1 /*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6 #include "linux/percpu.h"
7 #include "asm/pgalloc.h"
8 #include "asm/tlb.h"
9
10 /* For some reason, mmu_gathers are referenced when CONFIG_SMP is off. */
11 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
12
13 #ifdef CONFIG_SMP
14
15 #include "linux/sched.h"
16 #include "linux/module.h"
17 #include "linux/threads.h"
18 #include "linux/interrupt.h"
19 #include "linux/err.h"
20 #include "linux/hardirq.h"
21 #include "asm/smp.h"
22 #include "asm/processor.h"
23 #include "asm/spinlock.h"
24 #include "kern.h"
25 #include "irq_user.h"
26 #include "os.h"
27
28 /* Per CPU bogomips and other parameters
29 * The only piece used here is the ipi pipe, which is set before SMP is
30 * started and never changed.
31 */
32 struct cpuinfo_um cpu_data[NR_CPUS];
33
34 /* A statistic, can be a little off */
35 int num_reschedules_sent = 0;
36
37 /* Not changed after boot */
38 struct task_struct *idle_threads[NR_CPUS];
39
40 void smp_send_reschedule(int cpu)
41 {
42 os_write_file(cpu_data[cpu].ipi_pipe[1], "R", 1);
43 num_reschedules_sent++;
44 }
45
46 void smp_send_stop(void)
47 {
48 int i;
49
50 printk(KERN_INFO "Stopping all CPUs...");
51 for (i = 0; i < num_online_cpus(); i++) {
52 if (i == current_thread->cpu)
53 continue;
54 os_write_file(cpu_data[i].ipi_pipe[1], "S", 1);
55 }
56 printk(KERN_CONT "done\n");
57 }
58
59 static cpumask_t smp_commenced_mask = CPU_MASK_NONE;
60 static cpumask_t cpu_callin_map = CPU_MASK_NONE;
61
62 static int idle_proc(void *cpup)
63 {
64 int cpu = (int) cpup, err;
65
66 err = os_pipe(cpu_data[cpu].ipi_pipe, 1, 1);
67 if (err < 0)
68 panic("CPU#%d failed to create IPI pipe, err = %d", cpu, -err);
69
70 os_set_fd_async(cpu_data[cpu].ipi_pipe[0]);
71
72 wmb();
73 if (cpu_test_and_set(cpu, cpu_callin_map)) {
74 printk(KERN_ERR "huh, CPU#%d already present??\n", cpu);
75 BUG();
76 }
77
78 while (!cpu_isset(cpu, smp_commenced_mask))
79 cpu_relax();
80
81 notify_cpu_starting(cpu);
82 cpu_set(cpu, cpu_online_map);
83 default_idle();
84 return 0;
85 }
86
87 static struct task_struct *idle_thread(int cpu)
88 {
89 struct task_struct *new_task;
90
91 current->thread.request.u.thread.proc = idle_proc;
92 current->thread.request.u.thread.arg = (void *) cpu;
93 new_task = fork_idle(cpu);
94 if (IS_ERR(new_task))
95 panic("copy_process failed in idle_thread, error = %ld",
96 PTR_ERR(new_task));
97
98 cpu_tasks[cpu] = ((struct cpu_task)
99 { .pid = new_task->thread.mode.tt.extern_pid,
100 .task = new_task } );
101 idle_threads[cpu] = new_task;
102 panic("skas mode doesn't support SMP");
103 return new_task;
104 }
105
106 void smp_prepare_cpus(unsigned int maxcpus)
107 {
108 struct task_struct *idle;
109 unsigned long waittime;
110 int err, cpu, me = smp_processor_id();
111 int i;
112
113 for (i = 0; i < ncpus; ++i)
114 cpu_set(i, cpu_possible_map);
115
116 cpu_clear(me, cpu_online_map);
117 cpu_set(me, cpu_online_map);
118 cpu_set(me, cpu_callin_map);
119
120 err = os_pipe(cpu_data[me].ipi_pipe, 1, 1);
121 if (err < 0)
122 panic("CPU#0 failed to create IPI pipe, errno = %d", -err);
123
124 os_set_fd_async(cpu_data[me].ipi_pipe[0]);
125
126 for (cpu = 1; cpu < ncpus; cpu++) {
127 printk(KERN_INFO "Booting processor %d...\n", cpu);
128
129 idle = idle_thread(cpu);
130
131 init_idle(idle, cpu);
132
133 waittime = 200000000;
134 while (waittime-- && !cpu_isset(cpu, cpu_callin_map))
135 cpu_relax();
136
137 printk(KERN_INFO "%s\n",
138 cpu_isset(cpu, cpu_calling_map) ? "done" : "failed");
139 }
140 }
141
142 void smp_prepare_boot_cpu(void)
143 {
144 cpu_set(smp_processor_id(), cpu_online_map);
145 }
146
147 int __cpu_up(unsigned int cpu)
148 {
149 cpu_set(cpu, smp_commenced_mask);
150 while (!cpu_isset(cpu, cpu_online_map))
151 mb();
152 return 0;
153 }
154
155 int setup_profiling_timer(unsigned int multiplier)
156 {
157 printk(KERN_INFO "setup_profiling_timer\n");
158 return 0;
159 }
160
161 void smp_call_function_slave(int cpu);
162
163 void IPI_handler(int cpu)
164 {
165 unsigned char c;
166 int fd;
167
168 fd = cpu_data[cpu].ipi_pipe[0];
169 while (os_read_file(fd, &c, 1) == 1) {
170 switch (c) {
171 case 'C':
172 smp_call_function_slave(cpu);
173 break;
174
175 case 'R':
176 set_tsk_need_resched(current);
177 break;
178
179 case 'S':
180 printk(KERN_INFO "CPU#%d stopping\n", cpu);
181 while (1)
182 pause();
183 break;
184
185 default:
186 printk(KERN_ERR "CPU#%d received unknown IPI [%c]!\n",
187 cpu, c);
188 break;
189 }
190 }
191 }
192
193 int hard_smp_processor_id(void)
194 {
195 return pid_to_processor_id(os_getpid());
196 }
197
198 static DEFINE_SPINLOCK(call_lock);
199 static atomic_t scf_started;
200 static atomic_t scf_finished;
201 static void (*func)(void *info);
202 static void *info;
203
204 void smp_call_function_slave(int cpu)
205 {
206 atomic_inc(&scf_started);
207 (*func)(info);
208 atomic_inc(&scf_finished);
209 }
210
211 int smp_call_function(void (*_func)(void *info), void *_info, int wait)
212 {
213 int cpus = num_online_cpus() - 1;
214 int i;
215
216 if (!cpus)
217 return 0;
218
219 /* Can deadlock when called with interrupts disabled */
220 WARN_ON(irqs_disabled());
221
222 spin_lock_bh(&call_lock);
223 atomic_set(&scf_started, 0);
224 atomic_set(&scf_finished, 0);
225 func = _func;
226 info = _info;
227
228 for_each_online_cpu(i)
229 os_write_file(cpu_data[i].ipi_pipe[1], "C", 1);
230
231 while (atomic_read(&scf_started) != cpus)
232 barrier();
233
234 if (wait)
235 while (atomic_read(&scf_finished) != cpus)
236 barrier();
237
238 spin_unlock_bh(&call_lock);
239 return 0;
240 }
241
242 #endif
243
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