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 <asm/asm-offsets.h>
35 #include <asm/switch_to.h>
36 #include <asm/facility.h>
38 #include <asm/setup.h>
40 #include <asm/tlbflush.h>
41 #include <asm/vtimer.h>
42 #include <asm/lowcore.h>
45 #include <asm/debug.h>
46 #include <asm/os_info.h>
52 ec_call_function_single,
63 struct _lowcore *lowcore; /* lowcore page(s) for the cpu */
64 unsigned long async_stack; /* async stack for the cpu */
65 unsigned long panic_stack; /* panic stack for the cpu */
66 unsigned long ec_mask; /* bit mask for ec_xxx functions */
67 int state; /* physical cpu state */
68 int polarization; /* physical polarization */
69 u16 address; /* physical cpu address */
72 static u8 boot_cpu_type;
73 static u16 boot_cpu_address;
74 static struct pcpu pcpu_devices[NR_CPUS];
77 * The smp_cpu_state_mutex must be held when changing the state or polarization
78 * member of a pcpu data structure within the pcpu_devices arreay.
80 DEFINE_MUTEX(smp_cpu_state_mutex);
83 * Signal processor helper functions.
85 static inline int __pcpu_sigp_relax(u16 addr, u8 order, u32 parm, u32 *status)
90 cc = __pcpu_sigp(addr, order, parm, NULL);
91 if (cc != SIGP_CC_BUSY)
97 static int pcpu_sigp_retry(struct pcpu *pcpu, u8 order, u32 parm)
101 for (retry = 0; ; retry++) {
102 cc = __pcpu_sigp(pcpu->address, order, parm, NULL);
103 if (cc != SIGP_CC_BUSY)
111 static inline int pcpu_stopped(struct pcpu *pcpu)
113 u32 uninitialized_var(status);
115 if (__pcpu_sigp(pcpu->address, SIGP_SENSE,
116 0, &status) != SIGP_CC_STATUS_STORED)
118 return !!(status & (SIGP_STATUS_CHECK_STOP|SIGP_STATUS_STOPPED));
121 static inline int pcpu_running(struct pcpu *pcpu)
123 if (__pcpu_sigp(pcpu->address, SIGP_SENSE_RUNNING,
124 0, NULL) != SIGP_CC_STATUS_STORED)
126 /* Status stored condition code is equivalent to cpu not running. */
131 * Find struct pcpu by cpu address.
133 static struct pcpu *pcpu_find_address(const struct cpumask *mask, int address)
137 for_each_cpu(cpu, mask)
138 if (pcpu_devices[cpu].address == address)
139 return pcpu_devices + cpu;
143 static void pcpu_ec_call(struct pcpu *pcpu, int ec_bit)
147 if (test_and_set_bit(ec_bit, &pcpu->ec_mask))
149 order = pcpu_running(pcpu) ? SIGP_EXTERNAL_CALL : SIGP_EMERGENCY_SIGNAL;
150 pcpu_sigp_retry(pcpu, order, 0);
153 static int pcpu_alloc_lowcore(struct pcpu *pcpu, int cpu)
157 if (pcpu != &pcpu_devices[0]) {
158 pcpu->lowcore = (struct _lowcore *)
159 __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
160 pcpu->async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
161 pcpu->panic_stack = __get_free_page(GFP_KERNEL);
162 if (!pcpu->lowcore || !pcpu->panic_stack || !pcpu->async_stack)
166 memcpy(lc, &S390_lowcore, 512);
167 memset((char *) lc + 512, 0, sizeof(*lc) - 512);
168 lc->async_stack = pcpu->async_stack + ASYNC_SIZE
169 - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
170 lc->panic_stack = pcpu->panic_stack + PAGE_SIZE
171 - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
174 if (MACHINE_HAS_IEEE) {
175 lc->extended_save_area_addr = get_zeroed_page(GFP_KERNEL);
176 if (!lc->extended_save_area_addr)
180 if (vdso_alloc_per_cpu(lc))
183 lowcore_ptr[cpu] = lc;
184 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, (u32)(unsigned long) lc);
187 if (pcpu != &pcpu_devices[0]) {
188 free_page(pcpu->panic_stack);
189 free_pages(pcpu->async_stack, ASYNC_ORDER);
190 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
195 #ifdef CONFIG_HOTPLUG_CPU
197 static void pcpu_free_lowcore(struct pcpu *pcpu)
199 pcpu_sigp_retry(pcpu, SIGP_SET_PREFIX, 0);
200 lowcore_ptr[pcpu - pcpu_devices] = NULL;
202 if (MACHINE_HAS_IEEE) {
203 struct _lowcore *lc = pcpu->lowcore;
205 free_page((unsigned long) lc->extended_save_area_addr);
206 lc->extended_save_area_addr = 0;
209 vdso_free_per_cpu(pcpu->lowcore);
211 if (pcpu != &pcpu_devices[0]) {
212 free_page(pcpu->panic_stack);
213 free_pages(pcpu->async_stack, ASYNC_ORDER);
214 free_pages((unsigned long) pcpu->lowcore, LC_ORDER);
218 #endif /* CONFIG_HOTPLUG_CPU */
220 static void pcpu_prepare_secondary(struct pcpu *pcpu, int cpu)
222 struct _lowcore *lc = pcpu->lowcore;
224 if (MACHINE_HAS_TLB_LC)
225 cpumask_set_cpu(cpu, &init_mm.context.cpu_attach_mask);
226 cpumask_set_cpu(cpu, mm_cpumask(&init_mm));
227 atomic_inc(&init_mm.context.attach_count);
229 lc->percpu_offset = __per_cpu_offset[cpu];
230 lc->kernel_asce = S390_lowcore.kernel_asce;
231 lc->machine_flags = S390_lowcore.machine_flags;
232 lc->ftrace_func = S390_lowcore.ftrace_func;
233 lc->user_timer = lc->system_timer = lc->steal_timer = 0;
234 __ctl_store(lc->cregs_save_area, 0, 15);
235 save_access_regs((unsigned int *) lc->access_regs_save_area);
236 memcpy(lc->stfle_fac_list, S390_lowcore.stfle_fac_list,
240 static void pcpu_attach_task(struct pcpu *pcpu, struct task_struct *tsk)
242 struct _lowcore *lc = pcpu->lowcore;
243 struct thread_info *ti = task_thread_info(tsk);
245 lc->kernel_stack = (unsigned long) task_stack_page(tsk)
246 + THREAD_SIZE - STACK_FRAME_OVERHEAD - sizeof(struct pt_regs);
247 lc->thread_info = (unsigned long) task_thread_info(tsk);
248 lc->current_task = (unsigned long) tsk;
249 lc->user_timer = ti->user_timer;
250 lc->system_timer = ti->system_timer;
254 static void pcpu_start_fn(struct pcpu *pcpu, void (*func)(void *), void *data)
256 struct _lowcore *lc = pcpu->lowcore;
258 lc->restart_stack = lc->kernel_stack;
259 lc->restart_fn = (unsigned long) func;
260 lc->restart_data = (unsigned long) data;
261 lc->restart_source = -1UL;
262 pcpu_sigp_retry(pcpu, SIGP_RESTART, 0);
266 * Call function via PSW restart on pcpu and stop the current cpu.
268 static void pcpu_delegate(struct pcpu *pcpu, void (*func)(void *),
269 void *data, unsigned long stack)
271 struct _lowcore *lc = lowcore_ptr[pcpu - pcpu_devices];
272 unsigned long source_cpu = stap();
274 __load_psw_mask(PSW_KERNEL_BITS);
275 if (pcpu->address == source_cpu)
276 func(data); /* should not return */
277 /* Stop target cpu (if func returns this stops the current cpu). */
278 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
279 /* Restart func on the target cpu and stop the current cpu. */
280 mem_assign_absolute(lc->restart_stack, stack);
281 mem_assign_absolute(lc->restart_fn, (unsigned long) func);
282 mem_assign_absolute(lc->restart_data, (unsigned long) data);
283 mem_assign_absolute(lc->restart_source, source_cpu);
285 "0: sigp 0,%0,%2 # sigp restart to target cpu\n"
286 " brc 2,0b # busy, try again\n"
287 "1: sigp 0,%1,%3 # sigp stop to current cpu\n"
288 " brc 2,1b # busy, try again\n"
289 : : "d" (pcpu->address), "d" (source_cpu),
290 "K" (SIGP_RESTART), "K" (SIGP_STOP)
296 * Call function on an online CPU.
298 void smp_call_online_cpu(void (*func)(void *), void *data)
302 /* Use the current cpu if it is online. */
303 pcpu = pcpu_find_address(cpu_online_mask, stap());
305 /* Use the first online cpu. */
306 pcpu = pcpu_devices + cpumask_first(cpu_online_mask);
307 pcpu_delegate(pcpu, func, data, (unsigned long) restart_stack);
311 * Call function on the ipl CPU.
313 void smp_call_ipl_cpu(void (*func)(void *), void *data)
315 pcpu_delegate(&pcpu_devices[0], func, data,
316 pcpu_devices->panic_stack + PAGE_SIZE);
319 int smp_find_processor_id(u16 address)
323 for_each_present_cpu(cpu)
324 if (pcpu_devices[cpu].address == address)
329 int smp_vcpu_scheduled(int cpu)
331 return pcpu_running(pcpu_devices + cpu);
336 if (MACHINE_HAS_DIAG44)
337 asm volatile("diag 0,0,0x44");
340 void smp_yield_cpu(int cpu)
342 if (MACHINE_HAS_DIAG9C)
343 asm volatile("diag %0,0,0x9c"
344 : : "d" (pcpu_devices[cpu].address));
345 else if (MACHINE_HAS_DIAG44)
346 asm volatile("diag 0,0,0x44");
350 * Send cpus emergency shutdown signal. This gives the cpus the
351 * opportunity to complete outstanding interrupts.
353 static void smp_emergency_stop(cpumask_t *cpumask)
358 end = get_tod_clock() + (1000000UL << 12);
359 for_each_cpu(cpu, cpumask) {
360 struct pcpu *pcpu = pcpu_devices + cpu;
361 set_bit(ec_stop_cpu, &pcpu->ec_mask);
362 while (__pcpu_sigp(pcpu->address, SIGP_EMERGENCY_SIGNAL,
363 0, NULL) == SIGP_CC_BUSY &&
364 get_tod_clock() < end)
367 while (get_tod_clock() < end) {
368 for_each_cpu(cpu, cpumask)
369 if (pcpu_stopped(pcpu_devices + cpu))
370 cpumask_clear_cpu(cpu, cpumask);
371 if (cpumask_empty(cpumask))
378 * Stop all cpus but the current one.
380 void smp_send_stop(void)
385 /* Disable all interrupts/machine checks */
386 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
387 trace_hardirqs_off();
389 debug_set_critical();
390 cpumask_copy(&cpumask, cpu_online_mask);
391 cpumask_clear_cpu(smp_processor_id(), &cpumask);
393 if (oops_in_progress)
394 smp_emergency_stop(&cpumask);
396 /* stop all processors */
397 for_each_cpu(cpu, &cpumask) {
398 struct pcpu *pcpu = pcpu_devices + cpu;
399 pcpu_sigp_retry(pcpu, SIGP_STOP, 0);
400 while (!pcpu_stopped(pcpu))
406 * Stop the current cpu.
408 void smp_stop_cpu(void)
410 pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
415 * This is the main routine where commands issued by other
418 static void smp_handle_ext_call(void)
422 /* handle bit signal external calls */
423 bits = xchg(&pcpu_devices[smp_processor_id()].ec_mask, 0);
424 if (test_bit(ec_stop_cpu, &bits))
426 if (test_bit(ec_schedule, &bits))
428 if (test_bit(ec_call_function_single, &bits))
429 generic_smp_call_function_single_interrupt();
432 static void do_ext_call_interrupt(struct ext_code ext_code,
433 unsigned int param32, unsigned long param64)
435 inc_irq_stat(ext_code.code == 0x1202 ? IRQEXT_EXC : IRQEXT_EMS);
436 smp_handle_ext_call();
439 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
443 for_each_cpu(cpu, mask)
444 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
447 void arch_send_call_function_single_ipi(int cpu)
449 pcpu_ec_call(pcpu_devices + cpu, ec_call_function_single);
454 * this function sends a 'purge tlb' signal to another CPU.
456 static void smp_ptlb_callback(void *info)
461 void smp_ptlb_all(void)
463 on_each_cpu(smp_ptlb_callback, NULL, 1);
465 EXPORT_SYMBOL(smp_ptlb_all);
466 #endif /* ! CONFIG_64BIT */
469 * this function sends a 'reschedule' IPI to another CPU.
470 * it goes straight through and wastes no time serializing
471 * anything. Worst case is that we lose a reschedule ...
473 void smp_send_reschedule(int cpu)
475 pcpu_ec_call(pcpu_devices + cpu, ec_schedule);
479 * parameter area for the set/clear control bit callbacks
481 struct ec_creg_mask_parms {
483 unsigned long andval;
488 * callback for setting/clearing control bits
490 static void smp_ctl_bit_callback(void *info)
492 struct ec_creg_mask_parms *pp = info;
493 unsigned long cregs[16];
495 __ctl_store(cregs, 0, 15);
496 cregs[pp->cr] = (cregs[pp->cr] & pp->andval) | pp->orval;
497 __ctl_load(cregs, 0, 15);
501 * Set a bit in a control register of all cpus
503 void smp_ctl_set_bit(int cr, int bit)
505 struct ec_creg_mask_parms parms = { 1UL << bit, -1UL, cr };
507 on_each_cpu(smp_ctl_bit_callback, &parms, 1);
509 EXPORT_SYMBOL(smp_ctl_set_bit);
512 * Clear a bit in a control register of all cpus
514 void smp_ctl_clear_bit(int cr, int bit)
516 struct ec_creg_mask_parms parms = { 0, ~(1UL << bit), cr };
518 on_each_cpu(smp_ctl_bit_callback, &parms, 1);
520 EXPORT_SYMBOL(smp_ctl_clear_bit);
522 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_CRASH_DUMP)
524 static void __init smp_get_save_area(int cpu, u16 address)
526 void *lc = pcpu_devices[0].lowcore;
527 struct save_area *save_area;
529 if (is_kdump_kernel())
531 if (!OLDMEM_BASE && (address == boot_cpu_address ||
532 ipl_info.type != IPL_TYPE_FCP_DUMP))
534 save_area = dump_save_area_create(cpu);
536 panic("could not allocate memory for save area\n");
537 #ifdef CONFIG_CRASH_DUMP
538 if (address == boot_cpu_address) {
539 /* Copy the registers of the boot cpu. */
540 copy_oldmem_page(1, (void *) save_area, sizeof(*save_area),
541 SAVE_AREA_BASE - PAGE_SIZE, 0);
545 /* Get the registers of a non-boot cpu. */
546 __pcpu_sigp_relax(address, SIGP_STOP_AND_STORE_STATUS, 0, NULL);
547 memcpy_real(save_area, lc + SAVE_AREA_BASE, sizeof(*save_area));
550 int smp_store_status(int cpu)
554 pcpu = pcpu_devices + cpu;
555 if (__pcpu_sigp_relax(pcpu->address, SIGP_STOP_AND_STORE_STATUS,
556 0, NULL) != SIGP_CC_ORDER_CODE_ACCEPTED)
561 #else /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
563 static inline void smp_get_save_area(int cpu, u16 address) { }
565 #endif /* CONFIG_ZFCPDUMP || CONFIG_CRASH_DUMP */
567 void smp_cpu_set_polarization(int cpu, int val)
569 pcpu_devices[cpu].polarization = val;
572 int smp_cpu_get_polarization(int cpu)
574 return pcpu_devices[cpu].polarization;
577 static struct sclp_cpu_info *smp_get_cpu_info(void)
579 static int use_sigp_detection;
580 struct sclp_cpu_info *info;
583 info = kzalloc(sizeof(*info), GFP_KERNEL);
584 if (info && (use_sigp_detection || sclp_get_cpu_info(info))) {
585 use_sigp_detection = 1;
586 for (address = 0; address <= MAX_CPU_ADDRESS; address++) {
587 if (__pcpu_sigp_relax(address, SIGP_SENSE, 0, NULL) ==
588 SIGP_CC_NOT_OPERATIONAL)
590 info->cpu[info->configured].address = address;
593 info->combined = info->configured;
598 static int smp_add_present_cpu(int cpu);
600 static int __smp_rescan_cpus(struct sclp_cpu_info *info, int sysfs_add)
607 cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
608 cpu = cpumask_first(&avail);
609 for (i = 0; (i < info->combined) && (cpu < nr_cpu_ids); i++) {
610 if (info->has_cpu_type && info->cpu[i].type != boot_cpu_type)
612 if (pcpu_find_address(cpu_present_mask, info->cpu[i].address))
614 pcpu = pcpu_devices + cpu;
615 pcpu->address = info->cpu[i].address;
616 pcpu->state = (i >= info->configured) ?
617 CPU_STATE_STANDBY : CPU_STATE_CONFIGURED;
618 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
619 set_cpu_present(cpu, true);
620 if (sysfs_add && smp_add_present_cpu(cpu) != 0)
621 set_cpu_present(cpu, false);
624 cpu = cpumask_next(cpu, &avail);
629 static void __init smp_detect_cpus(void)
631 unsigned int cpu, c_cpus, s_cpus;
632 struct sclp_cpu_info *info;
634 info = smp_get_cpu_info();
636 panic("smp_detect_cpus failed to allocate memory\n");
637 if (info->has_cpu_type) {
638 for (cpu = 0; cpu < info->combined; cpu++) {
639 if (info->cpu[cpu].address != boot_cpu_address)
641 /* The boot cpu dictates the cpu type. */
642 boot_cpu_type = info->cpu[cpu].type;
647 for (cpu = 0; cpu < info->combined; cpu++) {
648 if (info->has_cpu_type && info->cpu[cpu].type != boot_cpu_type)
650 if (cpu < info->configured) {
651 smp_get_save_area(c_cpus, info->cpu[cpu].address);
656 pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
658 __smp_rescan_cpus(info, 0);
664 * Activate a secondary processor.
666 static void smp_start_secondary(void *cpuvoid)
668 S390_lowcore.last_update_clock = get_tod_clock();
669 S390_lowcore.restart_stack = (unsigned long) restart_stack;
670 S390_lowcore.restart_fn = (unsigned long) do_restart;
671 S390_lowcore.restart_data = 0;
672 S390_lowcore.restart_source = -1UL;
673 restore_access_regs(S390_lowcore.access_regs_save_area);
674 __ctl_load(S390_lowcore.cregs_save_area, 0, 15);
675 __load_psw_mask(PSW_KERNEL_BITS | PSW_MASK_DAT);
681 notify_cpu_starting(smp_processor_id());
682 set_cpu_online(smp_processor_id(), true);
683 inc_irq_stat(CPU_RST);
685 cpu_startup_entry(CPUHP_ONLINE);
688 /* Upping and downing of CPUs */
689 int __cpu_up(unsigned int cpu, struct task_struct *tidle)
694 pcpu = pcpu_devices + cpu;
695 if (pcpu->state != CPU_STATE_CONFIGURED)
697 if (pcpu_sigp_retry(pcpu, SIGP_INITIAL_CPU_RESET, 0) !=
698 SIGP_CC_ORDER_CODE_ACCEPTED)
701 rc = pcpu_alloc_lowcore(pcpu, cpu);
704 pcpu_prepare_secondary(pcpu, cpu);
705 pcpu_attach_task(pcpu, tidle);
706 pcpu_start_fn(pcpu, smp_start_secondary, NULL);
707 while (!cpu_online(cpu))
712 static unsigned int setup_possible_cpus __initdata;
714 static int __init _setup_possible_cpus(char *s)
716 get_option(&s, &setup_possible_cpus);
719 early_param("possible_cpus", _setup_possible_cpus);
721 #ifdef CONFIG_HOTPLUG_CPU
723 int __cpu_disable(void)
725 unsigned long cregs[16];
727 /* Handle possible pending IPIs */
728 smp_handle_ext_call();
729 set_cpu_online(smp_processor_id(), false);
730 /* Disable pseudo page faults on this cpu. */
732 /* Disable interrupt sources via control register. */
733 __ctl_store(cregs, 0, 15);
734 cregs[0] &= ~0x0000ee70UL; /* disable all external interrupts */
735 cregs[6] &= ~0xff000000UL; /* disable all I/O interrupts */
736 cregs[14] &= ~0x1f000000UL; /* disable most machine checks */
737 __ctl_load(cregs, 0, 15);
741 void __cpu_die(unsigned int cpu)
745 /* Wait until target cpu is down */
746 pcpu = pcpu_devices + cpu;
747 while (!pcpu_stopped(pcpu))
749 pcpu_free_lowcore(pcpu);
750 atomic_dec(&init_mm.context.attach_count);
751 cpumask_clear_cpu(cpu, mm_cpumask(&init_mm));
752 if (MACHINE_HAS_TLB_LC)
753 cpumask_clear_cpu(cpu, &init_mm.context.cpu_attach_mask);
756 void __noreturn cpu_die(void)
759 pcpu_sigp_retry(pcpu_devices + smp_processor_id(), SIGP_STOP, 0);
763 #endif /* CONFIG_HOTPLUG_CPU */
765 void __init smp_fill_possible_mask(void)
767 unsigned int possible, sclp, cpu;
769 sclp = sclp_get_max_cpu() ?: nr_cpu_ids;
770 possible = setup_possible_cpus ?: nr_cpu_ids;
771 possible = min(possible, sclp);
772 for (cpu = 0; cpu < possible && cpu < nr_cpu_ids; cpu++)
773 set_cpu_possible(cpu, true);
776 void __init smp_prepare_cpus(unsigned int max_cpus)
778 /* request the 0x1201 emergency signal external interrupt */
779 if (register_external_irq(EXT_IRQ_EMERGENCY_SIG, do_ext_call_interrupt))
780 panic("Couldn't request external interrupt 0x1201");
781 /* request the 0x1202 external call external interrupt */
782 if (register_external_irq(EXT_IRQ_EXTERNAL_CALL, do_ext_call_interrupt))
783 panic("Couldn't request external interrupt 0x1202");
787 void __init smp_prepare_boot_cpu(void)
789 struct pcpu *pcpu = pcpu_devices;
791 boot_cpu_address = stap();
792 pcpu->state = CPU_STATE_CONFIGURED;
793 pcpu->address = boot_cpu_address;
794 pcpu->lowcore = (struct _lowcore *)(unsigned long) store_prefix();
795 pcpu->async_stack = S390_lowcore.async_stack - ASYNC_SIZE
796 + STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
797 pcpu->panic_stack = S390_lowcore.panic_stack - PAGE_SIZE
798 + STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
799 S390_lowcore.percpu_offset = __per_cpu_offset[0];
800 smp_cpu_set_polarization(0, POLARIZATION_UNKNOWN);
801 set_cpu_present(0, true);
802 set_cpu_online(0, true);
805 void __init smp_cpus_done(unsigned int max_cpus)
809 void __init smp_setup_processor_id(void)
811 S390_lowcore.cpu_nr = 0;
815 * the frequency of the profiling timer can be changed
816 * by writing a multiplier value into /proc/profile.
818 * usually you want to run this on all CPUs ;)
820 int setup_profiling_timer(unsigned int multiplier)
825 #ifdef CONFIG_HOTPLUG_CPU
826 static ssize_t cpu_configure_show(struct device *dev,
827 struct device_attribute *attr, char *buf)
831 mutex_lock(&smp_cpu_state_mutex);
832 count = sprintf(buf, "%d\n", pcpu_devices[dev->id].state);
833 mutex_unlock(&smp_cpu_state_mutex);
837 static ssize_t cpu_configure_store(struct device *dev,
838 struct device_attribute *attr,
839 const char *buf, size_t count)
845 if (sscanf(buf, "%d %c", &val, &delim) != 1)
847 if (val != 0 && val != 1)
850 mutex_lock(&smp_cpu_state_mutex);
852 /* disallow configuration changes of online cpus and cpu 0 */
854 if (cpu_online(cpu) || cpu == 0)
856 pcpu = pcpu_devices + cpu;
860 if (pcpu->state != CPU_STATE_CONFIGURED)
862 rc = sclp_cpu_deconfigure(pcpu->address);
865 pcpu->state = CPU_STATE_STANDBY;
866 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
867 topology_expect_change();
870 if (pcpu->state != CPU_STATE_STANDBY)
872 rc = sclp_cpu_configure(pcpu->address);
875 pcpu->state = CPU_STATE_CONFIGURED;
876 smp_cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
877 topology_expect_change();
883 mutex_unlock(&smp_cpu_state_mutex);
885 return rc ? rc : count;
887 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
888 #endif /* CONFIG_HOTPLUG_CPU */
890 static ssize_t show_cpu_address(struct device *dev,
891 struct device_attribute *attr, char *buf)
893 return sprintf(buf, "%d\n", pcpu_devices[dev->id].address);
895 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
897 static struct attribute *cpu_common_attrs[] = {
898 #ifdef CONFIG_HOTPLUG_CPU
899 &dev_attr_configure.attr,
901 &dev_attr_address.attr,
905 static struct attribute_group cpu_common_attr_group = {
906 .attrs = cpu_common_attrs,
909 static ssize_t show_idle_count(struct device *dev,
910 struct device_attribute *attr, char *buf)
912 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
913 unsigned long long idle_count;
914 unsigned int sequence;
917 sequence = ACCESS_ONCE(idle->sequence);
918 idle_count = ACCESS_ONCE(idle->idle_count);
919 if (ACCESS_ONCE(idle->clock_idle_enter))
921 } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
922 return sprintf(buf, "%llu\n", idle_count);
924 static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
926 static ssize_t show_idle_time(struct device *dev,
927 struct device_attribute *attr, char *buf)
929 struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
930 unsigned long long now, idle_time, idle_enter, idle_exit;
931 unsigned int sequence;
934 now = get_tod_clock();
935 sequence = ACCESS_ONCE(idle->sequence);
936 idle_time = ACCESS_ONCE(idle->idle_time);
937 idle_enter = ACCESS_ONCE(idle->clock_idle_enter);
938 idle_exit = ACCESS_ONCE(idle->clock_idle_exit);
939 } while ((sequence & 1) || (ACCESS_ONCE(idle->sequence) != sequence));
940 idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
941 return sprintf(buf, "%llu\n", idle_time >> 12);
943 static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
945 static struct attribute *cpu_online_attrs[] = {
946 &dev_attr_idle_count.attr,
947 &dev_attr_idle_time_us.attr,
951 static struct attribute_group cpu_online_attr_group = {
952 .attrs = cpu_online_attrs,
955 static int smp_cpu_notify(struct notifier_block *self, unsigned long action,
958 unsigned int cpu = (unsigned int)(long)hcpu;
959 struct cpu *c = pcpu_devices[cpu].cpu;
960 struct device *s = &c->dev;
963 switch (action & ~CPU_TASKS_FROZEN) {
965 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
968 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
971 return notifier_from_errno(err);
974 static int smp_add_present_cpu(int cpu)
980 c = kzalloc(sizeof(*c), GFP_KERNEL);
983 pcpu_devices[cpu].cpu = c;
986 rc = register_cpu(c, cpu);
989 rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
992 if (cpu_online(cpu)) {
993 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
997 rc = topology_cpu_init(c);
1003 if (cpu_online(cpu))
1004 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1006 sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1008 #ifdef CONFIG_HOTPLUG_CPU
1015 #ifdef CONFIG_HOTPLUG_CPU
1017 int __ref smp_rescan_cpus(void)
1019 struct sclp_cpu_info *info;
1022 info = smp_get_cpu_info();
1026 mutex_lock(&smp_cpu_state_mutex);
1027 nr = __smp_rescan_cpus(info, 1);
1028 mutex_unlock(&smp_cpu_state_mutex);
1032 topology_schedule_update();
1036 static ssize_t __ref rescan_store(struct device *dev,
1037 struct device_attribute *attr,
1043 rc = smp_rescan_cpus();
1044 return rc ? rc : count;
1046 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1047 #endif /* CONFIG_HOTPLUG_CPU */
1049 static int __init s390_smp_init(void)
1053 #ifdef CONFIG_HOTPLUG_CPU
1054 rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1058 cpu_notifier_register_begin();
1059 for_each_present_cpu(cpu) {
1060 rc = smp_add_present_cpu(cpu);
1065 __hotcpu_notifier(smp_cpu_notify, 0);
1068 cpu_notifier_register_done();
1071 subsys_initcall(s390_smp_init);