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/pgtable.h>
43 #include <asm/pgalloc.h>
44 #include <asm/processor.h>
45 #include <asm/ptrace.h>
46 #include <asm/unistd.h>
47 #include <asm/cacheflush.h>
48
49 #undef DEBUG_SMP
50 #ifdef DEBUG_SMP
51 static int smp_debug_lvl = 0;
52 #define smp_debug(lvl, printargs...) \
53 if (lvl >= smp_debug_lvl) \
54 printk(printargs);
55 #else
56 #define smp_debug(lvl, ...) do { } while(0)
57 #endif /* DEBUG_SMP */
58
59 volatile struct task_struct *smp_init_current_idle_task;
60
61 /* track which CPU is booting */
62 static volatile int cpu_now_booting;
63
64 static int parisc_max_cpus = 1;
65
66 static DEFINE_PER_CPU(spinlock_t, ipi_lock);
67
68 enum ipi_message_type {
69 IPI_NOP=0,
70 IPI_RESCHEDULE=1,
71 IPI_CALL_FUNC,
72 IPI_CPU_START,
73 IPI_CPU_STOP,
74 IPI_CPU_TEST
75 };
76
77
78 /********** SMP inter processor interrupt and communication routines */
79
80 #undef PER_CPU_IRQ_REGION
81 #ifdef PER_CPU_IRQ_REGION
82 /* XXX REVISIT Ignore for now.
83 ** *May* need this "hook" to register IPI handler
84 ** once we have perCPU ExtIntr switch tables.
85 */
86 static void
ipi_init(int cpuid)87 ipi_init(int cpuid)
88 {
89 #error verify IRQ_OFFSET(IPI_IRQ) is ipi_interrupt() in new IRQ region
90
91 if(cpu_online(cpuid) )
92 {
93 switch_to_idle_task(current);
94 }
95
96 return;
97 }
98 #endif
99
100
101 /*
102 ** Yoink this CPU from the runnable list...
103 **
104 */
105 static void
halt_processor(void)106 halt_processor(void)
107 {
108 /* REVISIT : redirect I/O Interrupts to another CPU? */
109 /* REVISIT : does PM *know* this CPU isn't available? */
110 set_cpu_online(smp_processor_id(), false);
111 local_irq_disable();
112 __pdc_cpu_rendezvous();
113 for (;;)
114 ;
115 }
116
117
118 irqreturn_t __irq_entry
ipi_interrupt(int irq,void * dev_id)119 ipi_interrupt(int irq, void *dev_id)
120 {
121 int this_cpu = smp_processor_id();
122 struct cpuinfo_parisc *p = &per_cpu(cpu_data, this_cpu);
123 unsigned long ops;
124 unsigned long flags;
125
126 for (;;) {
127 spinlock_t *lock = &per_cpu(ipi_lock, this_cpu);
128 spin_lock_irqsave(lock, flags);
129 ops = p->pending_ipi;
130 p->pending_ipi = 0;
131 spin_unlock_irqrestore(lock, flags);
132
133 mb(); /* Order bit clearing and data access. */
134
135 if (!ops)
136 break;
137
138 while (ops) {
139 unsigned long which = ffz(~ops);
140
141 ops &= ~(1 << which);
142
143 switch (which) {
144 case IPI_NOP:
145 smp_debug(100, KERN_DEBUG "CPU%d IPI_NOP\n", this_cpu);
146 break;
147
148 case IPI_RESCHEDULE:
149 smp_debug(100, KERN_DEBUG "CPU%d IPI_RESCHEDULE\n", this_cpu);
150 inc_irq_stat(irq_resched_count);
151 scheduler_ipi();
152 break;
153
154 case IPI_CALL_FUNC:
155 smp_debug(100, KERN_DEBUG "CPU%d IPI_CALL_FUNC\n", this_cpu);
156 inc_irq_stat(irq_call_count);
157 generic_smp_call_function_interrupt();
158 break;
159
160 case IPI_CPU_START:
161 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_START\n", this_cpu);
162 break;
163
164 case IPI_CPU_STOP:
165 smp_debug(100, KERN_DEBUG "CPU%d IPI_CPU_STOP\n", this_cpu);
166 halt_processor();
167 break;
168
169 case IPI_CPU_TEST:
170 smp_debug(100, KERN_DEBUG "CPU%d is alive!\n", this_cpu);
171 break;
172
173 default:
174 printk(KERN_CRIT "Unknown IPI num on CPU%d: %lu\n",
175 this_cpu, which);
176 return IRQ_NONE;
177 } /* Switch */
178 /* let in any pending interrupts */
179 local_irq_enable();
180 local_irq_disable();
181 } /* while (ops) */
182 }
183 return IRQ_HANDLED;
184 }
185
186
187 static inline void
ipi_send(int cpu,enum ipi_message_type op)188 ipi_send(int cpu, enum ipi_message_type op)
189 {
190 struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpu);
191 spinlock_t *lock = &per_cpu(ipi_lock, cpu);
192 unsigned long flags;
193
194 spin_lock_irqsave(lock, flags);
195 p->pending_ipi |= 1 << op;
196 gsc_writel(IPI_IRQ - CPU_IRQ_BASE, p->hpa);
197 spin_unlock_irqrestore(lock, flags);
198 }
199
200 static void
send_IPI_mask(const struct cpumask * mask,enum ipi_message_type op)201 send_IPI_mask(const struct cpumask *mask, enum ipi_message_type op)
202 {
203 int cpu;
204
205 for_each_cpu(cpu, mask)
206 ipi_send(cpu, op);
207 }
208
209 static inline void
send_IPI_single(int dest_cpu,enum ipi_message_type op)210 send_IPI_single(int dest_cpu, enum ipi_message_type op)
211 {
212 BUG_ON(dest_cpu == NO_PROC_ID);
213
214 ipi_send(dest_cpu, op);
215 }
216
217 static inline void
send_IPI_allbutself(enum ipi_message_type op)218 send_IPI_allbutself(enum ipi_message_type op)
219 {
220 int i;
221
222 for_each_online_cpu(i) {
223 if (i != smp_processor_id())
224 send_IPI_single(i, op);
225 }
226 }
227
228
229 inline void
smp_send_stop(void)230 smp_send_stop(void) { send_IPI_allbutself(IPI_CPU_STOP); }
231
232 void
smp_send_reschedule(int cpu)233 smp_send_reschedule(int cpu) { send_IPI_single(cpu, IPI_RESCHEDULE); }
234
235 void
smp_send_all_nop(void)236 smp_send_all_nop(void)
237 {
238 send_IPI_allbutself(IPI_NOP);
239 }
240
arch_send_call_function_ipi_mask(const struct cpumask * mask)241 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
242 {
243 send_IPI_mask(mask, IPI_CALL_FUNC);
244 }
245
arch_send_call_function_single_ipi(int cpu)246 void arch_send_call_function_single_ipi(int cpu)
247 {
248 send_IPI_single(cpu, IPI_CALL_FUNC);
249 }
250
251 /*
252 * Called by secondaries to update state and initialize CPU registers.
253 */
254 static void __init
smp_cpu_init(int cpunum)255 smp_cpu_init(int cpunum)
256 {
257 extern void init_IRQ(void); /* arch/parisc/kernel/irq.c */
258 extern void start_cpu_itimer(void); /* arch/parisc/kernel/time.c */
259
260 /* Set modes and Enable floating point coprocessor */
261 init_per_cpu(cpunum);
262
263 disable_sr_hashing();
264
265 mb();
266
267 /* Well, support 2.4 linux scheme as well. */
268 if (cpu_online(cpunum)) {
269 extern void machine_halt(void); /* arch/parisc.../process.c */
270
271 printk(KERN_CRIT "CPU#%d already initialized!\n", cpunum);
272 machine_halt();
273 }
274
275 notify_cpu_starting(cpunum);
276
277 set_cpu_online(cpunum, true);
278
279 /* Initialise the idle task for this CPU */
280 mmgrab(&init_mm);
281 current->active_mm = &init_mm;
282 BUG_ON(current->mm);
283 enter_lazy_tlb(&init_mm, current);
284
285 init_IRQ(); /* make sure no IRQs are enabled or pending */
286 start_cpu_itimer();
287 }
288
289
290 /*
291 * Slaves start using C here. Indirectly called from smp_slave_stext.
292 * Do what start_kernel() and main() do for boot strap processor (aka monarch)
293 */
smp_callin(unsigned long pdce_proc)294 void __init smp_callin(unsigned long pdce_proc)
295 {
296 int slave_id = cpu_now_booting;
297
298 #ifdef CONFIG_64BIT
299 WARN_ON(((unsigned long)(PAGE0->mem_pdc_hi) << 32
300 | PAGE0->mem_pdc) != pdce_proc);
301 #endif
302
303 smp_cpu_init(slave_id);
304 preempt_disable();
305
306 flush_cache_all_local(); /* start with known state */
307 flush_tlb_all_local(NULL);
308
309 local_irq_enable(); /* Interrupts have been off until now */
310
311 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
312
313 /* NOTREACHED */
314 panic("smp_callin() AAAAaaaaahhhh....\n");
315 }
316
317 /*
318 * Bring one cpu online.
319 */
smp_boot_one_cpu(int cpuid,struct task_struct * idle)320 int smp_boot_one_cpu(int cpuid, struct task_struct *idle)
321 {
322 const struct cpuinfo_parisc *p = &per_cpu(cpu_data, cpuid);
323 long timeout;
324
325 task_thread_info(idle)->cpu = cpuid;
326
327 /* Let _start know what logical CPU we're booting
328 ** (offset into init_tasks[],cpu_data[])
329 */
330 cpu_now_booting = cpuid;
331
332 /*
333 ** boot strap code needs to know the task address since
334 ** it also contains the process stack.
335 */
336 smp_init_current_idle_task = idle ;
337 mb();
338
339 printk(KERN_INFO "Releasing cpu %d now, hpa=%lx\n", cpuid, p->hpa);
340
341 /*
342 ** This gets PDC to release the CPU from a very tight loop.
343 **
344 ** From the PA-RISC 2.0 Firmware Architecture Reference Specification:
345 ** "The MEM_RENDEZ vector specifies the location of OS_RENDEZ which
346 ** is executed after receiving the rendezvous signal (an interrupt to
347 ** EIR{0}). MEM_RENDEZ is valid only when it is nonzero and the
348 ** contents of memory are valid."
349 */
350 gsc_writel(TIMER_IRQ - CPU_IRQ_BASE, p->hpa);
351 mb();
352
353 /*
354 * OK, wait a bit for that CPU to finish staggering about.
355 * Slave will set a bit when it reaches smp_cpu_init().
356 * Once the "monarch CPU" sees the bit change, it can move on.
357 */
358 for (timeout = 0; timeout < 10000; timeout++) {
359 if(cpu_online(cpuid)) {
360 /* Which implies Slave has started up */
361 cpu_now_booting = 0;
362 smp_init_current_idle_task = NULL;
363 goto alive ;
364 }
365 udelay(100);
366 barrier();
367 }
368 printk(KERN_CRIT "SMP: CPU:%d is stuck.\n", cpuid);
369 return -1;
370
371 alive:
372 /* Remember the Slave data */
373 smp_debug(100, KERN_DEBUG "SMP: CPU:%d came alive after %ld _us\n",
374 cpuid, timeout * 100);
375 return 0;
376 }
377
smp_prepare_boot_cpu(void)378 void __init smp_prepare_boot_cpu(void)
379 {
380 int bootstrap_processor = per_cpu(cpu_data, 0).cpuid;
381
382 /* Setup BSP mappings */
383 printk(KERN_INFO "SMP: bootstrap CPU ID is %d\n", bootstrap_processor);
384
385 set_cpu_online(bootstrap_processor, true);
386 set_cpu_present(bootstrap_processor, true);
387 }
388
389
390
391 /*
392 ** inventory.c:do_inventory() hasn't yet been run and thus we
393 ** don't 'discover' the additional CPUs until later.
394 */
smp_prepare_cpus(unsigned int max_cpus)395 void __init smp_prepare_cpus(unsigned int max_cpus)
396 {
397 int cpu;
398
399 for_each_possible_cpu(cpu)
400 spin_lock_init(&per_cpu(ipi_lock, cpu));
401
402 init_cpu_present(cpumask_of(0));
403
404 parisc_max_cpus = max_cpus;
405 if (!max_cpus)
406 printk(KERN_INFO "SMP mode deactivated.\n");
407 }
408
409
smp_cpus_done(unsigned int cpu_max)410 void smp_cpus_done(unsigned int cpu_max)
411 {
412 return;
413 }
414
415
__cpu_up(unsigned int cpu,struct task_struct * tidle)416 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
417 {
418 if (cpu != 0 && cpu < parisc_max_cpus && smp_boot_one_cpu(cpu, tidle))
419 return -ENOSYS;
420
421 return cpu_online(cpu) ? 0 : -ENOSYS;
422 }
423
424 #ifdef CONFIG_PROC_FS
setup_profiling_timer(unsigned int multiplier)425 int setup_profiling_timer(unsigned int multiplier)
426 {
427 return -EINVAL;
428 }
429 #endif
430