GNU Linux-libre 5.15.72-gnu
[releases.git] / arch / parisc / kernel / smp.c
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 #include <linux/kgdb.h>
33
34 #include <linux/atomic.h>
35 #include <asm/current.h>
36 #include <asm/delay.h>
37 #include <asm/tlbflush.h>
38
39 #include <asm/io.h>
40 #include <asm/irq.h>            /* for CPU_IRQ_REGION and friends */
41 #include <asm/mmu_context.h>
42 #include <asm/page.h>
43 #include <asm/processor.h>
44 #include <asm/ptrace.h>
45 #include <asm/unistd.h>
46 #include <asm/cacheflush.h>
47
48 #undef DEBUG_SMP
49 #ifdef DEBUG_SMP
50 static int smp_debug_lvl = 0;
51 #define smp_debug(lvl, printargs...)            \
52                 if (lvl >= smp_debug_lvl)       \
53                         printk(printargs);
54 #else
55 #define smp_debug(lvl, ...)     do { } while(0)
56 #endif /* DEBUG_SMP */
57
58 volatile struct task_struct *smp_init_current_idle_task;
59
60 /* track which CPU is booting */
61 static volatile int cpu_now_booting;
62
63 static int parisc_max_cpus = 1;
64
65 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
66
67 enum ipi_message_type {
68         IPI_NOP=0,
69         IPI_RESCHEDULE=1,
70         IPI_CALL_FUNC,
71         IPI_CPU_START,
72         IPI_CPU_STOP,
73         IPI_CPU_TEST,
74 #ifdef CONFIG_KGDB
75         IPI_ENTER_KGDB,
76 #endif
77 };
78
79
80 /********** SMP inter processor interrupt and communication routines */
81
82 #undef PER_CPU_IRQ_REGION
83 #ifdef PER_CPU_IRQ_REGION
84 /* XXX REVISIT Ignore for now.
85 **    *May* need this "hook" to register IPI handler
86 **    once we have perCPU ExtIntr switch tables.
87 */
88 static void
89 ipi_init(int cpuid)
90 {
91 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
92
93         if(cpu_online(cpuid) )
94         {
95                 switch_to_idle_task(current);
96         }
97
98         return;
99 }
100 #endif
101
102
103 /*
104 ** Yoink this CPU from the runnable list... 
105 **
106 */
107 static void
108 halt_processor(void) 
109 {
110         /* REVISIT : redirect I/O Interrupts to another CPU? */
111         /* REVISIT : does PM *know* this CPU isn't available? */
112         set_cpu_online(smp_processor_id(), false);
113         local_irq_disable();
114         __pdc_cpu_rendezvous();
115         for (;;)
116                 ;
117 }
118
119
120 irqreturn_t __irq_entry
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                                 inc_irq_stat(irq_call_count);
159                                 generic_smp_call_function_interrupt();
160                                 break;
161
162                         case IPI_CPU_START:
163                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
164                                 break;
165
166                         case IPI_CPU_STOP:
167                                 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
168                                 halt_processor();
169                                 break;
170
171                         case IPI_CPU_TEST:
172                                 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
173                                 break;
174 #ifdef CONFIG_KGDB
175                         case IPI_ENTER_KGDB:
176                                 smp_debug(100, KERN_DEBUG "CPU%d ENTER_KGDB\n", this_cpu);
177                                 kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
178                                 break;
179 #endif
180                         default:
181                                 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
182                                         this_cpu, which);
183                                 return IRQ_NONE;
184                         } /* Switch */
185
186                         /* before doing more, let in any pending interrupts */
187                         if (ops) {
188                                 local_irq_enable();
189                                 local_irq_disable();
190                         }
191                 } /* while (ops) */
192         }
193         return IRQ_HANDLED;
194 }
195
196
197 static inline void
198 ipi_send(int cpu, enum ipi_message_type op)
199 {
200         struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
201         spinlock_t *lock = &per_cpu(ipi_lock, cpu);
202         unsigned long flags;
203
204         spin_lock_irqsave(lock, flags);
205         p->pending_ipi |= 1 << op;
206         gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
207         spin_unlock_irqrestore(lock, flags);
208 }
209
210 static void
211 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
212 {
213         int cpu;
214
215         for_each_cpu(cpu, mask)
216                 ipi_send(cpu, op);
217 }
218
219 static inline void
220 send_IPI_single(int dest_cpu, enum ipi_message_type op)
221 {
222         BUG_ON(dest_cpu == NO_PROC_ID);
223
224         ipi_send(dest_cpu, op);
225 }
226
227 static inline void
228 send_IPI_allbutself(enum ipi_message_type op)
229 {
230         int i;
231         
232         for_each_online_cpu(i) {
233                 if (i != smp_processor_id())
234                         send_IPI_single(i, op);
235         }
236 }
237
238 #ifdef CONFIG_KGDB
239 void kgdb_roundup_cpus(void)
240 {
241         send_IPI_allbutself(IPI_ENTER_KGDB);
242 }
243 #endif
244
245 inline void 
246 smp_send_stop(void)     { send_IPI_allbutself(IPI_CPU_STOP); }
247
248 void 
249 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
250
251 void
252 smp_send_all_nop(void)
253 {
254         send_IPI_allbutself(IPI_NOP);
255 }
256
257 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
258 {
259         send_IPI_mask(mask, IPI_CALL_FUNC);
260 }
261
262 void arch_send_call_function_single_ipi(int cpu)
263 {
264         send_IPI_single(cpu, IPI_CALL_FUNC);
265 }
266
267 /*
268  * Called by secondaries to update state and initialize CPU registers.
269  */
270 static void __init
271 smp_cpu_init(int cpunum)
272 {
273         extern void init_IRQ(void);    /* arch/parisc/kernel/irq.c */
274         extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
275
276         /* Set modes and Enable floating point coprocessor */
277         init_per_cpu(cpunum);
278
279         disable_sr_hashing();
280
281         mb();
282
283         /* Well, support 2.4 linux scheme as well. */
284         if (cpu_online(cpunum)) {
285                 extern void machine_halt(void); /* arch/parisc.../process.c */
286
287                 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
288                 machine_halt();
289         }
290
291         notify_cpu_starting(cpunum);
292
293         set_cpu_online(cpunum, true);
294
295         /* Initialise the idle task for this CPU */
296         mmgrab(&init_mm);
297         current->active_mm = &init_mm;
298         BUG_ON(current->mm);
299         enter_lazy_tlb(&init_mm, current);
300
301         init_IRQ();   /* make sure no IRQs are enabled or pending */
302         start_cpu_itimer();
303 }
304
305
306 /*
307  * Slaves start using C here. Indirectly called from smp_slave_stext.
308  * Do what start_kernel() and main() do for boot strap processor (aka monarch)
309  */
310 void __init smp_callin(unsigned long pdce_proc)
311 {
312         int slave_id = cpu_now_booting;
313
314 #ifdef CONFIG_64BIT
315         WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
316                         | PAGE0->mem_pdc) != pdce_proc);
317 #endif
318
319         smp_cpu_init(slave_id);
320
321         flush_cache_all_local(); /* start with known state */
322         flush_tlb_all_local(NULL);
323
324         local_irq_enable();  /* Interrupts have been off until now */
325
326         cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
327
328         /* NOTREACHED */
329         panic("smp_callin() AAAAaaaaahhhh....\n");
330 }
331
332 /*
333  * Bring one cpu online.
334  */
335 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
336 {
337         const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
338         long timeout;
339
340         task_thread_info(idle)->cpu = cpuid;
341
342         /* Let _start know what logical CPU we're booting
343         ** (offset into init_tasks[],cpu_data[])
344         */
345         cpu_now_booting = cpuid;
346
347         /* 
348         ** boot strap code needs to know the task address since
349         ** it also contains the process stack.
350         */
351         smp_init_current_idle_task = idle ;
352         mb();
353
354         printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
355
356         /*
357         ** This gets PDC to release the CPU from a very tight loop.
358         **
359         ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
360         ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which 
361         ** is executed after receiving the rendezvous signal (an interrupt to 
362         ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the 
363         ** contents of memory are valid."
364         */
365         gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
366         mb();
367
368         /* 
369          * OK, wait a bit for that CPU to finish staggering about. 
370          * Slave will set a bit when it reaches smp_cpu_init().
371          * Once the "monarch CPU" sees the bit change, it can move on.
372          */
373         for (timeout = 0; timeout < 10000; timeout++) {
374                 if(cpu_online(cpuid)) {
375                         /* Which implies Slave has started up */
376                         cpu_now_booting = 0;
377                         smp_init_current_idle_task = NULL;
378                         goto alive ;
379                 }
380                 udelay(100);
381                 barrier();
382         }
383         printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
384         return -1;
385
386 alive:
387         /* Remember the Slave data */
388         smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
389                 cpuid, timeout * 100);
390         return 0;
391 }
392
393 void __init smp_prepare_boot_cpu(void)
394 {
395         int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
396
397         /* Setup BSP mappings */
398         printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
399
400         set_cpu_online(bootstrap_processor, true);
401         set_cpu_present(bootstrap_processor, true);
402 }
403
404
405
406 /*
407 ** inventory.c:do_inventory() hasn't yet been run and thus we
408 ** don't 'discover' the additional CPUs until later.
409 */
410 void __init smp_prepare_cpus(unsigned int max_cpus)
411 {
412         int cpu;
413
414         for_each_possible_cpu(cpu)
415                 spin_lock_init(&per_cpu(ipi_lock, cpu));
416
417         init_cpu_present(cpumask_of(0));
418
419         parisc_max_cpus = max_cpus;
420         if (!max_cpus)
421                 printk(KERN_INFO "SMP mode deactivated.\n");
422 }
423
424
425 void smp_cpus_done(unsigned int cpu_max)
426 {
427         return;
428 }
429
430
431 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
432 {
433         if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
434                 return -ENOSYS;
435
436         return cpu_online(cpu) ? 0 : -ENOSYS;
437 }
438
439 #ifdef CONFIG_PROC_FS
440 int setup_profiling_timer(unsigned int multiplier)
441 {
442         return -EINVAL;
443 }
444 #endif