1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
|
// SPDX-License-Identifier: GPL-2.0-only
/*
* SMP initialisation and IPI support
* Based on arch/arm64/kernel/smp.c
*
* Copyright (C) 2012 ARM Ltd.
* Copyright (C) 2015 Regents of the University of California
* Copyright (C) 2017 SiFive
*/
#include <linux/arch_topology.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/percpu.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/of.h>
#include <linux/sched/task_stack.h>
#include <linux/sched/mm.h>
#include <asm/irq.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
#include <asm/sbi.h>
#include <asm/smp.h>
#include "head.h"
void *__cpu_up_stack_pointer[NR_CPUS];
void *__cpu_up_task_pointer[NR_CPUS];
static DECLARE_COMPLETION(cpu_running);
void __init smp_prepare_boot_cpu(void)
{
init_cpu_topology();
}
void __init smp_prepare_cpus(unsigned int max_cpus)
{
int cpuid;
/* This covers non-smp usecase mandated by "nosmp" option */
if (max_cpus == 0)
return;
for_each_possible_cpu(cpuid) {
if (cpuid == smp_processor_id())
continue;
set_cpu_present(cpuid, true);
}
}
void __init setup_smp(void)
{
struct device_node *dn;
int hart;
bool found_boot_cpu = false;
int cpuid = 1;
for_each_of_cpu_node(dn) {
hart = riscv_of_processor_hartid(dn);
if (hart < 0)
continue;
if (hart == cpuid_to_hartid_map(0)) {
BUG_ON(found_boot_cpu);
found_boot_cpu = 1;
continue;
}
if (cpuid >= NR_CPUS) {
pr_warn("Invalid cpuid [%d] for hartid [%d]\n",
cpuid, hart);
break;
}
cpuid_to_hartid_map(cpuid) = hart;
cpuid++;
}
BUG_ON(!found_boot_cpu);
if (cpuid > nr_cpu_ids)
pr_warn("Total number of cpus [%d] is greater than nr_cpus option value [%d]\n",
cpuid, nr_cpu_ids);
for (cpuid = 1; cpuid < nr_cpu_ids; cpuid++) {
if (cpuid_to_hartid_map(cpuid) != INVALID_HARTID)
set_cpu_possible(cpuid, true);
}
}
int __cpu_up(unsigned int cpu, struct task_struct *tidle)
{
int ret = 0;
int hartid = cpuid_to_hartid_map(cpu);
tidle->thread_info.cpu = cpu;
/*
* On RISC-V systems, all harts boot on their own accord. Our _start
* selects the first hart to boot the kernel and causes the remainder
* of the harts to spin in a loop waiting for their stack pointer to be
* setup by that main hart. Writing __cpu_up_stack_pointer signals to
* the spinning harts that they can continue the boot process.
*/
smp_mb();
WRITE_ONCE(__cpu_up_stack_pointer[hartid],
task_stack_page(tidle) + THREAD_SIZE);
WRITE_ONCE(__cpu_up_task_pointer[hartid], tidle);
lockdep_assert_held(&cpu_running);
wait_for_completion_timeout(&cpu_running,
msecs_to_jiffies(1000));
if (!cpu_online(cpu)) {
pr_crit("CPU%u: failed to come online\n", cpu);
ret = -EIO;
}
return ret;
}
void __init smp_cpus_done(unsigned int max_cpus)
{
}
/*
* C entry point for a secondary processor.
*/
asmlinkage __visible void __init smp_callin(void)
{
struct mm_struct *mm = &init_mm;
/* All kernel threads share the same mm context. */
mmgrab(mm);
current->active_mm = mm;
trap_init();
notify_cpu_starting(smp_processor_id());
update_siblings_masks(smp_processor_id());
set_cpu_online(smp_processor_id(), 1);
/*
* Remote TLB flushes are ignored while the CPU is offline, so emit
* a local TLB flush right now just in case.
*/
local_flush_tlb_all();
complete(&cpu_running);
/*
* Disable preemption before enabling interrupts, so we don't try to
* schedule a CPU that hasn't actually started yet.
*/
preempt_disable();
local_irq_enable();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
|
