1 /*
2 ** SMP Support
3 **
4 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
5 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
6 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
7 **
8 ** Lots of stuff stolen from arch/alpha/kernel/smp.c
9 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
10 **
11 ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
12 ** -grant (1/12/2001)
13 **
14 ** This program is free software; you can redistribute it and/or modify
15 ** it under the terms of the GNU General Public License as published by
16 ** the Free Software Foundation; either version 2 of the License, or
17 ** (at your option) any later version.
18 */
19 #include <linux/types.h>
20 #include <linux/spinlock.h>
21
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/sched/mm.h>
25 #include <linux/init.h>
26 #include <linux/interrupt.h>
27 #include <linux/smp.h>
28 #include <linux/kernel_stat.h>
29 #include <linux/mm.h>
30 #include <linux/err.h>
31 #include <linux/delay.h>
32 #include <linux/bitops.h>
33 #include <linux/ftrace.h>
34 #include <linux/cpu.h>
35
36 #include <linux/atomic.h>
37 #include <asm/current.h>
38 #include <asm/delay.h>
39 #include <asm/tlbflush.h>
40
41 #include <asm/io.h>
42 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
43 #include <asm/mmu_context.h>
44 #include <asm/page.h>
45 #include <asm/pgtable.h>
46 #include <asm/pgalloc.h>
47 #include <asm/processor.h>
48 #include <asm/ptrace.h>
49 #include <asm/unistd.h>
50 #include <asm/cacheflush.h>
51
52 #undef DEBUG_SMP
53 #ifdef DEBUG_SMP
54 static int smp_debug_lvl = 0;
55 #define smp_debug(lvl, printargs...) \
56 if (lvl >= smp_debug_lvl) \
57 printk(printargs);
58 #else
59 #define smp_debug(lvl, ...) do { } while(0)
60 #endif /* DEBUG_SMP */
61
62 volatile struct task_struct *smp_init_current_idle_task;
63
64 /* track which CPU is booting */
65 static volatile int cpu_now_booting;
66
67 static int parisc_max_cpus = 1;
68
69 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
70
71 enum ipi_message_type {
72 IPI_NOP=0,
73 IPI_RESCHEDULE=1,
74 IPI_CALL_FUNC,
75 IPI_CPU_START,
76 IPI_CPU_STOP,
77 IPI_CPU_TEST
78 };
79
80
81 /********** SMP inter processor interrupt and communication routines */
82
83 #undef PER_CPU_IRQ_REGION
84 #ifdef PER_CPU_IRQ_REGION
85 /* XXX REVISIT Ignore for now.
86 ** *May* need this "hook" to register IPI handler
87 ** once we have perCPU ExtIntr switch tables.
88 */
89 static void
ipi_init(int cpuid)90 ipi_init(int cpuid)
91 {
92 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
93
94 if(cpu_online(cpuid) )
95 {
96 switch_to_idle_task(current);
97 }
98
99 return;
100 }
101 #endif
102
103
104 /*
105 ** Yoink this CPU from the runnable list...
106 **
107 */
108 static void
halt_processor(void)109 halt_processor(void)
110 {
111 /* REVISIT : redirect I/O Interrupts to another CPU? */
112 /* REVISIT : does PM *know* this CPU isn't available? */
113 set_cpu_online(smp_processor_id(), false);
114 local_irq_disable();
115 for (;;)
116 ;
117 }
118
119
120 irqreturn_t __irq_entry
ipi_interrupt(int irq,void * dev_id)121 ipi_interrupt(int irq, void *dev_id)
122 {
123 int this_cpu = smp_processor_id();
124 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
125 unsigned long ops;
126 unsigned long flags;
127
128 for (;;) {
129 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
130 spin_lock_irqsave(lock, flags);
131 ops = p->pending_ipi;
132 p->pending_ipi = 0;
133 spin_unlock_irqrestore(lock, flags);
134
135 mb(); /* Order bit clearing and data access. */
136
137 if (!ops)
138 break;
139
140 while (ops) {
141 unsigned long which = ffz(~ops);
142
143 ops &= ~(1 << which);
144
145 switch (which) {
146 case IPI_NOP:
147 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
148 break;
149
150 case IPI_RESCHEDULE:
151 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
152 inc_irq_stat(irq_resched_count);
153 scheduler_ipi();
154 break;
155
156 case IPI_CALL_FUNC:
157 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
158 generic_smp_call_function_interrupt();
159 break;
160
161 case IPI_CPU_START:
162 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
163 break;
164
165 case IPI_CPU_STOP:
166 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
167 halt_processor();
168 break;
169
170 case IPI_CPU_TEST:
171 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
172 break;
173
174 default:
175 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
176 this_cpu, which);
177 return IRQ_NONE;
178 } /* Switch */
179 /* let in any pending interrupts */
180 local_irq_enable();
181 local_irq_disable();
182 } /* while (ops) */
183 }
184 return IRQ_HANDLED;
185 }
186
187
188 static inline void
ipi_send(int cpu,enum ipi_message_type op)189 ipi_send(int cpu, enum ipi_message_type op)
190 {
191 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
192 spinlock_t *lock = &per_cpu(ipi_lock, cpu);
193 unsigned long flags;
194
195 spin_lock_irqsave(lock, flags);
196 p->pending_ipi |= 1 << op;
197 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
198 spin_unlock_irqrestore(lock, flags);
199 }
200
201 static void
send_IPI_mask(const struct cpumask * mask,enum ipi_message_type op)202 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
203 {
204 int cpu;
205
206 for_each_cpu(cpu, mask)
207 ipi_send(cpu, op);
208 }
209
210 static inline void
send_IPI_single(int dest_cpu,enum ipi_message_type op)211 send_IPI_single(int dest_cpu, enum ipi_message_type op)
212 {
213 BUG_ON(dest_cpu == NO_PROC_ID);
214
215 ipi_send(dest_cpu, op);
216 }
217
218 static inline void
send_IPI_allbutself(enum ipi_message_type op)219 send_IPI_allbutself(enum ipi_message_type op)
220 {
221 int i;
222
223 for_each_online_cpu(i) {
224 if (i != smp_processor_id())
225 send_IPI_single(i, op);
226 }
227 }
228
229
230 inline void
smp_send_stop(void)231 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
232
233 void
smp_send_reschedule(int cpu)234 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
235
236 void
smp_send_all_nop(void)237 smp_send_all_nop(void)
238 {
239 send_IPI_allbutself(IPI_NOP);
240 }
241
arch_send_call_function_ipi_mask(const struct cpumask * mask)242 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
243 {
244 send_IPI_mask(mask, IPI_CALL_FUNC);
245 }
246
arch_send_call_function_single_ipi(int cpu)247 void arch_send_call_function_single_ipi(int cpu)
248 {
249 send_IPI_single(cpu, IPI_CALL_FUNC);
250 }
251
252 /*
253 * Called by secondaries to update state and initialize CPU registers.
254 */
255 static void __init
smp_cpu_init(int cpunum)256 smp_cpu_init(int cpunum)
257 {
258 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
259 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
260
261 /* Set modes and Enable floating point coprocessor */
262 init_per_cpu(cpunum);
263
264 disable_sr_hashing();
265
266 mb();
267
268 /* Well, support 2.4 linux scheme as well. */
269 if (cpu_online(cpunum)) {
270 extern void machine_halt(void); /* arch/parisc.../process.c */
271
272 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
273 machine_halt();
274 }
275
276 notify_cpu_starting(cpunum);
277
278 set_cpu_online(cpunum, true);
279
280 /* Initialise the idle task for this CPU */
281 mmgrab(&init_mm);
282 current->active_mm = &init_mm;
283 BUG_ON(current->mm);
284 enter_lazy_tlb(&init_mm, current);
285
286 init_IRQ(); /* make sure no IRQs are enabled or pending */
287 start_cpu_itimer();
288 }
289
290
291 /*
292 * Slaves start using C here. Indirectly called from smp_slave_stext.
293 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
294 */
smp_callin(void)295 void __init smp_callin(void)
296 {
297 int slave_id = cpu_now_booting;
298
299 smp_cpu_init(slave_id);
300 preempt_disable();
301
302 flush_cache_all_local(); /* start with known state */
303 flush_tlb_all_local(NULL);
304
305 local_irq_enable(); /* Interrupts have been off until now */
306
307 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
308
309 /* NOTREACHED */
310 panic("smp_callin() AAAAaaaaahhhh....\n");
311 }
312
313 /*
314 * Bring one cpu online.
315 */
smp_boot_one_cpu(int cpuid,struct task_struct * idle)316 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
317 {
318 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
319 long timeout;
320
321 task_thread_info(idle)->cpu = cpuid;
322
323 /* Let _start know what logical CPU we're booting
324 ** (offset into init_tasks[],cpu_data[])
325 */
326 cpu_now_booting = cpuid;
327
328 /*
329 ** boot strap code needs to know the task address since
330 ** it also contains the process stack.
331 */
332 smp_init_current_idle_task = idle ;
333 mb();
334
335 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
336
337 /*
338 ** This gets PDC to release the CPU from a very tight loop.
339 **
340 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
341 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
342 ** is executed after receiving the rendezvous signal (an interrupt to
343 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
344 ** contents of memory are valid."
345 */
346 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
347 mb();
348
349 /*
350 * OK, wait a bit for that CPU to finish staggering about.
351 * Slave will set a bit when it reaches smp_cpu_init().
352 * Once the "monarch CPU" sees the bit change, it can move on.
353 */
354 for (timeout = 0; timeout < 10000; timeout++) {
355 if(cpu_online(cpuid)) {
356 /* Which implies Slave has started up */
357 cpu_now_booting = 0;
358 smp_init_current_idle_task = NULL;
359 goto alive ;
360 }
361 udelay(100);
362 barrier();
363 }
364 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
365 return -1;
366
367 alive:
368 /* Remember the Slave data */
369 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
370 cpuid, timeout * 100);
371 return 0;
372 }
373
smp_prepare_boot_cpu(void)374 void __init smp_prepare_boot_cpu(void)
375 {
376 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
377
378 /* Setup BSP mappings */
379 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
380
381 set_cpu_online(bootstrap_processor, true);
382 set_cpu_present(bootstrap_processor, true);
383 }
384
385
386
387 /*
388 ** inventory.c:do_inventory() hasn't yet been run and thus we
389 ** don't 'discover' the additional CPUs until later.
390 */
smp_prepare_cpus(unsigned int max_cpus)391 void __init smp_prepare_cpus(unsigned int max_cpus)
392 {
393 int cpu;
394
395 for_each_possible_cpu(cpu)
396 spin_lock_init(&per_cpu(ipi_lock, cpu));
397
398 init_cpu_present(cpumask_of(0));
399
400 parisc_max_cpus = max_cpus;
401 if (!max_cpus)
402 printk(KERN_INFO "SMP mode deactivated.\n");
403 }
404
405
smp_cpus_done(unsigned int cpu_max)406 void smp_cpus_done(unsigned int cpu_max)
407 {
408 return;
409 }
410
411
__cpu_up(unsigned int cpu,struct task_struct * tidle)412 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
413 {
414 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
415 return -ENOSYS;
416
417 return cpu_online(cpu) ? 0 : -ENOSYS;
418 }
419
420 #ifdef CONFIG_PROC_FS
setup_profiling_timer(unsigned int multiplier)421 int setup_profiling_timer(unsigned int multiplier)
422 {
423 return -EINVAL;
424 }
425 #endif
426