1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Default generic APIC driver. This handles up to 8 CPUs.
4 *
5 * Copyright 2003 Andi Kleen, SuSE Labs.
6 *
7 * Generic x86 APIC driver probe layer.
8 */
9 #include <linux/export.h>
10 #include <linux/errno.h>
11 #include <linux/smp.h>
12
13 #include <xen/xen.h>
14
15 #include <asm/io_apic.h>
16 #include <asm/apic.h>
17 #include <asm/acpi.h>
18
19 #include "local.h"
20
21 static u32 default_get_apic_id(u32 x)
22 {
23 unsigned int ver = GET_APIC_VERSION(apic_read(APIC_LVR));
24
25 if (APIC_XAPIC(ver) || boot_cpu_has(X86_FEATURE_EXTD_APICID))
26 return (x >> 24) & 0xFF;
27 else
28 return (x >> 24) & 0x0F;
29 }
30
31 /* should be called last. */
32 static int probe_default(void)
33 {
34 return 1;
35 }
36
37 static struct apic apic_default __ro_after_init = {
38
39 .name = "default",
40 .probe = probe_default,
41
42 .dest_mode_logical = true,
43
44 .disable_esr = 0,
45
46 .init_apic_ldr = default_init_apic_ldr,
47 .cpu_present_to_apicid = default_cpu_present_to_apicid,
48
49 .max_apic_id = 0xFE,
50 .get_apic_id = default_get_apic_id,
51
52 .calc_dest_apicid = apic_flat_calc_apicid,
53
54 .send_IPI = default_send_IPI_single,
55 .send_IPI_mask = default_send_IPI_mask_logical,
56 .send_IPI_mask_allbutself = default_send_IPI_mask_allbutself_logical,
57 .send_IPI_allbutself = default_send_IPI_allbutself,
58 .send_IPI_all = default_send_IPI_all,
59 .send_IPI_self = default_send_IPI_self,
60
61 .read = native_apic_mem_read,
62 .write = native_apic_mem_write,
63 .eoi = native_apic_mem_eoi,
64 .icr_read = native_apic_icr_read,
65 .icr_write = native_apic_icr_write,
66 .wait_icr_idle = apic_mem_wait_icr_idle,
67 .safe_wait_icr_idle = apic_mem_wait_icr_idle_timeout,
68 };
69
70 apic_driver(apic_default);
71
72 struct apic *apic __ro_after_init = &apic_default;
73 EXPORT_SYMBOL_GPL(apic);
74
75 static int cmdline_apic __initdata;
76 static int __init parse_apic(char *arg)
77 {
78 struct apic **drv;
79
80 if (!arg)
81 return -EINVAL;
82
83 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
84 if (!strcmp((*drv)->name, arg)) {
85 apic_install_driver(*drv);
86 cmdline_apic = 1;
87 return 0;
88 }
89 }
90
91 /* Parsed again by __setup for debug/verbose */
92 return 0;
93 }
94 early_param("apic", parse_apic);
95
96 void __init x86_32_probe_bigsmp_early(void)
97 {
98 if (nr_cpu_ids <= 8 || xen_pv_domain())
99 return;
100
101 if (IS_ENABLED(CONFIG_X86_BIGSMP)) {
102 switch (boot_cpu_data.x86_vendor) {
103 case X86_VENDOR_INTEL:
104 if (!APIC_XAPIC(boot_cpu_apic_version))
105 break;
106 /* P4 and above */
107 fallthrough;
108 case X86_VENDOR_HYGON:
109 case X86_VENDOR_AMD:
110 if (apic_bigsmp_possible(cmdline_apic))
111 return;
112 break;
113 }
114 }
115 pr_info("Limiting to 8 possible CPUs\n");
116 set_nr_cpu_ids(8);
117 }
118
119 void __init x86_32_install_bigsmp(void)
120 {
121 if (nr_cpu_ids > 8 && !xen_pv_domain())
122 apic_bigsmp_force();
123 }
124
125 void __init x86_32_probe_apic(void)
126 {
127 if (!cmdline_apic) {
128 struct apic **drv;
129
130 for (drv = __apicdrivers; drv < __apicdrivers_end; drv++) {
131 if ((*drv)->probe()) {
132 apic_install_driver(*drv);
133 break;
134 }
135 }
136 /* Not visible without early console */
137 if (drv == __apicdrivers_end)
138 panic("Didn't find an APIC driver");
139 }
140 }
141
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