Merge with rsync://rsync.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git
[linux-2.6] / 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 EXPORT_SYMBOL(machine_restart);
303
304 void machine_halt(void)
305 {
306         console_unblank();
307         _machine_halt();
308 }
309
310 EXPORT_SYMBOL(machine_halt);
311
312 void machine_power_off(void)
313 {
314         console_unblank();
315         _machine_power_off();
316 }
317
318 EXPORT_SYMBOL(machine_power_off);
319
320 static void __init
321 add_memory_hole(unsigned long start, unsigned long end)
322 {
323         unsigned long dma_pfn = MAX_DMA_ADDRESS >> PAGE_SHIFT;
324
325         if (end <= dma_pfn)
326                 zholes_size[ZONE_DMA] += end - start + 1;
327         else if (start > dma_pfn)
328                 zholes_size[ZONE_NORMAL] += end - start + 1;
329         else {
330                 zholes_size[ZONE_DMA] += dma_pfn - start + 1;
331                 zholes_size[ZONE_NORMAL] += end - dma_pfn;
332         }
333 }
334
335 static void __init
336 parse_cmdline_early(char **cmdline_p)
337 {
338         char c = ' ', cn, *to = command_line, *from = COMMAND_LINE;
339         unsigned long delay = 0;
340
341         /* Save unparsed command line copy for /proc/cmdline */
342         memcpy(saved_command_line, COMMAND_LINE, COMMAND_LINE_SIZE);
343         saved_command_line[COMMAND_LINE_SIZE-1] = '\0';
344
345         for (;;) {
346                 /*
347                  * "mem=XXX[kKmM]" sets memsize
348                  */
349                 if (c == ' ' && strncmp(from, "mem=", 4) == 0) {
350                         memory_end = simple_strtoul(from+4, &from, 0);
351                         if ( *from == 'K' || *from == 'k' ) {
352                                 memory_end = memory_end << 10;
353                                 from++;
354                         } else if ( *from == 'M' || *from == 'm' ) {
355                                 memory_end = memory_end << 20;
356                                 from++;
357                         }
358                 }
359                 /*
360                  * "ipldelay=XXX[sm]" sets ipl delay in seconds or minutes
361                  */
362                 if (c == ' ' && strncmp(from, "ipldelay=", 9) == 0) {
363                         delay = simple_strtoul(from+9, &from, 0);
364                         if (*from == 's' || *from == 'S') {
365                                 delay = delay*1000000;
366                                 from++;
367                         } else if (*from == 'm' || *from == 'M') {
368                                 delay = delay*60*1000000;
369                                 from++;
370                         }
371                         /* now wait for the requested amount of time */
372                         udelay(delay);
373                 }
374                 cn = *(from++);
375                 if (!cn)
376                         break;
377                 if (cn == '\n')
378                         cn = ' ';  /* replace newlines with space */
379                 if (cn == 0x0d)
380                         cn = ' ';  /* replace 0x0d with space */
381                 if (cn == ' ' && c == ' ')
382                         continue;  /* remove additional spaces */
383                 c = cn;
384                 if (to - command_line >= COMMAND_LINE_SIZE)
385                         break;
386                 *(to++) = c;
387         }
388         if (c == ' ' && to > command_line) to--;
389         *to = '\0';
390         *cmdline_p = command_line;
391 }
392
393 static void __init
394 setup_lowcore(void)
395 {
396         struct _lowcore *lc;
397         int lc_pages;
398
399         /*
400          * Setup lowcore for boot cpu
401          */
402         lc_pages = sizeof(void *) == 8 ? 2 : 1;
403         lc = (struct _lowcore *)
404                 __alloc_bootmem(lc_pages * PAGE_SIZE, lc_pages * PAGE_SIZE, 0);
405         memset(lc, 0, lc_pages * PAGE_SIZE);
406         lc->restart_psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
407         lc->restart_psw.addr =
408                 PSW_ADDR_AMODE | (unsigned long) restart_int_handler;
409         lc->external_new_psw.mask = PSW_KERNEL_BITS;
410         lc->external_new_psw.addr =
411                 PSW_ADDR_AMODE | (unsigned long) ext_int_handler;
412         lc->svc_new_psw.mask = PSW_KERNEL_BITS | PSW_MASK_IO | PSW_MASK_EXT;
413         lc->svc_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) system_call;
414         lc->program_new_psw.mask = PSW_KERNEL_BITS;
415         lc->program_new_psw.addr =
416                 PSW_ADDR_AMODE | (unsigned long)pgm_check_handler;
417         lc->mcck_new_psw.mask =
418                 PSW_KERNEL_BITS & ~PSW_MASK_MCHECK & ~PSW_MASK_DAT;
419         lc->mcck_new_psw.addr =
420                 PSW_ADDR_AMODE | (unsigned long) mcck_int_handler;
421         lc->io_new_psw.mask = PSW_KERNEL_BITS;
422         lc->io_new_psw.addr = PSW_ADDR_AMODE | (unsigned long) io_int_handler;
423         lc->ipl_device = S390_lowcore.ipl_device;
424         lc->jiffy_timer = -1LL;
425         lc->kernel_stack = ((unsigned long) &init_thread_union) + THREAD_SIZE;
426         lc->async_stack = (unsigned long)
427                 __alloc_bootmem(ASYNC_SIZE, ASYNC_SIZE, 0) + ASYNC_SIZE;
428         lc->panic_stack = (unsigned long)
429                 __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0) + PAGE_SIZE;
430         lc->current_task = (unsigned long) init_thread_union.thread_info.task;
431         lc->thread_info = (unsigned long) &init_thread_union;
432 #ifndef CONFIG_ARCH_S390X
433         if (MACHINE_HAS_IEEE) {
434                 lc->extended_save_area_addr = (__u32)
435                         __alloc_bootmem(PAGE_SIZE, PAGE_SIZE, 0);
436                 /* enable extended save area */
437                 ctl_set_bit(14, 29);
438         }
439 #endif
440 #ifdef CONFIG_ARCH_S390X
441         if (MACHINE_HAS_DIAG44)
442                 lc->diag44_opcode = 0x83000044;
443         else
444                 lc->diag44_opcode = 0x07000700;
445 #endif /* CONFIG_ARCH_S390X */
446         set_prefix((u32)(unsigned long) lc);
447 }
448
449 static void __init
450 setup_resources(void)
451 {
452         struct resource *res;
453         int i;
454
455         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
456                 res = alloc_bootmem_low(sizeof(struct resource));
457                 res->flags = IORESOURCE_BUSY | IORESOURCE_MEM;
458                 switch (memory_chunk[i].type) {
459                 case CHUNK_READ_WRITE:
460                         res->name = "System RAM";
461                         break;
462                 case CHUNK_READ_ONLY:
463                         res->name = "System ROM";
464                         res->flags |= IORESOURCE_READONLY;
465                         break;
466                 default:
467                         res->name = "reserved";
468                 }
469                 res->start = memory_chunk[i].addr;
470                 res->end = memory_chunk[i].addr +  memory_chunk[i].size - 1;
471                 request_resource(&iomem_resource, res);
472                 request_resource(res, &code_resource);
473                 request_resource(res, &data_resource);
474         }
475 }
476
477 static void __init
478 setup_memory(void)
479 {
480         unsigned long bootmap_size;
481         unsigned long start_pfn, end_pfn, init_pfn;
482         unsigned long last_rw_end;
483         int i;
484
485         /*
486          * partially used pages are not usable - thus
487          * we are rounding upwards:
488          */
489         start_pfn = (__pa(&_end) + PAGE_SIZE - 1) >> PAGE_SHIFT;
490         end_pfn = max_pfn = memory_end >> PAGE_SHIFT;
491
492         /* Initialize storage key for kernel pages */
493         for (init_pfn = 0 ; init_pfn < start_pfn; init_pfn++)
494                 page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);
495
496         /*
497          * Initialize the boot-time allocator (with low memory only):
498          */
499         bootmap_size = init_bootmem(start_pfn, end_pfn);
500
501         /*
502          * Register RAM areas with the bootmem allocator.
503          */
504         last_rw_end = start_pfn;
505
506         for (i = 0; i < MEMORY_CHUNKS && memory_chunk[i].size > 0; i++) {
507                 unsigned long start_chunk, end_chunk;
508
509                 if (memory_chunk[i].type != CHUNK_READ_WRITE)
510                         continue;
511                 start_chunk = (memory_chunk[i].addr + PAGE_SIZE - 1);
512                 start_chunk >>= PAGE_SHIFT;
513                 end_chunk = (memory_chunk[i].addr + memory_chunk[i].size);
514                 end_chunk >>= PAGE_SHIFT;
515                 if (start_chunk < start_pfn)
516                         start_chunk = start_pfn;
517                 if (end_chunk > end_pfn)
518                         end_chunk = end_pfn;
519                 if (start_chunk < end_chunk) {
520                         /* Initialize storage key for RAM pages */
521                         for (init_pfn = start_chunk ; init_pfn < end_chunk;
522                              init_pfn++)
523                                 page_set_storage_key(init_pfn << PAGE_SHIFT,
524                                                      PAGE_DEFAULT_KEY);
525                         free_bootmem(start_chunk << PAGE_SHIFT,
526                                      (end_chunk - start_chunk) << PAGE_SHIFT);
527                         if (last_rw_end < start_chunk)
528                                 add_memory_hole(last_rw_end, start_chunk - 1);
529                         last_rw_end = end_chunk;
530                 }
531         }
532
533         psw_set_key(PAGE_DEFAULT_KEY);
534
535         if (last_rw_end < end_pfn - 1)
536                 add_memory_hole(last_rw_end, end_pfn - 1);
537
538         /*
539          * Reserve the bootmem bitmap itself as well. We do this in two
540          * steps (first step was init_bootmem()) because this catches
541          * the (very unlikely) case of us accidentally initializing the
542          * bootmem allocator with an invalid RAM area.
543          */
544         reserve_bootmem(start_pfn << PAGE_SHIFT, bootmap_size);
545
546 #ifdef CONFIG_BLK_DEV_INITRD
547         if (INITRD_START) {
548                 if (INITRD_START + INITRD_SIZE <= memory_end) {
549                         reserve_bootmem(INITRD_START, INITRD_SIZE);
550                         initrd_start = INITRD_START;
551                         initrd_end = initrd_start + INITRD_SIZE;
552                 } else {
553                         printk("initrd extends beyond end of memory "
554                                "(0x%08lx > 0x%08lx)\ndisabling initrd\n",
555                                initrd_start + INITRD_SIZE, memory_end);
556                         initrd_start = initrd_end = 0;
557                 }
558         }
559 #endif
560 }
561
562 /*
563  * Setup function called from init/main.c just after the banner
564  * was printed.
565  */
566
567 void __init
568 setup_arch(char **cmdline_p)
569 {
570         /*
571          * print what head.S has found out about the machine
572          */
573 #ifndef CONFIG_ARCH_S390X
574         printk((MACHINE_IS_VM) ?
575                "We are running under VM (31 bit mode)\n" :
576                "We are running native (31 bit mode)\n");
577         printk((MACHINE_HAS_IEEE) ?
578                "This machine has an IEEE fpu\n" :
579                "This machine has no IEEE fpu\n");
580 #else /* CONFIG_ARCH_S390X */
581         printk((MACHINE_IS_VM) ?
582                "We are running under VM (64 bit mode)\n" :
583                "We are running native (64 bit mode)\n");
584 #endif /* CONFIG_ARCH_S390X */
585
586         ROOT_DEV = Root_RAM0;
587 #ifndef CONFIG_ARCH_S390X
588         memory_end = memory_size & ~0x400000UL;  /* align memory end to 4MB */
589         /*
590          * We need some free virtual space to be able to do vmalloc.
591          * On a machine with 2GB memory we make sure that we have at
592          * least 128 MB free space for vmalloc.
593          */
594         if (memory_end > 1920*1024*1024)
595                 memory_end = 1920*1024*1024;
596 #else /* CONFIG_ARCH_S390X */
597         memory_end = memory_size & ~0x200000UL;  /* detected in head.s */
598 #endif /* CONFIG_ARCH_S390X */
599
600         init_mm.start_code = PAGE_OFFSET;
601         init_mm.end_code = (unsigned long) &_etext;
602         init_mm.end_data = (unsigned long) &_edata;
603         init_mm.brk = (unsigned long) &_end;
604
605         parse_cmdline_early(cmdline_p);
606
607         setup_memory();
608         setup_resources();
609         setup_lowcore();
610
611         cpu_init();
612         __cpu_logical_map[0] = S390_lowcore.cpu_data.cpu_addr;
613
614         /*
615          * Create kernel page tables and switch to virtual addressing.
616          */
617         paging_init();
618
619         /* Setup default console */
620         conmode_default();
621 }
622
623 void print_cpu_info(struct cpuinfo_S390 *cpuinfo)
624 {
625    printk("cpu %d "
626 #ifdef CONFIG_SMP
627            "phys_idx=%d "
628 #endif
629            "vers=%02X ident=%06X machine=%04X unused=%04X\n",
630            cpuinfo->cpu_nr,
631 #ifdef CONFIG_SMP
632            cpuinfo->cpu_addr,
633 #endif
634            cpuinfo->cpu_id.version,
635            cpuinfo->cpu_id.ident,
636            cpuinfo->cpu_id.machine,
637            cpuinfo->cpu_id.unused);
638 }
639
640 /*
641  * show_cpuinfo - Get information on one CPU for use by procfs.
642  */
643
644 static int show_cpuinfo(struct seq_file *m, void *v)
645 {
646         struct cpuinfo_S390 *cpuinfo;
647         unsigned long n = (unsigned long) v - 1;
648
649         if (!n) {
650                 seq_printf(m, "vendor_id       : IBM/S390\n"
651                                "# processors    : %i\n"
652                                "bogomips per cpu: %lu.%02lu\n",
653                                num_online_cpus(), loops_per_jiffy/(500000/HZ),
654                                (loops_per_jiffy/(5000/HZ))%100);
655         }
656         if (cpu_online(n)) {
657 #ifdef CONFIG_SMP
658                 if (smp_processor_id() == n)
659                         cpuinfo = &S390_lowcore.cpu_data;
660                 else
661                         cpuinfo = &lowcore_ptr[n]->cpu_data;
662 #else
663                 cpuinfo = &S390_lowcore.cpu_data;
664 #endif
665                 seq_printf(m, "processor %li: "
666                                "version = %02X,  "
667                                "identification = %06X,  "
668                                "machine = %04X\n",
669                                n, cpuinfo->cpu_id.version,
670                                cpuinfo->cpu_id.ident,
671                                cpuinfo->cpu_id.machine);
672         }
673         return 0;
674 }
675
676 static void *c_start(struct seq_file *m, loff_t *pos)
677 {
678         return *pos < NR_CPUS ? (void *)((unsigned long) *pos + 1) : NULL;
679 }
680 static void *c_next(struct seq_file *m, void *v, loff_t *pos)
681 {
682         ++*pos;
683         return c_start(m, pos);
684 }
685 static void c_stop(struct seq_file *m, void *v)
686 {
687 }
688 struct seq_operations cpuinfo_op = {
689         .start  = c_start,
690         .next   = c_next,
691         .stop   = c_stop,
692         .show   = show_cpuinfo,
693 };
694