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
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
|
/*
* Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
* Licensed under the GPL
*/
#include "linux/percpu.h"
#include "asm/pgalloc.h"
#include "asm/tlb.h"
#ifdef CONFIG_SMP
#include "linux/sched.h"
#include "linux/module.h"
#include "linux/threads.h"
#include "linux/interrupt.h"
#include "linux/err.h"
#include "linux/hardirq.h"
#include "asm/smp.h"
#include "asm/processor.h"
#include "asm/spinlock.h"
#include "kern.h"
#include "irq_user.h"
#include "os.h"
/* Per CPU bogomips and other parameters
* The only piece used here is the ipi pipe, which is set before SMP is
* started and never changed.
*/
struct cpuinfo_um cpu_data[NR_CPUS];
/* A statistic, can be a little off */
int num_reschedules_sent = 0;
/* Not changed after boot */
struct task_struct *idle_threads[NR_CPUS];
void smp_send_reschedule(int cpu)
{
os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
num_reschedules_sent++;
}
void smp_send_stop(void)
{
int i;
printk(KERN_INFO "Stopping all CPUs...");
for (i = 0; i < num_online_cpus(); i++) {
if (i == current_thread->cpu)
continue;
os_write_file(cpu_data[i].ipi_pipe[1], "S", 1);
}
printk(KERN_CONT "done\n");
}
static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
static cpumask_t cpu_callin_map = CPU_MASK_NONE;
static int idle_proc(void *cpup)
{
int cpu = (int) cpup, err;
err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1);
if (err < 0)
panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err);
os_set_fd_async(cpu_data[cpu].ipi_pipe[0]);
wmb();
if (cpu_test_and_set(cpu, cpu_callin_map)) {
printk(KERN_ERR "huh, CPU#%d already present??\n", cpu);
BUG();
}
while (!cpu_isset(cpu, smp_commenced_mask))
cpu_relax();
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
default_idle();
return 0;
}
static struct task_struct *idle_thread(int cpu)
{
struct task_struct *new_task;
current->thread.request.u.thread.proc = idle_proc;
current->thread.request.u.thread.arg = (void *) cpu;
new_task = fork_idle(cpu);
if (IS_ERR(new_task))
panic("copy_process failed in idle_thread, error = %ld",
PTR_ERR(new_task));
cpu_tasks[cpu] = ((struct cpu_task)
{ .pid = new_task->thread.mode.tt.extern_pid,
.task = new_task } );
idle_threads[cpu] = new_task;
panic("skas mode doesn't support SMP");
return new_task;
}
void smp_prepare_cpus(unsigned int maxcpus)
{
struct task_struct *idle;
unsigned long waittime;
int err, cpu, me = smp_processor_id();
int i;
for (i = 0; i < ncpus; ++i)
set_cpu_possible(i, true);
set_cpu_online(me, true);
cpu_set(me, cpu_callin_map);
err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
if (err < 0)
panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
os_set_fd_async(cpu_data[me].ipi_pipe[0]);
for (cpu = 1; cpu < ncpus; cpu++) {
printk(KERN_INFO "Booting processor %d...\n", cpu);
idle = idle_thread(cpu);
init_idle(idle, cpu);
waittime = 200000000;
while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
cpu_relax();
printk(KERN_INFO "%s\n",
cpu_isset(cpu, cpu_calling_map) ? "done" : "failed");
}
}
void smp_prepare_boot_cpu(void)
{
set_cpu_online(smp_processor_id(), true);
}
int __cpu_up(unsigned int cpu)
{
cpu_set(cpu, smp_commenced_mask);
while (!cpu_online(cpu))
mb();
return 0;
}
int setup_profiling_timer(unsigned int multiplier)
{
printk(KERN_INFO "setup_profiling_timer\n");
return 0;
}
void smp_call_function_slave(int cpu);
void IPI_handler(int cpu)
{
unsigned char c;
int fd;
fd = cpu_data[cpu].ipi_pipe[0];
while (os_read_file(fd, &c, 1) == 1) {
switch (c) {
case 'C':
smp_call_function_slave(cpu);
break;
case 'R':
scheduler_ipi();
break;
case 'S':
printk(KERN_INFO "CPU#%d stopping\n", cpu);
while (1)
pause();
break;
default:
printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n",
cpu, c);
break;
}
}
}
int hard_smp_processor_id(void)
{
return pid_to_processor_id(os_getpid());
}
static DEFINE_SPINLOCK(call_lock);
static atomic_t scf_started;
static atomic_t scf_finished;
static void (*func)(void *info);
static void *info;
void smp_call_function_slave(int cpu)
{
atomic_inc(&scf_started);
(*func)(info);
atomic_inc(&scf_finished);
}
int smp_call_function(void (*_func)(void *info), void *_info, int wait)
{
int cpus = num_online_cpus() - 1;
int i;
if (!cpus)
return 0;
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
spin_lock_bh(&call_lock);
atomic_set(&scf_started, 0);
atomic_set(&scf_finished, 0);
func = _func;
info = _info;
for_each_online_cpu(i)
os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
while (atomic_read(&scf_started) != cpus)
barrier();
if (wait)
while (atomic_read(&scf_finished) != cpus)
barrier();
spin_unlock_bh(&call_lock);
return 0;
}
#endif
|
