security: optimize avc_audit() common path
[linux-2.6.git] / arch / s390 / kernel / smp.c
1 /*
2  *  arch/s390/kernel/smp.c
3  *
4  *    Copyright IBM Corp. 1999, 2009
5  *    Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
6  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
7  *               Heiko Carstens (heiko.carstens@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  * We work with logical cpu numbering everywhere we can. The only
14  * functions using the real cpu address (got from STAP) are the sigp
15  * functions. For all other functions we use the identity mapping.
16  * That means that cpu_number_map[i] == i for every cpu. cpu_number_map is
17  * used e.g. to find the idle task belonging to a logical cpu. Every array
18  * in the kernel is sorted by the logical cpu number and not by the physical
19  * one which is causing all the confusion with __cpu_logical_map and
20  * cpu_number_map in other architectures.
21  */
22
23 #define KMSG_COMPONENT "cpu"
24 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
25
26 #include <linux/workqueue.h>
27 #include <linux/module.h>
28 #include <linux/init.h>
29 #include <linux/mm.h>
30 #include <linux/err.h>
31 #include <linux/spinlock.h>
32 #include <linux/kernel_stat.h>
33 #include <linux/delay.h>
34 #include <linux/cache.h>
35 #include <linux/interrupt.h>
36 #include <linux/irqflags.h>
37 #include <linux/cpu.h>
38 #include <linux/timex.h>
39 #include <linux/bootmem.h>
40 #include <linux/slab.h>
41 #include <linux/crash_dump.h>
42 #include <asm/asm-offsets.h>
43 #include <asm/ipl.h>
44 #include <asm/setup.h>
45 #include <asm/sigp.h>
46 #include <asm/pgalloc.h>
47 #include <asm/irq.h>
48 #include <asm/cpcmd.h>
49 #include <asm/tlbflush.h>
50 #include <asm/timer.h>
51 #include <asm/lowcore.h>
52 #include <asm/sclp.h>
53 #include <asm/cputime.h>
54 #include <asm/vdso.h>
55 #include <asm/cpu.h>
56 #include "entry.h"
57
58 /* logical cpu to cpu address */
59 unsigned short __cpu_logical_map[NR_CPUS];
60
61 static struct task_struct *current_set[NR_CPUS];
62
63 static u8 smp_cpu_type;
64 static int smp_use_sigp_detection;
65
66 enum s390_cpu_state {
67         CPU_STATE_STANDBY,
68         CPU_STATE_CONFIGURED,
69 };
70
71 DEFINE_MUTEX(smp_cpu_state_mutex);
72 static int smp_cpu_state[NR_CPUS];
73
74 static DEFINE_PER_CPU(struct cpu, cpu_devices);
75
76 static void smp_ext_bitcall(int, int);
77
78 static int raw_cpu_stopped(int cpu)
79 {
80         u32 status;
81
82         switch (raw_sigp_ps(&status, 0, cpu, sigp_sense)) {
83         case sigp_status_stored:
84                 /* Check for stopped and check stop state */
85                 if (status & 0x50)
86                         return 1;
87                 break;
88         default:
89                 break;
90         }
91         return 0;
92 }
93
94 static inline int cpu_stopped(int cpu)
95 {
96         return raw_cpu_stopped(cpu_logical_map(cpu));
97 }
98
99 /*
100  * Ensure that PSW restart is done on an online CPU
101  */
102 void smp_restart_with_online_cpu(void)
103 {
104         int cpu;
105
106         for_each_online_cpu(cpu) {
107                 if (stap() == __cpu_logical_map[cpu]) {
108                         /* We are online: Enable DAT again and return */
109                         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
110                         return;
111                 }
112         }
113         /* We are not online: Do PSW restart on an online CPU */
114         while (sigp(cpu, sigp_restart) == sigp_busy)
115                 cpu_relax();
116         /* And stop ourself */
117         while (raw_sigp(stap(), sigp_stop) == sigp_busy)
118                 cpu_relax();
119         for (;;);
120 }
121
122 void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
123 {
124         struct _lowcore *lc, *current_lc;
125         struct stack_frame *sf;
126         struct pt_regs *regs;
127         unsigned long sp;
128
129         if (smp_processor_id() == 0)
130                 func(data);
131         __load_psw_mask(PSW_DEFAULT_KEY | PSW_MASK_BASE |
132                         PSW_MASK_EA | PSW_MASK_BA);
133         /* Disable lowcore protection */
134         __ctl_clear_bit(0, 28);
135         current_lc = lowcore_ptr[smp_processor_id()];
136         lc = lowcore_ptr[0];
137         if (!lc)
138                 lc = current_lc;
139         lc->restart_psw.mask =
140                 PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_EA | PSW_MASK_BA;
141         lc->restart_psw.addr = PSW_ADDR_AMODE | (unsigned long) smp_restart_cpu;
142         if (!cpu_online(0))
143                 smp_switch_to_cpu(func, data, 0, stap(), __cpu_logical_map[0]);
144         while (sigp(0, sigp_stop_and_store_status) == sigp_busy)
145                 cpu_relax();
146         sp = lc->panic_stack;
147         sp -= sizeof(struct pt_regs);
148         regs = (struct pt_regs *) sp;
149         memcpy(&regs->gprs, &current_lc->gpregs_save_area, sizeof(regs->gprs));
150         regs->psw = current_lc->psw_save_area;
151         sp -= STACK_FRAME_OVERHEAD;
152         sf = (struct stack_frame *) sp;
153         sf->back_chain = 0;
154         smp_switch_to_cpu(func, data, sp, stap(), __cpu_logical_map[0]);
155 }
156
157 static void smp_stop_cpu(void)
158 {
159         while (sigp(smp_processor_id(), sigp_stop) == sigp_busy)
160                 cpu_relax();
161 }
162
163 void smp_send_stop(void)
164 {
165         cpumask_t cpumask;
166         int cpu;
167         u64 end;
168
169         /* Disable all interrupts/machine checks */
170         __load_psw_mask(psw_kernel_bits | PSW_MASK_DAT);
171         trace_hardirqs_off();
172
173         cpumask_copy(&cpumask, cpu_online_mask);
174         cpumask_clear_cpu(smp_processor_id(), &cpumask);
175
176         if (oops_in_progress) {
177                 /*
178                  * Give the other cpus the opportunity to complete
179                  * outstanding interrupts before stopping them.
180                  */
181                 end = get_clock() + (1000000UL << 12);
182                 for_each_cpu(cpu, &cpumask) {
183                         set_bit(ec_stop_cpu, (unsigned long *)
184                                 &lowcore_ptr[cpu]->ext_call_fast);
185                         while (sigp(cpu, sigp_emergency_signal) == sigp_busy &&
186                                get_clock() < end)
187                                 cpu_relax();
188                 }
189                 while (get_clock() < end) {
190                         for_each_cpu(cpu, &cpumask)
191                                 if (cpu_stopped(cpu))
192                                         cpumask_clear_cpu(cpu, &cpumask);
193                         if (cpumask_empty(&cpumask))
194                                 break;
195                         cpu_relax();
196                 }
197         }
198
199         /* stop all processors */
200         for_each_cpu(cpu, &cpumask) {
201                 while (sigp(cpu, sigp_stop) == sigp_busy)
202                         cpu_relax();
203                 while (!cpu_stopped(cpu))
204                         cpu_relax();
205         }
206 }
207
208 /*
209  * This is the main routine where commands issued by other
210  * cpus are handled.
211  */
212
213 static void do_ext_call_interrupt(unsigned int ext_int_code,
214                                   unsigned int param32, unsigned long param64)
215 {
216         unsigned long bits;
217
218         if ((ext_int_code & 0xffff) == 0x1202)
219                 kstat_cpu(smp_processor_id()).irqs[EXTINT_EXC]++;
220         else
221                 kstat_cpu(smp_processor_id()).irqs[EXTINT_EMS]++;
222         /*
223          * handle bit signal external calls
224          */
225         bits = xchg(&S390_lowcore.ext_call_fast, 0);
226
227         if (test_bit(ec_stop_cpu, &bits))
228                 smp_stop_cpu();
229
230         if (test_bit(ec_schedule, &bits))
231                 scheduler_ipi();
232
233         if (test_bit(ec_call_function, &bits))
234                 generic_smp_call_function_interrupt();
235
236         if (test_bit(ec_call_function_single, &bits))
237                 generic_smp_call_function_single_interrupt();
238
239 }
240
241 /*
242  * Send an external call sigp to another cpu and return without waiting
243  * for its completion.
244  */
245 static void smp_ext_bitcall(int cpu, int sig)
246 {
247         int order;
248
249         /*
250          * Set signaling bit in lowcore of target cpu and kick it
251          */
252         set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
253         while (1) {
254                 order = smp_vcpu_scheduled(cpu) ?
255                         sigp_external_call : sigp_emergency_signal;
256                 if (sigp(cpu, order) != sigp_busy)
257                         break;
258                 udelay(10);
259         }
260 }
261
262 void arch_send_call_function_ipi_mask(const struct cpumask *mask)
263 {
264         int cpu;
265
266         for_each_cpu(cpu, mask)
267                 smp_ext_bitcall(cpu, ec_call_function);
268 }
269
270 void arch_send_call_function_single_ipi(int cpu)
271 {
272         smp_ext_bitcall(cpu, ec_call_function_single);
273 }
274
275 #ifndef CONFIG_64BIT
276 /*
277  * this function sends a 'purge tlb' signal to another CPU.
278  */
279 static void smp_ptlb_callback(void *info)
280 {
281         __tlb_flush_local();
282 }
283
284 void smp_ptlb_all(void)
285 {
286         on_each_cpu(smp_ptlb_callback, NULL, 1);
287 }
288 EXPORT_SYMBOL(smp_ptlb_all);
289 #endif /* ! CONFIG_64BIT */
290
291 /*
292  * this function sends a 'reschedule' IPI to another CPU.
293  * it goes straight through and wastes no time serializing
294  * anything. Worst case is that we lose a reschedule ...
295  */
296 void smp_send_reschedule(int cpu)
297 {
298         smp_ext_bitcall(cpu, ec_schedule);
299 }
300
301 /*
302  * parameter area for the set/clear control bit callbacks
303  */
304 struct ec_creg_mask_parms {
305         unsigned long orvals[16];
306         unsigned long andvals[16];
307 };
308
309 /*
310  * callback for setting/clearing control bits
311  */
312 static void smp_ctl_bit_callback(void *info)
313 {
314         struct ec_creg_mask_parms *pp = info;
315         unsigned long cregs[16];
316         int i;
317
318         __ctl_store(cregs, 0, 15);
319         for (i = 0; i <= 15; i++)
320                 cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
321         __ctl_load(cregs, 0, 15);
322 }
323
324 /*
325  * Set a bit in a control register of all cpus
326  */
327 void smp_ctl_set_bit(int cr, int bit)
328 {
329         struct ec_creg_mask_parms parms;
330
331         memset(&parms.orvals, 0, sizeof(parms.orvals));
332         memset(&parms.andvals, 0xff, sizeof(parms.andvals));
333         parms.orvals[cr] = 1UL << bit;
334         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
335 }
336 EXPORT_SYMBOL(smp_ctl_set_bit);
337
338 /*
339  * Clear a bit in a control register of all cpus
340  */
341 void smp_ctl_clear_bit(int cr, int bit)
342 {
343         struct ec_creg_mask_parms parms;
344
345         memset(&parms.orvals, 0, sizeof(parms.orvals));
346         memset(&parms.andvals, 0xff, sizeof(parms.andvals));
347         parms.andvals[cr] = ~(1UL << bit);
348         on_each_cpu(smp_ctl_bit_callback, &parms, 1);
349 }
350 EXPORT_SYMBOL(smp_ctl_clear_bit);
351
352 #if defined(CONFIG_ZFCPDUMP) || defined(CONFIG_CRASH_DUMP)
353
354 static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)
355 {
356         if (ipl_info.type != IPL_TYPE_FCP_DUMP && !OLDMEM_BASE)
357                 return;
358         if (is_kdump_kernel())
359                 return;
360         if (cpu >= NR_CPUS) {
361                 pr_warning("CPU %i exceeds the maximum %i and is excluded from "
362                            "the dump\n", cpu, NR_CPUS - 1);
363                 return;
364         }
365         zfcpdump_save_areas[cpu] = kmalloc(sizeof(struct save_area), GFP_KERNEL);
366         while (raw_sigp(phy_cpu, sigp_stop_and_store_status) == sigp_busy)
367                 cpu_relax();
368         memcpy_real(zfcpdump_save_areas[cpu],
369                     (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
370                     sizeof(struct save_area));
371 }
372
373 struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
374 EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
375
376 #else
377
378 static inline void smp_get_save_area(unsigned int cpu, unsigned int phy_cpu) { }
379
380 #endif /* CONFIG_ZFCPDUMP */
381
382 static int cpu_known(int cpu_id)
383 {
384         int cpu;
385
386         for_each_present_cpu(cpu) {
387                 if (__cpu_logical_map[cpu] == cpu_id)
388                         return 1;
389         }
390         return 0;
391 }
392
393 static int smp_rescan_cpus_sigp(cpumask_t avail)
394 {
395         int cpu_id, logical_cpu;
396
397         logical_cpu = cpumask_first(&avail);
398         if (logical_cpu >= nr_cpu_ids)
399                 return 0;
400         for (cpu_id = 0; cpu_id <= MAX_CPU_ADDRESS; cpu_id++) {
401                 if (cpu_known(cpu_id))
402                         continue;
403                 __cpu_logical_map[logical_cpu] = cpu_id;
404                 cpu_set_polarization(logical_cpu, POLARIZATION_UNKNOWN);
405                 if (!cpu_stopped(logical_cpu))
406                         continue;
407                 set_cpu_present(logical_cpu, true);
408                 smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
409                 logical_cpu = cpumask_next(logical_cpu, &avail);
410                 if (logical_cpu >= nr_cpu_ids)
411                         break;
412         }
413         return 0;
414 }
415
416 static int smp_rescan_cpus_sclp(cpumask_t avail)
417 {
418         struct sclp_cpu_info *info;
419         int cpu_id, logical_cpu, cpu;
420         int rc;
421
422         logical_cpu = cpumask_first(&avail);
423         if (logical_cpu >= nr_cpu_ids)
424                 return 0;
425         info = kmalloc(sizeof(*info), GFP_KERNEL);
426         if (!info)
427                 return -ENOMEM;
428         rc = sclp_get_cpu_info(info);
429         if (rc)
430                 goto out;
431         for (cpu = 0; cpu < info->combined; cpu++) {
432                 if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
433                         continue;
434                 cpu_id = info->cpu[cpu].address;
435                 if (cpu_known(cpu_id))
436                         continue;
437                 __cpu_logical_map[logical_cpu] = cpu_id;
438                 cpu_set_polarization(logical_cpu, POLARIZATION_UNKNOWN);
439                 set_cpu_present(logical_cpu, true);
440                 if (cpu >= info->configured)
441                         smp_cpu_state[logical_cpu] = CPU_STATE_STANDBY;
442                 else
443                         smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
444                 logical_cpu = cpumask_next(logical_cpu, &avail);
445                 if (logical_cpu >= nr_cpu_ids)
446                         break;
447         }
448 out:
449         kfree(info);
450         return rc;
451 }
452
453 static int __smp_rescan_cpus(void)
454 {
455         cpumask_t avail;
456
457         cpumask_xor(&avail, cpu_possible_mask, cpu_present_mask);
458         if (smp_use_sigp_detection)
459                 return smp_rescan_cpus_sigp(avail);
460         else
461                 return smp_rescan_cpus_sclp(avail);
462 }
463
464 static void __init smp_detect_cpus(void)
465 {
466         unsigned int cpu, c_cpus, s_cpus;
467         struct sclp_cpu_info *info;
468         u16 boot_cpu_addr, cpu_addr;
469
470         c_cpus = 1;
471         s_cpus = 0;
472         boot_cpu_addr = __cpu_logical_map[0];
473         info = kmalloc(sizeof(*info), GFP_KERNEL);
474         if (!info)
475                 panic("smp_detect_cpus failed to allocate memory\n");
476 #ifdef CONFIG_CRASH_DUMP
477         if (OLDMEM_BASE && !is_kdump_kernel()) {
478                 struct save_area *save_area;
479
480                 save_area = kmalloc(sizeof(*save_area), GFP_KERNEL);
481                 if (!save_area)
482                         panic("could not allocate memory for save area\n");
483                 copy_oldmem_page(1, (void *) save_area, sizeof(*save_area),
484                                  0x200, 0);
485                 zfcpdump_save_areas[0] = save_area;
486         }
487 #endif
488         /* Use sigp detection algorithm if sclp doesn't work. */
489         if (sclp_get_cpu_info(info)) {
490                 smp_use_sigp_detection = 1;
491                 for (cpu = 0; cpu <= MAX_CPU_ADDRESS; cpu++) {
492                         if (cpu == boot_cpu_addr)
493                                 continue;
494                         if (!raw_cpu_stopped(cpu))
495                                 continue;
496                         smp_get_save_area(c_cpus, cpu);
497                         c_cpus++;
498                 }
499                 goto out;
500         }
501
502         if (info->has_cpu_type) {
503                 for (cpu = 0; cpu < info->combined; cpu++) {
504                         if (info->cpu[cpu].address == boot_cpu_addr) {
505                                 smp_cpu_type = info->cpu[cpu].type;
506                                 break;
507                         }
508                 }
509         }
510
511         for (cpu = 0; cpu < info->combined; cpu++) {
512                 if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
513                         continue;
514                 cpu_addr = info->cpu[cpu].address;
515                 if (cpu_addr == boot_cpu_addr)
516                         continue;
517                 if (!raw_cpu_stopped(cpu_addr)) {
518                         s_cpus++;
519                         continue;
520                 }
521                 smp_get_save_area(c_cpus, cpu_addr);
522                 c_cpus++;
523         }
524 out:
525         kfree(info);
526         pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
527         get_online_cpus();
528         __smp_rescan_cpus();
529         put_online_cpus();
530 }
531
532 /*
533  *      Activate a secondary processor.
534  */
535 int __cpuinit start_secondary(void *cpuvoid)
536 {
537         cpu_init();
538         preempt_disable();
539         init_cpu_timer();
540         init_cpu_vtimer();
541         pfault_init();
542
543         notify_cpu_starting(smp_processor_id());
544         ipi_call_lock();
545         set_cpu_online(smp_processor_id(), true);
546         ipi_call_unlock();
547         __ctl_clear_bit(0, 28); /* Disable lowcore protection */
548         S390_lowcore.restart_psw.mask =
549                 PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_EA | PSW_MASK_BA;
550         S390_lowcore.restart_psw.addr =
551                 PSW_ADDR_AMODE | (unsigned long) psw_restart_int_handler;
552         __ctl_set_bit(0, 28); /* Enable lowcore protection */
553         local_irq_enable();
554         /* cpu_idle will call schedule for us */
555         cpu_idle();
556         return 0;
557 }
558
559 struct create_idle {
560         struct work_struct work;
561         struct task_struct *idle;
562         struct completion done;
563         int cpu;
564 };
565
566 static void __cpuinit smp_fork_idle(struct work_struct *work)
567 {
568         struct create_idle *c_idle;
569
570         c_idle = container_of(work, struct create_idle, work);
571         c_idle->idle = fork_idle(c_idle->cpu);
572         complete(&c_idle->done);
573 }
574
575 static int __cpuinit smp_alloc_lowcore(int cpu)
576 {
577         unsigned long async_stack, panic_stack;
578         struct _lowcore *lowcore;
579
580         lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
581         if (!lowcore)
582                 return -ENOMEM;
583         async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
584         panic_stack = __get_free_page(GFP_KERNEL);
585         if (!panic_stack || !async_stack)
586                 goto out;
587         memcpy(lowcore, &S390_lowcore, 512);
588         memset((char *)lowcore + 512, 0, sizeof(*lowcore) - 512);
589         lowcore->async_stack = async_stack + ASYNC_SIZE;
590         lowcore->panic_stack = panic_stack + PAGE_SIZE;
591         lowcore->restart_psw.mask =
592                 PSW_DEFAULT_KEY | PSW_MASK_BASE | PSW_MASK_EA | PSW_MASK_BA;
593         lowcore->restart_psw.addr =
594                 PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
595         if (user_mode != HOME_SPACE_MODE)
596                 lowcore->restart_psw.mask |= PSW_ASC_HOME;
597 #ifndef CONFIG_64BIT
598         if (MACHINE_HAS_IEEE) {
599                 unsigned long save_area;
600
601                 save_area = get_zeroed_page(GFP_KERNEL);
602                 if (!save_area)
603                         goto out;
604                 lowcore->extended_save_area_addr = (u32) save_area;
605         }
606 #else
607         if (vdso_alloc_per_cpu(cpu, lowcore))
608                 goto out;
609 #endif
610         lowcore_ptr[cpu] = lowcore;
611         return 0;
612
613 out:
614         free_page(panic_stack);
615         free_pages(async_stack, ASYNC_ORDER);
616         free_pages((unsigned long) lowcore, LC_ORDER);
617         return -ENOMEM;
618 }
619
620 static void smp_free_lowcore(int cpu)
621 {
622         struct _lowcore *lowcore;
623
624         lowcore = lowcore_ptr[cpu];
625 #ifndef CONFIG_64BIT
626         if (MACHINE_HAS_IEEE)
627                 free_page((unsigned long) lowcore->extended_save_area_addr);
628 #else
629         vdso_free_per_cpu(cpu, lowcore);
630 #endif
631         free_page(lowcore->panic_stack - PAGE_SIZE);
632         free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
633         free_pages((unsigned long) lowcore, LC_ORDER);
634         lowcore_ptr[cpu] = NULL;
635 }
636
637 /* Upping and downing of CPUs */
638 int __cpuinit __cpu_up(unsigned int cpu)
639 {
640         struct _lowcore *cpu_lowcore;
641         struct create_idle c_idle;
642         struct task_struct *idle;
643         struct stack_frame *sf;
644         u32 lowcore;
645         int ccode;
646
647         if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
648                 return -EIO;
649         idle = current_set[cpu];
650         if (!idle) {
651                 c_idle.done = COMPLETION_INITIALIZER_ONSTACK(c_idle.done);
652                 INIT_WORK_ONSTACK(&c_idle.work, smp_fork_idle);
653                 c_idle.cpu = cpu;
654                 schedule_work(&c_idle.work);
655                 wait_for_completion(&c_idle.done);
656                 if (IS_ERR(c_idle.idle))
657                         return PTR_ERR(c_idle.idle);
658                 idle = c_idle.idle;
659                 current_set[cpu] = c_idle.idle;
660         }
661         init_idle(idle, cpu);
662         if (smp_alloc_lowcore(cpu))
663                 return -ENOMEM;
664         do {
665                 ccode = sigp(cpu, sigp_initial_cpu_reset);
666                 if (ccode == sigp_busy)
667                         udelay(10);
668                 if (ccode == sigp_not_operational)
669                         goto err_out;
670         } while (ccode == sigp_busy);
671
672         lowcore = (u32)(unsigned long)lowcore_ptr[cpu];
673         while (sigp_p(lowcore, cpu, sigp_set_prefix) == sigp_busy)
674                 udelay(10);
675
676         cpu_lowcore = lowcore_ptr[cpu];
677         cpu_lowcore->kernel_stack = (unsigned long)
678                 task_stack_page(idle) + THREAD_SIZE;
679         cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
680         sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
681                                      - sizeof(struct pt_regs)
682                                      - sizeof(struct stack_frame));
683         memset(sf, 0, sizeof(struct stack_frame));
684         sf->gprs[9] = (unsigned long) sf;
685         cpu_lowcore->gpregs_save_area[15] = (unsigned long) sf;
686         __ctl_store(cpu_lowcore->cregs_save_area, 0, 15);
687         atomic_inc(&init_mm.context.attach_count);
688         asm volatile(
689                 "       stam    0,15,0(%0)"
690                 : : "a" (&cpu_lowcore->access_regs_save_area) : "memory");
691         cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
692         cpu_lowcore->current_task = (unsigned long) idle;
693         cpu_lowcore->cpu_nr = cpu;
694         cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce;
695         cpu_lowcore->machine_flags = S390_lowcore.machine_flags;
696         cpu_lowcore->ftrace_func = S390_lowcore.ftrace_func;
697         memcpy(cpu_lowcore->stfle_fac_list, S390_lowcore.stfle_fac_list,
698                MAX_FACILITY_BIT/8);
699         eieio();
700
701         while (sigp(cpu, sigp_restart) == sigp_busy)
702                 udelay(10);
703
704         while (!cpu_online(cpu))
705                 cpu_relax();
706         return 0;
707
708 err_out:
709         smp_free_lowcore(cpu);
710         return -EIO;
711 }
712
713 static int __init setup_possible_cpus(char *s)
714 {
715         int pcpus, cpu;
716
717         pcpus = simple_strtoul(s, NULL, 0);
718         init_cpu_possible(cpumask_of(0));
719         for (cpu = 1; cpu < pcpus && cpu < nr_cpu_ids; cpu++)
720                 set_cpu_possible(cpu, true);
721         return 0;
722 }
723 early_param("possible_cpus", setup_possible_cpus);
724
725 #ifdef CONFIG_HOTPLUG_CPU
726
727 int __cpu_disable(void)
728 {
729         struct ec_creg_mask_parms cr_parms;
730         int cpu = smp_processor_id();
731
732         set_cpu_online(cpu, false);
733
734         /* Disable pfault pseudo page faults on this cpu. */
735         pfault_fini();
736
737         memset(&cr_parms.orvals, 0, sizeof(cr_parms.orvals));
738         memset(&cr_parms.andvals, 0xff, sizeof(cr_parms.andvals));
739
740         /* disable all external interrupts */
741         cr_parms.orvals[0] = 0;
742         cr_parms.andvals[0] = ~(1 << 15 | 1 << 14 | 1 << 13 | 1 << 11 |
743                                 1 << 10 | 1 <<  9 | 1 <<  6 | 1 <<  5 |
744                                 1 <<  4);
745         /* disable all I/O interrupts */
746         cr_parms.orvals[6] = 0;
747         cr_parms.andvals[6] = ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28 |
748                                 1 << 27 | 1 << 26 | 1 << 25 | 1 << 24);
749         /* disable most machine checks */
750         cr_parms.orvals[14] = 0;
751         cr_parms.andvals[14] = ~(1 << 28 | 1 << 27 | 1 << 26 |
752                                  1 << 25 | 1 << 24);
753
754         smp_ctl_bit_callback(&cr_parms);
755
756         return 0;
757 }
758
759 void __cpu_die(unsigned int cpu)
760 {
761         /* Wait until target cpu is down */
762         while (!cpu_stopped(cpu))
763                 cpu_relax();
764         while (sigp_p(0, cpu, sigp_set_prefix) == sigp_busy)
765                 udelay(10);
766         smp_free_lowcore(cpu);
767         atomic_dec(&init_mm.context.attach_count);
768 }
769
770 void __noreturn cpu_die(void)
771 {
772         idle_task_exit();
773         while (sigp(smp_processor_id(), sigp_stop) == sigp_busy)
774                 cpu_relax();
775         for (;;);
776 }
777
778 #endif /* CONFIG_HOTPLUG_CPU */
779
780 void __init smp_prepare_cpus(unsigned int max_cpus)
781 {
782 #ifndef CONFIG_64BIT
783         unsigned long save_area = 0;
784 #endif
785         unsigned long async_stack, panic_stack;
786         struct _lowcore *lowcore;
787
788         smp_detect_cpus();
789
790         /* request the 0x1201 emergency signal external interrupt */
791         if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
792                 panic("Couldn't request external interrupt 0x1201");
793         /* request the 0x1202 external call external interrupt */
794         if (register_external_interrupt(0x1202, do_ext_call_interrupt) != 0)
795                 panic("Couldn't request external interrupt 0x1202");
796
797         /* Reallocate current lowcore, but keep its contents. */
798         lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
799         panic_stack = __get_free_page(GFP_KERNEL);
800         async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
801         BUG_ON(!lowcore || !panic_stack || !async_stack);
802 #ifndef CONFIG_64BIT
803         if (MACHINE_HAS_IEEE)
804                 save_area = get_zeroed_page(GFP_KERNEL);
805 #endif
806         local_irq_disable();
807         local_mcck_disable();
808         lowcore_ptr[smp_processor_id()] = lowcore;
809         *lowcore = S390_lowcore;
810         lowcore->panic_stack = panic_stack + PAGE_SIZE;
811         lowcore->async_stack = async_stack + ASYNC_SIZE;
812 #ifndef CONFIG_64BIT
813         if (MACHINE_HAS_IEEE)
814                 lowcore->extended_save_area_addr = (u32) save_area;
815 #endif
816         set_prefix((u32)(unsigned long) lowcore);
817         local_mcck_enable();
818         local_irq_enable();
819 #ifdef CONFIG_64BIT
820         if (vdso_alloc_per_cpu(smp_processor_id(), &S390_lowcore))
821                 BUG();
822 #endif
823 }
824
825 void __init smp_prepare_boot_cpu(void)
826 {
827         BUG_ON(smp_processor_id() != 0);
828
829         current_thread_info()->cpu = 0;
830         set_cpu_present(0, true);
831         set_cpu_online(0, true);
832         S390_lowcore.percpu_offset = __per_cpu_offset[0];
833         current_set[0] = current;
834         smp_cpu_state[0] = CPU_STATE_CONFIGURED;
835         cpu_set_polarization(0, POLARIZATION_UNKNOWN);
836 }
837
838 void __init smp_cpus_done(unsigned int max_cpus)
839 {
840 }
841
842 void __init smp_setup_processor_id(void)
843 {
844         S390_lowcore.cpu_nr = 0;
845         __cpu_logical_map[0] = stap();
846 }
847
848 /*
849  * the frequency of the profiling timer can be changed
850  * by writing a multiplier value into /proc/profile.
851  *
852  * usually you want to run this on all CPUs ;)
853  */
854 int setup_profiling_timer(unsigned int multiplier)
855 {
856         return 0;
857 }
858
859 #ifdef CONFIG_HOTPLUG_CPU
860 static ssize_t cpu_configure_show(struct device *dev,
861                                 struct device_attribute *attr, char *buf)
862 {
863         ssize_t count;
864
865         mutex_lock(&smp_cpu_state_mutex);
866         count = sprintf(buf, "%d\n", smp_cpu_state[dev->id]);
867         mutex_unlock(&smp_cpu_state_mutex);
868         return count;
869 }
870
871 static ssize_t cpu_configure_store(struct device *dev,
872                                   struct device_attribute *attr,
873                                   const char *buf, size_t count)
874 {
875         int cpu = dev->id;
876         int val, rc;
877         char delim;
878
879         if (sscanf(buf, "%d %c", &val, &delim) != 1)
880                 return -EINVAL;
881         if (val != 0 && val != 1)
882                 return -EINVAL;
883
884         get_online_cpus();
885         mutex_lock(&smp_cpu_state_mutex);
886         rc = -EBUSY;
887         /* disallow configuration changes of online cpus and cpu 0 */
888         if (cpu_online(cpu) || cpu == 0)
889                 goto out;
890         rc = 0;
891         switch (val) {
892         case 0:
893                 if (smp_cpu_state[cpu] == CPU_STATE_CONFIGURED) {
894                         rc = sclp_cpu_deconfigure(__cpu_logical_map[cpu]);
895                         if (!rc) {
896                                 smp_cpu_state[cpu] = CPU_STATE_STANDBY;
897                                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
898                                 topology_expect_change();
899                         }
900                 }
901                 break;
902         case 1:
903                 if (smp_cpu_state[cpu] == CPU_STATE_STANDBY) {
904                         rc = sclp_cpu_configure(__cpu_logical_map[cpu]);
905                         if (!rc) {
906                                 smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;
907                                 cpu_set_polarization(cpu, POLARIZATION_UNKNOWN);
908                                 topology_expect_change();
909                         }
910                 }
911                 break;
912         default:
913                 break;
914         }
915 out:
916         mutex_unlock(&smp_cpu_state_mutex);
917         put_online_cpus();
918         return rc ? rc : count;
919 }
920 static DEVICE_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
921 #endif /* CONFIG_HOTPLUG_CPU */
922
923 static ssize_t show_cpu_address(struct device *dev,
924                                 struct device_attribute *attr, char *buf)
925 {
926         return sprintf(buf, "%d\n", __cpu_logical_map[dev->id]);
927 }
928 static DEVICE_ATTR(address, 0444, show_cpu_address, NULL);
929
930 static struct attribute *cpu_common_attrs[] = {
931 #ifdef CONFIG_HOTPLUG_CPU
932         &dev_attr_configure.attr,
933 #endif
934         &dev_attr_address.attr,
935         NULL,
936 };
937
938 static struct attribute_group cpu_common_attr_group = {
939         .attrs = cpu_common_attrs,
940 };
941
942 static ssize_t show_capability(struct device *dev,
943                                 struct device_attribute *attr, char *buf)
944 {
945         unsigned int capability;
946         int rc;
947
948         rc = get_cpu_capability(&capability);
949         if (rc)
950                 return rc;
951         return sprintf(buf, "%u\n", capability);
952 }
953 static DEVICE_ATTR(capability, 0444, show_capability, NULL);
954
955 static ssize_t show_idle_count(struct device *dev,
956                                 struct device_attribute *attr, char *buf)
957 {
958         struct s390_idle_data *idle;
959         unsigned long long idle_count;
960         unsigned int sequence;
961
962         idle = &per_cpu(s390_idle, dev->id);
963 repeat:
964         sequence = idle->sequence;
965         smp_rmb();
966         if (sequence & 1)
967                 goto repeat;
968         idle_count = idle->idle_count;
969         if (idle->idle_enter)
970                 idle_count++;
971         smp_rmb();
972         if (idle->sequence != sequence)
973                 goto repeat;
974         return sprintf(buf, "%llu\n", idle_count);
975 }
976 static DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
977
978 static ssize_t show_idle_time(struct device *dev,
979                                 struct device_attribute *attr, char *buf)
980 {
981         struct s390_idle_data *idle;
982         unsigned long long now, idle_time, idle_enter;
983         unsigned int sequence;
984
985         idle = &per_cpu(s390_idle, dev->id);
986         now = get_clock();
987 repeat:
988         sequence = idle->sequence;
989         smp_rmb();
990         if (sequence & 1)
991                 goto repeat;
992         idle_time = idle->idle_time;
993         idle_enter = idle->idle_enter;
994         if (idle_enter != 0ULL && idle_enter < now)
995                 idle_time += now - idle_enter;
996         smp_rmb();
997         if (idle->sequence != sequence)
998                 goto repeat;
999         return sprintf(buf, "%llu\n", idle_time >> 12);
1000 }
1001 static DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
1002
1003 static struct attribute *cpu_online_attrs[] = {
1004         &dev_attr_capability.attr,
1005         &dev_attr_idle_count.attr,
1006         &dev_attr_idle_time_us.attr,
1007         NULL,
1008 };
1009
1010 static struct attribute_group cpu_online_attr_group = {
1011         .attrs = cpu_online_attrs,
1012 };
1013
1014 static int __cpuinit smp_cpu_notify(struct notifier_block *self,
1015                                     unsigned long action, void *hcpu)
1016 {
1017         unsigned int cpu = (unsigned int)(long)hcpu;
1018         struct cpu *c = &per_cpu(cpu_devices, cpu);
1019         struct device *s = &c->dev;
1020         struct s390_idle_data *idle;
1021         int err = 0;
1022
1023         switch (action) {
1024         case CPU_ONLINE:
1025         case CPU_ONLINE_FROZEN:
1026                 idle = &per_cpu(s390_idle, cpu);
1027                 memset(idle, 0, sizeof(struct s390_idle_data));
1028                 err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1029                 break;
1030         case CPU_DEAD:
1031         case CPU_DEAD_FROZEN:
1032                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1033                 break;
1034         }
1035         return notifier_from_errno(err);
1036 }
1037
1038 static struct notifier_block __cpuinitdata smp_cpu_nb = {
1039         .notifier_call = smp_cpu_notify,
1040 };
1041
1042 static int __devinit smp_add_present_cpu(int cpu)
1043 {
1044         struct cpu *c = &per_cpu(cpu_devices, cpu);
1045         struct device *s = &c->dev;
1046         int rc;
1047
1048         c->hotpluggable = 1;
1049         rc = register_cpu(c, cpu);
1050         if (rc)
1051                 goto out;
1052         rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
1053         if (rc)
1054                 goto out_cpu;
1055         if (cpu_online(cpu)) {
1056                 rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
1057                 if (rc)
1058                         goto out_online;
1059         }
1060         rc = topology_cpu_init(c);
1061         if (rc)
1062                 goto out_topology;
1063         return 0;
1064
1065 out_topology:
1066         if (cpu_online(cpu))
1067                 sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
1068 out_online:
1069         sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
1070 out_cpu:
1071 #ifdef CONFIG_HOTPLUG_CPU
1072         unregister_cpu(c);
1073 #endif
1074 out:
1075         return rc;
1076 }
1077
1078 #ifdef CONFIG_HOTPLUG_CPU
1079
1080 int __ref smp_rescan_cpus(void)
1081 {
1082         cpumask_t newcpus;
1083         int cpu;
1084         int rc;
1085
1086         get_online_cpus();
1087         mutex_lock(&smp_cpu_state_mutex);
1088         cpumask_copy(&newcpus, cpu_present_mask);
1089         rc = __smp_rescan_cpus();
1090         if (rc)
1091                 goto out;
1092         cpumask_andnot(&newcpus, cpu_present_mask, &newcpus);
1093         for_each_cpu(cpu, &newcpus) {
1094                 rc = smp_add_present_cpu(cpu);
1095                 if (rc)
1096                         set_cpu_present(cpu, false);
1097         }
1098         rc = 0;
1099 out:
1100         mutex_unlock(&smp_cpu_state_mutex);
1101         put_online_cpus();
1102         if (!cpumask_empty(&newcpus))
1103                 topology_schedule_update();
1104         return rc;
1105 }
1106
1107 static ssize_t __ref rescan_store(struct device *dev,
1108                                   struct device_attribute *attr,
1109                                   const char *buf,
1110                                   size_t count)
1111 {
1112         int rc;
1113
1114         rc = smp_rescan_cpus();
1115         return rc ? rc : count;
1116 }
1117 static DEVICE_ATTR(rescan, 0200, NULL, rescan_store);
1118 #endif /* CONFIG_HOTPLUG_CPU */
1119
1120 static int __init s390_smp_init(void)
1121 {
1122         int cpu, rc;
1123
1124         register_cpu_notifier(&smp_cpu_nb);
1125 #ifdef CONFIG_HOTPLUG_CPU
1126         rc = device_create_file(cpu_subsys.dev_root, &dev_attr_rescan);
1127         if (rc)
1128                 return rc;
1129 #endif
1130         for_each_present_cpu(cpu) {
1131                 rc = smp_add_present_cpu(cpu);
1132                 if (rc)
1133                         return rc;
1134         }
1135         return 0;
1136 }
1137 subsys_initcall(s390_smp_init);