a12183989a79b8e461df14b380ecacaf950fe018
[linux-2.6.git] / arch / s390 / kernel / setup.c
1 /*
2  *  arch/s390/kernel/setup.c
3  *
4  *  S390 version
5  *    Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
6  *    Author(s): Hartmut Penner (hp@de.ibm.com),
7  *               Martin Schwidefsky (schwidefsky@de.ibm.com)
8  *
9  *  Derived from "arch/i386/kernel/setup.c"
10  *    Copyright (C) 1995, Linus Torvalds
11  */
12
13 /*
14  * This file handles the architecture-dependent parts of initialization
15  */
16
17 #include <linux/errno.h>
18 #include <linux/module.h>
19 #include <linux/sched.h>
20 #include <linux/kernel.h>
21 #include <linux/mm.h>
22 #include <linux/stddef.h>
23 #include <linux/unistd.h>
24 #include <linux/ptrace.h>
25 #include <linux/slab.h>
26 #include <linux/user.h>
27 #include <linux/a.out.h>
28 #include <linux/tty.h>
29 #include <linux/ioport.h>
30 #include <linux/delay.h>
31 #include <linux/config.h>
32 #include <linux/init.h>
33 #include <linux/initrd.h>
34 #include <linux/bootmem.h>
35 #include <linux/root_dev.h>
36 #include <linux/console.h>
37 #include <linux/seq_file.h>
38 #include <linux/kernel_stat.h>
39
40 #include <asm/uaccess.h>
41 #include <asm/system.h>
42 #include <asm/smp.h>
43 #include <asm/mmu_context.h>
44 #include <asm/cpcmd.h>
45 #include <asm/lowcore.h>
46 #include <asm/irq.h>
47 #include <asm/page.h>
48 #include <asm/ptrace.h>
49
50 /*
51  * Machine setup..
52  */
53 unsigned int console_mode = 0;
54 unsigned int console_devno = -1;
55 unsigned int console_irq = -1;
56 unsigned long memory_size = 0;
57 unsigned long machine_flags = 0;
58 struct {
59         unsigned long addr, size, type;
60 } memory_chunk[MEMORY_CHUNKS] = { { 0 } };
61 #define CHUNK_READ_WRITE 0
62 #define CHUNK_READ_ONLY 1
63 volatile int __cpu_logical_map[NR_CPUS]; /* logical cpu to cpu address */
64 unsigned long __initdata zholes_size[MAX_NR_ZONES];
65 static unsigned long __initdata memory_end;
66
67 /*
68  * Setup options
69  */
70 extern int _text,_etext, _edata, _end;
71
72 /*
73  * This is set up by the setup-routine at boot-time
74  * for S390 need to find out, what we have to setup
75  * using address 0x10400 ...
76  */
77
78 #include <asm/setup.h>
79
80 static char command_line[COMMAND_LINE_SIZE] = { 0, };
81
82 static struct resource code_resource = {
83         .name  = "Kernel code",
84         .start = (unsigned long) &_text,
85         .end = (unsigned long) &_etext - 1,
86         .flags = IORESOURCE_BUSY | IORESOURCE_MEM,
87 };
88
89 static struct resource data_resource = {
90         .name = "Kernel data",
91         .start = (unsigned long) &_etext,
92         .end = (unsigned long) &_edata - 1,
93         .flags = IORESOURCE_BUSY | IORESOURCE_MEM,
94 };
95
96 /*
97  * cpu_init() initializes state that is per-CPU.
98  */
99 void __devinit cpu_init (void)
100 {
101         int addr = hard_smp_processor_id();
102
103         /*
104          * Store processor id in lowcore (used e.g. in timer_interrupt)
105          */
106         asm volatile ("stidp %0": "=m" (S390_lowcore.cpu_data.cpu_id));
107         S390_lowcore.cpu_data.cpu_addr = addr;
108
109         /*
110          * Force FPU initialization:
111          */
112         clear_thread_flag(TIF_USEDFPU);
113         clear_used_math();
114
115         atomic_inc(&init_mm.mm_count);
116         current->active_mm = &init_mm;
117         if (current->mm)
118                 BUG();
119         enter_lazy_tlb(&init_mm, current);
120 }
121
122 /*
123  * VM halt and poweroff setup routines
124  */
125 char vmhalt_cmd[128] = "";
126 char vmpoff_cmd[128] = "";
127
128 static inline void strncpy_skip_quote(char *dst, char *src, int n)
129 {
130         int sx, dx;
131
132         dx = 0;
133         for (sx = 0; src[sx] != 0; sx++) {
134                 if (src[sx] == '"') continue;
135                 dst[dx++] = src[sx];
136                 if (dx >= n) break;
137         }
138 }
139
140 static int __init vmhalt_setup(char *str)
141 {
142         strncpy_skip_quote(vmhalt_cmd, str, 127);
143         vmhalt_cmd[127] = 0;
144         return 1;
145 }
146
147 __setup("vmhalt=", vmhalt_setup);
148
149 static int __init vmpoff_setup(char *str)
150 {
151         strncpy_skip_quote(vmpoff_cmd, str, 127);
152         vmpoff_cmd[127] = 0;
153         return 1;
154 }
155
156 __setup("vmpoff=", vmpoff_setup);
157
158 /*
159  * condev= and conmode= setup parameter.
160  */
161
162 static int __init condev_setup(char *str)
163 {
164         int vdev;
165
166         vdev = simple_strtoul(str, &str, 0);
167         if (vdev >= 0 && vdev < 65536) {
168                 console_devno = vdev;
169                 console_irq = -1;
170         }
171         return 1;
172 }
173
174 __setup("condev=", condev_setup);
175
176 static int __init conmode_setup(char *str)
177 {
178 #if defined(CONFIG_SCLP_CONSOLE)
179         if (strncmp(str, "hwc", 4) == 0 || strncmp(str, "sclp", 5) == 0)
180                 SET_CONSOLE_SCLP;
181 #endif
182 #if defined(CONFIG_TN3215_CONSOLE)
183         if (strncmp(str, "3215", 5) == 0)
184                 SET_CONSOLE_3215;
185 #endif
186 #if defined(CONFIG_TN3270_CONSOLE)
187         if (strncmp(str, "3270", 5) == 0)
188                 SET_CONSOLE_3270;
189 #endif
190         return 1;
191 }
192
193 __setup("conmode=", conmode_setup);
194
195 static void __init conmode_default(void)
196 {
197         char query_buffer[1024];
198         char *ptr;
199
200         if (MACHINE_IS_VM) {
201                 __cpcmd("QUERY CONSOLE", query_buffer, 1024, NULL);
202                 console_devno = simple_strtoul(query_buffer + 5, NULL, 16);
203                 ptr = strstr(query_buffer, "SUBCHANNEL =");
204                 console_irq = simple_strtoul(ptr + 13, NULL, 16);
205                 __cpcmd("QUERY TERM", query_buffer, 1024, NULL);
206                 ptr = strstr(query_buffer, "CONMODE");
207                 /*
208                  * Set the conmode to 3215 so that the device recognition 
209                  * will set the cu_type of the console to 3215. If the
210                  * conmode is 3270 and we don't set it back then both
211                  * 3215 and the 3270 driver will try to access the console
212                  * device (3215 as console and 3270 as normal tty).
213                  */
214                 __cpcmd("TERM CONMODE 3215", NULL, 0, NULL);
215                 if (ptr == NULL) {
216 #if defined(CONFIG_SCLP_CONSOLE)
217                         SET_CONSOLE_SCLP;
218 #endif
219                         return;
220                 }
221                 if (strncmp(ptr + 8, "3270", 4) == 0) {
222 #if defined(CONFIG_TN3270_CONSOLE)
223                         SET_CONSOLE_3270;
224 #elif defined(CONFIG_TN3215_CONSOLE)
225                         SET_CONSOLE_3215;
226 #elif defined(CONFIG_SCLP_CONSOLE)
227                         SET_CONSOLE_SCLP;
228 #endif
229                 } else if (strncmp(ptr + 8, "3215", 4) == 0) {
230 #if defined(CONFIG_TN3215_CONSOLE)
231                         SET_CONSOLE_3215;
232 #elif defined(CONFIG_TN3270_CONSOLE)
233                         SET_CONSOLE_3270;
234 #elif defined(CONFIG_SCLP_CONSOLE)
235                         SET_CONSOLE_SCLP;
236 #endif
237                 }
238         } else if (MACHINE_IS_P390) {
239 #if defined(CONFIG_TN3215_CONSOLE)
240                 SET_CONSOLE_3215;
241 #elif defined(CONFIG_TN3270_CONSOLE)
242                 SET_CONSOLE_3270;
243 #endif
244         } else {
245 #if defined(CONFIG_SCLP_CONSOLE)
246                 SET_CONSOLE_SCLP;
247 #endif
248         }
249 }
250
251 #ifdef CONFIG_SMP
252 extern void machine_restart_smp(char *);
253 extern void machine_halt_smp(void);
254 extern void machine_power_off_smp(void);
255
256 void (*_machine_restart)(char *command) = machine_restart_smp;
257 void (*_machine_halt)(void) = machine_halt_smp;
258 void (*_machine_power_off)(void) = machine_power_off_smp;
259 #else
260 /*
261  * Reboot, halt and power_off routines for non SMP.
262  */
263 extern void reipl(unsigned long devno);
264 static void do_machine_restart_nonsmp(char * __unused)
265 {
266         if (MACHINE_IS_VM)
267                 cpcmd ("IPL", NULL, 0);
268         else
269                 reipl (0x10000 | S390_lowcore.ipl_device);
270 }
271
272 static void do_machine_halt_nonsmp(void)
273 {
274         if (MACHINE_IS_VM && strlen(vmhalt_cmd) > 0)
275                 cpcmd(vmhalt_cmd, NULL, 0);
276         signal_processor(smp_processor_id(), sigp_stop_and_store_status);
277 }
278
279 static void do_machine_power_off_nonsmp(void)
280 {
281         if (MACHINE_IS_VM && strlen(vmpoff_cmd) > 0)
282                 cpcmd(vmpoff_cmd, NULL, 0);
283         signal_processor(smp_processor_id(), sigp_stop_and_store_status);
284 }
285
286 void (*_machine_restart)(char *command) = do_machine_restart_nonsmp;
287 void (*_machine_halt)(void) = do_machine_halt_nonsmp;
288 void (*_machine_power_off)(void) = do_machine_power_off_nonsmp;
289 #endif
290
291  /*
292  * Reboot, halt and power_off stubs. They just call _machine_restart,
293  * _machine_halt or _machine_power_off. 
294  */
295
296 void machine_restart(char *command)
297 {
298         console_unblank();
299         _machine_restart(command);
300 }
301
302 void machine_halt(void)
303 {
304         console_unblank();
305         _machine_halt();
306 }
307
308 void machine_power_off(void)
309 {
310         console_unblank();
311         _machine_power_off();
312 }
313
314 static void __init
315 add_memory_hole(unsigned long start, unsigned long end)
316 {
317         unsigned long dma_pfn = MAX_DMA_ADDRESS >> PAGE_SHIFT;
318
319         if (end <= dma_pfn)
320                 zholes_size[ZONE_DMA] += end - start + 1;
321         else if (start > dma_pfn)
322                 zholes_size[ZONE_NORMAL] += end - start + 1;
323         else {
324                 zholes_size[ZONE_DMA] += dma_pfn - start + 1;
325                 zholes_size[ZONE_NORMAL] += end - dma_pfn;
326         }
327 }
328
329 static void __init
330 parse_cmdline_early(char **cmdline_p)
331 {
332         char c = ' ', cn, *to = command_line, *from = COMMAND_LINE;
333         unsigned long delay = 0;
334
335         /* Save unparsed command line copy for /proc/cmdline */
336         memcpy(saved_command_line, COMMAND_LINE, COMMAND_LINE_SIZE);
337         saved_command_line[COMMAND_LINE_SIZE-1] = '\0';
338
339         for (;;) {
340                 /*
341                  * "mem=XXX[kKmM]" sets memsize
342                  */
343                 if (c == ' ' && strncmp(from, "mem=", 4) == 0) {
344                         memory_end = simple_strtoul(from+4, &from, 0);
345                         if ( *from == 'K' || *from == 'k' ) {
346                                 memory_end = memory_end << 10;
347                                 from++;
348                         } else if ( *from == 'M' || *from == 'm' ) {
349                                 memory_end = memory_end << 20;
350                                 from++;
351                         }
352                 }
353                 /*
354                  * "ipldelay=XXX[sm]" sets ipl delay in seconds or minutes
355                  */
356                 if (c == ' ' && strncmp(from, "ipldelay=", 9) == 0) {
357                         delay = simple_strtoul(from+9, &from, 0);
358                         if (*from == 's' || *from == 'S') {
359                                 delay = delay*1000000;
360                                 from++;
361                         } else if (*from == 'm' || *from == 'M') {
362                                 delay = delay*60*1000000;
363                                 from++;
364                         }
365                         /* now wait for the requested amount of time */
366                         udelay(delay);
367                 }
368                 cn = *(from++);
369                 if (!cn)
370                         break;
371                 if (cn == '\n')
372                         cn = ' ';  /* replace newlines with space */
373                 if (cn == 0x0d)
374                         cn = ' ';  /* replace 0x0d with space */
375                 if (cn == ' ' && c == ' ')
376                         continue;  /* remove additional spaces */
377                 c = cn;
378                 if (to - command_line >= COMMAND_LINE_SIZE)
379                         break;
380                 *(to++) = c;
381         }
382         if (c == ' ' && to > command_line) to--;
383         *to = '\0';
384         *cmdline_p = command_line;
385 }
386
387 static void __init
388 setup_lowcore(void)
389 {
390         struct _lowcore *lc;
391         int lc_pages;
392
393         /*
394          * Setup lowcore for boot cpu
395          */
396         lc_pages = sizeof(void *) == 8 ? 2 : 1;
397         lc = (struct _lowcore *)
398                 __alloc_bootmem(lc_pages * PAGE_SIZE, lc_pages * PAGE_SIZE, 0);
399         memset(lc, 0, lc_pages * PAGE_SIZE);
400         lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
401         lc->restart_psw.addr =
402                 PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
403         lc->external_new_psw.mask = PSW_KERNEL_BITS;
404         lc->external_new_psw.addr =
405                 PSW_ADDR_AMODE | (unsigned long) ext_int_handler;
406         lc->svc_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
407         lc->svc_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) system_call;
408         lc->program_new_psw.mask = PSW_KERNEL_BITS;
409         lc->program_new_psw.addr =
410                 PSW_ADDR_AMODE | (unsigned long)pgm_check_handler;
411         lc->mcck_new_psw.mask =
412                 PSW_KERNEL_BITS & ~PSW_MASK_MCHECK & ~PSW_MASK_DAT;
413         lc->mcck_new_psw.addr =
414                 PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
415         lc->io_new_psw.mask = PSW_KERNEL_BITS;
416         lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler;
417         lc->ipl_device = S390_lowcore.ipl_device;
418         lc->jiffy_timer = -1LL;
419         lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE;
420         lc->async_stack = (unsigned long)
421                 __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + ASYNC_SIZE;
422         lc->panic_stack = (unsigned long)
423                 __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + PAGE_SIZE;
424         lc->current_task = (unsigned long) init_thread_union.thread_info.task;
425         lc->thread_info = (unsigned long) &init_thread_union;
426 #ifndef CONFIG_ARCH_S390X
427         if (MACHINE_HAS_IEEE) {
428                 lc->extended_save_area_addr = (__u32)
429                         __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0);
430                 /* enable extended save area */
431                 ctl_set_bit(14, 29);
432         }
433 #endif
434 #ifdef CONFIG_ARCH_S390X
435         if (MACHINE_HAS_DIAG44)
436                 lc->diag44_opcode = 0x83000044;
437         else
438                 lc->diag44_opcode = 0x07000700;
439 #endif /* CONFIG_ARCH_S390X */
440         set_prefix((u32)(unsigned long) lc);
441 }
442
443 static void __init
444 setup_resources(void)
445 {
446         struct resource *res;
447         int i;
448
449         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
450                 res = alloc_bootmem_low(sizeof(struct resource));
451                 res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
452                 switch (memory_chunk[i].type) {
453                 case CHUNK_READ_WRITE:
454                         res->name = "System RAM";
455                         break;
456                 case CHUNK_READ_ONLY:
457                         res->name = "System ROM";
458                         res->flags |= IORESOURCE_READONLY;
459                         break;
460                 default:
461                         res->name = "reserved";
462                 }
463                 res->start = memory_chunk[i].addr;
464                 res->end = memory_chunk[i].addr +  memory_chunk[i].size - 1;
465                 request_resource(&iomem_resource, res);
466                 request_resource(res, &code_resource);
467                 request_resource(res, &data_resource);
468         }
469 }
470
471 static void __init
472 setup_memory(void)
473 {
474         unsigned long bootmap_size;
475         unsigned long start_pfn, end_pfn, init_pfn;
476         unsigned long last_rw_end;
477         int i;
478
479         /*
480          * partially used pages are not usable - thus
481          * we are rounding upwards:
482          */
483         start_pfn = (__pa(&_end) + PAGE_SIZE - 1) >> PAGE_SHIFT;
484         end_pfn = max_pfn = memory_end >> PAGE_SHIFT;
485
486         /* Initialize storage key for kernel pages */
487         for (init_pfn = 0 ; init_pfn < start_pfn; init_pfn++)
488                 page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);
489
490         /*
491          * Initialize the boot-time allocator (with low memory only):
492          */
493         bootmap_size = init_bootmem(start_pfn, end_pfn);
494
495         /*
496          * Register RAM areas with the bootmem allocator.
497          */
498         last_rw_end = start_pfn;
499
500         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
501                 unsigned long start_chunk, end_chunk;
502
503                 if (memory_chunk[i].type != CHUNK_READ_WRITE)
504                         continue;
505                 start_chunk = (memory_chunk[i].addr + PAGE_SIZE - 1);
506                 start_chunk >>= PAGE_SHIFT;
507                 end_chunk = (memory_chunk[i].addr + memory_chunk[i].size);
508                 end_chunk >>= PAGE_SHIFT;
509                 if (start_chunk < start_pfn)
510                         start_chunk = start_pfn;
511                 if (end_chunk > end_pfn)
512                         end_chunk = end_pfn;
513                 if (start_chunk < end_chunk) {
514                         /* Initialize storage key for RAM pages */
515                         for (init_pfn = start_chunk ; init_pfn < end_chunk;
516                              init_pfn++)
517                                 page_set_storage_key(init_pfn << PAGE_SHIFT,
518                                                      PAGE_DEFAULT_KEY);
519                         free_bootmem(start_chunk << PAGE_SHIFT,
520                                      (end_chunk - start_chunk) << PAGE_SHIFT);
521                         if (last_rw_end < start_chunk)
522                                 add_memory_hole(last_rw_end, start_chunk - 1);
523                         last_rw_end = end_chunk;
524                 }
525         }
526
527         psw_set_key(PAGE_DEFAULT_KEY);
528
529         if (last_rw_end < end_pfn - 1)
530                 add_memory_hole(last_rw_end, end_pfn - 1);
531
532         /*
533          * Reserve the bootmem bitmap itself as well. We do this in two
534          * steps (first step was init_bootmem()) because this catches
535          * the (very unlikely) case of us accidentally initializing the
536          * bootmem allocator with an invalid RAM area.
537          */
538         reserve_bootmem(start_pfn << PAGE_SHIFT, bootmap_size);
539
540 #ifdef CONFIG_BLK_DEV_INITRD
541         if (INITRD_START) {
542                 if (INITRD_START + INITRD_SIZE <= memory_end) {
543                         reserve_bootmem(INITRD_START, INITRD_SIZE);
544                         initrd_start = INITRD_START;
545                         initrd_end = initrd_start + INITRD_SIZE;
546                 } else {
547                         printk("initrd extends beyond end of memory "
548                                "(0x%08lx > 0x%08lx)\ndisabling initrd\n",
549                                initrd_start + INITRD_SIZE, memory_end);
550                         initrd_start = initrd_end = 0;
551                 }
552         }
553 #endif
554 }
555
556 /*
557  * Setup function called from init/main.c just after the banner
558  * was printed.
559  */
560
561 void __init
562 setup_arch(char **cmdline_p)
563 {
564         /*
565          * print what head.S has found out about the machine
566          */
567 #ifndef CONFIG_ARCH_S390X
568         printk((MACHINE_IS_VM) ?
569                "We are running under VM (31 bit mode)\n" :
570                "We are running native (31 bit mode)\n");
571         printk((MACHINE_HAS_IEEE) ?
572                "This machine has an IEEE fpu\n" :
573                "This machine has no IEEE fpu\n");
574 #else /* CONFIG_ARCH_S390X */
575         printk((MACHINE_IS_VM) ?
576                "We are running under VM (64 bit mode)\n" :
577                "We are running native (64 bit mode)\n");
578 #endif /* CONFIG_ARCH_S390X */
579
580         ROOT_DEV = Root_RAM0;
581 #ifndef CONFIG_ARCH_S390X
582         memory_end = memory_size & ~0x400000UL;  /* align memory end to 4MB */
583         /*
584          * We need some free virtual space to be able to do vmalloc.
585          * On a machine with 2GB memory we make sure that we have at
586          * least 128 MB free space for vmalloc.
587          */
588         if (memory_end > 1920*1024*1024)
589                 memory_end = 1920*1024*1024;
590 #else /* CONFIG_ARCH_S390X */
591         memory_end = memory_size & ~0x200000UL;  /* detected in head.s */
592 #endif /* CONFIG_ARCH_S390X */
593
594         init_mm.start_code = PAGE_OFFSET;
595         init_mm.end_code = (unsigned long) &_etext;
596         init_mm.end_data = (unsigned long) &_edata;
597         init_mm.brk = (unsigned long) &_end;
598
599         parse_cmdline_early(cmdline_p);
600
601         setup_memory();
602         setup_resources();
603         setup_lowcore();
604
605         cpu_init();
606         __cpu_logical_map[0] = S390_lowcore.cpu_data.cpu_addr;
607
608         /*
609          * Create kernel page tables and switch to virtual addressing.
610          */
611         paging_init();
612
613         /* Setup default console */
614         conmode_default();
615 }
616
617 void print_cpu_info(struct cpuinfo_S390 *cpuinfo)
618 {
619    printk("cpu %d "
620 #ifdef CONFIG_SMP
621            "phys_idx=%d "
622 #endif
623            "vers=%02X ident=%06X machine=%04X unused=%04X\n",
624            cpuinfo->cpu_nr,
625 #ifdef CONFIG_SMP
626            cpuinfo->cpu_addr,
627 #endif
628            cpuinfo->cpu_id.version,
629            cpuinfo->cpu_id.ident,
630            cpuinfo->cpu_id.machine,
631            cpuinfo->cpu_id.unused);
632 }
633
634 /*
635  * show_cpuinfo - Get information on one CPU for use by procfs.
636  */
637
638 static int show_cpuinfo(struct seq_file *m, void *v)
639 {
640         struct cpuinfo_S390 *cpuinfo;
641         unsigned long n = (unsigned long) v - 1;
642
643         if (!n) {
644                 seq_printf(m, "vendor_id       : IBM/S390\n"
645                                "# processors    : %i\n"
646                                "bogomips per cpu: %lu.%02lu\n",
647                                num_online_cpus(), loops_per_jiffy/(500000/HZ),
648                                (loops_per_jiffy/(5000/HZ))%100);
649         }
650         if (cpu_online(n)) {
651 #ifdef CONFIG_SMP
652                 if (smp_processor_id() == n)
653                         cpuinfo = &S390_lowcore.cpu_data;
654                 else
655                         cpuinfo = &lowcore_ptr[n]->cpu_data;
656 #else
657                 cpuinfo = &S390_lowcore.cpu_data;
658 #endif
659                 seq_printf(m, "processor %li: "
660                                "version = %02X,  "
661                                "identification = %06X,  "
662                                "machine = %04X\n",
663                                n, cpuinfo->cpu_id.version,
664                                cpuinfo->cpu_id.ident,
665                                cpuinfo->cpu_id.machine);
666         }
667         return 0;
668 }
669
670 static void *c_start(struct seq_file *m, loff_t *pos)
671 {
672         return *pos < NR_CPUS ? (void *)((unsigned long) *pos + 1) : NULL;
673 }
674 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
675 {
676         ++*pos;
677         return c_start(m, pos);
678 }
679 static void c_stop(struct seq_file *m, void *v)
680 {
681 }
682 struct seq_operations cpuinfo_op = {
683         .start  = c_start,
684         .next   = c_next,
685         .stop   = c_stop,
686         .show   = show_cpuinfo,
687 };
688