1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/cpuhotplug.h>
4 #include <linux/cpumask.h>
5 #include <linux/slab.h>
6 #include <linux/mm.h>
7
8 #include <asm/apic.h>
9
10 #include "local.h"
11
12 struct cluster_mask {
13 unsigned int clusterid;
14 int node;
15 struct cpumask mask;
16 };
17
18 static DEFINE_PER_CPU(u32, x86_cpu_to_logical_apicid);
19 static DEFINE_PER_CPU(cpumask_var_t, ipi_mask);
20 static DEFINE_PER_CPU(struct cluster_mask *, cluster_masks);
21 static struct cluster_mask *cluster_hotplug_mask;
22
x2apic_acpi_madt_oem_check(char * oem_id,char * oem_table_id)23 static int x2apic_acpi_madt_oem_check(char *oem_id, char *oem_table_id)
24 {
25 return x2apic_enabled();
26 }
27
x2apic_send_IPI(int cpu,int vector)28 static void x2apic_send_IPI(int cpu, int vector)
29 {
30 u32 dest = per_cpu(x86_cpu_to_logical_apicid, cpu);
31
32 /* x2apic MSRs are special and need a special fence: */
33 weak_wrmsr_fence();
34 __x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL);
35 }
36
37 static void
__x2apic_send_IPI_mask(const struct cpumask * mask,int vector,int apic_dest)38 __x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest)
39 {
40 unsigned int cpu, clustercpu;
41 struct cpumask *tmpmsk;
42 unsigned long flags;
43 u32 dest;
44
45 /* x2apic MSRs are special and need a special fence: */
46 weak_wrmsr_fence();
47 local_irq_save(flags);
48
49 tmpmsk = this_cpu_cpumask_var_ptr(ipi_mask);
50 cpumask_copy(tmpmsk, mask);
51 /* If IPI should not be sent to self, clear current CPU */
52 if (apic_dest != APIC_DEST_ALLINC)
53 __cpumask_clear_cpu(smp_processor_id(), tmpmsk);
54
55 /* Collapse cpus in a cluster so a single IPI per cluster is sent */
56 for_each_cpu(cpu, tmpmsk) {
57 struct cluster_mask *cmsk = per_cpu(cluster_masks, cpu);
58
59 dest = 0;
60 for_each_cpu_and(clustercpu, tmpmsk, &cmsk->mask)
61 dest |= per_cpu(x86_cpu_to_logical_apicid, clustercpu);
62
63 if (!dest)
64 continue;
65
66 __x2apic_send_IPI_dest(dest, vector, APIC_DEST_LOGICAL);
67 /* Remove cluster CPUs from tmpmask */
68 cpumask_andnot(tmpmsk, tmpmsk, &cmsk->mask);
69 }
70
71 local_irq_restore(flags);
72 }
73
x2apic_send_IPI_mask(const struct cpumask * mask,int vector)74 static void x2apic_send_IPI_mask(const struct cpumask *mask, int vector)
75 {
76 __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLINC);
77 }
78
79 static void
x2apic_send_IPI_mask_allbutself(const struct cpumask * mask,int vector)80 x2apic_send_IPI_mask_allbutself(const struct cpumask *mask, int vector)
81 {
82 __x2apic_send_IPI_mask(mask, vector, APIC_DEST_ALLBUT);
83 }
84
x2apic_send_IPI_allbutself(int vector)85 static void x2apic_send_IPI_allbutself(int vector)
86 {
87 __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLBUT);
88 }
89
x2apic_send_IPI_all(int vector)90 static void x2apic_send_IPI_all(int vector)
91 {
92 __x2apic_send_IPI_shorthand(vector, APIC_DEST_ALLINC);
93 }
94
x2apic_calc_apicid(unsigned int cpu)95 static u32 x2apic_calc_apicid(unsigned int cpu)
96 {
97 return per_cpu(x86_cpu_to_logical_apicid, cpu);
98 }
99
init_x2apic_ldr(void)100 static void init_x2apic_ldr(void)
101 {
102 struct cluster_mask *cmsk = this_cpu_read(cluster_masks);
103 u32 cluster, apicid = apic_read(APIC_LDR);
104 unsigned int cpu;
105
106 this_cpu_write(x86_cpu_to_logical_apicid, apicid);
107
108 if (cmsk)
109 goto update;
110
111 cluster = apicid >> 16;
112 for_each_online_cpu(cpu) {
113 cmsk = per_cpu(cluster_masks, cpu);
114 /* Matching cluster found. Link and update it. */
115 if (cmsk && cmsk->clusterid == cluster)
116 goto update;
117 }
118 cmsk = cluster_hotplug_mask;
119 cmsk->clusterid = cluster;
120 cluster_hotplug_mask = NULL;
121 update:
122 this_cpu_write(cluster_masks, cmsk);
123 cpumask_set_cpu(smp_processor_id(), &cmsk->mask);
124 }
125
alloc_clustermask(unsigned int cpu,int node)126 static int alloc_clustermask(unsigned int cpu, int node)
127 {
128 if (per_cpu(cluster_masks, cpu))
129 return 0;
130 /*
131 * If a hotplug spare mask exists, check whether it's on the right
132 * node. If not, free it and allocate a new one.
133 */
134 if (cluster_hotplug_mask) {
135 if (cluster_hotplug_mask->node == node)
136 return 0;
137 kfree(cluster_hotplug_mask);
138 }
139
140 cluster_hotplug_mask = kzalloc_node(sizeof(*cluster_hotplug_mask),
141 GFP_KERNEL, node);
142 if (!cluster_hotplug_mask)
143 return -ENOMEM;
144 cluster_hotplug_mask->node = node;
145 return 0;
146 }
147
x2apic_prepare_cpu(unsigned int cpu)148 static int x2apic_prepare_cpu(unsigned int cpu)
149 {
150 if (alloc_clustermask(cpu, cpu_to_node(cpu)) < 0)
151 return -ENOMEM;
152 if (!zalloc_cpumask_var(&per_cpu(ipi_mask, cpu), GFP_KERNEL))
153 return -ENOMEM;
154 return 0;
155 }
156
x2apic_dead_cpu(unsigned int dead_cpu)157 static int x2apic_dead_cpu(unsigned int dead_cpu)
158 {
159 struct cluster_mask *cmsk = per_cpu(cluster_masks, dead_cpu);
160
161 if (cmsk)
162 cpumask_clear_cpu(dead_cpu, &cmsk->mask);
163 free_cpumask_var(per_cpu(ipi_mask, dead_cpu));
164 return 0;
165 }
166
x2apic_cluster_probe(void)167 static int x2apic_cluster_probe(void)
168 {
169 if (!x2apic_mode)
170 return 0;
171
172 if (cpuhp_setup_state(CPUHP_X2APIC_PREPARE, "x86/x2apic:prepare",
173 x2apic_prepare_cpu, x2apic_dead_cpu) < 0) {
174 pr_err("Failed to register X2APIC_PREPARE\n");
175 return 0;
176 }
177 init_x2apic_ldr();
178 return 1;
179 }
180
181 static struct apic apic_x2apic_cluster __ro_after_init = {
182
183 .name = "cluster x2apic",
184 .probe = x2apic_cluster_probe,
185 .acpi_madt_oem_check = x2apic_acpi_madt_oem_check,
186 .apic_id_valid = x2apic_apic_id_valid,
187 .apic_id_registered = x2apic_apic_id_registered,
188
189 .delivery_mode = APIC_DELIVERY_MODE_FIXED,
190 .dest_mode_logical = true,
191
192 .disable_esr = 0,
193
194 .check_apicid_used = NULL,
195 .init_apic_ldr = init_x2apic_ldr,
196 .ioapic_phys_id_map = NULL,
197 .setup_apic_routing = NULL,
198 .cpu_present_to_apicid = default_cpu_present_to_apicid,
199 .apicid_to_cpu_present = NULL,
200 .check_phys_apicid_present = default_check_phys_apicid_present,
201 .phys_pkg_id = x2apic_phys_pkg_id,
202
203 .get_apic_id = x2apic_get_apic_id,
204 .set_apic_id = x2apic_set_apic_id,
205
206 .calc_dest_apicid = x2apic_calc_apicid,
207
208 .send_IPI = x2apic_send_IPI,
209 .send_IPI_mask = x2apic_send_IPI_mask,
210 .send_IPI_mask_allbutself = x2apic_send_IPI_mask_allbutself,
211 .send_IPI_allbutself = x2apic_send_IPI_allbutself,
212 .send_IPI_all = x2apic_send_IPI_all,
213 .send_IPI_self = x2apic_send_IPI_self,
214
215 .inquire_remote_apic = NULL,
216
217 .read = native_apic_msr_read,
218 .write = native_apic_msr_write,
219 .eoi_write = native_apic_msr_eoi_write,
220 .icr_read = native_x2apic_icr_read,
221 .icr_write = native_x2apic_icr_write,
222 .wait_icr_idle = native_x2apic_wait_icr_idle,
223 .safe_wait_icr_idle = native_safe_x2apic_wait_icr_idle,
224 };
225
226 apic_driver(apic_x2apic_cluster);
227