVERY_MODE_FIXED,
49 .dest_mode_logical = true,
50
51 .disable_esr = 0,
52
53 .check_apicid_used = default_check_apicid_used,
54 .ioapic_phys_id_map = default_ioapic_phys_id_map,
55 .cpu_present_to_apicid = default_cpu_present_to_apicid,
56
57 .phys_pkg_id = noop_phys_pkg_id,
58
59 .max_apic_id = 0xFE,
60 .get_apic_id = noop_get_apic_id,
61
62 .calc_dest_apicid = apic_flat_calc_apicid,
63
64 .send_IPI = noop_send_IPI,
65 .send_IPI_mask = noop_send_IPI_mask,
66 .send_IPI_mask_allbutself = noop_send_IPI_mask_allbutself,
67 .send_IPI_allbutself = noop_send_IPI_allbutself,
68 .send_IPI_all = noop_send_IPI_all,
69 .send_IPI_self = noop_send_IPI_self,
70
71 .wakeup_secondary_cpu = noop_wakeup_secondary_cpu,
72
73 .read = noop_apic_read,
74 .write = noop_apic_write,
75 .eoi = noop_apic_eoi,
76 .icr_read = noop_apic_icr_read,
77 .icr_write = noop_apic_icr_write,
78 };
79