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