2 * SMP related functions
4 * Copyright IBM Corp. 1999, 2012
5 * Author(s): Denis Joseph Barrow,
6 * Martin Schwidefsky <schwidefsky@de.ibm.com>,
7 * Heiko Carstens <heiko.carstens@de.ibm.com>,
9 * based on other smp stuff by
10 * (c) 1995 Alan Cox, CymruNET Ltd <alan@cymru.net>
11 * (c) 1998 Ingo Molnar
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.
18 #define KMSG_COMPONENT "cpu"
19 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
21 #include <linux/workqueue.h>
22 #include <linux/module.h>
23 #include <linux/init.h>
25 #include <linux/err.h>
26 #include <linux/spinlock.h>
27 #include <linux/kernel_stat.h>
28 #include <linux/delay.h>
29 #include <linux/interrupt.h>
30 #include <linux/irqflags.h>
31 #include <linux/cpu.h>
32 #include <linux/slab.h>
33 #include <linux/crash_dump.h>
34 #include <linux/memblock.h>
35 #include <asm/asm-offsets.h>
37 #include <asm/switch_to.h>
38 #include <asm/facility.h>
40 #include <asm/setup.h>
42 #include <asm/tlbflush.h>
43 #include <asm/vtimer.h>
44 #include <asm/lowcore.h>
47 #include <asm/debug.h>
48 #include <asm/os_info.h>
55 ec_call_function_single,
64 static DEFINE_PER_CPU(struct cpu *, cpu_device);
67 struct _lowcore *lowcore; /* lowcore page(s) for the cpu */
68 unsigned long ec_mask; /* bit mask for ec_xxx functions */
69 signed char state; /* physical cpu state */
70 signed char polarization; /* physical polarization */
71 u16 address; /* physical cpu address */
74 static u8 boot_core_type;
75 static struct pcpu pcpu_devices[NR_CPUS];
77 unsigned int smp_cpu_mt_shift;
78 EXPORT_SYMBOL(smp_cpu_mt_shift);
80 unsigned int smp_cpu_mtid;
81 EXPORT_SYMBOL(smp_cpu_mtid);
83 static unsigned int smp_max_threads __initdata = -1U;
85 static int __init early_nosmt(char *s)
90 early_param("nosmt", early_nosmt);
92 static int __init early_smt(char *s)
94 get_option(&s, &smp_max_threads);
97 early_param("smt", early_smt);
100 * The smp_cpu_state_mutex must be held when changing the state or polarization
101 * member of a pcpu data structure within the pcpu_devices arreay.
103 DEFINE_MUTEX(smp_cpu_state_mutex);
106 * Signal processor helper functions.
108 static inline int __pcpu_sigp_relax(u16 addr, u8 order, unsigned long parm,
114 cc = __pcpu_sigp(addr, order, parm, NULL);
115 if (cc != SIGP_CC_BUSY)
121 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
125 for (retry = 0; ; retry++) {
126 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
127 if (cc != SIGP_CC_BUSY)
135 static inline int pcpu_stopped(struct pcpu *pcpu)
137 u32 uninitialized_var(status);
139 if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
140 0, &status) != SIGP_CC_STATUS_STORED)
142 return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
145 static inline int pcpu_running(struct pcpu *pcpu)
147 if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
148 0, NULL) != SIGP_CC_STATUS_STORED)
150 /* Status stored condition code is equivalent to cpu not running. */
155 * Find struct pcpu by cpu address.
157 static struct pcpu *pcpu_find_address(const struct cpumask *mask, u16 address)
161 for_each_cpu(cpu, mask)
162 if (pcpu_devices[cpu].address == address)
163 return pcpu_devices + cpu;
167 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
171 if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
173 order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
174 pcpu_sigp_retry(pcpu, order, 0);
177 #define ASYNC_FRAME_OFFSET (ASYNC_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
178 #define PANIC_FRAME_OFFSET (PAGE_SIZE - STACK_FRAME_OVERHEAD - __PT_SIZE)
180 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
182 unsigned long async_stack, panic_stack;
185 if (pcpu != &pcpu_devices[0]) {
186 pcpu->lowcore = (struct _lowcore *)
187 __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
188 async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
189 panic_stack = __get_free_page(GFP_KERNEL);
190 if (!pcpu->lowcore || !panic_stack || !async_stack)
193 async_stack = pcpu->lowcore->async_stack - ASYNC_FRAME_OFFSET;
194 panic_stack = pcpu->lowcore->panic_stack - PANIC_FRAME_OFFSET;
197 memcpy(lc, &S390_lowcore, 512);
198 memset((char *) lc + 512, 0, sizeof(*lc) - 512);
199 lc->async_stack = async_stack + ASYNC_FRAME_OFFSET;
200 lc->panic_stack = panic_stack + PANIC_FRAME_OFFSET;
202 lc->spinlock_lockval = arch_spin_lockval(cpu);
204 lc->vector_save_area_addr =
205 (unsigned long) &lc->vector_save_area;
206 if (vdso_alloc_per_cpu(lc))
208 lowcore_ptr[cpu] = lc;
209 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
212 if (pcpu != &pcpu_devices[0]) {
213 free_page(panic_stack);
214 free_pages(async_stack, ASYNC_ORDER);
215 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
220 #ifdef CONFIG_HOTPLUG_CPU
222 static void pcpu_free_lowcore(struct pcpu *pcpu)
224 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
225 lowcore_ptr[pcpu - pcpu_devices] = NULL;
226 vdso_free_per_cpu(pcpu->lowcore);
227 if (pcpu == &pcpu_devices[0])
229 free_page(pcpu->lowcore->panic_stack-PANIC_FRAME_OFFSET);
230 free_pages(pcpu->lowcore->async_stack-ASYNC_FRAME_OFFSET, ASYNC_ORDER);
231 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
234 #endif /* CONFIG_HOTPLUG_CPU */
236 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
238 struct _lowcore *lc = pcpu->lowcore;
240 if (MACHINE_HAS_TLB_LC)
241 cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
242 cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
243 atomic_inc(&init_mm.context.attach_count);
245 lc->spinlock_lockval = arch_spin_lockval(cpu);
246 lc->percpu_offset = __per_cpu_offset[cpu];
247 lc->kernel_asce = S390_lowcore.kernel_asce;
248 lc->machine_flags = S390_lowcore.machine_flags;
249 lc->user_timer = lc->system_timer = lc->steal_timer = 0;
250 __ctl_store(lc->cregs_save_area, 0, 15);
251 save_access_regs((unsigned int *) lc->access_regs_save_area);
252 memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
256 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
258 struct _lowcore *lc = pcpu->lowcore;
259 struct thread_info *ti = task_thread_info(tsk);
261 lc->kernel_stack = (unsigned long) task_stack_page(tsk)
262 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
263 lc->thread_info = (unsigned long) task_thread_info(tsk);
264 lc->current_task = (unsigned long) tsk;
266 lc->current_pid = tsk->pid;
267 lc->user_timer = ti->user_timer;
268 lc->system_timer = ti->system_timer;
272 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
274 struct _lowcore *lc = pcpu->lowcore;
276 lc->restart_stack = lc->kernel_stack;
277 lc->restart_fn = (unsigned long) func;
278 lc->restart_data = (unsigned long) data;
279 lc->restart_source = -1UL;
280 pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
284 * Call function via PSW restart on pcpu and stop the current cpu.
286 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
287 void *data, unsigned long stack)
289 struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
290 unsigned long source_cpu = stap();
292 __load_psw_mask(PSW_KERNEL_BITS);
293 if (pcpu->address == source_cpu)
294 func(data); /* should not return */
295 /* Stop target cpu (if func returns this stops the current cpu). */
296 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
297 /* Restart func on the target cpu and stop the current cpu. */
298 mem_assign_absolute(lc->restart_stack, stack);
299 mem_assign_absolute(lc->restart_fn, (unsigned long) func);
300 mem_assign_absolute(lc->restart_data, (unsigned long) data);
301 mem_assign_absolute(lc->restart_source, source_cpu);
303 "0: sigp 0,%0,%2 # sigp restart to target cpu\n"
304 " brc 2,0b # busy, try again\n"
305 "1: sigp 0,%1,%3 # sigp stop to current cpu\n"
306 " brc 2,1b # busy, try again\n"
307 : : "d" (pcpu->address), "d" (source_cpu),
308 "K" (SIGP_RESTART), "K" (SIGP_STOP)
314 * Enable additional logical cpus for multi-threading.
316 static int pcpu_set_smt(unsigned int mtid)
318 register unsigned long reg1 asm ("1") = (unsigned long) mtid;
321 if (smp_cpu_mtid == mtid)
324 " sigp %1,0,%2 # sigp set multi-threading\n"
327 : "=d" (cc) : "d" (reg1), "K" (SIGP_SET_MULTI_THREADING)
331 smp_cpu_mt_shift = 0;
332 while (smp_cpu_mtid >= (1U << smp_cpu_mt_shift))
334 pcpu_devices[0].address = stap();
340 * Call function on an online CPU.
342 void smp_call_online_cpu(void (*func)(void *), void *data)
346 /* Use the current cpu if it is online. */
347 pcpu = pcpu_find_address(cpu_online_mask, stap());
349 /* Use the first online cpu. */
350 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
351 pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
355 * Call function on the ipl CPU.
357 void smp_call_ipl_cpu(void (*func)(void *), void *data)
359 pcpu_delegate(&pcpu_devices[0], func, data,
360 pcpu_devices->lowcore->panic_stack -
361 PANIC_FRAME_OFFSET + PAGE_SIZE);
364 int smp_find_processor_id(u16 address)
368 for_each_present_cpu(cpu)
369 if (pcpu_devices[cpu].address == address)
374 int smp_vcpu_scheduled(int cpu)
376 return pcpu_running(pcpu_devices + cpu);
379 void smp_yield_cpu(int cpu)
381 if (MACHINE_HAS_DIAG9C) {
382 diag_stat_inc_norecursion(DIAG_STAT_X09C);
383 asm volatile("diag %0,0,0x9c"
384 : : "d" (pcpu_devices[cpu].address));
385 } else if (MACHINE_HAS_DIAG44) {
386 diag_stat_inc_norecursion(DIAG_STAT_X044);
387 asm volatile("diag 0,0,0x44");
392 * Send cpus emergency shutdown signal. This gives the cpus the
393 * opportunity to complete outstanding interrupts.
395 static void smp_emergency_stop(cpumask_t *cpumask)
400 end = get_tod_clock() + (1000000UL << 12);
401 for_each_cpu(cpu, cpumask) {
402 struct pcpu *pcpu = pcpu_devices + cpu;
403 set_bit(ec_stop_cpu, &pcpu->ec_mask);
404 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
405 0, NULL) == SIGP_CC_BUSY &&
406 get_tod_clock() < end)
409 while (get_tod_clock() < end) {
410 for_each_cpu(cpu, cpumask)
411 if (pcpu_stopped(pcpu_devices + cpu))
412 cpumask_clear_cpu(cpu, cpumask);
413 if (cpumask_empty(cpumask))
420 * Stop all cpus but the current one.
422 void smp_send_stop(void)
427 /* Disable all interrupts/machine checks */
428 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
429 trace_hardirqs_off();
431 debug_set_critical();
432 cpumask_copy(&cpumask, cpu_online_mask);
433 cpumask_clear_cpu(smp_processor_id(), &cpumask);
435 if (oops_in_progress)
436 smp_emergency_stop(&cpumask);
438 /* stop all processors */
439 for_each_cpu(cpu, &cpumask) {
440 struct pcpu *pcpu = pcpu_devices + cpu;
441 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
442 while (!pcpu_stopped(pcpu))
448 * This is the main routine where commands issued by other
451 static void smp_handle_ext_call(void)
455 /* handle bit signal external calls */
456 bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
457 if (test_bit(ec_stop_cpu, &bits))
459 if (test_bit(ec_schedule, &bits))
461 if (test_bit(ec_call_function_single, &bits))
462 generic_smp_call_function_single_interrupt();
465 static void do_ext_call_interrupt(struct ext_code ext_code,
466 unsigned int param32, unsigned long param64)
468 inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
469 smp_handle_ext_call();
472 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
476 for_each_cpu(cpu, mask)
477 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
480 void arch_send_call_function_single_ipi(int cpu)
482 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
486 * this function sends a 'reschedule' IPI to another CPU.
487 * it goes straight through and wastes no time serializing
488 * anything. Worst case is that we lose a reschedule ...
490 void smp_send_reschedule(int cpu)
492 pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
496 * parameter area for the set/clear control bit callbacks
498 struct ec_creg_mask_parms {
500 unsigned long andval;
505 * callback for setting/clearing control bits
507 static void smp_ctl_bit_callback(void *info)
509 struct ec_creg_mask_parms *pp = info;
510 unsigned long cregs[16];
512 __ctl_store(cregs, 0, 15);
513 cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
514 __ctl_load(cregs, 0, 15);
518 * Set a bit in a control register of all cpus
520 void smp_ctl_set_bit(int cr, int bit)
522 struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
524 on_each_cpu(smp_ctl_bit_callback, &parms, 1);
526 EXPORT_SYMBOL(smp_ctl_set_bit);
529 * Clear a bit in a control register of all cpus
531 void smp_ctl_clear_bit(int cr, int bit)
533 struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
535 on_each_cpu(smp_ctl_bit_callback, &parms, 1);
537 EXPORT_SYMBOL(smp_ctl_clear_bit);
539 #ifdef CONFIG_CRASH_DUMP
541 static void __init __smp_store_cpu_state(struct save_area_ext *sa_ext,
542 u16 address, int is_boot_cpu)
544 void *lc = (void *)(unsigned long) store_prefix();
548 /* Copy the registers of the boot CPU. */
549 copy_oldmem_page(1, (void *) &sa_ext->sa, sizeof(sa_ext->sa),
550 SAVE_AREA_BASE - PAGE_SIZE, 0);
552 save_vx_regs_safe(sa_ext->vx_regs);
555 /* Get the registers of a non-boot cpu. */
556 __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
557 memcpy_real(&sa_ext->sa, lc + SAVE_AREA_BASE, sizeof(sa_ext->sa));
560 /* Get the VX registers */
561 vx_sa = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
563 panic("could not allocate memory for VX save area\n");
564 __pcpu_sigp_relax(address, SIGP_STORE_ADDITIONAL_STATUS, vx_sa, NULL);
565 memcpy(sa_ext->vx_regs, (void *) vx_sa, sizeof(sa_ext->vx_regs));
566 memblock_free(vx_sa, PAGE_SIZE);
569 int smp_store_status(int cpu)
574 pcpu = pcpu_devices + cpu;
575 if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
576 0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
580 vx_sa = __pa(pcpu->lowcore->vector_save_area_addr);
581 __pcpu_sigp_relax(pcpu->address, SIGP_STORE_ADDITIONAL_STATUS,
586 #endif /* CONFIG_CRASH_DUMP */
589 * Collect CPU state of the previous, crashed system.
590 * There are four cases:
591 * 1) standard zfcp dump
592 * condition: OLDMEM_BASE == NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
593 * The state for all CPUs except the boot CPU needs to be collected
594 * with sigp stop-and-store-status. The boot CPU state is located in
595 * the absolute lowcore of the memory stored in the HSA. The zcore code
596 * will allocate the save area and copy the boot CPU state from the HSA.
597 * 2) stand-alone kdump for SCSI (zfcp dump with swapped memory)
598 * condition: OLDMEM_BASE != NULL && ipl_info.type == IPL_TYPE_FCP_DUMP
599 * The state for all CPUs except the boot CPU needs to be collected
600 * with sigp stop-and-store-status. The firmware or the boot-loader
601 * stored the registers of the boot CPU in the absolute lowcore in the
602 * memory of the old system.
603 * 3) kdump and the old kernel did not store the CPU state,
604 * or stand-alone kdump for DASD
605 * condition: OLDMEM_BASE != NULL && !is_kdump_kernel()
606 * The state for all CPUs except the boot CPU needs to be collected
607 * with sigp stop-and-store-status. The kexec code or the boot-loader
608 * stored the registers of the boot CPU in the memory of the old system.
609 * 4) kdump and the old kernel stored the CPU state
610 * condition: OLDMEM_BASE != NULL && is_kdump_kernel()
611 * The state of all CPUs is stored in ELF sections in the memory of the
612 * old system. The ELF sections are picked up by the crash_dump code
613 * via elfcorehdr_addr.
615 void __init smp_save_dump_cpus(void)
617 #ifdef CONFIG_CRASH_DUMP
618 int addr, cpu, boot_cpu_addr, max_cpu_addr;
619 struct save_area_ext *sa_ext;
622 if (is_kdump_kernel())
623 /* Previous system stored the CPU states. Nothing to do. */
625 if (!(OLDMEM_BASE || ipl_info.type == IPL_TYPE_FCP_DUMP))
626 /* No previous system present, normal boot. */
628 /* Set multi-threading state to the previous system. */
629 pcpu_set_smt(sclp.mtid_prev);
630 max_cpu_addr = SCLP_MAX_CORES << sclp.mtid_prev;
631 for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
632 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
633 SIGP_CC_NOT_OPERATIONAL)
637 dump_save_areas.areas = (void *)memblock_alloc(sizeof(void *) * cpu, 8);
638 dump_save_areas.count = cpu;
639 boot_cpu_addr = stap();
640 for (cpu = 0, addr = 0; addr <= max_cpu_addr; addr++) {
641 if (__pcpu_sigp_relax(addr, SIGP_SENSE, 0, NULL) ==
642 SIGP_CC_NOT_OPERATIONAL)
644 sa_ext = (void *) memblock_alloc(sizeof(*sa_ext), 8);
645 dump_save_areas.areas[cpu] = sa_ext;
647 panic("could not allocate memory for save area\n");
648 is_boot_cpu = (addr == boot_cpu_addr);
650 if (is_boot_cpu && !OLDMEM_BASE)
651 /* Skip boot CPU for standard zfcp dump. */
653 /* Get state for this CPU. */
654 __smp_store_cpu_state(sa_ext, addr, is_boot_cpu);
658 #endif /* CONFIG_CRASH_DUMP */
661 void smp_cpu_set_polarization(int cpu, int val)
663 pcpu_devices[cpu].polarization = val;
666 int smp_cpu_get_polarization(int cpu)
668 return pcpu_devices[cpu].polarization;
671 static struct sclp_core_info *smp_get_core_info(void)
673 static int use_sigp_detection;
674 struct sclp_core_info *info;
677 info = kzalloc(sizeof(*info), GFP_KERNEL);
678 if (info && (use_sigp_detection || sclp_get_core_info(info))) {
679 use_sigp_detection = 1;
681 address < (SCLP_MAX_CORES << smp_cpu_mt_shift);
682 address += (1U << smp_cpu_mt_shift)) {
683 if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
684 SIGP_CC_NOT_OPERATIONAL)
686 info->core[info->configured].core_id =
687 address >> smp_cpu_mt_shift;
690 info->combined = info->configured;
695 static int smp_add_present_cpu(int cpu);
697 static int __smp_rescan_cpus(struct sclp_core_info *info, int sysfs_add)
705 cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
706 cpu = cpumask_first(&avail);
707 for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
708 if (sclp.has_core_type && info->core[i].type != boot_core_type)
710 address = info->core[i].core_id << smp_cpu_mt_shift;
711 for (j = 0; j <= smp_cpu_mtid; j++) {
712 if (pcpu_find_address(cpu_present_mask, address + j))
714 pcpu = pcpu_devices + cpu;
715 pcpu->address = address + j;
717 (cpu >= info->configured*(smp_cpu_mtid + 1)) ?
718 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
719 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
720 set_cpu_present(cpu, true);
721 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
722 set_cpu_present(cpu, false);
725 cpu = cpumask_next(cpu, &avail);
726 if (cpu >= nr_cpu_ids)
733 static void __init smp_detect_cpus(void)
735 unsigned int cpu, mtid, c_cpus, s_cpus;
736 struct sclp_core_info *info;
739 /* Get CPU information */
740 info = smp_get_core_info();
742 panic("smp_detect_cpus failed to allocate memory\n");
744 /* Find boot CPU type */
745 if (sclp.has_core_type) {
747 for (cpu = 0; cpu < info->combined; cpu++)
748 if (info->core[cpu].core_id == address) {
749 /* The boot cpu dictates the cpu type. */
750 boot_core_type = info->core[cpu].type;
753 if (cpu >= info->combined)
754 panic("Could not find boot CPU type");
757 /* Set multi-threading state for the current system */
758 mtid = boot_core_type ? sclp.mtid : sclp.mtid_cp;
759 mtid = (mtid < smp_max_threads) ? mtid : smp_max_threads - 1;
762 /* Print number of CPUs */
764 for (cpu = 0; cpu < info->combined; cpu++) {
765 if (sclp.has_core_type &&
766 info->core[cpu].type != boot_core_type)
768 if (cpu < info->configured)
769 c_cpus += smp_cpu_mtid + 1;
771 s_cpus += smp_cpu_mtid + 1;
773 pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
775 /* Add CPUs present at boot */
777 __smp_rescan_cpus(info, 0);
783 * Activate a secondary processor.
785 static void smp_start_secondary(void *cpuvoid)
787 S390_lowcore.last_update_clock = get_tod_clock();
788 S390_lowcore.restart_stack = (unsigned long) restart_stack;
789 S390_lowcore.restart_fn = (unsigned long) do_restart;
790 S390_lowcore.restart_data = 0;
791 S390_lowcore.restart_source = -1UL;
792 restore_access_regs(S390_lowcore.access_regs_save_area);
793 __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
794 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
800 notify_cpu_starting(smp_processor_id());
801 set_cpu_online(smp_processor_id(), true);
802 inc_irq_stat(CPU_RST);
804 cpu_startup_entry(CPUHP_ONLINE);
807 /* Upping and downing of CPUs */
808 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
813 pcpu = pcpu_devices + cpu;
814 if (pcpu->state != CPU_STATE_CONFIGURED)
816 base = cpu - (cpu % (smp_cpu_mtid + 1));
817 for (i = 0; i <= smp_cpu_mtid; i++) {
818 if (base + i < nr_cpu_ids)
819 if (cpu_online(base + i))
823 * If this is the first CPU of the core to get online
824 * do an initial CPU reset.
826 if (i > smp_cpu_mtid &&
827 pcpu_sigp_retry(pcpu_devices + base, SIGP_INITIAL_CPU_RESET, 0) !=
828 SIGP_CC_ORDER_CODE_ACCEPTED)
831 rc = pcpu_alloc_lowcore(pcpu, cpu);
834 pcpu_prepare_secondary(pcpu, cpu);
835 pcpu_attach_task(pcpu, tidle);
836 pcpu_start_fn(pcpu, smp_start_secondary, NULL);
837 /* Wait until cpu puts itself in the online & active maps */
838 while (!cpu_online(cpu) || !cpu_active(cpu))
843 static unsigned int setup_possible_cpus __initdata;
845 static int __init _setup_possible_cpus(char *s)
847 get_option(&s, &setup_possible_cpus);
850 early_param("possible_cpus", _setup_possible_cpus);
852 #ifdef CONFIG_HOTPLUG_CPU
854 int __cpu_disable(void)
856 unsigned long cregs[16];
858 /* Handle possible pending IPIs */
859 smp_handle_ext_call();
860 set_cpu_online(smp_processor_id(), false);
861 /* Disable pseudo page faults on this cpu. */
863 /* Disable interrupt sources via control register. */
864 __ctl_store(cregs, 0, 15);
865 cregs[0] &= ~0x0000ee70UL; /* disable all external interrupts */
866 cregs[6] &= ~0xff000000UL; /* disable all I/O interrupts */
867 cregs[14] &= ~0x1f000000UL; /* disable most machine checks */
868 __ctl_load(cregs, 0, 15);
869 clear_cpu_flag(CIF_NOHZ_DELAY);
873 void __cpu_die(unsigned int cpu)
877 /* Wait until target cpu is down */
878 pcpu = pcpu_devices + cpu;
879 while (!pcpu_stopped(pcpu))
881 pcpu_free_lowcore(pcpu);
882 atomic_dec(&init_mm.context.attach_count);
883 cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
884 if (MACHINE_HAS_TLB_LC)
885 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
888 void __noreturn cpu_die(void)
891 pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
895 #endif /* CONFIG_HOTPLUG_CPU */
897 void __init smp_fill_possible_mask(void)
899 unsigned int possible, sclp_max, cpu;
901 sclp_max = max(sclp.mtid, sclp.mtid_cp) + 1;
902 sclp_max = min(smp_max_threads, sclp_max);
903 sclp_max = sclp.max_cores * sclp_max ?: nr_cpu_ids;
904 possible = setup_possible_cpus ?: nr_cpu_ids;
905 possible = min(possible, sclp_max);
906 for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
907 set_cpu_possible(cpu, true);
910 void __init smp_prepare_cpus(unsigned int max_cpus)
912 /* request the 0x1201 emergency signal external interrupt */
913 if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
914 panic("Couldn't request external interrupt 0x1201");
915 /* request the 0x1202 external call external interrupt */
916 if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
917 panic("Couldn't request external interrupt 0x1202");
921 void __init smp_prepare_boot_cpu(void)
923 struct pcpu *pcpu = pcpu_devices;
925 pcpu->state = CPU_STATE_CONFIGURED;
926 pcpu->address = stap();
927 pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
928 S390_lowcore.percpu_offset = __per_cpu_offset[0];
929 smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
930 set_cpu_present(0, true);
931 set_cpu_online(0, true);
934 void __init smp_cpus_done(unsigned int max_cpus)
938 void __init smp_setup_processor_id(void)
940 S390_lowcore.cpu_nr = 0;
941 S390_lowcore.spinlock_lockval = arch_spin_lockval(0);
945 * the frequency of the profiling timer can be changed
946 * by writing a multiplier value into /proc/profile.
948 * usually you want to run this on all CPUs ;)
950 int setup_profiling_timer(unsigned int multiplier)
955 #ifdef CONFIG_HOTPLUG_CPU
956 static ssize_t cpu_configure_show(struct device *dev,
957 struct device_attribute *attr, char *buf)
961 mutex_lock(&smp_cpu_state_mutex);
962 count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
963 mutex_unlock(&smp_cpu_state_mutex);
967 static ssize_t cpu_configure_store(struct device *dev,
968 struct device_attribute *attr,
969 const char *buf, size_t count)
975 if (sscanf(buf, "%d %c", &val, &delim) != 1)
977 if (val != 0 && val != 1)
980 mutex_lock(&smp_cpu_state_mutex);
982 /* disallow configuration changes of online cpus and cpu 0 */
984 cpu -= cpu % (smp_cpu_mtid + 1);
987 for (i = 0; i <= smp_cpu_mtid; i++)
988 if (cpu_online(cpu + i))
990 pcpu = pcpu_devices + cpu;
994 if (pcpu->state != CPU_STATE_CONFIGURED)
996 rc = sclp_core_deconfigure(pcpu->address >> smp_cpu_mt_shift);
999 for (i = 0; i <= smp_cpu_mtid; i++) {
1000 if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1002 pcpu[i].state = CPU_STATE_STANDBY;
1003 smp_cpu_set_polarization(cpu + i,
1004 POLARIZATION_UNKNOWN);
1006 topology_expect_change();
1009 if (pcpu->state != CPU_STATE_STANDBY)
1011 rc = sclp_core_configure(pcpu->address >> smp_cpu_mt_shift);
1014 for (i = 0; i <= smp_cpu_mtid; i++) {
1015 if (cpu + i >= nr_cpu_ids || !cpu_present(cpu + i))
1017 pcpu[i].state = CPU_STATE_CONFIGURED;
1018 smp_cpu_set_polarization(cpu + i,
1019 POLARIZATION_UNKNOWN);
1021 topology_expect_change();
1027 mutex_unlock(&smp_cpu_state_mutex);
1029 return rc ? rc : count;
1031 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
1032 #endif /* CONFIG_HOTPLUG_CPU */
1034 static ssize_t show_cpu_address(struct device *dev,
1035 struct device_attribute *attr, char *buf)
1037 return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
1039 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
1041 static struct attribute *cpu_common_attrs[] = {
1042 #ifdef CONFIG_HOTPLUG_CPU
1043 &dev_attr_configure.attr,
1045 &dev_attr_address.attr,
1049 static struct attribute_group cpu_common_attr_group = {
1050 .attrs = cpu_common_attrs,
1053 static struct attribute *cpu_online_attrs[] = {
1054 &dev_attr_idle_count.attr,
1055 &dev_attr_idle_time_us.attr,
1059 static struct attribute_group cpu_online_attr_group = {
1060 .attrs = cpu_online_attrs,
1063 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
1066 unsigned int cpu = (unsigned int)(long)hcpu;
1067 struct device *s = &per_cpu(cpu_device, cpu)->dev;
1070 switch (action & ~CPU_TASKS_FROZEN) {
1072 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1075 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1078 return notifier_from_errno(err);
1081 static int smp_add_present_cpu(int cpu)
1087 c = kzalloc(sizeof(*c), GFP_KERNEL);
1090 per_cpu(cpu_device, cpu) = c;
1092 c->hotpluggable = 1;
1093 rc = register_cpu(c, cpu);
1096 rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1099 if (cpu_online(cpu)) {
1100 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1104 rc = topology_cpu_init(c);
1110 if (cpu_online(cpu))
1111 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1113 sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1115 #ifdef CONFIG_HOTPLUG_CPU
1122 #ifdef CONFIG_HOTPLUG_CPU
1124 int __ref smp_rescan_cpus(void)
1126 struct sclp_core_info *info;
1129 info = smp_get_core_info();
1133 mutex_lock(&smp_cpu_state_mutex);
1134 nr = __smp_rescan_cpus(info, 1);
1135 mutex_unlock(&smp_cpu_state_mutex);
1139 topology_schedule_update();
1143 static ssize_t __ref rescan_store(struct device *dev,
1144 struct device_attribute *attr,
1150 rc = smp_rescan_cpus();
1151 return rc ? rc : count;
1153 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1154 #endif /* CONFIG_HOTPLUG_CPU */
1156 static int __init s390_smp_init(void)
1160 #ifdef CONFIG_HOTPLUG_CPU
1161 rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1165 cpu_notifier_register_begin();
1166 for_each_present_cpu(cpu) {
1167 rc = smp_add_present_cpu(cpu);
1172 __hotcpu_notifier(smp_cpu_notify, 0);
1175 cpu_notifier_register_done();
1178 subsys_initcall(s390_smp_init);