1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * SMP initialisation and IPI support
4 * Based on arch/arm64/kernel/smp.c
5 *
6 * Copyright (C) 2012 ARM Ltd.
7 * Copyright (C) 2015 Regents of the University of California
8 * Copyright (C) 2017 SiFive
9 */
10
11 #include <linux/acpi.h>
12 #include <linux/arch_topology.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/kernel.h>
16 #include <linux/mm.h>
17 #include <linux/sched.h>
18 #include <linux/kernel_stat.h>
19 #include <linux/notifier.h>
20 #include <linux/cpu.h>
21 #include <linux/percpu.h>
22 #include <linux/delay.h>
23 #include <linux/err.h>
24 #include <linux/irq.h>
25 #include <linux/of.h>
26 #include <linux/sched/task_stack.h>
27 #include <linux/sched/mm.h>
28 #include <asm/cpu_ops.h>
29 #include <asm/cpufeature.h>
30 #include <asm/irq.h>
31 #include <asm/mmu_context.h>
32 #include <asm/numa.h>
33 #include <asm/tlbflush.h>
34 #include <asm/sections.h>
35 #include <asm/smp.h>
36 #include <uapi/asm/hwcap.h>
37 #include <asm/vector.h>
38
39 #include "head.h"
40
41 static DECLARE_COMPLETION(cpu_running);
42
smp_prepare_boot_cpu(void)43 void __init smp_prepare_boot_cpu(void)
44 {
45 }
46
smp_prepare_cpus(unsigned int max_cpus)47 void __init smp_prepare_cpus(unsigned int max_cpus)
48 {
49 int cpuid;
50 int ret;
51 unsigned int curr_cpuid;
52
53 init_cpu_topology();
54
55 curr_cpuid = smp_processor_id();
56 store_cpu_topology(curr_cpuid);
57 numa_store_cpu_info(curr_cpuid);
58 numa_add_cpu(curr_cpuid);
59
60 /* This covers non-smp usecase mandated by "nosmp" option */
61 if (max_cpus == 0)
62 return;
63
64 for_each_possible_cpu(cpuid) {
65 if (cpuid == curr_cpuid)
66 continue;
67 if (cpu_ops[cpuid]->cpu_prepare) {
68 ret = cpu_ops[cpuid]->cpu_prepare(cpuid);
69 if (ret)
70 continue;
71 }
72 set_cpu_present(cpuid, true);
73 numa_store_cpu_info(cpuid);
74 }
75 }
76
77 #ifdef CONFIG_ACPI
78 static unsigned int cpu_count = 1;
79
acpi_parse_rintc(union acpi_subtable_headers * header,const unsigned long end)80 static int __init acpi_parse_rintc(union acpi_subtable_headers *header, const unsigned long end)
81 {
82 unsigned long hart;
83 static bool found_boot_cpu;
84 struct acpi_madt_rintc *processor = (struct acpi_madt_rintc *)header;
85
86 /*
87 * Each RINTC structure in MADT will have a flag. If ACPI_MADT_ENABLED
88 * bit in the flag is not enabled, it means OS should not try to enable
89 * the cpu to which RINTC belongs.
90 */
91 if (!(processor->flags & ACPI_MADT_ENABLED))
92 return 0;
93
94 if (BAD_MADT_ENTRY(processor, end))
95 return -EINVAL;
96
97 acpi_table_print_madt_entry(&header->common);
98
99 hart = processor->hart_id;
100 if (hart == INVALID_HARTID) {
101 pr_warn("Invalid hartid\n");
102 return 0;
103 }
104
105 if (hart == cpuid_to_hartid_map(0)) {
106 BUG_ON(found_boot_cpu);
107 found_boot_cpu = true;
108 early_map_cpu_to_node(0, acpi_numa_get_nid(cpu_count));
109 return 0;
110 }
111
112 if (cpu_count >= NR_CPUS) {
113 pr_warn("NR_CPUS is too small for the number of ACPI tables.\n");
114 return 0;
115 }
116
117 cpuid_to_hartid_map(cpu_count) = hart;
118 early_map_cpu_to_node(cpu_count, acpi_numa_get_nid(cpu_count));
119 cpu_count++;
120
121 return 0;
122 }
123
acpi_parse_and_init_cpus(void)124 static void __init acpi_parse_and_init_cpus(void)
125 {
126 int cpuid;
127
128 cpu_set_ops(0);
129
130 acpi_table_parse_madt(ACPI_MADT_TYPE_RINTC, acpi_parse_rintc, 0);
131
132 for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
133 if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) {
134 cpu_set_ops(cpuid);
135 set_cpu_possible(cpuid, true);
136 }
137 }
138 }
139 #else
140 #define acpi_parse_and_init_cpus(...) do { } while (0)
141 #endif
142
of_parse_and_init_cpus(void)143 static void __init of_parse_and_init_cpus(void)
144 {
145 struct device_node *dn;
146 unsigned long hart;
147 bool found_boot_cpu = false;
148 int cpuid = 1;
149 int rc;
150
151 cpu_set_ops(0);
152
153 for_each_of_cpu_node(dn) {
154 rc = riscv_early_of_processor_hartid(dn, &hart);
155 if (rc < 0)
156 continue;
157
158 if (hart == cpuid_to_hartid_map(0)) {
159 BUG_ON(found_boot_cpu);
160 found_boot_cpu = 1;
161 early_map_cpu_to_node(0, of_node_to_nid(dn));
162 continue;
163 }
164 if (cpuid >= NR_CPUS) {
165 pr_warn("Invalid cpuid [%d] for hartid [%lu]\n",
166 cpuid, hart);
167 continue;
168 }
169
170 cpuid_to_hartid_map(cpuid) = hart;
171 early_map_cpu_to_node(cpuid, of_node_to_nid(dn));
172 cpuid++;
173 }
174
175 BUG_ON(!found_boot_cpu);
176
177 if (cpuid > nr_cpu_ids)
178 pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n",
179 cpuid, nr_cpu_ids);
180
181 for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
182 if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID) {
183 cpu_set_ops(cpuid);
184 set_cpu_possible(cpuid, true);
185 }
186 }
187 }
188
setup_smp(void)189 void __init setup_smp(void)
190 {
191 if (acpi_disabled)
192 of_parse_and_init_cpus();
193 else
194 acpi_parse_and_init_cpus();
195 }
196
start_secondary_cpu(int cpu,struct task_struct * tidle)197 static int start_secondary_cpu(int cpu, struct task_struct *tidle)
198 {
199 if (cpu_ops[cpu]->cpu_start)
200 return cpu_ops[cpu]->cpu_start(cpu, tidle);
201
202 return -EOPNOTSUPP;
203 }
204
__cpu_up(unsigned int cpu,struct task_struct * tidle)205 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
206 {
207 int ret = 0;
208 tidle->thread_info.cpu = cpu;
209
210 ret = start_secondary_cpu(cpu, tidle);
211 if (!ret) {
212 wait_for_completion_timeout(&cpu_running,
213 msecs_to_jiffies(1000));
214
215 if (!cpu_online(cpu)) {
216 pr_crit("CPU%u: failed to come online\n", cpu);
217 ret = -EIO;
218 }
219 } else {
220 pr_crit("CPU%u: failed to start\n", cpu);
221 }
222
223 return ret;
224 }
225
smp_cpus_done(unsigned int max_cpus)226 void __init smp_cpus_done(unsigned int max_cpus)
227 {
228 }
229
230 /*
231 * C entry point for a secondary processor.
232 */
smp_callin(void)233 asmlinkage __visible void smp_callin(void)
234 {
235 struct mm_struct *mm = &init_mm;
236 unsigned int curr_cpuid = smp_processor_id();
237
238 /* All kernel threads share the same mm context. */
239 mmgrab(mm);
240 current->active_mm = mm;
241
242 store_cpu_topology(curr_cpuid);
243 notify_cpu_starting(curr_cpuid);
244
245 riscv_ipi_enable();
246
247 numa_add_cpu(curr_cpuid);
248 set_cpu_online(curr_cpuid, 1);
249 check_unaligned_access(curr_cpuid);
250
251 if (has_vector()) {
252 if (riscv_v_setup_vsize())
253 elf_hwcap &= ~COMPAT_HWCAP_ISA_V;
254 }
255
256 /*
257 * Remote TLB flushes are ignored while the CPU is offline, so emit
258 * a local TLB flush right now just in case.
259 */
260 local_flush_tlb_all();
261 complete(&cpu_running);
262 /*
263 * Disable preemption before enabling interrupts, so we don't try to
264 * schedule a CPU that hasn't actually started yet.
265 */
266 local_irq_enable();
267 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
268 }
269