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