Root/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/module.h>
27#include <linux/init.h>
28#include <linux/mm.h>
29#include <linux/err.h>
30#include <linux/spinlock.h>
31#include <linux/kernel_stat.h>
32#include <linux/delay.h>
33#include <linux/cache.h>
34#include <linux/interrupt.h>
35#include <linux/irqflags.h>
36#include <linux/cpu.h>
37#include <linux/timex.h>
38#include <linux/bootmem.h>
39#include <linux/slab.h>
40#include <asm/asm-offsets.h>
41#include <asm/ipl.h>
42#include <asm/setup.h>
43#include <asm/sigp.h>
44#include <asm/pgalloc.h>
45#include <asm/irq.h>
46#include <asm/s390_ext.h>
47#include <asm/cpcmd.h>
48#include <asm/tlbflush.h>
49#include <asm/timer.h>
50#include <asm/lowcore.h>
51#include <asm/sclp.h>
52#include <asm/cputime.h>
53#include <asm/vdso.h>
54#include <asm/cpu.h>
55#include "entry.h"
56
57/* logical cpu to cpu address */
58unsigned short __cpu_logical_map[NR_CPUS];
59
60static struct task_struct *current_set[NR_CPUS];
61
62static u8 smp_cpu_type;
63static int smp_use_sigp_detection;
64
65enum s390_cpu_state {
66    CPU_STATE_STANDBY,
67    CPU_STATE_CONFIGURED,
68};
69
70DEFINE_MUTEX(smp_cpu_state_mutex);
71int smp_cpu_polarization[NR_CPUS];
72static int smp_cpu_state[NR_CPUS];
73static int cpu_management;
74
75static DEFINE_PER_CPU(struct cpu, cpu_devices);
76
77static void smp_ext_bitcall(int, int);
78
79static int raw_cpu_stopped(int cpu)
80{
81    u32 status;
82
83    switch (raw_sigp_ps(&status, 0, cpu, sigp_sense)) {
84    case sigp_status_stored:
85        /* Check for stopped and check stop state */
86        if (status & 0x50)
87            return 1;
88        break;
89    default:
90        break;
91    }
92    return 0;
93}
94
95static inline int cpu_stopped(int cpu)
96{
97    return raw_cpu_stopped(cpu_logical_map(cpu));
98}
99
100void smp_switch_to_ipl_cpu(void (*func)(void *), void *data)
101{
102    struct _lowcore *lc, *current_lc;
103    struct stack_frame *sf;
104    struct pt_regs *regs;
105    unsigned long sp;
106
107    if (smp_processor_id() == 0)
108        func(data);
109    __load_psw_mask(PSW_BASE_BITS | PSW_DEFAULT_KEY);
110    /* Disable lowcore protection */
111    __ctl_clear_bit(0, 28);
112    current_lc = lowcore_ptr[smp_processor_id()];
113    lc = lowcore_ptr[0];
114    if (!lc)
115        lc = current_lc;
116    lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
117    lc->restart_psw.addr = PSW_ADDR_AMODE | (unsigned long) smp_restart_cpu;
118    if (!cpu_online(0))
119        smp_switch_to_cpu(func, data, 0, stap(), __cpu_logical_map[0]);
120    while (sigp(0, sigp_stop_and_store_status) == sigp_busy)
121        cpu_relax();
122    sp = lc->panic_stack;
123    sp -= sizeof(struct pt_regs);
124    regs = (struct pt_regs *) sp;
125    memcpy(&regs->gprs, &current_lc->gpregs_save_area, sizeof(regs->gprs));
126    regs->psw = lc->psw_save_area;
127    sp -= STACK_FRAME_OVERHEAD;
128    sf = (struct stack_frame *) sp;
129    sf->back_chain = regs->gprs[15];
130    smp_switch_to_cpu(func, data, sp, stap(), __cpu_logical_map[0]);
131}
132
133void smp_send_stop(void)
134{
135    int cpu, rc;
136
137    /* Disable all interrupts/machine checks */
138    __load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
139    trace_hardirqs_off();
140
141    /* stop all processors */
142    for_each_online_cpu(cpu) {
143        if (cpu == smp_processor_id())
144            continue;
145        do {
146            rc = sigp(cpu, sigp_stop);
147        } while (rc == sigp_busy);
148
149        while (!cpu_stopped(cpu))
150            cpu_relax();
151    }
152}
153
154/*
155 * This is the main routine where commands issued by other
156 * cpus are handled.
157 */
158
159static void do_ext_call_interrupt(unsigned int ext_int_code,
160                  unsigned int param32, unsigned long param64)
161{
162    unsigned long bits;
163
164    /*
165     * handle bit signal external calls
166     *
167     * For the ec_schedule signal we have to do nothing. All the work
168     * is done automatically when we return from the interrupt.
169     */
170    bits = xchg(&S390_lowcore.ext_call_fast, 0);
171
172    if (test_bit(ec_call_function, &bits))
173        generic_smp_call_function_interrupt();
174
175    if (test_bit(ec_call_function_single, &bits))
176        generic_smp_call_function_single_interrupt();
177}
178
179/*
180 * Send an external call sigp to another cpu and return without waiting
181 * for its completion.
182 */
183static void smp_ext_bitcall(int cpu, int sig)
184{
185    /*
186     * Set signaling bit in lowcore of target cpu and kick it
187     */
188    set_bit(sig, (unsigned long *) &lowcore_ptr[cpu]->ext_call_fast);
189    while (sigp(cpu, sigp_emergency_signal) == sigp_busy)
190        udelay(10);
191}
192
193void arch_send_call_function_ipi_mask(const struct cpumask *mask)
194{
195    int cpu;
196
197    for_each_cpu(cpu, mask)
198        smp_ext_bitcall(cpu, ec_call_function);
199}
200
201void arch_send_call_function_single_ipi(int cpu)
202{
203    smp_ext_bitcall(cpu, ec_call_function_single);
204}
205
206#ifndef CONFIG_64BIT
207/*
208 * this function sends a 'purge tlb' signal to another CPU.
209 */
210static void smp_ptlb_callback(void *info)
211{
212    __tlb_flush_local();
213}
214
215void smp_ptlb_all(void)
216{
217    on_each_cpu(smp_ptlb_callback, NULL, 1);
218}
219EXPORT_SYMBOL(smp_ptlb_all);
220#endif /* ! CONFIG_64BIT */
221
222/*
223 * this function sends a 'reschedule' IPI to another CPU.
224 * it goes straight through and wastes no time serializing
225 * anything. Worst case is that we lose a reschedule ...
226 */
227void smp_send_reschedule(int cpu)
228{
229    smp_ext_bitcall(cpu, ec_schedule);
230}
231
232/*
233 * parameter area for the set/clear control bit callbacks
234 */
235struct ec_creg_mask_parms {
236    unsigned long orvals[16];
237    unsigned long andvals[16];
238};
239
240/*
241 * callback for setting/clearing control bits
242 */
243static void smp_ctl_bit_callback(void *info)
244{
245    struct ec_creg_mask_parms *pp = info;
246    unsigned long cregs[16];
247    int i;
248
249    __ctl_store(cregs, 0, 15);
250    for (i = 0; i <= 15; i++)
251        cregs[i] = (cregs[i] & pp->andvals[i]) | pp->orvals[i];
252    __ctl_load(cregs, 0, 15);
253}
254
255/*
256 * Set a bit in a control register of all cpus
257 */
258void smp_ctl_set_bit(int cr, int bit)
259{
260    struct ec_creg_mask_parms parms;
261
262    memset(&parms.orvals, 0, sizeof(parms.orvals));
263    memset(&parms.andvals, 0xff, sizeof(parms.andvals));
264    parms.orvals[cr] = 1 << bit;
265    on_each_cpu(smp_ctl_bit_callback, &parms, 1);
266}
267EXPORT_SYMBOL(smp_ctl_set_bit);
268
269/*
270 * Clear a bit in a control register of all cpus
271 */
272void smp_ctl_clear_bit(int cr, int bit)
273{
274    struct ec_creg_mask_parms parms;
275
276    memset(&parms.orvals, 0, sizeof(parms.orvals));
277    memset(&parms.andvals, 0xff, sizeof(parms.andvals));
278    parms.andvals[cr] = ~(1L << bit);
279    on_each_cpu(smp_ctl_bit_callback, &parms, 1);
280}
281EXPORT_SYMBOL(smp_ctl_clear_bit);
282
283#ifdef CONFIG_ZFCPDUMP
284
285static void __init smp_get_save_area(unsigned int cpu, unsigned int phy_cpu)
286{
287    if (ipl_info.type != IPL_TYPE_FCP_DUMP)
288        return;
289    if (cpu >= NR_CPUS) {
290        pr_warning("CPU %i exceeds the maximum %i and is excluded from "
291               "the dump\n", cpu, NR_CPUS - 1);
292        return;
293    }
294    zfcpdump_save_areas[cpu] = kmalloc(sizeof(struct save_area), GFP_KERNEL);
295    while (raw_sigp(phy_cpu, sigp_stop_and_store_status) == sigp_busy)
296        cpu_relax();
297    memcpy_real(zfcpdump_save_areas[cpu],
298            (void *)(unsigned long) store_prefix() + SAVE_AREA_BASE,
299            sizeof(struct save_area));
300}
301
302struct save_area *zfcpdump_save_areas[NR_CPUS + 1];
303EXPORT_SYMBOL_GPL(zfcpdump_save_areas);
304
305#else
306
307static inline void smp_get_save_area(unsigned int cpu, unsigned int phy_cpu) { }
308
309#endif /* CONFIG_ZFCPDUMP */
310
311static int cpu_known(int cpu_id)
312{
313    int cpu;
314
315    for_each_present_cpu(cpu) {
316        if (__cpu_logical_map[cpu] == cpu_id)
317            return 1;
318    }
319    return 0;
320}
321
322static int smp_rescan_cpus_sigp(cpumask_t avail)
323{
324    int cpu_id, logical_cpu;
325
326    logical_cpu = cpumask_first(&avail);
327    if (logical_cpu >= nr_cpu_ids)
328        return 0;
329    for (cpu_id = 0; cpu_id <= MAX_CPU_ADDRESS; cpu_id++) {
330        if (cpu_known(cpu_id))
331            continue;
332        __cpu_logical_map[logical_cpu] = cpu_id;
333        smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
334        if (!cpu_stopped(logical_cpu))
335            continue;
336        cpu_set(logical_cpu, cpu_present_map);
337        smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
338        logical_cpu = cpumask_next(logical_cpu, &avail);
339        if (logical_cpu >= nr_cpu_ids)
340            break;
341    }
342    return 0;
343}
344
345static int smp_rescan_cpus_sclp(cpumask_t avail)
346{
347    struct sclp_cpu_info *info;
348    int cpu_id, logical_cpu, cpu;
349    int rc;
350
351    logical_cpu = cpumask_first(&avail);
352    if (logical_cpu >= nr_cpu_ids)
353        return 0;
354    info = kmalloc(sizeof(*info), GFP_KERNEL);
355    if (!info)
356        return -ENOMEM;
357    rc = sclp_get_cpu_info(info);
358    if (rc)
359        goto out;
360    for (cpu = 0; cpu < info->combined; cpu++) {
361        if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
362            continue;
363        cpu_id = info->cpu[cpu].address;
364        if (cpu_known(cpu_id))
365            continue;
366        __cpu_logical_map[logical_cpu] = cpu_id;
367        smp_cpu_polarization[logical_cpu] = POLARIZATION_UNKNWN;
368        cpu_set(logical_cpu, cpu_present_map);
369        if (cpu >= info->configured)
370            smp_cpu_state[logical_cpu] = CPU_STATE_STANDBY;
371        else
372            smp_cpu_state[logical_cpu] = CPU_STATE_CONFIGURED;
373        logical_cpu = cpumask_next(logical_cpu, &avail);
374        if (logical_cpu >= nr_cpu_ids)
375            break;
376    }
377out:
378    kfree(info);
379    return rc;
380}
381
382static int __smp_rescan_cpus(void)
383{
384    cpumask_t avail;
385
386    cpus_xor(avail, cpu_possible_map, cpu_present_map);
387    if (smp_use_sigp_detection)
388        return smp_rescan_cpus_sigp(avail);
389    else
390        return smp_rescan_cpus_sclp(avail);
391}
392
393static void __init smp_detect_cpus(void)
394{
395    unsigned int cpu, c_cpus, s_cpus;
396    struct sclp_cpu_info *info;
397    u16 boot_cpu_addr, cpu_addr;
398
399    c_cpus = 1;
400    s_cpus = 0;
401    boot_cpu_addr = __cpu_logical_map[0];
402    info = kmalloc(sizeof(*info), GFP_KERNEL);
403    if (!info)
404        panic("smp_detect_cpus failed to allocate memory\n");
405    /* Use sigp detection algorithm if sclp doesn't work. */
406    if (sclp_get_cpu_info(info)) {
407        smp_use_sigp_detection = 1;
408        for (cpu = 0; cpu <= MAX_CPU_ADDRESS; cpu++) {
409            if (cpu == boot_cpu_addr)
410                continue;
411            if (!raw_cpu_stopped(cpu))
412                continue;
413            smp_get_save_area(c_cpus, cpu);
414            c_cpus++;
415        }
416        goto out;
417    }
418
419    if (info->has_cpu_type) {
420        for (cpu = 0; cpu < info->combined; cpu++) {
421            if (info->cpu[cpu].address == boot_cpu_addr) {
422                smp_cpu_type = info->cpu[cpu].type;
423                break;
424            }
425        }
426    }
427
428    for (cpu = 0; cpu < info->combined; cpu++) {
429        if (info->has_cpu_type && info->cpu[cpu].type != smp_cpu_type)
430            continue;
431        cpu_addr = info->cpu[cpu].address;
432        if (cpu_addr == boot_cpu_addr)
433            continue;
434        if (!raw_cpu_stopped(cpu_addr)) {
435            s_cpus++;
436            continue;
437        }
438        smp_get_save_area(c_cpus, cpu_addr);
439        c_cpus++;
440    }
441out:
442    kfree(info);
443    pr_info("%d configured CPUs, %d standby CPUs\n", c_cpus, s_cpus);
444    get_online_cpus();
445    __smp_rescan_cpus();
446    put_online_cpus();
447}
448
449/*
450 * Activate a secondary processor.
451 */
452int __cpuinit start_secondary(void *cpuvoid)
453{
454    /* Setup the cpu */
455    cpu_init();
456    preempt_disable();
457    /* Enable TOD clock interrupts on the secondary cpu. */
458    init_cpu_timer();
459    /* Enable cpu timer interrupts on the secondary cpu. */
460    init_cpu_vtimer();
461    /* Enable pfault pseudo page faults on this cpu. */
462    pfault_init();
463
464    /* call cpu notifiers */
465    notify_cpu_starting(smp_processor_id());
466    /* Mark this cpu as online */
467    ipi_call_lock();
468    cpu_set(smp_processor_id(), cpu_online_map);
469    ipi_call_unlock();
470    /* Switch on interrupts */
471    local_irq_enable();
472    /* Print info about this processor */
473    print_cpu_info();
474    /* cpu_idle will call schedule for us */
475    cpu_idle();
476    return 0;
477}
478
479static void __init smp_create_idle(unsigned int cpu)
480{
481    struct task_struct *p;
482
483    /*
484     * don't care about the psw and regs settings since we'll never
485     * reschedule the forked task.
486     */
487    p = fork_idle(cpu);
488    if (IS_ERR(p))
489        panic("failed fork for CPU %u: %li", cpu, PTR_ERR(p));
490    current_set[cpu] = p;
491}
492
493static int __cpuinit smp_alloc_lowcore(int cpu)
494{
495    unsigned long async_stack, panic_stack;
496    struct _lowcore *lowcore;
497
498    lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
499    if (!lowcore)
500        return -ENOMEM;
501    async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
502    panic_stack = __get_free_page(GFP_KERNEL);
503    if (!panic_stack || !async_stack)
504        goto out;
505    memcpy(lowcore, &S390_lowcore, 512);
506    memset((char *)lowcore + 512, 0, sizeof(*lowcore) - 512);
507    lowcore->async_stack = async_stack + ASYNC_SIZE;
508    lowcore->panic_stack = panic_stack + PAGE_SIZE;
509
510#ifndef CONFIG_64BIT
511    if (MACHINE_HAS_IEEE) {
512        unsigned long save_area;
513
514        save_area = get_zeroed_page(GFP_KERNEL);
515        if (!save_area)
516            goto out;
517        lowcore->extended_save_area_addr = (u32) save_area;
518    }
519#else
520    if (vdso_alloc_per_cpu(cpu, lowcore))
521        goto out;
522#endif
523    lowcore_ptr[cpu] = lowcore;
524    return 0;
525
526out:
527    free_page(panic_stack);
528    free_pages(async_stack, ASYNC_ORDER);
529    free_pages((unsigned long) lowcore, LC_ORDER);
530    return -ENOMEM;
531}
532
533static void smp_free_lowcore(int cpu)
534{
535    struct _lowcore *lowcore;
536
537    lowcore = lowcore_ptr[cpu];
538#ifndef CONFIG_64BIT
539    if (MACHINE_HAS_IEEE)
540        free_page((unsigned long) lowcore->extended_save_area_addr);
541#else
542    vdso_free_per_cpu(cpu, lowcore);
543#endif
544    free_page(lowcore->panic_stack - PAGE_SIZE);
545    free_pages(lowcore->async_stack - ASYNC_SIZE, ASYNC_ORDER);
546    free_pages((unsigned long) lowcore, LC_ORDER);
547    lowcore_ptr[cpu] = NULL;
548}
549
550/* Upping and downing of CPUs */
551int __cpuinit __cpu_up(unsigned int cpu)
552{
553    struct _lowcore *cpu_lowcore;
554    struct task_struct *idle;
555    struct stack_frame *sf;
556    u32 lowcore;
557    int ccode;
558
559    if (smp_cpu_state[cpu] != CPU_STATE_CONFIGURED)
560        return -EIO;
561    if (smp_alloc_lowcore(cpu))
562        return -ENOMEM;
563    do {
564        ccode = sigp(cpu, sigp_initial_cpu_reset);
565        if (ccode == sigp_busy)
566            udelay(10);
567        if (ccode == sigp_not_operational)
568            goto err_out;
569    } while (ccode == sigp_busy);
570
571    lowcore = (u32)(unsigned long)lowcore_ptr[cpu];
572    while (sigp_p(lowcore, cpu, sigp_set_prefix) == sigp_busy)
573        udelay(10);
574
575    idle = current_set[cpu];
576    cpu_lowcore = lowcore_ptr[cpu];
577    cpu_lowcore->kernel_stack = (unsigned long)
578        task_stack_page(idle) + THREAD_SIZE;
579    cpu_lowcore->thread_info = (unsigned long) task_thread_info(idle);
580    sf = (struct stack_frame *) (cpu_lowcore->kernel_stack
581                     - sizeof(struct pt_regs)
582                     - sizeof(struct stack_frame));
583    memset(sf, 0, sizeof(struct stack_frame));
584    sf->gprs[9] = (unsigned long) sf;
585    cpu_lowcore->save_area[15] = (unsigned long) sf;
586    __ctl_store(cpu_lowcore->cregs_save_area, 0, 15);
587    atomic_inc(&init_mm.context.attach_count);
588    asm volatile(
589        " stam 0,15,0(%0)"
590        : : "a" (&cpu_lowcore->access_regs_save_area) : "memory");
591    cpu_lowcore->percpu_offset = __per_cpu_offset[cpu];
592    cpu_lowcore->current_task = (unsigned long) idle;
593    cpu_lowcore->cpu_nr = cpu;
594    cpu_lowcore->kernel_asce = S390_lowcore.kernel_asce;
595    cpu_lowcore->machine_flags = S390_lowcore.machine_flags;
596    cpu_lowcore->ftrace_func = S390_lowcore.ftrace_func;
597    memcpy(cpu_lowcore->stfle_fac_list, S390_lowcore.stfle_fac_list,
598           MAX_FACILITY_BIT/8);
599    eieio();
600
601    while (sigp(cpu, sigp_restart) == sigp_busy)
602        udelay(10);
603
604    while (!cpu_online(cpu))
605        cpu_relax();
606    return 0;
607
608err_out:
609    smp_free_lowcore(cpu);
610    return -EIO;
611}
612
613static int __init setup_possible_cpus(char *s)
614{
615    int pcpus, cpu;
616
617    pcpus = simple_strtoul(s, NULL, 0);
618    init_cpu_possible(cpumask_of(0));
619    for (cpu = 1; cpu < pcpus && cpu < nr_cpu_ids; cpu++)
620        set_cpu_possible(cpu, true);
621    return 0;
622}
623early_param("possible_cpus", setup_possible_cpus);
624
625#ifdef CONFIG_HOTPLUG_CPU
626
627int __cpu_disable(void)
628{
629    struct ec_creg_mask_parms cr_parms;
630    int cpu = smp_processor_id();
631
632    cpu_clear(cpu, cpu_online_map);
633
634    /* Disable pfault pseudo page faults on this cpu. */
635    pfault_fini();
636
637    memset(&cr_parms.orvals, 0, sizeof(cr_parms.orvals));
638    memset(&cr_parms.andvals, 0xff, sizeof(cr_parms.andvals));
639
640    /* disable all external interrupts */
641    cr_parms.orvals[0] = 0;
642    cr_parms.andvals[0] = ~(1 << 15 | 1 << 14 | 1 << 13 | 1 << 12 |
643                1 << 11 | 1 << 10 | 1 << 6 | 1 << 4);
644    /* disable all I/O interrupts */
645    cr_parms.orvals[6] = 0;
646    cr_parms.andvals[6] = ~(1 << 31 | 1 << 30 | 1 << 29 | 1 << 28 |
647                1 << 27 | 1 << 26 | 1 << 25 | 1 << 24);
648    /* disable most machine checks */
649    cr_parms.orvals[14] = 0;
650    cr_parms.andvals[14] = ~(1 << 28 | 1 << 27 | 1 << 26 |
651                 1 << 25 | 1 << 24);
652
653    smp_ctl_bit_callback(&cr_parms);
654
655    return 0;
656}
657
658void __cpu_die(unsigned int cpu)
659{
660    /* Wait until target cpu is down */
661    while (!cpu_stopped(cpu))
662        cpu_relax();
663    while (sigp_p(0, cpu, sigp_set_prefix) == sigp_busy)
664        udelay(10);
665    smp_free_lowcore(cpu);
666    atomic_dec(&init_mm.context.attach_count);
667    pr_info("Processor %d stopped\n", cpu);
668}
669
670void cpu_die(void)
671{
672    idle_task_exit();
673    while (sigp(smp_processor_id(), sigp_stop) == sigp_busy)
674        cpu_relax();
675    for (;;);
676}
677
678#endif /* CONFIG_HOTPLUG_CPU */
679
680void __init smp_prepare_cpus(unsigned int max_cpus)
681{
682#ifndef CONFIG_64BIT
683    unsigned long save_area = 0;
684#endif
685    unsigned long async_stack, panic_stack;
686    struct _lowcore *lowcore;
687    unsigned int cpu;
688
689    smp_detect_cpus();
690
691    /* request the 0x1201 emergency signal external interrupt */
692    if (register_external_interrupt(0x1201, do_ext_call_interrupt) != 0)
693        panic("Couldn't request external interrupt 0x1201");
694    print_cpu_info();
695
696    /* Reallocate current lowcore, but keep its contents. */
697    lowcore = (void *) __get_free_pages(GFP_KERNEL | GFP_DMA, LC_ORDER);
698    panic_stack = __get_free_page(GFP_KERNEL);
699    async_stack = __get_free_pages(GFP_KERNEL, ASYNC_ORDER);
700    BUG_ON(!lowcore || !panic_stack || !async_stack);
701#ifndef CONFIG_64BIT
702    if (MACHINE_HAS_IEEE)
703        save_area = get_zeroed_page(GFP_KERNEL);
704#endif
705    local_irq_disable();
706    local_mcck_disable();
707    lowcore_ptr[smp_processor_id()] = lowcore;
708    *lowcore = S390_lowcore;
709    lowcore->panic_stack = panic_stack + PAGE_SIZE;
710    lowcore->async_stack = async_stack + ASYNC_SIZE;
711#ifndef CONFIG_64BIT
712    if (MACHINE_HAS_IEEE)
713        lowcore->extended_save_area_addr = (u32) save_area;
714#endif
715    set_prefix((u32)(unsigned long) lowcore);
716    local_mcck_enable();
717    local_irq_enable();
718#ifdef CONFIG_64BIT
719    if (vdso_alloc_per_cpu(smp_processor_id(), &S390_lowcore))
720        BUG();
721#endif
722    for_each_possible_cpu(cpu)
723        if (cpu != smp_processor_id())
724            smp_create_idle(cpu);
725}
726
727void __init smp_prepare_boot_cpu(void)
728{
729    BUG_ON(smp_processor_id() != 0);
730
731    current_thread_info()->cpu = 0;
732    cpu_set(0, cpu_present_map);
733    cpu_set(0, cpu_online_map);
734    S390_lowcore.percpu_offset = __per_cpu_offset[0];
735    current_set[0] = current;
736    smp_cpu_state[0] = CPU_STATE_CONFIGURED;
737    smp_cpu_polarization[0] = POLARIZATION_UNKNWN;
738}
739
740void __init smp_cpus_done(unsigned int max_cpus)
741{
742}
743
744void __init smp_setup_processor_id(void)
745{
746    S390_lowcore.cpu_nr = 0;
747    __cpu_logical_map[0] = stap();
748}
749
750/*
751 * the frequency of the profiling timer can be changed
752 * by writing a multiplier value into /proc/profile.
753 *
754 * usually you want to run this on all CPUs ;)
755 */
756int setup_profiling_timer(unsigned int multiplier)
757{
758    return 0;
759}
760
761#ifdef CONFIG_HOTPLUG_CPU
762static ssize_t cpu_configure_show(struct sys_device *dev,
763                struct sysdev_attribute *attr, char *buf)
764{
765    ssize_t count;
766
767    mutex_lock(&smp_cpu_state_mutex);
768    count = sprintf(buf, "%d\n", smp_cpu_state[dev->id]);
769    mutex_unlock(&smp_cpu_state_mutex);
770    return count;
771}
772
773static ssize_t cpu_configure_store(struct sys_device *dev,
774                  struct sysdev_attribute *attr,
775                  const char *buf, size_t count)
776{
777    int cpu = dev->id;
778    int val, rc;
779    char delim;
780
781    if (sscanf(buf, "%d %c", &val, &delim) != 1)
782        return -EINVAL;
783    if (val != 0 && val != 1)
784        return -EINVAL;
785
786    get_online_cpus();
787    mutex_lock(&smp_cpu_state_mutex);
788    rc = -EBUSY;
789    /* disallow configuration changes of online cpus and cpu 0 */
790    if (cpu_online(cpu) || cpu == 0)
791        goto out;
792    rc = 0;
793    switch (val) {
794    case 0:
795        if (smp_cpu_state[cpu] == CPU_STATE_CONFIGURED) {
796            rc = sclp_cpu_deconfigure(__cpu_logical_map[cpu]);
797            if (!rc) {
798                smp_cpu_state[cpu] = CPU_STATE_STANDBY;
799                smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
800            }
801        }
802        break;
803    case 1:
804        if (smp_cpu_state[cpu] == CPU_STATE_STANDBY) {
805            rc = sclp_cpu_configure(__cpu_logical_map[cpu]);
806            if (!rc) {
807                smp_cpu_state[cpu] = CPU_STATE_CONFIGURED;
808                smp_cpu_polarization[cpu] = POLARIZATION_UNKNWN;
809            }
810        }
811        break;
812    default:
813        break;
814    }
815out:
816    mutex_unlock(&smp_cpu_state_mutex);
817    put_online_cpus();
818    return rc ? rc : count;
819}
820static SYSDEV_ATTR(configure, 0644, cpu_configure_show, cpu_configure_store);
821#endif /* CONFIG_HOTPLUG_CPU */
822
823static ssize_t cpu_polarization_show(struct sys_device *dev,
824                     struct sysdev_attribute *attr, char *buf)
825{
826    int cpu = dev->id;
827    ssize_t count;
828
829    mutex_lock(&smp_cpu_state_mutex);
830    switch (smp_cpu_polarization[cpu]) {
831    case POLARIZATION_HRZ:
832        count = sprintf(buf, "horizontal\n");
833        break;
834    case POLARIZATION_VL:
835        count = sprintf(buf, "vertical:low\n");
836        break;
837    case POLARIZATION_VM:
838        count = sprintf(buf, "vertical:medium\n");
839        break;
840    case POLARIZATION_VH:
841        count = sprintf(buf, "vertical:high\n");
842        break;
843    default:
844        count = sprintf(buf, "unknown\n");
845        break;
846    }
847    mutex_unlock(&smp_cpu_state_mutex);
848    return count;
849}
850static SYSDEV_ATTR(polarization, 0444, cpu_polarization_show, NULL);
851
852static ssize_t show_cpu_address(struct sys_device *dev,
853                struct sysdev_attribute *attr, char *buf)
854{
855    return sprintf(buf, "%d\n", __cpu_logical_map[dev->id]);
856}
857static SYSDEV_ATTR(address, 0444, show_cpu_address, NULL);
858
859
860static struct attribute *cpu_common_attrs[] = {
861#ifdef CONFIG_HOTPLUG_CPU
862    &attr_configure.attr,
863#endif
864    &attr_address.attr,
865    &attr_polarization.attr,
866    NULL,
867};
868
869static struct attribute_group cpu_common_attr_group = {
870    .attrs = cpu_common_attrs,
871};
872
873static ssize_t show_capability(struct sys_device *dev,
874                struct sysdev_attribute *attr, char *buf)
875{
876    unsigned int capability;
877    int rc;
878
879    rc = get_cpu_capability(&capability);
880    if (rc)
881        return rc;
882    return sprintf(buf, "%u\n", capability);
883}
884static SYSDEV_ATTR(capability, 0444, show_capability, NULL);
885
886static ssize_t show_idle_count(struct sys_device *dev,
887                struct sysdev_attribute *attr, char *buf)
888{
889    struct s390_idle_data *idle;
890    unsigned long long idle_count;
891    unsigned int sequence;
892
893    idle = &per_cpu(s390_idle, dev->id);
894repeat:
895    sequence = idle->sequence;
896    smp_rmb();
897    if (sequence & 1)
898        goto repeat;
899    idle_count = idle->idle_count;
900    if (idle->idle_enter)
901        idle_count++;
902    smp_rmb();
903    if (idle->sequence != sequence)
904        goto repeat;
905    return sprintf(buf, "%llu\n", idle_count);
906}
907static SYSDEV_ATTR(idle_count, 0444, show_idle_count, NULL);
908
909static ssize_t show_idle_time(struct sys_device *dev,
910                struct sysdev_attribute *attr, char *buf)
911{
912    struct s390_idle_data *idle;
913    unsigned long long now, idle_time, idle_enter;
914    unsigned int sequence;
915
916    idle = &per_cpu(s390_idle, dev->id);
917    now = get_clock();
918repeat:
919    sequence = idle->sequence;
920    smp_rmb();
921    if (sequence & 1)
922        goto repeat;
923    idle_time = idle->idle_time;
924    idle_enter = idle->idle_enter;
925    if (idle_enter != 0ULL && idle_enter < now)
926        idle_time += now - idle_enter;
927    smp_rmb();
928    if (idle->sequence != sequence)
929        goto repeat;
930    return sprintf(buf, "%llu\n", idle_time >> 12);
931}
932static SYSDEV_ATTR(idle_time_us, 0444, show_idle_time, NULL);
933
934static struct attribute *cpu_online_attrs[] = {
935    &attr_capability.attr,
936    &attr_idle_count.attr,
937    &attr_idle_time_us.attr,
938    NULL,
939};
940
941static struct attribute_group cpu_online_attr_group = {
942    .attrs = cpu_online_attrs,
943};
944
945static int __cpuinit smp_cpu_notify(struct notifier_block *self,
946                    unsigned long action, void *hcpu)
947{
948    unsigned int cpu = (unsigned int)(long)hcpu;
949    struct cpu *c = &per_cpu(cpu_devices, cpu);
950    struct sys_device *s = &c->sysdev;
951    struct s390_idle_data *idle;
952    int err = 0;
953
954    switch (action) {
955    case CPU_ONLINE:
956    case CPU_ONLINE_FROZEN:
957        idle = &per_cpu(s390_idle, cpu);
958        memset(idle, 0, sizeof(struct s390_idle_data));
959        err = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
960        break;
961    case CPU_DEAD:
962    case CPU_DEAD_FROZEN:
963        sysfs_remove_group(&s->kobj, &cpu_online_attr_group);
964        break;
965    }
966    return notifier_from_errno(err);
967}
968
969static struct notifier_block __cpuinitdata smp_cpu_nb = {
970    .notifier_call = smp_cpu_notify,
971};
972
973static int __devinit smp_add_present_cpu(int cpu)
974{
975    struct cpu *c = &per_cpu(cpu_devices, cpu);
976    struct sys_device *s = &c->sysdev;
977    int rc;
978
979    c->hotpluggable = 1;
980    rc = register_cpu(c, cpu);
981    if (rc)
982        goto out;
983    rc = sysfs_create_group(&s->kobj, &cpu_common_attr_group);
984    if (rc)
985        goto out_cpu;
986    if (!cpu_online(cpu))
987        goto out;
988    rc = sysfs_create_group(&s->kobj, &cpu_online_attr_group);
989    if (!rc)
990        return 0;
991    sysfs_remove_group(&s->kobj, &cpu_common_attr_group);
992out_cpu:
993#ifdef CONFIG_HOTPLUG_CPU
994    unregister_cpu(c);
995#endif
996out:
997    return rc;
998}
999
1000#ifdef CONFIG_HOTPLUG_CPU
1001
1002int __ref smp_rescan_cpus(void)
1003{
1004    cpumask_t newcpus;
1005    int cpu;
1006    int rc;
1007
1008    get_online_cpus();
1009    mutex_lock(&smp_cpu_state_mutex);
1010    newcpus = cpu_present_map;
1011    rc = __smp_rescan_cpus();
1012    if (rc)
1013        goto out;
1014    cpus_andnot(newcpus, cpu_present_map, newcpus);
1015    for_each_cpu_mask(cpu, newcpus) {
1016        rc = smp_add_present_cpu(cpu);
1017        if (rc)
1018            cpu_clear(cpu, cpu_present_map);
1019    }
1020    rc = 0;
1021out:
1022    mutex_unlock(&smp_cpu_state_mutex);
1023    put_online_cpus();
1024    if (!cpus_empty(newcpus))
1025        topology_schedule_update();
1026    return rc;
1027}
1028
1029static ssize_t __ref rescan_store(struct sysdev_class *class,
1030                  struct sysdev_class_attribute *attr,
1031                  const char *buf,
1032                  size_t count)
1033{
1034    int rc;
1035
1036    rc = smp_rescan_cpus();
1037    return rc ? rc : count;
1038}
1039static SYSDEV_CLASS_ATTR(rescan, 0200, NULL, rescan_store);
1040#endif /* CONFIG_HOTPLUG_CPU */
1041
1042static ssize_t dispatching_show(struct sysdev_class *class,
1043                struct sysdev_class_attribute *attr,
1044                char *buf)
1045{
1046    ssize_t count;
1047
1048    mutex_lock(&smp_cpu_state_mutex);
1049    count = sprintf(buf, "%d\n", cpu_management);
1050    mutex_unlock(&smp_cpu_state_mutex);
1051    return count;
1052}
1053
1054static ssize_t dispatching_store(struct sysdev_class *dev,
1055                 struct sysdev_class_attribute *attr,
1056                 const char *buf,
1057                 size_t count)
1058{
1059    int val, rc;
1060    char delim;
1061
1062    if (sscanf(buf, "%d %c", &val, &delim) != 1)
1063        return -EINVAL;
1064    if (val != 0 && val != 1)
1065        return -EINVAL;
1066    rc = 0;
1067    get_online_cpus();
1068    mutex_lock(&smp_cpu_state_mutex);
1069    if (cpu_management == val)
1070        goto out;
1071    rc = topology_set_cpu_management(val);
1072    if (!rc)
1073        cpu_management = val;
1074out:
1075    mutex_unlock(&smp_cpu_state_mutex);
1076    put_online_cpus();
1077    return rc ? rc : count;
1078}
1079static SYSDEV_CLASS_ATTR(dispatching, 0644, dispatching_show,
1080             dispatching_store);
1081
1082static int __init topology_init(void)
1083{
1084    int cpu;
1085    int rc;
1086
1087    register_cpu_notifier(&smp_cpu_nb);
1088
1089#ifdef CONFIG_HOTPLUG_CPU
1090    rc = sysdev_class_create_file(&cpu_sysdev_class, &attr_rescan);
1091    if (rc)
1092        return rc;
1093#endif
1094    rc = sysdev_class_create_file(&cpu_sysdev_class, &attr_dispatching);
1095    if (rc)
1096        return rc;
1097    for_each_present_cpu(cpu) {
1098        rc = smp_add_present_cpu(cpu);
1099        if (rc)
1100            return rc;
1101    }
1102    return 0;
1103}
1104subsys_initcall(topology_init);
1105

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