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
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
|
// 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/cpu.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/profile.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <asm/clint.h>
#include <asm/sbi.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>
enum ipi_message_type {
IPI_RESCHEDULE,
IPI_CALL_FUNC,
IPI_CPU_STOP,
IPI_MAX
};
unsigned long __cpuid_to_hartid_map[NR_CPUS] = {
[0 ... NR_CPUS-1] = INVALID_HARTID
};
void __init smp_setup_processor_id(void)
{
cpuid_to_hartid_map(0) = boot_cpu_hartid;
}
/* A collection of single bit ipi messages. */
static struct {
unsigned long stats[IPI_MAX] ____cacheline_aligned;
unsigned long bits ____cacheline_aligned;
} ipi_data[NR_CPUS] __cacheline_aligned;
int riscv_hartid_to_cpuid(int hartid)
{
int i;
for (i = 0; i < NR_CPUS; i++)
if (cpuid_to_hartid_map(i) == hartid)
return i;
pr_err("Couldn't find cpu id for hartid [%d]\n", hartid);
return i;
}
void riscv_cpuid_to_hartid_mask(const struct cpumask *in, struct cpumask *out)
{
int cpu;
cpumask_clear(out);
for_each_cpu(cpu, in)
cpumask_set_cpu(cpuid_to_hartid_map(cpu), out);
}
EXPORT_SYMBOL_GPL(riscv_cpuid_to_hartid_mask);
bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
{
return phys_id == cpuid_to_hartid_map(cpu);
}
/* Unsupported */
int setup_profiling_timer(unsigned int multiplier)
{
return -EINVAL;
}
static void ipi_stop(void)
{
set_cpu_online(smp_processor_id(), false);
while (1)
wait_for_interrupt();
}
static void send_ipi_mask(const struct cpumask *mask, enum ipi_message_type op)
{
struct cpumask hartid_mask;
int cpu;
smp_mb__before_atomic();
for_each_cpu(cpu, mask)
set_bit(op, &ipi_data[cpu].bits);
smp_mb__after_atomic();
riscv_cpuid_to_hartid_mask(mask, &hartid_mask);
if (IS_ENABLED(CONFIG_RISCV_SBI))
sbi_send_ipi(cpumask_bits(&hartid_mask));
else
clint_send_ipi_mask(mask);
}
static void send_ipi_single(int cpu, enum ipi_message_type op)
{
int hartid = cpuid_to_hartid_map(cpu);
smp_mb__before_atomic();
set_bit(op, &ipi_data[cpu].bits);
smp_mb__after_atomic();
if (IS_ENABLED(CONFIG_RISCV_SBI))
sbi_send_ipi(cpumask_bits(cpumask_of(hartid)));
else
clint_send_ipi_single(hartid);
}
static inline void clear_ipi(void)
{
if (IS_ENABLED(CONFIG_RISCV_SBI))
csr_clear(CSR_IP, IE_SIE);
else
clint_clear_ipi(cpuid_to_hartid_map(smp_processor_id()));
}
void riscv_software_interrupt(void)
{
unsigned long *pending_ipis = &ipi_data[smp_processor_id()].bits;
unsigned long *stats = ipi_data[smp_processor_id()].stats;
clear_ipi();
while (true) {
unsigned long ops;
/* Order bit clearing and data access. */
mb();
ops = xchg(pending_ipis, 0);
if (ops == 0)
return;
if (ops & (1 << IPI_RESCHEDULE)) {
stats[IPI_RESCHEDULE]++;
scheduler_ipi();
}
if (ops & (1 << IPI_CALL_FUNC)) {
stats[IPI_CALL_FUNC]++;
generic_smp_call_function_interrupt();
}
if (ops & (1 << IPI_CPU_STOP)) {
stats[IPI_CPU_STOP]++;
ipi_stop();
}
BUG_ON((ops >> IPI_MAX) != 0);
/* Order data access and bit testing. */
mb();
}
}
static const char * const ipi_names[] = {
[IPI_RESCHEDULE] = "Rescheduling interrupts",
[IPI_CALL_FUNC] = "Function call interrupts",
[IPI_CPU_STOP] = "CPU stop interrupts",
};
void show_ipi_stats(struct seq_file *p, int prec)
{
unsigned int cpu, i;
for (i = 0; i < IPI_MAX; i++) {
seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i,
prec >= 4 ? " " : "");
for_each_online_cpu(cpu)
seq_printf(p, "%10lu ", ipi_data[cpu].stats[i]);
seq_printf(p, " %s\n", ipi_names[i]);
}
}
void arch_send_call_function_ipi_mask(struct cpumask *mask)
{
send_ipi_mask(mask, IPI_CALL_FUNC);
}
void arch_send_call_function_single_ipi(int cpu)
{
send_ipi_single(cpu, IPI_CALL_FUNC);
}
void smp_send_stop(void)
{
unsigned long timeout;
if (num_online_cpus() > 1) {
cpumask_t mask;
cpumask_copy(&mask, cpu_online_mask);
cpumask_clear_cpu(smp_processor_id(), &mask);
if (system_state <= SYSTEM_RUNNING)
pr_crit("SMP: stopping secondary CPUs\n");
send_ipi_mask(&mask, IPI_CPU_STOP);
}
/* Wait up to one second for other CPUs to stop */
timeout = USEC_PER_SEC;
while (num_online_cpus() > 1 && timeout--)
udelay(1);
if (num_online_cpus() > 1)
pr_warn("SMP: failed to stop secondary CPUs %*pbl\n",
cpumask_pr_args(cpu_online_mask));
}
void smp_send_reschedule(int cpu)
{
send_ipi_single(cpu, IPI_RESCHEDULE);
}
EXPORT_SYMBOL_GPL(smp_send_reschedule);
|
