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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SMP related functions
4 *
5 * Copyright IBM Corp. 1999, 2012
6 * Author(s): Denis Joseph Barrow,
7 * Martin Schwidefsky <schwidefsky@de.ibm.com>,
8 *
9 * based on other smp stuff by
10 * (c) 1995 Alan Cox, CymruNET Ltd <alan@cymru.net>
11 * (c) 1998 Ingo Molnar
12 *
13 * The code outside of smp.c uses logical cpu numbers, only smp.c does
14 * the translation of logical to physical cpu ids. All new code that
15 * operates on physical cpu numbers needs to go into smp.c.
16 */
17
18#define KMSG_COMPONENT "cpu"
19#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
20
21#include <linux/workqueue.h>
22#include <linux/memblock.h>
23#include <linux/export.h>
24#include <linux/init.h>
25#include <linux/mm.h>
26#include <linux/err.h>
27#include <linux/spinlock.h>
28#include <linux/kernel_stat.h>
29#include <linux/delay.h>
30#include <linux/interrupt.h>
31#include <linux/irqflags.h>
32#include <linux/irq_work.h>
33#include <linux/cpu.h>
34#include <linux/slab.h>
35#include <linux/sched/hotplug.h>
36#include <linux/sched/task_stack.h>
37#include <linux/crash_dump.h>
38#include <linux/kprobes.h>
39#include <asm/asm-offsets.h>
40#include <asm/diag.h>
41#include <asm/switch_to.h>
42#include <asm/facility.h>
43#include <asm/ipl.h>
44#include <asm/setup.h>
45#include <asm/irq.h>
46#include <asm/tlbflush.h>
47#include <asm/vtimer.h>
48#include <asm/abs_lowcore.h>
49#include <asm/sclp.h>
50#include <asm/debug.h>
51#include <asm/os_info.h>
52#include <asm/sigp.h>
53#include <asm/idle.h>
54#include <asm/nmi.h>
55#include <asm/stacktrace.h>
56#include <asm/topology.h>
57#include <asm/vdso.h>
58#include <asm/maccess.h>
59#include "entry.h"
60
61enum {
62 ec_schedule = 0,
63 ec_call_function_single,
64 ec_stop_cpu,
65 ec_mcck_pending,
66 ec_irq_work,
67};
68
69enum {
70 CPU_STATE_STANDBY,
71 CPU_STATE_CONFIGURED,
72};
73
74static DEFINE_PER_CPU(struct cpu *, cpu_device);
75
76struct pcpu {
77 unsigned long ec_mask; /* bit mask for ec_xxx functions */
78 unsigned long ec_clk; /* sigp timestamp for ec_xxx */
79 signed char state; /* physical cpu state */
80 signed char polarization; /* physical polarization */
81 u16 address; /* physical cpu address */
82};
83
84static u8 boot_core_type;
85static struct pcpu pcpu_devices[NR_CPUS];
86
87unsigned int smp_cpu_mt_shift;
88EXPORT_SYMBOL(smp_cpu_mt_shift);
89
90unsigned int smp_cpu_mtid;
91EXPORT_SYMBOL(smp_cpu_mtid);
92
93#ifdef CONFIG_CRASH_DUMP
94__vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
95#endif
96
97static unsigned int smp_max_threads __initdata = -1U;
98cpumask_t cpu_setup_mask;
99
100static int __init early_nosmt(char *s)
101{
102 smp_max_threads = 1;
103 return 0;
104}
105early_param("nosmt", early_nosmt);
106
107static int __init early_smt(char *s)
108{
109 get_option(&s, &smp_max_threads);
110 return 0;
111}
112early_param("smt", early_smt);
113
114/*
115 * The smp_cpu_state_mutex must be held when changing the state or polarization
116 * member of a pcpu data structure within the pcpu_devices arreay.
117 */
118DEFINE_MUTEX(smp_cpu_state_mutex);
119
120/*
121 * Signal processor helper functions.
122 */
123static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
124{
125 int cc;
126
127 while (1) {
128 cc = __pcpu_sigp(addr, order, parm, NULL);
129 if (cc != SIGP_CC_BUSY)
130 return cc;
131 cpu_relax();
132 }
133}
134
135static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
136{
137 int cc, retry;
138
139 for (retry = 0; ; retry++) {
140 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
141 if (cc != SIGP_CC_BUSY)
142 break;
143 if (retry >= 3)
144 udelay(10);
145 }
146 return cc;
147}
148
149static inline int pcpu_stopped(struct pcpu *pcpu)
150{
151 u32 status;
152
153 if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
154 0, &status) != SIGP_CC_STATUS_STORED)
155 return 0;
156 return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
157}
158
159static inline int pcpu_running(struct pcpu *pcpu)
160{
161 if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
162 0, NULL) != SIGP_CC_STATUS_STORED)
163 return 1;
164 /* Status stored condition code is equivalent to cpu not running. */
165 return 0;
166}
167
168/*
169 * Find struct pcpu by cpu address.
170 */
171static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
172{
173 int cpu;
174
175 for_each_cpu(cpu, mask)
176 if (pcpu_devices[cpu].address == address)
177 return pcpu_devices + cpu;
178 return NULL;
179}
180
181static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
182{
183 int order;
184
185 if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
186 return;
187 order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
188 pcpu->ec_clk = get_tod_clock_fast();
189 pcpu_sigp_retry(pcpu, order, 0);
190}
191
192static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
193{
194 unsigned long async_stack, nodat_stack, mcck_stack;
195 struct lowcore *lc;
196
197 lc = (struct lowcore *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
198 nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
199 async_stack = stack_alloc();
200 mcck_stack = stack_alloc();
201 if (!lc || !nodat_stack || !async_stack || !mcck_stack)
202 goto out;
203 memcpy(lc, &S390_lowcore, 512);
204 memset((char *) lc + 512, 0, sizeof(*lc) - 512);
205 lc->async_stack = async_stack + STACK_INIT_OFFSET;
206 lc->nodat_stack = nodat_stack + STACK_INIT_OFFSET;
207 lc->mcck_stack = mcck_stack + STACK_INIT_OFFSET;
208 lc->cpu_nr = cpu;
209 lc->spinlock_lockval = arch_spin_lockval(cpu);
210 lc->spinlock_index = 0;
211 lc->return_lpswe = gen_lpswe(__LC_RETURN_PSW);
212 lc->return_mcck_lpswe = gen_lpswe(__LC_RETURN_MCCK_PSW);
213 lc->preempt_count = PREEMPT_DISABLED;
214 if (nmi_alloc_mcesa(&lc->mcesad))
215 goto out;
216 if (abs_lowcore_map(cpu, lc, true))
217 goto out_mcesa;
218 lowcore_ptr[cpu] = lc;
219 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, __pa(lc));
220 return 0;
221
222out_mcesa:
223 nmi_free_mcesa(&lc->mcesad);
224out:
225 stack_free(mcck_stack);
226 stack_free(async_stack);
227 free_pages(nodat_stack, THREAD_SIZE_ORDER);
228 free_pages((unsigned long) lc, LC_ORDER);
229 return -ENOMEM;
230}
231
232static void pcpu_free_lowcore(struct pcpu *pcpu)
233{
234 unsigned long async_stack, nodat_stack, mcck_stack;
235 struct lowcore *lc;
236 int cpu;
237
238 cpu = pcpu - pcpu_devices;
239 lc = lowcore_ptr[cpu];
240 nodat_stack = lc->nodat_stack - STACK_INIT_OFFSET;
241 async_stack = lc->async_stack - STACK_INIT_OFFSET;
242 mcck_stack = lc->mcck_stack - STACK_INIT_OFFSET;
243 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
244 lowcore_ptr[cpu] = NULL;
245 abs_lowcore_unmap(cpu);
246 nmi_free_mcesa(&lc->mcesad);
247 stack_free(async_stack);
248 stack_free(mcck_stack);
249 free_pages(nodat_stack, THREAD_SIZE_ORDER);
250 free_pages((unsigned long) lc, LC_ORDER);
251}
252
253static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
254{
255 struct lowcore *lc = lowcore_ptr[cpu];
256
257 cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
258 cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
259 lc->cpu_nr = cpu;
260 lc->restart_flags = RESTART_FLAG_CTLREGS;
261 lc->spinlock_lockval = arch_spin_lockval(cpu);
262 lc->spinlock_index = 0;
263 lc->percpu_offset = __per_cpu_offset[cpu];
264 lc->kernel_asce = S390_lowcore.kernel_asce;
265 lc->user_asce = s390_invalid_asce;
266 lc->machine_flags = S390_lowcore.machine_flags;
267 lc->user_timer = lc->system_timer =
268 lc->steal_timer = lc->avg_steal_timer = 0;
269 __ctl_store(lc->cregs_save_area, 0, 15);
270 lc->cregs_save_area[1] = lc->kernel_asce;
271 lc->cregs_save_area[7] = lc->user_asce;
272 save_access_regs((unsigned int *) lc->access_regs_save_area);
273 arch_spin_lock_setup(cpu);
274}
275
276static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
277{
278 struct lowcore *lc;
279 int cpu;
280
281 cpu = pcpu - pcpu_devices;
282 lc = lowcore_ptr[cpu];
283 lc->kernel_stack = (unsigned long) task_stack_page(tsk)
284 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
285 lc->current_task = (unsigned long) tsk;
286 lc->lpp = LPP_MAGIC;
287 lc->current_pid = tsk->pid;
288 lc->user_timer = tsk->thread.user_timer;
289 lc->guest_timer = tsk->thread.guest_timer;
290 lc->system_timer = tsk->thread.system_timer;
291 lc->hardirq_timer = tsk->thread.hardirq_timer;
292 lc->softirq_timer = tsk->thread.softirq_timer;
293 lc->steal_timer = 0;
294}
295
296static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
297{
298 struct lowcore *lc;
299 int cpu;
300
301 cpu = pcpu - pcpu_devices;
302 lc = lowcore_ptr[cpu];
303 lc->restart_stack = lc->kernel_stack;
304 lc->restart_fn = (unsigned long) func;
305 lc->restart_data = (unsigned long) data;
306 lc->restart_source = -1U;
307 pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
308}
309
310typedef void (pcpu_delegate_fn)(void *);
311
312/*
313 * Call function via PSW restart on pcpu and stop the current cpu.
314 */
315static void __pcpu_delegate(pcpu_delegate_fn *func, void *data)
316{
317 func(data); /* should not return */
318}
319
320static void pcpu_delegate(struct pcpu *pcpu,
321 pcpu_delegate_fn *func,
322 void *data, unsigned long stack)
323{
324 struct lowcore *lc, *abs_lc;
325 unsigned int source_cpu;
326 unsigned long flags;
327
328 lc = lowcore_ptr[pcpu - pcpu_devices];
329 source_cpu = stap();
330 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
331 if (pcpu->address == source_cpu) {
332 call_on_stack(2, stack, void, __pcpu_delegate,
333 pcpu_delegate_fn *, func, void *, data);
334 }
335 /* Stop target cpu (if func returns this stops the current cpu). */
336 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
337 /* Restart func on the target cpu and stop the current cpu. */
338 if (lc) {
339 lc->restart_stack = stack;
340 lc->restart_fn = (unsigned long)func;
341 lc->restart_data = (unsigned long)data;
342 lc->restart_source = source_cpu;
343 } else {
344 abs_lc = get_abs_lowcore(&flags);
345 abs_lc->restart_stack = stack;
346 abs_lc->restart_fn = (unsigned long)func;
347 abs_lc->restart_data = (unsigned long)data;
348 abs_lc->restart_source = source_cpu;
349 put_abs_lowcore(abs_lc, flags);
350 }
351 __bpon();
352 asm volatile(
353 "0: sigp 0,%0,%2 # sigp restart to target cpu\n"
354 " brc 2,0b # busy, try again\n"
355 "1: sigp 0,%1,%3 # sigp stop to current cpu\n"
356 " brc 2,1b # busy, try again\n"
357 : : "d" (pcpu->address), "d" (source_cpu),
358 "K" (SIGP_RESTART), "K" (SIGP_STOP)
359 : "0", "1", "cc");
360 for (;;) ;
361}
362
363/*
364 * Enable additional logical cpus for multi-threading.
365 */
366static int pcpu_set_smt(unsigned int mtid)
367{
368 int cc;
369
370 if (smp_cpu_mtid == mtid)
371 return 0;
372 cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
373 if (cc == 0) {
374 smp_cpu_mtid = mtid;
375 smp_cpu_mt_shift = 0;
376 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
377 smp_cpu_mt_shift++;
378 pcpu_devices[0].address = stap();
379 }
380 return cc;
381}
382
383/*
384 * Call function on an online CPU.
385 */
386void smp_call_online_cpu(void (*func)(void *), void *data)
387{
388 struct pcpu *pcpu;
389
390 /* Use the current cpu if it is online. */
391 pcpu = pcpu_find_address(cpu_online_mask, stap());
392 if (!pcpu)
393 /* Use the first online cpu. */
394 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
395 pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
396}
397
398/*
399 * Call function on the ipl CPU.
400 */
401void smp_call_ipl_cpu(void (*func)(void *), void *data)
402{
403 struct lowcore *lc = lowcore_ptr[0];
404
405 if (pcpu_devices[0].address == stap())
406 lc = &S390_lowcore;
407
408 pcpu_delegate(&pcpu_devices[0], func, data,
409 lc->nodat_stack);
410}
411
412int smp_find_processor_id(u16 address)
413{
414 int cpu;
415
416 for_each_present_cpu(cpu)
417 if (pcpu_devices[cpu].address == address)
418 return cpu;
419 return -1;
420}
421
422void schedule_mcck_handler(void)
423{
424 pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_mcck_pending);
425}
426
427bool notrace arch_vcpu_is_preempted(int cpu)
428{
429 if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
430 return false;
431 if (pcpu_running(pcpu_devices + cpu))
432 return false;
433 return true;
434}
435EXPORT_SYMBOL(arch_vcpu_is_preempted);
436
437void notrace smp_yield_cpu(int cpu)
438{
439 if (!MACHINE_HAS_DIAG9C)
440 return;
441 diag_stat_inc_norecursion(DIAG_STAT_X09C);
442 asm volatile("diag %0,0,0x9c"
443 : : "d" (pcpu_devices[cpu].address));
444}
445EXPORT_SYMBOL_GPL(smp_yield_cpu);
446
447/*
448 * Send cpus emergency shutdown signal. This gives the cpus the
449 * opportunity to complete outstanding interrupts.
450 */
451void notrace smp_emergency_stop(void)
452{
453 static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED;
454 static cpumask_t cpumask;
455 u64 end;
456 int cpu;
457
458 arch_spin_lock(&lock);
459 cpumask_copy(&cpumask, cpu_online_mask);
460 cpumask_clear_cpu(smp_processor_id(), &cpumask);
461
462 end = get_tod_clock() + (1000000UL << 12);
463 for_each_cpu(cpu, &cpumask) {
464 struct pcpu *pcpu = pcpu_devices + cpu;
465 set_bit(ec_stop_cpu, &pcpu->ec_mask);
466 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
467 0, NULL) == SIGP_CC_BUSY &&
468 get_tod_clock() < end)
469 cpu_relax();
470 }
471 while (get_tod_clock() < end) {
472 for_each_cpu(cpu, &cpumask)
473 if (pcpu_stopped(pcpu_devices + cpu))
474 cpumask_clear_cpu(cpu, &cpumask);
475 if (cpumask_empty(&cpumask))
476 break;
477 cpu_relax();
478 }
479 arch_spin_unlock(&lock);
480}
481NOKPROBE_SYMBOL(smp_emergency_stop);
482
483/*
484 * Stop all cpus but the current one.
485 */
486void smp_send_stop(void)
487{
488 int cpu;
489
490 /* Disable all interrupts/machine checks */
491 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
492 trace_hardirqs_off();
493
494 debug_set_critical();
495
496 if (oops_in_progress)
497 smp_emergency_stop();
498
499 /* stop all processors */
500 for_each_online_cpu(cpu) {
501 if (cpu == smp_processor_id())
502 continue;
503 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
504 while (!pcpu_stopped(pcpu_devices + cpu))
505 cpu_relax();
506 }
507}
508
509/*
510 * This is the main routine where commands issued by other
511 * cpus are handled.
512 */
513static void smp_handle_ext_call(void)
514{
515 unsigned long bits;
516
517 /* handle bit signal external calls */
518 bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
519 if (test_bit(ec_stop_cpu, &bits))
520 smp_stop_cpu();
521 if (test_bit(ec_schedule, &bits))
522 scheduler_ipi();
523 if (test_bit(ec_call_function_single, &bits))
524 generic_smp_call_function_single_interrupt();
525 if (test_bit(ec_mcck_pending, &bits))
526 __s390_handle_mcck();
527 if (test_bit(ec_irq_work, &bits))
528 irq_work_run();
529}
530
531static void do_ext_call_interrupt(struct ext_code ext_code,
532 unsigned int param32, unsigned long param64)
533{
534 inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
535 smp_handle_ext_call();
536}
537
538void arch_send_call_function_ipi_mask(const struct cpumask *mask)
539{
540 int cpu;
541
542 for_each_cpu(cpu, mask)
543 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
544}
545
546void arch_send_call_function_single_ipi(int cpu)
547{
548 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
549}
550
551/*
552 * this function sends a 'reschedule' IPI to another CPU.
553 * it goes straight through and wastes no time serializing
554 * anything. Worst case is that we lose a reschedule ...
555 */
556void smp_send_reschedule(int cpu)
557{
558 pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
559}
560
561#ifdef CONFIG_IRQ_WORK
562void arch_irq_work_raise(void)
563{
564 pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_irq_work);
565}
566#endif
567
568/*
569 * parameter area for the set/clear control bit callbacks
570 */
571struct ec_creg_mask_parms {
572 unsigned long orval;
573 unsigned long andval;
574 int cr;
575};
576
577/*
578 * callback for setting/clearing control bits
579 */
580static void smp_ctl_bit_callback(void *info)
581{
582 struct ec_creg_mask_parms *pp = info;
583 unsigned long cregs[16];
584
585 __ctl_store(cregs, 0, 15);
586 cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
587 __ctl_load(cregs, 0, 15);
588}
589
590static DEFINE_SPINLOCK(ctl_lock);
591
592void smp_ctl_set_clear_bit(int cr, int bit, bool set)
593{
594 struct ec_creg_mask_parms parms = { .cr = cr, };
595 struct lowcore *abs_lc;
596 unsigned long flags;
597 u64 ctlreg;
598
599 if (set) {
600 parms.orval = 1UL << bit;
601 parms.andval = -1UL;
602 } else {
603 parms.orval = 0;
604 parms.andval = ~(1UL << bit);
605 }
606 spin_lock(&ctl_lock);
607 abs_lc = get_abs_lowcore(&flags);
608 ctlreg = abs_lc->cregs_save_area[cr];
609 ctlreg = (ctlreg & parms.andval) | parms.orval;
610 abs_lc->cregs_save_area[cr] = ctlreg;
611 put_abs_lowcore(abs_lc, flags);
612 spin_unlock(&ctl_lock);
613 on_each_cpu(smp_ctl_bit_callback, &parms, 1);
614}
615EXPORT_SYMBOL(smp_ctl_set_clear_bit);
616
617#ifdef CONFIG_CRASH_DUMP
618
619int smp_store_status(int cpu)
620{
621 struct lowcore *lc;
622 struct pcpu *pcpu;
623 unsigned long pa;
624
625 pcpu = pcpu_devices + cpu;
626 lc = lowcore_ptr[cpu];
627 pa = __pa(&lc->floating_pt_save_area);
628 if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
629 pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
630 return -EIO;
631 if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
632 return 0;
633 pa = lc->mcesad & MCESA_ORIGIN_MASK;
634 if (MACHINE_HAS_GS)
635 pa |= lc->mcesad & MCESA_LC_MASK;
636 if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
637 pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
638 return -EIO;
639 return 0;
640}
641
642/*
643 * Collect CPU state of the previous, crashed system.
644 * There are four cases:
645 * 1) standard zfcp/nvme dump
646 * condition: OLDMEM_BASE == NULL && is_ipl_type_dump() == true
647 * The state for all CPUs except the boot CPU needs to be collected
648 * with sigp stop-and-store-status. The boot CPU state is located in
649 * the absolute lowcore of the memory stored in the HSA. The zcore code
650 * will copy the boot CPU state from the HSA.
651 * 2) stand-alone kdump for SCSI/NVMe (zfcp/nvme dump with swapped memory)
652 * condition: OLDMEM_BASE != NULL && is_ipl_type_dump() == true
653 * The state for all CPUs except the boot CPU needs to be collected
654 * with sigp stop-and-store-status. The firmware or the boot-loader
655 * stored the registers of the boot CPU in the absolute lowcore in the
656 * memory of the old system.
657 * 3) kdump and the old kernel did not store the CPU state,
658 * or stand-alone kdump for DASD
659 * condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
660 * The state for all CPUs except the boot CPU needs to be collected
661 * with sigp stop-and-store-status. The kexec code or the boot-loader
662 * stored the registers of the boot CPU in the memory of the old system.
663 * 4) kdump and the old kernel stored the CPU state
664 * condition: OLDMEM_BASE != NULL && is_kdump_kernel()
665 * This case does not exist for s390 anymore, setup_arch explicitly
666 * deactivates the elfcorehdr= kernel parameter
667 */
668static bool dump_available(void)
669{
670 return oldmem_data.start || is_ipl_type_dump();
671}
672
673void __init smp_save_dump_ipl_cpu(void)
674{
675 struct save_area *sa;
676 void *regs;
677
678 if (!dump_available())
679 return;
680 sa = save_area_alloc(true);
681 regs = memblock_alloc(512, 8);
682 if (!sa || !regs)
683 panic("could not allocate memory for boot CPU save area\n");
684 copy_oldmem_kernel(regs, __LC_FPREGS_SAVE_AREA, 512);
685 save_area_add_regs(sa, regs);
686 memblock_free(regs, 512);
687 if (MACHINE_HAS_VX)
688 save_area_add_vxrs(sa, boot_cpu_vector_save_area);
689}
690
691void __init smp_save_dump_secondary_cpus(void)
692{
693 int addr, boot_cpu_addr, max_cpu_addr;
694 struct save_area *sa;
695 void *page;
696
697 if (!dump_available())
698 return;
699 /* Allocate a page as dumping area for the store status sigps */
700 page = memblock_alloc_low(PAGE_SIZE, PAGE_SIZE);
701 if (!page)
702 panic("ERROR: Failed to allocate %lx bytes below %lx\n",
703 PAGE_SIZE, 1UL << 31);
704
705 /* Set multi-threading state to the previous system. */
706 pcpu_set_smt(sclp.mtid_prev);
707 boot_cpu_addr = stap();
708 max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
709 for (addr = 0; addr <= max_cpu_addr; addr++) {
710 if (addr == boot_cpu_addr)
711 continue;
712 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
713 SIGP_CC_NOT_OPERATIONAL)
714 continue;
715 sa = save_area_alloc(false);
716 if (!sa)
717 panic("could not allocate memory for save area\n");
718 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, __pa(page));
719 save_area_add_regs(sa, page);
720 if (MACHINE_HAS_VX) {
721 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, __pa(page));
722 save_area_add_vxrs(sa, page);
723 }
724 }
725 memblock_free(page, PAGE_SIZE);
726 diag_amode31_ops.diag308_reset();
727 pcpu_set_smt(0);
728}
729#endif /* CONFIG_CRASH_DUMP */
730
731void smp_cpu_set_polarization(int cpu, int val)
732{
733 pcpu_devices[cpu].polarization = val;
734}
735
736int smp_cpu_get_polarization(int cpu)
737{
738 return pcpu_devices[cpu].polarization;
739}
740
741int smp_cpu_get_cpu_address(int cpu)
742{
743 return pcpu_devices[cpu].address;
744}
745
746static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
747{
748 static int use_sigp_detection;
749 int address;
750
751 if (use_sigp_detection || sclp_get_core_info(info, early)) {
752 use_sigp_detection = 1;
753 for (address = 0;
754 address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
755 address += (1U << smp_cpu_mt_shift)) {
756 if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
757 SIGP_CC_NOT_OPERATIONAL)
758 continue;
759 info->core[info->configured].core_id =
760 address >> smp_cpu_mt_shift;
761 info->configured++;
762 }
763 info->combined = info->configured;
764 }
765}
766
767static int smp_add_present_cpu(int cpu);
768
769static int smp_add_core(struct sclp_core_entry *core, cpumask_t *avail,
770 bool configured, bool early)
771{
772 struct pcpu *pcpu;
773 int cpu, nr, i;
774 u16 address;
775
776 nr = 0;
777 if (sclp.has_core_type && core->type != boot_core_type)
778 return nr;
779 cpu = cpumask_first(avail);
780 address = core->core_id << smp_cpu_mt_shift;
781 for (i = 0; (i <= smp_cpu_mtid) && (cpu < nr_cpu_ids); i++) {
782 if (pcpu_find_address(cpu_present_mask, address + i))
783 continue;
784 pcpu = pcpu_devices + cpu;
785 pcpu->address = address + i;
786 if (configured)
787 pcpu->state = CPU_STATE_CONFIGURED;
788 else
789 pcpu->state = CPU_STATE_STANDBY;
790 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
791 set_cpu_present(cpu, true);
792 if (!early && smp_add_present_cpu(cpu) != 0)
793 set_cpu_present(cpu, false);
794 else
795 nr++;
796 cpumask_clear_cpu(cpu, avail);
797 cpu = cpumask_next(cpu, avail);
798 }
799 return nr;
800}
801
802static int __smp_rescan_cpus(struct sclp_core_info *info, bool early)
803{
804 struct sclp_core_entry *core;
805 static cpumask_t avail;
806 bool configured;
807 u16 core_id;
808 int nr, i;
809
810 cpus_read_lock();
811 mutex_lock(&smp_cpu_state_mutex);
812 nr = 0;
813 cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
814 /*
815 * Add IPL core first (which got logical CPU number 0) to make sure
816 * that all SMT threads get subsequent logical CPU numbers.
817 */
818 if (early) {
819 core_id = pcpu_devices[0].address >> smp_cpu_mt_shift;
820 for (i = 0; i < info->configured; i++) {
821 core = &info->core[i];
822 if (core->core_id == core_id) {
823 nr += smp_add_core(core, &avail, true, early);
824 break;
825 }
826 }
827 }
828 for (i = 0; i < info->combined; i++) {
829 configured = i < info->configured;
830 nr += smp_add_core(&info->core[i], &avail, configured, early);
831 }
832 mutex_unlock(&smp_cpu_state_mutex);
833 cpus_read_unlock();
834 return nr;
835}
836
837void __init smp_detect_cpus(void)
838{
839 unsigned int cpu, mtid, c_cpus, s_cpus;
840 struct sclp_core_info *info;
841 u16 address;
842
843 /* Get CPU information */
844 info = memblock_alloc(sizeof(*info), 8);
845 if (!info)
846 panic("%s: Failed to allocate %zu bytes align=0x%x\n",
847 __func__, sizeof(*info), 8);
848 smp_get_core_info(info, 1);
849 /* Find boot CPU type */
850 if (sclp.has_core_type) {
851 address = stap();
852 for (cpu = 0; cpu < info->combined; cpu++)
853 if (info->core[cpu].core_id == address) {
854 /* The boot cpu dictates the cpu type. */
855 boot_core_type = info->core[cpu].type;
856 break;
857 }
858 if (cpu >= info->combined)
859 panic("Could not find boot CPU type");
860 }
861
862 /* Set multi-threading state for the current system */
863 mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
864 mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
865 pcpu_set_smt(mtid);
866
867 /* Print number of CPUs */
868 c_cpus = s_cpus = 0;
869 for (cpu = 0; cpu < info->combined; cpu++) {
870 if (sclp.has_core_type &&
871 info->core[cpu].type != boot_core_type)
872 continue;
873 if (cpu < info->configured)
874 c_cpus += smp_cpu_mtid + 1;
875 else
876 s_cpus += smp_cpu_mtid + 1;
877 }
878 pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
879
880 /* Add CPUs present at boot */
881 __smp_rescan_cpus(info, true);
882 memblock_free(info, sizeof(*info));
883}
884
885/*
886 * Activate a secondary processor.
887 */
888static void smp_start_secondary(void *cpuvoid)
889{
890 int cpu = raw_smp_processor_id();
891
892 S390_lowcore.last_update_clock = get_tod_clock();
893 S390_lowcore.restart_stack = (unsigned long)restart_stack;
894 S390_lowcore.restart_fn = (unsigned long)do_restart;
895 S390_lowcore.restart_data = 0;
896 S390_lowcore.restart_source = -1U;
897 S390_lowcore.restart_flags = 0;
898 restore_access_regs(S390_lowcore.access_regs_save_area);
899 cpu_init();
900 rcu_cpu_starting(cpu);
901 init_cpu_timer();
902 vtime_init();
903 vdso_getcpu_init();
904 pfault_init();
905 cpumask_set_cpu(cpu, &cpu_setup_mask);
906 update_cpu_masks();
907 notify_cpu_starting(cpu);
908 if (topology_cpu_dedicated(cpu))
909 set_cpu_flag(CIF_DEDICATED_CPU);
910 else
911 clear_cpu_flag(CIF_DEDICATED_CPU);
912 set_cpu_online(cpu, true);
913 inc_irq_stat(CPU_RST);
914 local_irq_enable();
915 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
916}
917
918/* Upping and downing of CPUs */
919int __cpu_up(unsigned int cpu, struct task_struct *tidle)
920{
921 struct pcpu *pcpu = pcpu_devices + cpu;
922 int rc;
923
924 if (pcpu->state != CPU_STATE_CONFIGURED)
925 return -EIO;
926 if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
927 SIGP_CC_ORDER_CODE_ACCEPTED)
928 return -EIO;
929
930 rc = pcpu_alloc_lowcore(pcpu, cpu);
931 if (rc)
932 return rc;
933 pcpu_prepare_secondary(pcpu, cpu);
934 pcpu_attach_task(pcpu, tidle);
935 pcpu_start_fn(pcpu, smp_start_secondary, NULL);
936 /* Wait until cpu puts itself in the online & active maps */
937 while (!cpu_online(cpu))
938 cpu_relax();
939 return 0;
940}
941
942static unsigned int setup_possible_cpus __initdata;
943
944static int __init _setup_possible_cpus(char *s)
945{
946 get_option(&s, &setup_possible_cpus);
947 return 0;
948}
949early_param("possible_cpus", _setup_possible_cpus);
950
951int __cpu_disable(void)
952{
953 unsigned long cregs[16];
954 int cpu;
955
956 /* Handle possible pending IPIs */
957 smp_handle_ext_call();
958 cpu = smp_processor_id();
959 set_cpu_online(cpu, false);
960 cpumask_clear_cpu(cpu, &cpu_setup_mask);
961 update_cpu_masks();
962 /* Disable pseudo page faults on this cpu. */
963 pfault_fini();
964 /* Disable interrupt sources via control register. */
965 __ctl_store(cregs, 0, 15);
966 cregs[0] &= ~0x0000ee70UL; /* disable all external interrupts */
967 cregs[6] &= ~0xff000000UL; /* disable all I/O interrupts */
968 cregs[14] &= ~0x1f000000UL; /* disable most machine checks */
969 __ctl_load(cregs, 0, 15);
970 clear_cpu_flag(CIF_NOHZ_DELAY);
971 return 0;
972}
973
974void __cpu_die(unsigned int cpu)
975{
976 struct pcpu *pcpu;
977
978 /* Wait until target cpu is down */
979 pcpu = pcpu_devices + cpu;
980 while (!pcpu_stopped(pcpu))
981 cpu_relax();
982 pcpu_free_lowcore(pcpu);
983 cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
984 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
985}
986
987void __noreturn cpu_die(void)
988{
989 idle_task_exit();
990 __bpon();
991 pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
992 for (;;) ;
993}
994
995void __init smp_fill_possible_mask(void)
996{
997 unsigned int possible, sclp_max, cpu;
998
999 sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
1000 sclp_max = min(smp_max_threads, sclp_max);
1001 sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
1002 possible = setup_possible_cpus ?: nr_cpu_ids;
1003 possible = min(possible, sclp_max);
1004 for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
1005 set_cpu_possible(cpu, true);
1006}
1007
1008void __init smp_prepare_cpus(unsigned int max_cpus)
1009{
1010 /* request the 0x1201 emergency signal external interrupt */
1011 if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
1012 panic("Couldn't request external interrupt 0x1201");
1013 /* request the 0x1202 external call external interrupt */
1014 if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
1015 panic("Couldn't request external interrupt 0x1202");
1016}
1017
1018void __init smp_prepare_boot_cpu(void)
1019{
1020 struct pcpu *pcpu = pcpu_devices;
1021
1022 WARN_ON(!cpu_present(0) || !cpu_online(0));
1023 pcpu->state = CPU_STATE_CONFIGURED;
1024 S390_lowcore.percpu_offset = __per_cpu_offset[0];
1025 smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
1026}
1027
1028void __init smp_setup_processor_id(void)
1029{
1030 pcpu_devices[0].address = stap();
1031 S390_lowcore.cpu_nr = 0;
1032 S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
1033 S390_lowcore.spinlock_index = 0;
1034}
1035
1036/*
1037 * the frequency of the profiling timer can be changed
1038 * by writing a multiplier value into /proc/profile.
1039 *
1040 * usually you want to run this on all CPUs ;)
1041 */
1042int setup_profiling_timer(unsigned int multiplier)
1043{
1044 return 0;
1045}
1046
1047static ssize_t cpu_configure_show(struct device *dev,
1048 struct device_attribute *attr, char *buf)
1049{
1050 ssize_t count;
1051
1052 mutex_lock(&smp_cpu_state_mutex);
1053 count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
1054 mutex_unlock(&smp_cpu_state_mutex);
1055 return count;
1056}
1057
1058static ssize_t cpu_configure_store(struct device *dev,
1059 struct device_attribute *attr,
1060 const char *buf, size_t count)
1061{
1062 struct pcpu *pcpu;
1063 int cpu, val, rc, i;
1064 char delim;
1065
1066 if (sscanf(buf, "%d %c", &val, &delim) != 1)
1067 return -EINVAL;
1068 if (val != 0 && val != 1)
1069 return -EINVAL;
1070 cpus_read_lock();
1071 mutex_lock(&smp_cpu_state_mutex);
1072 rc = -EBUSY;
1073 /* disallow configuration changes of online cpus and cpu 0 */
1074 cpu = dev->id;
1075 cpu = smp_get_base_cpu(cpu);
1076 if (cpu == 0)
1077 goto out;
1078 for (i = 0; i <= smp_cpu_mtid; i++)
1079 if (cpu_online(cpu + i))
1080 goto out;
1081 pcpu = pcpu_devices + cpu;
1082 rc = 0;
1083 switch (val) {
1084 case 0:
1085 if (pcpu->state != CPU_STATE_CONFIGURED)
1086 break;
1087 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1088 if (rc)
1089 break;
1090 for (i = 0; i <= smp_cpu_mtid; i++) {
1091 if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1092 continue;
1093 pcpu[i].state = CPU_STATE_STANDBY;
1094 smp_cpu_set_polarization(cpu + i,
1095 POLARIZATION_UNKNOWN);
1096 }
1097 topology_expect_change();
1098 break;
1099 case 1:
1100 if (pcpu->state != CPU_STATE_STANDBY)
1101 break;
1102 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1103 if (rc)
1104 break;
1105 for (i = 0; i <= smp_cpu_mtid; i++) {
1106 if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1107 continue;
1108 pcpu[i].state = CPU_STATE_CONFIGURED;
1109 smp_cpu_set_polarization(cpu + i,
1110 POLARIZATION_UNKNOWN);
1111 }
1112 topology_expect_change();
1113 break;
1114 default:
1115 break;
1116 }
1117out:
1118 mutex_unlock(&smp_cpu_state_mutex);
1119 cpus_read_unlock();
1120 return rc ? rc : count;
1121}
1122static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1123
1124static ssize_t show_cpu_address(struct device *dev,
1125 struct device_attribute *attr, char *buf)
1126{
1127 return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1128}
1129static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1130
1131static struct attribute *cpu_common_attrs[] = {
1132 &dev_attr_configure.attr,
1133 &dev_attr_address.attr,
1134 NULL,
1135};
1136
1137static struct attribute_group cpu_common_attr_group = {
1138 .attrs = cpu_common_attrs,
1139};
1140
1141static struct attribute *cpu_online_attrs[] = {
1142 &dev_attr_idle_count.attr,
1143 &dev_attr_idle_time_us.attr,
1144 NULL,
1145};
1146
1147static struct attribute_group cpu_online_attr_group = {
1148 .attrs = cpu_online_attrs,
1149};
1150
1151static int smp_cpu_online(unsigned int cpu)
1152{
1153 struct device *s = &per_cpu(cpu_device, cpu)->dev;
1154
1155 return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1156}
1157
1158static int smp_cpu_pre_down(unsigned int cpu)
1159{
1160 struct device *s = &per_cpu(cpu_device, cpu)->dev;
1161
1162 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1163 return 0;
1164}
1165
1166static int smp_add_present_cpu(int cpu)
1167{
1168 struct device *s;
1169 struct cpu *c;
1170 int rc;
1171
1172 c = kzalloc(sizeof(*c), GFP_KERNEL);
1173 if (!c)
1174 return -ENOMEM;
1175 per_cpu(cpu_device, cpu) = c;
1176 s = &c->dev;
1177 c->hotpluggable = 1;
1178 rc = register_cpu(c, cpu);
1179 if (rc)
1180 goto out;
1181 rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1182 if (rc)
1183 goto out_cpu;
1184 rc = topology_cpu_init(c);
1185 if (rc)
1186 goto out_topology;
1187 return 0;
1188
1189out_topology:
1190 sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1191out_cpu:
1192 unregister_cpu(c);
1193out:
1194 return rc;
1195}
1196
1197int __ref smp_rescan_cpus(void)
1198{
1199 struct sclp_core_info *info;
1200 int nr;
1201
1202 info = kzalloc(sizeof(*info), GFP_KERNEL);
1203 if (!info)
1204 return -ENOMEM;
1205 smp_get_core_info(info, 0);
1206 nr = __smp_rescan_cpus(info, false);
1207 kfree(info);
1208 if (nr)
1209 topology_schedule_update();
1210 return 0;
1211}
1212
1213static ssize_t __ref rescan_store(struct device *dev,
1214 struct device_attribute *attr,
1215 const char *buf,
1216 size_t count)
1217{
1218 int rc;
1219
1220 rc = lock_device_hotplug_sysfs();
1221 if (rc)
1222 return rc;
1223 rc = smp_rescan_cpus();
1224 unlock_device_hotplug();
1225 return rc ? rc : count;
1226}
1227static DEVICE_ATTR_WO(rescan);
1228
1229static int __init s390_smp_init(void)
1230{
1231 int cpu, rc = 0;
1232
1233 rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1234 if (rc)
1235 return rc;
1236 for_each_present_cpu(cpu) {
1237 rc = smp_add_present_cpu(cpu);
1238 if (rc)
1239 goto out;
1240 }
1241
1242 rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1243 smp_cpu_online, smp_cpu_pre_down);
1244 rc = rc <= 0 ? rc : 0;
1245out:
1246 return rc;
1247}
1248subsys_initcall(s390_smp_init);
1249
1250static __always_inline void set_new_lowcore(struct lowcore *lc)
1251{
1252 union register_pair dst, src;
1253 u32 pfx;
1254
1255 src.even = (unsigned long) &S390_lowcore;
1256 src.odd = sizeof(S390_lowcore);
1257 dst.even = (unsigned long) lc;
1258 dst.odd = sizeof(*lc);
1259 pfx = __pa(lc);
1260
1261 asm volatile(
1262 " mvcl %[dst],%[src]\n"
1263 " spx %[pfx]\n"
1264 : [dst] "+&d" (dst.pair), [src] "+&d" (src.pair)
1265 : [pfx] "Q" (pfx)
1266 : "memory", "cc");
1267}
1268
1269int __init smp_reinit_ipl_cpu(void)
1270{
1271 unsigned long async_stack, nodat_stack, mcck_stack;
1272 struct lowcore *lc, *lc_ipl;
1273 unsigned long flags, cr0;
1274 u64 mcesad;
1275
1276 lc_ipl = lowcore_ptr[0];
1277 lc = (struct lowcore *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
1278 nodat_stack = __get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER);
1279 async_stack = stack_alloc();
1280 mcck_stack = stack_alloc();
1281 if (!lc || !nodat_stack || !async_stack || !mcck_stack || nmi_alloc_mcesa(&mcesad))
1282 panic("Couldn't allocate memory");
1283
1284 local_irq_save(flags);
1285 local_mcck_disable();
1286 set_new_lowcore(lc);
1287 S390_lowcore.nodat_stack = nodat_stack + STACK_INIT_OFFSET;
1288 S390_lowcore.async_stack = async_stack + STACK_INIT_OFFSET;
1289 S390_lowcore.mcck_stack = mcck_stack + STACK_INIT_OFFSET;
1290 __ctl_store(cr0, 0, 0);
1291 __ctl_clear_bit(0, 28); /* disable lowcore protection */
1292 S390_lowcore.mcesad = mcesad;
1293 __ctl_load(cr0, 0, 0);
1294 if (abs_lowcore_map(0, lc, false))
1295 panic("Couldn't remap absolute lowcore");
1296 lowcore_ptr[0] = lc;
1297 local_mcck_enable();
1298 local_irq_restore(flags);
1299
1300 free_pages(lc_ipl->async_stack - STACK_INIT_OFFSET, THREAD_SIZE_ORDER);
1301 memblock_free_late(__pa(lc_ipl->mcck_stack - STACK_INIT_OFFSET), THREAD_SIZE);
1302 memblock_free_late(__pa(lc_ipl), sizeof(*lc_ipl));
1303
1304 return 0;
1305}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SMP related functions
4 *
5 * Copyright IBM Corp. 1999, 2012
6 * Author(s): Denis Joseph Barrow,
7 * Martin Schwidefsky <schwidefsky@de.ibm.com>,
8 * Heiko Carstens <heiko.carstens@de.ibm.com>,
9 *
10 * based on other smp stuff by
11 * (c) 1995 Alan Cox, CymruNET Ltd <alan@cymru.net>
12 * (c) 1998 Ingo Molnar
13 *
14 * The code outside of smp.c uses logical cpu numbers, only smp.c does
15 * the translation of logical to physical cpu ids. All new code that
16 * operates on physical cpu numbers needs to go into smp.c.
17 */
18
19#define KMSG_COMPONENT "cpu"
20#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
21
22#include <linux/workqueue.h>
23#include <linux/bootmem.h>
24#include <linux/export.h>
25#include <linux/init.h>
26#include <linux/mm.h>
27#include <linux/err.h>
28#include <linux/spinlock.h>
29#include <linux/kernel_stat.h>
30#include <linux/delay.h>
31#include <linux/interrupt.h>
32#include <linux/irqflags.h>
33#include <linux/cpu.h>
34#include <linux/slab.h>
35#include <linux/sched/hotplug.h>
36#include <linux/sched/task_stack.h>
37#include <linux/crash_dump.h>
38#include <linux/memblock.h>
39#include <linux/kprobes.h>
40#include <asm/asm-offsets.h>
41#include <asm/diag.h>
42#include <asm/switch_to.h>
43#include <asm/facility.h>
44#include <asm/ipl.h>
45#include <asm/setup.h>
46#include <asm/irq.h>
47#include <asm/tlbflush.h>
48#include <asm/vtimer.h>
49#include <asm/lowcore.h>
50#include <asm/sclp.h>
51#include <asm/vdso.h>
52#include <asm/debug.h>
53#include <asm/os_info.h>
54#include <asm/sigp.h>
55#include <asm/idle.h>
56#include <asm/nmi.h>
57#include <asm/topology.h>
58#include "entry.h"
59
60enum {
61 ec_schedule = 0,
62 ec_call_function_single,
63 ec_stop_cpu,
64};
65
66enum {
67 CPU_STATE_STANDBY,
68 CPU_STATE_CONFIGURED,
69};
70
71static DEFINE_PER_CPU(struct cpu *, cpu_device);
72
73struct pcpu {
74 struct lowcore *lowcore; /* lowcore page(s) for the cpu */
75 unsigned long ec_mask; /* bit mask for ec_xxx functions */
76 unsigned long ec_clk; /* sigp timestamp for ec_xxx */
77 signed char state; /* physical cpu state */
78 signed char polarization; /* physical polarization */
79 u16 address; /* physical cpu address */
80};
81
82static u8 boot_core_type;
83static struct pcpu pcpu_devices[NR_CPUS];
84
85unsigned int smp_cpu_mt_shift;
86EXPORT_SYMBOL(smp_cpu_mt_shift);
87
88unsigned int smp_cpu_mtid;
89EXPORT_SYMBOL(smp_cpu_mtid);
90
91#ifdef CONFIG_CRASH_DUMP
92__vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
93#endif
94
95static unsigned int smp_max_threads __initdata = -1U;
96
97static int __init early_nosmt(char *s)
98{
99 smp_max_threads = 1;
100 return 0;
101}
102early_param("nosmt", early_nosmt);
103
104static int __init early_smt(char *s)
105{
106 get_option(&s, &smp_max_threads);
107 return 0;
108}
109early_param("smt", early_smt);
110
111/*
112 * The smp_cpu_state_mutex must be held when changing the state or polarization
113 * member of a pcpu data structure within the pcpu_devices arreay.
114 */
115DEFINE_MUTEX(smp_cpu_state_mutex);
116
117/*
118 * Signal processor helper functions.
119 */
120static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm)
121{
122 int cc;
123
124 while (1) {
125 cc = __pcpu_sigp(addr, order, parm, NULL);
126 if (cc != SIGP_CC_BUSY)
127 return cc;
128 cpu_relax();
129 }
130}
131
132static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
133{
134 int cc, retry;
135
136 for (retry = 0; ; retry++) {
137 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
138 if (cc != SIGP_CC_BUSY)
139 break;
140 if (retry >= 3)
141 udelay(10);
142 }
143 return cc;
144}
145
146static inline int pcpu_stopped(struct pcpu *pcpu)
147{
148 u32 uninitialized_var(status);
149
150 if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
151 0, &status) != SIGP_CC_STATUS_STORED)
152 return 0;
153 return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
154}
155
156static inline int pcpu_running(struct pcpu *pcpu)
157{
158 if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
159 0, NULL) != SIGP_CC_STATUS_STORED)
160 return 1;
161 /* Status stored condition code is equivalent to cpu not running. */
162 return 0;
163}
164
165/*
166 * Find struct pcpu by cpu address.
167 */
168static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
169{
170 int cpu;
171
172 for_each_cpu(cpu, mask)
173 if (pcpu_devices[cpu].address == address)
174 return pcpu_devices + cpu;
175 return NULL;
176}
177
178static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
179{
180 int order;
181
182 if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
183 return;
184 order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
185 pcpu->ec_clk = get_tod_clock_fast();
186 pcpu_sigp_retry(pcpu, order, 0);
187}
188
189#define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
190#define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
191
192static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
193{
194 unsigned long async_stack, panic_stack;
195 struct lowcore *lc;
196
197 if (pcpu != &pcpu_devices[0]) {
198 pcpu->lowcore = (struct lowcore *)
199 __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
200 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
201 panic_stack = __get_free_page(GFP_KERNEL);
202 if (!pcpu->lowcore || !panic_stack || !async_stack)
203 goto out;
204 } else {
205 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
206 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
207 }
208 lc = pcpu->lowcore;
209 memcpy(lc, &S390_lowcore, 512);
210 memset((char *) lc + 512, 0, sizeof(*lc) - 512);
211 lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
212 lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
213 lc->cpu_nr = cpu;
214 lc->spinlock_lockval = arch_spin_lockval(cpu);
215 lc->spinlock_index = 0;
216 lc->br_r1_trampoline = 0x07f1; /* br %r1 */
217 if (nmi_alloc_per_cpu(lc))
218 goto out;
219 if (vdso_alloc_per_cpu(lc))
220 goto out_mcesa;
221 lowcore_ptr[cpu] = lc;
222 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
223 return 0;
224
225out_mcesa:
226 nmi_free_per_cpu(lc);
227out:
228 if (pcpu != &pcpu_devices[0]) {
229 free_page(panic_stack);
230 free_pages(async_stack, ASYNC_ORDER);
231 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
232 }
233 return -ENOMEM;
234}
235
236#ifdef CONFIG_HOTPLUG_CPU
237
238static void pcpu_free_lowcore(struct pcpu *pcpu)
239{
240 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
241 lowcore_ptr[pcpu - pcpu_devices] = NULL;
242 vdso_free_per_cpu(pcpu->lowcore);
243 nmi_free_per_cpu(pcpu->lowcore);
244 if (pcpu == &pcpu_devices[0])
245 return;
246 free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
247 free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
248 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
249}
250
251#endif /* CONFIG_HOTPLUG_CPU */
252
253static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
254{
255 struct lowcore *lc = pcpu->lowcore;
256
257 cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
258 cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
259 lc->cpu_nr = cpu;
260 lc->spinlock_lockval = arch_spin_lockval(cpu);
261 lc->spinlock_index = 0;
262 lc->percpu_offset = __per_cpu_offset[cpu];
263 lc->kernel_asce = S390_lowcore.kernel_asce;
264 lc->machine_flags = S390_lowcore.machine_flags;
265 lc->user_timer = lc->system_timer = lc->steal_timer = 0;
266 __ctl_store(lc->cregs_save_area, 0, 15);
267 save_access_regs((unsigned int *) lc->access_regs_save_area);
268 memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
269 sizeof(lc->stfle_fac_list));
270 memcpy(lc->alt_stfle_fac_list, S390_lowcore.alt_stfle_fac_list,
271 sizeof(lc->alt_stfle_fac_list));
272 arch_spin_lock_setup(cpu);
273}
274
275static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
276{
277 struct lowcore *lc = pcpu->lowcore;
278
279 lc->kernel_stack = (unsigned long) task_stack_page(tsk)
280 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
281 lc->current_task = (unsigned long) tsk;
282 lc->lpp = LPP_MAGIC;
283 lc->current_pid = tsk->pid;
284 lc->user_timer = tsk->thread.user_timer;
285 lc->guest_timer = tsk->thread.guest_timer;
286 lc->system_timer = tsk->thread.system_timer;
287 lc->hardirq_timer = tsk->thread.hardirq_timer;
288 lc->softirq_timer = tsk->thread.softirq_timer;
289 lc->steal_timer = 0;
290}
291
292static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
293{
294 struct lowcore *lc = pcpu->lowcore;
295
296 lc->restart_stack = lc->kernel_stack;
297 lc->restart_fn = (unsigned long) func;
298 lc->restart_data = (unsigned long) data;
299 lc->restart_source = -1UL;
300 pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
301}
302
303/*
304 * Call function via PSW restart on pcpu and stop the current cpu.
305 */
306static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
307 void *data, unsigned long stack)
308{
309 struct lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
310 unsigned long source_cpu = stap();
311
312 __load_psw_mask(PSW_KERNEL_BITS);
313 if (pcpu->address == source_cpu)
314 func(data); /* should not return */
315 /* Stop target cpu (if func returns this stops the current cpu). */
316 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
317 /* Restart func on the target cpu and stop the current cpu. */
318 mem_assign_absolute(lc->restart_stack, stack);
319 mem_assign_absolute(lc->restart_fn, (unsigned long) func);
320 mem_assign_absolute(lc->restart_data, (unsigned long) data);
321 mem_assign_absolute(lc->restart_source, source_cpu);
322 __bpon();
323 asm volatile(
324 "0: sigp 0,%0,%2 # sigp restart to target cpu\n"
325 " brc 2,0b # busy, try again\n"
326 "1: sigp 0,%1,%3 # sigp stop to current cpu\n"
327 " brc 2,1b # busy, try again\n"
328 : : "d" (pcpu->address), "d" (source_cpu),
329 "K" (SIGP_RESTART), "K" (SIGP_STOP)
330 : "0", "1", "cc");
331 for (;;) ;
332}
333
334/*
335 * Enable additional logical cpus for multi-threading.
336 */
337static int pcpu_set_smt(unsigned int mtid)
338{
339 int cc;
340
341 if (smp_cpu_mtid == mtid)
342 return 0;
343 cc = __pcpu_sigp(0, SIGP_SET_MULTI_THREADING, mtid, NULL);
344 if (cc == 0) {
345 smp_cpu_mtid = mtid;
346 smp_cpu_mt_shift = 0;
347 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
348 smp_cpu_mt_shift++;
349 pcpu_devices[0].address = stap();
350 }
351 return cc;
352}
353
354/*
355 * Call function on an online CPU.
356 */
357void smp_call_online_cpu(void (*func)(void *), void *data)
358{
359 struct pcpu *pcpu;
360
361 /* Use the current cpu if it is online. */
362 pcpu = pcpu_find_address(cpu_online_mask, stap());
363 if (!pcpu)
364 /* Use the first online cpu. */
365 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
366 pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
367}
368
369/*
370 * Call function on the ipl CPU.
371 */
372void smp_call_ipl_cpu(void (*func)(void *), void *data)
373{
374 pcpu_delegate(&pcpu_devices[0], func, data,
375 pcpu_devices->lowcore->panic_stack -
376 PANIC_FRAME_OFFSET + PAGE_SIZE);
377}
378
379int smp_find_processor_id(u16 address)
380{
381 int cpu;
382
383 for_each_present_cpu(cpu)
384 if (pcpu_devices[cpu].address == address)
385 return cpu;
386 return -1;
387}
388
389bool arch_vcpu_is_preempted(int cpu)
390{
391 if (test_cpu_flag_of(CIF_ENABLED_WAIT, cpu))
392 return false;
393 if (pcpu_running(pcpu_devices + cpu))
394 return false;
395 return true;
396}
397EXPORT_SYMBOL(arch_vcpu_is_preempted);
398
399void smp_yield_cpu(int cpu)
400{
401 if (MACHINE_HAS_DIAG9C) {
402 diag_stat_inc_norecursion(DIAG_STAT_X09C);
403 asm volatile("diag %0,0,0x9c"
404 : : "d" (pcpu_devices[cpu].address));
405 } else if (MACHINE_HAS_DIAG44) {
406 diag_stat_inc_norecursion(DIAG_STAT_X044);
407 asm volatile("diag 0,0,0x44");
408 }
409}
410
411/*
412 * Send cpus emergency shutdown signal. This gives the cpus the
413 * opportunity to complete outstanding interrupts.
414 */
415void notrace smp_emergency_stop(void)
416{
417 cpumask_t cpumask;
418 u64 end;
419 int cpu;
420
421 cpumask_copy(&cpumask, cpu_online_mask);
422 cpumask_clear_cpu(smp_processor_id(), &cpumask);
423
424 end = get_tod_clock() + (1000000UL << 12);
425 for_each_cpu(cpu, &cpumask) {
426 struct pcpu *pcpu = pcpu_devices + cpu;
427 set_bit(ec_stop_cpu, &pcpu->ec_mask);
428 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
429 0, NULL) == SIGP_CC_BUSY &&
430 get_tod_clock() < end)
431 cpu_relax();
432 }
433 while (get_tod_clock() < end) {
434 for_each_cpu(cpu, &cpumask)
435 if (pcpu_stopped(pcpu_devices + cpu))
436 cpumask_clear_cpu(cpu, &cpumask);
437 if (cpumask_empty(&cpumask))
438 break;
439 cpu_relax();
440 }
441}
442NOKPROBE_SYMBOL(smp_emergency_stop);
443
444/*
445 * Stop all cpus but the current one.
446 */
447void smp_send_stop(void)
448{
449 int cpu;
450
451 /* Disable all interrupts/machine checks */
452 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
453 trace_hardirqs_off();
454
455 debug_set_critical();
456
457 if (oops_in_progress)
458 smp_emergency_stop();
459
460 /* stop all processors */
461 for_each_online_cpu(cpu) {
462 if (cpu == smp_processor_id())
463 continue;
464 pcpu_sigp_retry(pcpu_devices + cpu, SIGP_STOP, 0);
465 while (!pcpu_stopped(pcpu_devices + cpu))
466 cpu_relax();
467 }
468}
469
470/*
471 * This is the main routine where commands issued by other
472 * cpus are handled.
473 */
474static void smp_handle_ext_call(void)
475{
476 unsigned long bits;
477
478 /* handle bit signal external calls */
479 bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
480 if (test_bit(ec_stop_cpu, &bits))
481 smp_stop_cpu();
482 if (test_bit(ec_schedule, &bits))
483 scheduler_ipi();
484 if (test_bit(ec_call_function_single, &bits))
485 generic_smp_call_function_single_interrupt();
486}
487
488static void do_ext_call_interrupt(struct ext_code ext_code,
489 unsigned int param32, unsigned long param64)
490{
491 inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
492 smp_handle_ext_call();
493}
494
495void arch_send_call_function_ipi_mask(const struct cpumask *mask)
496{
497 int cpu;
498
499 for_each_cpu(cpu, mask)
500 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
501}
502
503void arch_send_call_function_single_ipi(int cpu)
504{
505 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
506}
507
508/*
509 * this function sends a 'reschedule' IPI to another CPU.
510 * it goes straight through and wastes no time serializing
511 * anything. Worst case is that we lose a reschedule ...
512 */
513void smp_send_reschedule(int cpu)
514{
515 pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
516}
517
518/*
519 * parameter area for the set/clear control bit callbacks
520 */
521struct ec_creg_mask_parms {
522 unsigned long orval;
523 unsigned long andval;
524 int cr;
525};
526
527/*
528 * callback for setting/clearing control bits
529 */
530static void smp_ctl_bit_callback(void *info)
531{
532 struct ec_creg_mask_parms *pp = info;
533 unsigned long cregs[16];
534
535 __ctl_store(cregs, 0, 15);
536 cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
537 __ctl_load(cregs, 0, 15);
538}
539
540/*
541 * Set a bit in a control register of all cpus
542 */
543void smp_ctl_set_bit(int cr, int bit)
544{
545 struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
546
547 on_each_cpu(smp_ctl_bit_callback, &parms, 1);
548}
549EXPORT_SYMBOL(smp_ctl_set_bit);
550
551/*
552 * Clear a bit in a control register of all cpus
553 */
554void smp_ctl_clear_bit(int cr, int bit)
555{
556 struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
557
558 on_each_cpu(smp_ctl_bit_callback, &parms, 1);
559}
560EXPORT_SYMBOL(smp_ctl_clear_bit);
561
562#ifdef CONFIG_CRASH_DUMP
563
564int smp_store_status(int cpu)
565{
566 struct pcpu *pcpu = pcpu_devices + cpu;
567 unsigned long pa;
568
569 pa = __pa(&pcpu->lowcore->floating_pt_save_area);
570 if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_STATUS_AT_ADDRESS,
571 pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
572 return -EIO;
573 if (!MACHINE_HAS_VX && !MACHINE_HAS_GS)
574 return 0;
575 pa = __pa(pcpu->lowcore->mcesad & MCESA_ORIGIN_MASK);
576 if (MACHINE_HAS_GS)
577 pa |= pcpu->lowcore->mcesad & MCESA_LC_MASK;
578 if (__pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
579 pa) != SIGP_CC_ORDER_CODE_ACCEPTED)
580 return -EIO;
581 return 0;
582}
583
584/*
585 * Collect CPU state of the previous, crashed system.
586 * There are four cases:
587 * 1) standard zfcp dump
588 * condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
589 * The state for all CPUs except the boot CPU needs to be collected
590 * with sigp stop-and-store-status. The boot CPU state is located in
591 * the absolute lowcore of the memory stored in the HSA. The zcore code
592 * will copy the boot CPU state from the HSA.
593 * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
594 * condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
595 * The state for all CPUs except the boot CPU needs to be collected
596 * with sigp stop-and-store-status. The firmware or the boot-loader
597 * stored the registers of the boot CPU in the absolute lowcore in the
598 * memory of the old system.
599 * 3) kdump and the old kernel did not store the CPU state,
600 * or stand-alone kdump for DASD
601 * condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
602 * The state for all CPUs except the boot CPU needs to be collected
603 * with sigp stop-and-store-status. The kexec code or the boot-loader
604 * stored the registers of the boot CPU in the memory of the old system.
605 * 4) kdump and the old kernel stored the CPU state
606 * condition: OLDMEM_BASE != NULL && is_kdump_kernel()
607 * This case does not exist for s390 anymore, setup_arch explicitly
608 * deactivates the elfcorehdr= kernel parameter
609 */
610static __init void smp_save_cpu_vxrs(struct save_area *sa, u16 addr,
611 bool is_boot_cpu, unsigned long page)
612{
613 __vector128 *vxrs = (__vector128 *) page;
614
615 if (is_boot_cpu)
616 vxrs = boot_cpu_vector_save_area;
617 else
618 __pcpu_sigp_relax(addr, SIGP_STORE_ADDITIONAL_STATUS, page);
619 save_area_add_vxrs(sa, vxrs);
620}
621
622static __init void smp_save_cpu_regs(struct save_area *sa, u16 addr,
623 bool is_boot_cpu, unsigned long page)
624{
625 void *regs = (void *) page;
626
627 if (is_boot_cpu)
628 copy_oldmem_kernel(regs, (void *) __LC_FPREGS_SAVE_AREA, 512);
629 else
630 __pcpu_sigp_relax(addr, SIGP_STORE_STATUS_AT_ADDRESS, page);
631 save_area_add_regs(sa, regs);
632}
633
634void __init smp_save_dump_cpus(void)
635{
636 int addr, boot_cpu_addr, max_cpu_addr;
637 struct save_area *sa;
638 unsigned long page;
639 bool is_boot_cpu;
640
641 if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
642 /* No previous system present, normal boot. */
643 return;
644 /* Allocate a page as dumping area for the store status sigps */
645 page = memblock_alloc_base(PAGE_SIZE, PAGE_SIZE, 1UL << 31);
646 /* Set multi-threading state to the previous system. */
647 pcpu_set_smt(sclp.mtid_prev);
648 boot_cpu_addr = stap();
649 max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
650 for (addr = 0; addr <= max_cpu_addr; addr++) {
651 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0) ==
652 SIGP_CC_NOT_OPERATIONAL)
653 continue;
654 is_boot_cpu = (addr == boot_cpu_addr);
655 /* Allocate save area */
656 sa = save_area_alloc(is_boot_cpu);
657 if (!sa)
658 panic("could not allocate memory for save area\n");
659 if (MACHINE_HAS_VX)
660 /* Get the vector registers */
661 smp_save_cpu_vxrs(sa, addr, is_boot_cpu, page);
662 /*
663 * For a zfcp dump OLDMEM_BASE == NULL and the registers
664 * of the boot CPU are stored in the HSA. To retrieve
665 * these registers an SCLP request is required which is
666 * done by drivers/s390/char/zcore.c:init_cpu_info()
667 */
668 if (!is_boot_cpu || OLDMEM_BASE)
669 /* Get the CPU registers */
670 smp_save_cpu_regs(sa, addr, is_boot_cpu, page);
671 }
672 memblock_free(page, PAGE_SIZE);
673 diag308_reset();
674 pcpu_set_smt(0);
675}
676#endif /* CONFIG_CRASH_DUMP */
677
678void smp_cpu_set_polarization(int cpu, int val)
679{
680 pcpu_devices[cpu].polarization = val;
681}
682
683int smp_cpu_get_polarization(int cpu)
684{
685 return pcpu_devices[cpu].polarization;
686}
687
688static void __ref smp_get_core_info(struct sclp_core_info *info, int early)
689{
690 static int use_sigp_detection;
691 int address;
692
693 if (use_sigp_detection || sclp_get_core_info(info, early)) {
694 use_sigp_detection = 1;
695 for (address = 0;
696 address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
697 address += (1U << smp_cpu_mt_shift)) {
698 if (__pcpu_sigp_relax(address, SIGP_SENSE, 0) ==
699 SIGP_CC_NOT_OPERATIONAL)
700 continue;
701 info->core[info->configured].core_id =
702 address >> smp_cpu_mt_shift;
703 info->configured++;
704 }
705 info->combined = info->configured;
706 }
707}
708
709static int smp_add_present_cpu(int cpu);
710
711static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
712{
713 struct pcpu *pcpu;
714 cpumask_t avail;
715 int cpu, nr, i, j;
716 u16 address;
717
718 nr = 0;
719 cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
720 cpu = cpumask_first(&avail);
721 for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
722 if (sclp.has_core_type && info->core[i].type != boot_core_type)
723 continue;
724 address = info->core[i].core_id << smp_cpu_mt_shift;
725 for (j = 0; j <= smp_cpu_mtid; j++) {
726 if (pcpu_find_address(cpu_present_mask, address + j))
727 continue;
728 pcpu = pcpu_devices + cpu;
729 pcpu->address = address + j;
730 pcpu->state =
731 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
732 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
733 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
734 set_cpu_present(cpu, true);
735 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
736 set_cpu_present(cpu, false);
737 else
738 nr++;
739 cpu = cpumask_next(cpu, &avail);
740 if (cpu >= nr_cpu_ids)
741 break;
742 }
743 }
744 return nr;
745}
746
747void __init smp_detect_cpus(void)
748{
749 unsigned int cpu, mtid, c_cpus, s_cpus;
750 struct sclp_core_info *info;
751 u16 address;
752
753 /* Get CPU information */
754 info = memblock_virt_alloc(sizeof(*info), 8);
755 smp_get_core_info(info, 1);
756 /* Find boot CPU type */
757 if (sclp.has_core_type) {
758 address = stap();
759 for (cpu = 0; cpu < info->combined; cpu++)
760 if (info->core[cpu].core_id == address) {
761 /* The boot cpu dictates the cpu type. */
762 boot_core_type = info->core[cpu].type;
763 break;
764 }
765 if (cpu >= info->combined)
766 panic("Could not find boot CPU type");
767 }
768
769 /* Set multi-threading state for the current system */
770 mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
771 mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
772 pcpu_set_smt(mtid);
773
774 /* Print number of CPUs */
775 c_cpus = s_cpus = 0;
776 for (cpu = 0; cpu < info->combined; cpu++) {
777 if (sclp.has_core_type &&
778 info->core[cpu].type != boot_core_type)
779 continue;
780 if (cpu < info->configured)
781 c_cpus += smp_cpu_mtid + 1;
782 else
783 s_cpus += smp_cpu_mtid + 1;
784 }
785 pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
786
787 /* Add CPUs present at boot */
788 get_online_cpus();
789 __smp_rescan_cpus(info, 0);
790 put_online_cpus();
791 memblock_free_early((unsigned long)info, sizeof(*info));
792}
793
794/*
795 * Activate a secondary processor.
796 */
797static void smp_start_secondary(void *cpuvoid)
798{
799 int cpu = smp_processor_id();
800
801 S390_lowcore.last_update_clock = get_tod_clock();
802 S390_lowcore.restart_stack = (unsigned long) restart_stack;
803 S390_lowcore.restart_fn = (unsigned long) do_restart;
804 S390_lowcore.restart_data = 0;
805 S390_lowcore.restart_source = -1UL;
806 restore_access_regs(S390_lowcore.access_regs_save_area);
807 __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
808 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
809 cpu_init();
810 preempt_disable();
811 init_cpu_timer();
812 vtime_init();
813 pfault_init();
814 notify_cpu_starting(cpu);
815 if (topology_cpu_dedicated(cpu))
816 set_cpu_flag(CIF_DEDICATED_CPU);
817 else
818 clear_cpu_flag(CIF_DEDICATED_CPU);
819 set_cpu_online(cpu, true);
820 inc_irq_stat(CPU_RST);
821 local_irq_enable();
822 cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
823}
824
825/* Upping and downing of CPUs */
826int __cpu_up(unsigned int cpu, struct task_struct *tidle)
827{
828 struct pcpu *pcpu;
829 int base, i, rc;
830
831 pcpu = pcpu_devices + cpu;
832 if (pcpu->state != CPU_STATE_CONFIGURED)
833 return -EIO;
834 base = smp_get_base_cpu(cpu);
835 for (i = 0; i <= smp_cpu_mtid; i++) {
836 if (base + i < nr_cpu_ids)
837 if (cpu_online(base + i))
838 break;
839 }
840 /*
841 * If this is the first CPU of the core to get online
842 * do an initial CPU reset.
843 */
844 if (i > smp_cpu_mtid &&
845 pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
846 SIGP_CC_ORDER_CODE_ACCEPTED)
847 return -EIO;
848
849 rc = pcpu_alloc_lowcore(pcpu, cpu);
850 if (rc)
851 return rc;
852 pcpu_prepare_secondary(pcpu, cpu);
853 pcpu_attach_task(pcpu, tidle);
854 pcpu_start_fn(pcpu, smp_start_secondary, NULL);
855 /* Wait until cpu puts itself in the online & active maps */
856 while (!cpu_online(cpu))
857 cpu_relax();
858 return 0;
859}
860
861static unsigned int setup_possible_cpus __initdata;
862
863static int __init _setup_possible_cpus(char *s)
864{
865 get_option(&s, &setup_possible_cpus);
866 return 0;
867}
868early_param("possible_cpus", _setup_possible_cpus);
869
870#ifdef CONFIG_HOTPLUG_CPU
871
872int __cpu_disable(void)
873{
874 unsigned long cregs[16];
875
876 /* Handle possible pending IPIs */
877 smp_handle_ext_call();
878 set_cpu_online(smp_processor_id(), false);
879 /* Disable pseudo page faults on this cpu. */
880 pfault_fini();
881 /* Disable interrupt sources via control register. */
882 __ctl_store(cregs, 0, 15);
883 cregs[0] &= ~0x0000ee70UL; /* disable all external interrupts */
884 cregs[6] &= ~0xff000000UL; /* disable all I/O interrupts */
885 cregs[14] &= ~0x1f000000UL; /* disable most machine checks */
886 __ctl_load(cregs, 0, 15);
887 clear_cpu_flag(CIF_NOHZ_DELAY);
888 return 0;
889}
890
891void __cpu_die(unsigned int cpu)
892{
893 struct pcpu *pcpu;
894
895 /* Wait until target cpu is down */
896 pcpu = pcpu_devices + cpu;
897 while (!pcpu_stopped(pcpu))
898 cpu_relax();
899 pcpu_free_lowcore(pcpu);
900 cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
901 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
902}
903
904void __noreturn cpu_die(void)
905{
906 idle_task_exit();
907 __bpon();
908 pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
909 for (;;) ;
910}
911
912#endif /* CONFIG_HOTPLUG_CPU */
913
914void __init smp_fill_possible_mask(void)
915{
916 unsigned int possible, sclp_max, cpu;
917
918 sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
919 sclp_max = min(smp_max_threads, sclp_max);
920 sclp_max = (sclp.max_cores * sclp_max) ?: nr_cpu_ids;
921 possible = setup_possible_cpus ?: nr_cpu_ids;
922 possible = min(possible, sclp_max);
923 for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
924 set_cpu_possible(cpu, true);
925}
926
927void __init smp_prepare_cpus(unsigned int max_cpus)
928{
929 /* request the 0x1201 emergency signal external interrupt */
930 if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
931 panic("Couldn't request external interrupt 0x1201");
932 /* request the 0x1202 external call external interrupt */
933 if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
934 panic("Couldn't request external interrupt 0x1202");
935}
936
937void __init smp_prepare_boot_cpu(void)
938{
939 struct pcpu *pcpu = pcpu_devices;
940
941 WARN_ON(!cpu_present(0) || !cpu_online(0));
942 pcpu->state = CPU_STATE_CONFIGURED;
943 pcpu->lowcore = (struct lowcore *)(unsigned long) store_prefix();
944 S390_lowcore.percpu_offset = __per_cpu_offset[0];
945 smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
946}
947
948void __init smp_cpus_done(unsigned int max_cpus)
949{
950}
951
952void __init smp_setup_processor_id(void)
953{
954 pcpu_devices[0].address = stap();
955 S390_lowcore.cpu_nr = 0;
956 S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
957 S390_lowcore.spinlock_index = 0;
958}
959
960/*
961 * the frequency of the profiling timer can be changed
962 * by writing a multiplier value into /proc/profile.
963 *
964 * usually you want to run this on all CPUs ;)
965 */
966int setup_profiling_timer(unsigned int multiplier)
967{
968 return 0;
969}
970
971#ifdef CONFIG_HOTPLUG_CPU
972static ssize_t cpu_configure_show(struct device *dev,
973 struct device_attribute *attr, char *buf)
974{
975 ssize_t count;
976
977 mutex_lock(&smp_cpu_state_mutex);
978 count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
979 mutex_unlock(&smp_cpu_state_mutex);
980 return count;
981}
982
983static ssize_t cpu_configure_store(struct device *dev,
984 struct device_attribute *attr,
985 const char *buf, size_t count)
986{
987 struct pcpu *pcpu;
988 int cpu, val, rc, i;
989 char delim;
990
991 if (sscanf(buf, "%d %c", &val, &delim) != 1)
992 return -EINVAL;
993 if (val != 0 && val != 1)
994 return -EINVAL;
995 get_online_cpus();
996 mutex_lock(&smp_cpu_state_mutex);
997 rc = -EBUSY;
998 /* disallow configuration changes of online cpus and cpu 0 */
999 cpu = dev->id;
1000 cpu = smp_get_base_cpu(cpu);
1001 if (cpu == 0)
1002 goto out;
1003 for (i = 0; i <= smp_cpu_mtid; i++)
1004 if (cpu_online(cpu + i))
1005 goto out;
1006 pcpu = pcpu_devices + cpu;
1007 rc = 0;
1008 switch (val) {
1009 case 0:
1010 if (pcpu->state != CPU_STATE_CONFIGURED)
1011 break;
1012 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
1013 if (rc)
1014 break;
1015 for (i = 0; i <= smp_cpu_mtid; i++) {
1016 if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1017 continue;
1018 pcpu[i].state = CPU_STATE_STANDBY;
1019 smp_cpu_set_polarization(cpu + i,
1020 POLARIZATION_UNKNOWN);
1021 }
1022 topology_expect_change();
1023 break;
1024 case 1:
1025 if (pcpu->state != CPU_STATE_STANDBY)
1026 break;
1027 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1028 if (rc)
1029 break;
1030 for (i = 0; i <= smp_cpu_mtid; i++) {
1031 if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1032 continue;
1033 pcpu[i].state = CPU_STATE_CONFIGURED;
1034 smp_cpu_set_polarization(cpu + i,
1035 POLARIZATION_UNKNOWN);
1036 }
1037 topology_expect_change();
1038 break;
1039 default:
1040 break;
1041 }
1042out:
1043 mutex_unlock(&smp_cpu_state_mutex);
1044 put_online_cpus();
1045 return rc ? rc : count;
1046}
1047static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1048#endif /* CONFIG_HOTPLUG_CPU */
1049
1050static ssize_t show_cpu_address(struct device *dev,
1051 struct device_attribute *attr, char *buf)
1052{
1053 return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1054}
1055static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1056
1057static struct attribute *cpu_common_attrs[] = {
1058#ifdef CONFIG_HOTPLUG_CPU
1059 &dev_attr_configure.attr,
1060#endif
1061 &dev_attr_address.attr,
1062 NULL,
1063};
1064
1065static struct attribute_group cpu_common_attr_group = {
1066 .attrs = cpu_common_attrs,
1067};
1068
1069static struct attribute *cpu_online_attrs[] = {
1070 &dev_attr_idle_count.attr,
1071 &dev_attr_idle_time_us.attr,
1072 NULL,
1073};
1074
1075static struct attribute_group cpu_online_attr_group = {
1076 .attrs = cpu_online_attrs,
1077};
1078
1079static int smp_cpu_online(unsigned int cpu)
1080{
1081 struct device *s = &per_cpu(cpu_device, cpu)->dev;
1082
1083 return sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1084}
1085static int smp_cpu_pre_down(unsigned int cpu)
1086{
1087 struct device *s = &per_cpu(cpu_device, cpu)->dev;
1088
1089 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1090 return 0;
1091}
1092
1093static int smp_add_present_cpu(int cpu)
1094{
1095 struct device *s;
1096 struct cpu *c;
1097 int rc;
1098
1099 c = kzalloc(sizeof(*c), GFP_KERNEL);
1100 if (!c)
1101 return -ENOMEM;
1102 per_cpu(cpu_device, cpu) = c;
1103 s = &c->dev;
1104 c->hotpluggable = 1;
1105 rc = register_cpu(c, cpu);
1106 if (rc)
1107 goto out;
1108 rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1109 if (rc)
1110 goto out_cpu;
1111 rc = topology_cpu_init(c);
1112 if (rc)
1113 goto out_topology;
1114 return 0;
1115
1116out_topology:
1117 sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1118out_cpu:
1119#ifdef CONFIG_HOTPLUG_CPU
1120 unregister_cpu(c);
1121#endif
1122out:
1123 return rc;
1124}
1125
1126#ifdef CONFIG_HOTPLUG_CPU
1127
1128int __ref smp_rescan_cpus(void)
1129{
1130 struct sclp_core_info *info;
1131 int nr;
1132
1133 info = kzalloc(sizeof(*info), GFP_KERNEL);
1134 if (!info)
1135 return -ENOMEM;
1136 smp_get_core_info(info, 0);
1137 get_online_cpus();
1138 mutex_lock(&smp_cpu_state_mutex);
1139 nr = __smp_rescan_cpus(info, 1);
1140 mutex_unlock(&smp_cpu_state_mutex);
1141 put_online_cpus();
1142 kfree(info);
1143 if (nr)
1144 topology_schedule_update();
1145 return 0;
1146}
1147
1148static ssize_t __ref rescan_store(struct device *dev,
1149 struct device_attribute *attr,
1150 const char *buf,
1151 size_t count)
1152{
1153 int rc;
1154
1155 rc = smp_rescan_cpus();
1156 return rc ? rc : count;
1157}
1158static DEVICE_ATTR_WO(rescan);
1159#endif /* CONFIG_HOTPLUG_CPU */
1160
1161static int __init s390_smp_init(void)
1162{
1163 int cpu, rc = 0;
1164
1165#ifdef CONFIG_HOTPLUG_CPU
1166 rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1167 if (rc)
1168 return rc;
1169#endif
1170 for_each_present_cpu(cpu) {
1171 rc = smp_add_present_cpu(cpu);
1172 if (rc)
1173 goto out;
1174 }
1175
1176 rc = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "s390/smp:online",
1177 smp_cpu_online, smp_cpu_pre_down);
1178 rc = rc <= 0 ? rc : 0;
1179out:
1180 return rc;
1181}
1182subsys_initcall(s390_smp_init);