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 
61 enum {
62 	ec_schedule = 0,
63 	ec_call_function_single,
64 	ec_stop_cpu,
65 	ec_mcck_pending,
66 	ec_irq_work,
67 };
68 
69 enum {
70 	CPU_STATE_STANDBY,
71 	CPU_STATE_CONFIGURED,
72 };
73 
74 static DEFINE_PER_CPU(struct cpu *, cpu_device);
75 
76 struct 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 
84 static u8 boot_core_type;
85 static struct pcpu pcpu_devices[NR_CPUS];
86 
87 unsigned int smp_cpu_mt_shift;
88 EXPORT_SYMBOL(smp_cpu_mt_shift);
89 
90 unsigned int smp_cpu_mtid;
91 EXPORT_SYMBOL(smp_cpu_mtid);
92 
93 #ifdef CONFIG_CRASH_DUMP
94 __vector128 __initdata boot_cpu_vector_save_area[__NUM_VXRS];
95 #endif
96 
97 static unsigned int smp_max_threads __initdata = -1U;
98 cpumask_t cpu_setup_mask;
99 
early_nosmt(char * s)100 static int __init early_nosmt(char *s)
101 {
102 	smp_max_threads = 1;
103 	return 0;
104 }
105 early_param("nosmt", early_nosmt);
106 
early_smt(char * s)107 static int __init early_smt(char *s)
108 {
109 	get_option(&s, &smp_max_threads);
110 	return 0;
111 }
112 early_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  */
118 DEFINE_MUTEX(smp_cpu_state_mutex);
119 
120 /*
121  * Signal processor helper functions.
122  */
__pcpu_sigp_relax(u16 addr,u8 order,unsigned long parm)123 static 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 
pcpu_sigp_retry(struct pcpu * pcpu,u8 order,u32 parm)135 static 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 
pcpu_stopped(struct pcpu * pcpu)149 static 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 
pcpu_running(struct pcpu * pcpu)159 static 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  */
pcpu_find_address(const struct cpumask * mask,u16 address)171 static 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 
pcpu_ec_call(struct pcpu * pcpu,int ec_bit)181 static 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 
pcpu_alloc_lowcore(struct pcpu * pcpu,int cpu)192 static 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 
222 out_mcesa:
223 	nmi_free_mcesa(&lc->mcesad);
224 out:
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 
pcpu_free_lowcore(struct pcpu * pcpu)232 static 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 
pcpu_prepare_secondary(struct pcpu * pcpu,int cpu)253 static 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 
pcpu_attach_task(struct pcpu * pcpu,struct task_struct * tsk)276 static 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 
pcpu_start_fn(struct pcpu * pcpu,void (* func)(void *),void * data)296 static 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 
310 typedef void (pcpu_delegate_fn)(void *);
311 
312 /*
313  * Call function via PSW restart on pcpu and stop the current cpu.
314  */
__pcpu_delegate(pcpu_delegate_fn * func,void * data)315 static void __pcpu_delegate(pcpu_delegate_fn *func, void *data)
316 {
317 	func(data);	/* should not return */
318 }
319 
pcpu_delegate(struct pcpu * pcpu,pcpu_delegate_fn * func,void * data,unsigned long stack)320 static 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  */
pcpu_set_smt(unsigned int mtid)366 static 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  */
smp_call_online_cpu(void (* func)(void *),void * data)386 void 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  */
smp_call_ipl_cpu(void (* func)(void *),void * data)401 void 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 
smp_find_processor_id(u16 address)412 int 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 
schedule_mcck_handler(void)422 void schedule_mcck_handler(void)
423 {
424 	pcpu_ec_call(pcpu_devices + smp_processor_id(), ec_mcck_pending);
425 }
426 
arch_vcpu_is_preempted(int cpu)427 bool 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 }
435 EXPORT_SYMBOL(arch_vcpu_is_preempted);
436 
smp_yield_cpu(int cpu)437 void 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 }
445 EXPORT_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  */
smp_emergency_stop(void)451 void 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 }
481 NOKPROBE_SYMBOL(smp_emergency_stop);
482 
483 /*
484  * Stop all cpus but the current one.
485  */
smp_send_stop(void)486 void 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  */
smp_handle_ext_call(void)513 static 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 
do_ext_call_interrupt(struct ext_code ext_code,unsigned int param32,unsigned long param64)531 static 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 
arch_send_call_function_ipi_mask(const struct cpumask * mask)538 void 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 
arch_send_call_function_single_ipi(int cpu)546 void 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  */
smp_send_reschedule(int cpu)556 void smp_send_reschedule(int cpu)
557 {
558 	pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
559 }
560 
561 #ifdef CONFIG_IRQ_WORK
arch_irq_work_raise(void)562 void 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  */
571 struct 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  */
smp_ctl_bit_callback(void * info)580 static 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 
590 static DEFINE_SPINLOCK(ctl_lock);
591 
smp_ctl_set_clear_bit(int cr,int bit,bool set)592 void 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 }
615 EXPORT_SYMBOL(smp_ctl_set_clear_bit);
616 
617 #ifdef CONFIG_CRASH_DUMP
618 
smp_store_status(int cpu)619 int 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  */
dump_available(void)668 static bool dump_available(void)
669 {
670 	return oldmem_data.start || is_ipl_type_dump();
671 }
672 
smp_save_dump_ipl_cpu(void)673 void __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 
smp_save_dump_secondary_cpus(void)691 void __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 
smp_cpu_set_polarization(int cpu,int val)731 void smp_cpu_set_polarization(int cpu, int val)
732 {
733 	pcpu_devices[cpu].polarization = val;
734 }
735 
smp_cpu_get_polarization(int cpu)736 int smp_cpu_get_polarization(int cpu)
737 {
738 	return pcpu_devices[cpu].polarization;
739 }
740 
smp_cpu_get_cpu_address(int cpu)741 int smp_cpu_get_cpu_address(int cpu)
742 {
743 	return pcpu_devices[cpu].address;
744 }
745 
smp_get_core_info(struct sclp_core_info * info,int early)746 static 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 
767 static int smp_add_present_cpu(int cpu);
768 
smp_add_core(struct sclp_core_entry * core,cpumask_t * avail,bool configured,bool early)769 static 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 
__smp_rescan_cpus(struct sclp_core_info * info,bool early)802 static 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 
smp_detect_cpus(void)837 void __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  */
smp_start_secondary(void * cpuvoid)888 static 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 */
__cpu_up(unsigned int cpu,struct task_struct * tidle)919 int __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 
942 static unsigned int setup_possible_cpus __initdata;
943 
_setup_possible_cpus(char * s)944 static int __init _setup_possible_cpus(char *s)
945 {
946 	get_option(&s, &setup_possible_cpus);
947 	return 0;
948 }
949 early_param("possible_cpus", _setup_possible_cpus);
950 
__cpu_disable(void)951 int __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 
__cpu_die(unsigned int cpu)974 void __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 
cpu_die(void)987 void __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 
smp_fill_possible_mask(void)995 void __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 
smp_prepare_cpus(unsigned int max_cpus)1008 void __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 
smp_prepare_boot_cpu(void)1018 void __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 
smp_setup_processor_id(void)1028 void __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  */
setup_profiling_timer(unsigned int multiplier)1042 int setup_profiling_timer(unsigned int multiplier)
1043 {
1044 	return 0;
1045 }
1046 
cpu_configure_show(struct device * dev,struct device_attribute * attr,char * buf)1047 static 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 
cpu_configure_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1058 static 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 	}
1117 out:
1118 	mutex_unlock(&smp_cpu_state_mutex);
1119 	cpus_read_unlock();
1120 	return rc ? rc : count;
1121 }
1122 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1123 
show_cpu_address(struct device * dev,struct device_attribute * attr,char * buf)1124 static 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 }
1129 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1130 
1131 static struct attribute *cpu_common_attrs[] = {
1132 	&dev_attr_configure.attr,
1133 	&dev_attr_address.attr,
1134 	NULL,
1135 };
1136 
1137 static struct attribute_group cpu_common_attr_group = {
1138 	.attrs = cpu_common_attrs,
1139 };
1140 
1141 static struct attribute *cpu_online_attrs[] = {
1142 	&dev_attr_idle_count.attr,
1143 	&dev_attr_idle_time_us.attr,
1144 	NULL,
1145 };
1146 
1147 static struct attribute_group cpu_online_attr_group = {
1148 	.attrs = cpu_online_attrs,
1149 };
1150 
smp_cpu_online(unsigned int cpu)1151 static 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 
smp_cpu_pre_down(unsigned int cpu)1158 static 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 
smp_add_present_cpu(int cpu)1166 static 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 
1189 out_topology:
1190 	sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1191 out_cpu:
1192 	unregister_cpu(c);
1193 out:
1194 	return rc;
1195 }
1196 
smp_rescan_cpus(void)1197 int __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 
rescan_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)1213 static 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 }
1227 static DEVICE_ATTR_WO(rescan);
1228 
s390_smp_init(void)1229 static 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;
1245 out:
1246 	return rc;
1247 }
1248 subsys_initcall(s390_smp_init);
1249 
set_new_lowcore(struct lowcore * lc)1250 static __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 
smp_reinit_ipl_cpu(void)1269 int __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 }
1306