1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 ** SMP Support
4 **
5 ** Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
6 ** Copyright (C) 1999 David Mosberger-Tang <davidm@hpl.hp.com>
7 ** Copyright (C) 2001,2004 Grant Grundler <grundler@parisc-linux.org>
8 **
9 ** Lots of stuff stolen from arch/alpha/kernel/smp.c
10 ** ...and then parisc stole from arch/ia64/kernel/smp.c. Thanks David! :^)
11 **
12 ** Thanks to John Curry and Ullas Ponnadi. I learned a lot from their work.
13 ** -grant (1/12/2001)
14 **
15 */
16 #include <linux/types.h>
17 #include <linux/spinlock.h>
18
19 #include <linux/kernel.h>
20 #include <linux/module.h>
21 #include <linux/sched/mm.h>
22 #include <linux/init.h>
23 #include <linux/interrupt.h>
24 #include <linux/smp.h>
25 #include <linux/kernel_stat.h>
26 #include <linux/mm.h>
27 #include <linux/err.h>
28 #include <linux/delay.h>
29 #include <linux/bitops.h>
30 #include <linux/ftrace.h>
31 #include <linux/cpu.h>
32
33 #include <linux/atomic.h>
34 #include <asm/current.h>
35 #include <asm/delay.h>
36 #include <asm/tlbflush.h>
37
38 #include <asm/io.h>
39 #include <asm/irq.h> /* for CPU_IRQ_REGION and friends */
40 #include <asm/mmu_context.h>
41 #include <asm/page.h>
42 #include <asm/processor.h>
43 #include <asm/ptrace.h>
44 #include <asm/unistd.h>
45 #include <asm/cacheflush.h>
46
47 #undef DEBUG_SMP
48 #ifdef DEBUG_SMP
49 static int smp_debug_lvl = 0;
50 #define smp_debug(lvl, printargs...) \
51 if (lvl >= smp_debug_lvl) \
52 printk(printargs);
53 #else
54 #define smp_debug(lvl, ...) do { } while(0)
55 #endif /* DEBUG_SMP */
56
57 volatile struct task_struct *smp_init_current_idle_task;
58
59 /* track which CPU is booting */
60 static volatile int cpu_now_booting;
61
62 static int parisc_max_cpus = 1;
63
64 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
65
66 enum ipi_message_type {
67 IPI_NOP=0,
68 IPI_RESCHEDULE=1,
69 IPI_CALL_FUNC,
70 IPI_CPU_START,
71 IPI_CPU_STOP,
72 IPI_CPU_TEST
73 };
74
75
76 /********** SMP inter processor interrupt and communication routines */
77
78 #undef PER_CPU_IRQ_REGION
79 #ifdef PER_CPU_IRQ_REGION
80 /* XXX REVISIT Ignore for now.
81 ** *May* need this "hook" to register IPI handler
82 ** once we have perCPU ExtIntr switch tables.
83 */
84 static void
ipi_init(int cpuid)85 ipi_init(int cpuid)
86 {
87 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
88
89 if(cpu_online(cpuid) )
90 {
91 switch_to_idle_task(current);
92 }
93
94 return;
95 }
96 #endif
97
98
99 /*
100 ** Yoink this CPU from the runnable list...
101 **
102 */
103 static void
halt_processor(void)104 halt_processor(void)
105 {
106 /* REVISIT : redirect I/O Interrupts to another CPU? */
107 /* REVISIT : does PM *know* this CPU isn't available? */
108 set_cpu_online(smp_processor_id(), false);
109 local_irq_disable();
110 __pdc_cpu_rendezvous();
111 for (;;)
112 ;
113 }
114
115
116 irqreturn_t __irq_entry
ipi_interrupt(int irq,void * dev_id)117 ipi_interrupt(int irq, void *dev_id)
118 {
119 int this_cpu = smp_processor_id();
120 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
121 unsigned long ops;
122 unsigned long flags;
123
124 for (;;) {
125 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
126 spin_lock_irqsave(lock, flags);
127 ops = p->pending_ipi;
128 p->pending_ipi = 0;
129 spin_unlock_irqrestore(lock, flags);
130
131 mb(); /* Order bit clearing and data access. */
132
133 if (!ops)
134 break;
135
136 while (ops) {
137 unsigned long which = ffz(~ops);
138
139 ops &= ~(1 << which);
140
141 switch (which) {
142 case IPI_NOP:
143 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
144 break;
145
146 case IPI_RESCHEDULE:
147 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
148 inc_irq_stat(irq_resched_count);
149 scheduler_ipi();
150 break;
151
152 case IPI_CALL_FUNC:
153 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
154 inc_irq_stat(irq_call_count);
155 generic_smp_call_function_interrupt();
156 break;
157
158 case IPI_CPU_START:
159 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
160 break;
161
162 case IPI_CPU_STOP:
163 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
164 halt_processor();
165 break;
166
167 case IPI_CPU_TEST:
168 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
169 break;
170
171 default:
172 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
173 this_cpu, which);
174 return IRQ_NONE;
175 } /* Switch */
176
177 /* before doing more, let in any pending interrupts */
178 if (ops) {
179 local_irq_enable();
180 local_irq_disable();
181 }
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(unsigned long pdce_proc)295 void __init smp_callin(unsigned long pdce_proc)
296 {
297 int slave_id = cpu_now_booting;
298
299 #ifdef CONFIG_64BIT
300 WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
301 | PAGE0->mem_pdc) != pdce_proc);
302 #endif
303
304 smp_cpu_init(slave_id);
305 preempt_disable();
306
307 flush_cache_all_local(); /* start with known state */
308 flush_tlb_all_local(NULL);
309
310 local_irq_enable(); /* Interrupts have been off until now */
311
312 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
313
314 /* NOTREACHED */
315 panic("smp_callin() AAAAaaaaahhhh....\n");
316 }
317
318 /*
319 * Bring one cpu online.
320 */
smp_boot_one_cpu(int cpuid,struct task_struct * idle)321 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
322 {
323 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
324 long timeout;
325
326 task_thread_info(idle)->cpu = cpuid;
327
328 /* Let _start know what logical CPU we're booting
329 ** (offset into init_tasks[],cpu_data[])
330 */
331 cpu_now_booting = cpuid;
332
333 /*
334 ** boot strap code needs to know the task address since
335 ** it also contains the process stack.
336 */
337 smp_init_current_idle_task = idle ;
338 mb();
339
340 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
341
342 /*
343 ** This gets PDC to release the CPU from a very tight loop.
344 **
345 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
346 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
347 ** is executed after receiving the rendezvous signal (an interrupt to
348 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
349 ** contents of memory are valid."
350 */
351 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
352 mb();
353
354 /*
355 * OK, wait a bit for that CPU to finish staggering about.
356 * Slave will set a bit when it reaches smp_cpu_init().
357 * Once the "monarch CPU" sees the bit change, it can move on.
358 */
359 for (timeout = 0; timeout < 10000; timeout++) {
360 if(cpu_online(cpuid)) {
361 /* Which implies Slave has started up */
362 cpu_now_booting = 0;
363 smp_init_current_idle_task = NULL;
364 goto alive ;
365 }
366 udelay(100);
367 barrier();
368 }
369 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
370 return -1;
371
372 alive:
373 /* Remember the Slave data */
374 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
375 cpuid, timeout * 100);
376 return 0;
377 }
378
smp_prepare_boot_cpu(void)379 void __init smp_prepare_boot_cpu(void)
380 {
381 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
382
383 /* Setup BSP mappings */
384 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
385
386 set_cpu_online(bootstrap_processor, true);
387 set_cpu_present(bootstrap_processor, true);
388 }
389
390
391
392 /*
393 ** inventory.c:do_inventory() hasn't yet been run and thus we
394 ** don't 'discover' the additional CPUs until later.
395 */
smp_prepare_cpus(unsigned int max_cpus)396 void __init smp_prepare_cpus(unsigned int max_cpus)
397 {
398 int cpu;
399
400 for_each_possible_cpu(cpu)
401 spin_lock_init(&per_cpu(ipi_lock, cpu));
402
403 init_cpu_present(cpumask_of(0));
404
405 parisc_max_cpus = max_cpus;
406 if (!max_cpus)
407 printk(KERN_INFO "SMP mode deactivated.\n");
408 }
409
410
smp_cpus_done(unsigned int cpu_max)411 void smp_cpus_done(unsigned int cpu_max)
412 {
413 return;
414 }
415
416
__cpu_up(unsigned int cpu,struct task_struct * tidle)417 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
418 {
419 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
420 return -ENOSYS;
421
422 return cpu_online(cpu) ? 0 : -ENOSYS;
423 }
424
425 #ifdef CONFIG_PROC_FS
setup_profiling_timer(unsigned int multiplier)426 int setup_profiling_timer(unsigned int multiplier)
427 {
428 return -EINVAL;
429 }
430 #endif
431