GNU Linux-libre 6.1.91-gnu
[releases.git] / arch / xtensa / kernel / setup.c
1 /*
2  * arch/xtensa/kernel/setup.c
3  *
4  * This file is subject to the terms and conditions of the GNU General Public
5  * License.  See the file "COPYING" in the main directory of this archive
6  * for more details.
7  *
8  * Copyright (C) 1995  Linus Torvalds
9  * Copyright (C) 2001 - 2005  Tensilica Inc.
10  * Copyright (C) 2014 - 2016  Cadence Design Systems Inc.
11  *
12  * Chris Zankel <chris@zankel.net>
13  * Joe Taylor   <joe@tensilica.com, joetylr@yahoo.com>
14  * Kevin Chea
15  * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
16  */
17
18 #include <linux/errno.h>
19 #include <linux/init.h>
20 #include <linux/mm.h>
21 #include <linux/proc_fs.h>
22 #include <linux/screen_info.h>
23 #include <linux/kernel.h>
24 #include <linux/percpu.h>
25 #include <linux/cpu.h>
26 #include <linux/of.h>
27 #include <linux/of_fdt.h>
28
29 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
30 # include <linux/console.h>
31 #endif
32
33 #ifdef CONFIG_PROC_FS
34 # include <linux/seq_file.h>
35 #endif
36
37 #include <asm/bootparam.h>
38 #include <asm/kasan.h>
39 #include <asm/mmu_context.h>
40 #include <asm/page.h>
41 #include <asm/param.h>
42 #include <asm/platform.h>
43 #include <asm/processor.h>
44 #include <asm/sections.h>
45 #include <asm/setup.h>
46 #include <asm/smp.h>
47 #include <asm/sysmem.h>
48 #include <asm/timex.h>
49
50 #if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
51 struct screen_info screen_info = {
52         .orig_x = 0,
53         .orig_y = 24,
54         .orig_video_cols = 80,
55         .orig_video_lines = 24,
56         .orig_video_isVGA = 1,
57         .orig_video_points = 16,
58 };
59 #endif
60
61 #ifdef CONFIG_BLK_DEV_INITRD
62 extern unsigned long initrd_start;
63 extern unsigned long initrd_end;
64 extern int initrd_below_start_ok;
65 #endif
66
67 #ifdef CONFIG_USE_OF
68 void *dtb_start = __dtb_start;
69 #endif
70
71 extern unsigned long loops_per_jiffy;
72
73 /* Command line specified as configuration option. */
74
75 static char __initdata command_line[COMMAND_LINE_SIZE];
76
77 #ifdef CONFIG_CMDLINE_BOOL
78 static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
79 #endif
80
81 #ifdef CONFIG_PARSE_BOOTPARAM
82 /*
83  * Boot parameter parsing.
84  *
85  * The Xtensa port uses a list of variable-sized tags to pass data to
86  * the kernel. The first tag must be a BP_TAG_FIRST tag for the list
87  * to be recognised. The list is terminated with a zero-sized
88  * BP_TAG_LAST tag.
89  */
90
91 typedef struct tagtable {
92         u32 tag;
93         int (*parse)(const bp_tag_t*);
94 } tagtable_t;
95
96 #define __tagtable(tag, fn) static tagtable_t __tagtable_##fn           \
97         __section(".taglist") __attribute__((used)) = { tag, fn }
98
99 /* parse current tag */
100
101 static int __init parse_tag_mem(const bp_tag_t *tag)
102 {
103         struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data);
104
105         if (mi->type != MEMORY_TYPE_CONVENTIONAL)
106                 return -1;
107
108         return memblock_add(mi->start, mi->end - mi->start);
109 }
110
111 __tagtable(BP_TAG_MEMORY, parse_tag_mem);
112
113 #ifdef CONFIG_BLK_DEV_INITRD
114
115 static int __init parse_tag_initrd(const bp_tag_t* tag)
116 {
117         struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data);
118
119         initrd_start = (unsigned long)__va(mi->start);
120         initrd_end = (unsigned long)__va(mi->end);
121
122         return 0;
123 }
124
125 __tagtable(BP_TAG_INITRD, parse_tag_initrd);
126
127 #endif /* CONFIG_BLK_DEV_INITRD */
128
129 #ifdef CONFIG_USE_OF
130
131 static int __init parse_tag_fdt(const bp_tag_t *tag)
132 {
133         dtb_start = __va(tag->data[0]);
134         return 0;
135 }
136
137 __tagtable(BP_TAG_FDT, parse_tag_fdt);
138
139 #endif /* CONFIG_USE_OF */
140
141 static int __init parse_tag_cmdline(const bp_tag_t* tag)
142 {
143         strscpy(command_line, (char *)(tag->data), COMMAND_LINE_SIZE);
144         return 0;
145 }
146
147 __tagtable(BP_TAG_COMMAND_LINE, parse_tag_cmdline);
148
149 static int __init parse_bootparam(const bp_tag_t* tag)
150 {
151         extern tagtable_t __tagtable_begin, __tagtable_end;
152         tagtable_t *t;
153
154         /* Boot parameters must start with a BP_TAG_FIRST tag. */
155
156         if (tag->id != BP_TAG_FIRST) {
157                 pr_warn("Invalid boot parameters!\n");
158                 return 0;
159         }
160
161         tag = (bp_tag_t*)((unsigned long)tag + sizeof(bp_tag_t) + tag->size);
162
163         /* Parse all tags. */
164
165         while (tag != NULL && tag->id != BP_TAG_LAST) {
166                 for (t = &__tagtable_begin; t < &__tagtable_end; t++) {
167                         if (tag->id == t->tag) {
168                                 t->parse(tag);
169                                 break;
170                         }
171                 }
172                 if (t == &__tagtable_end)
173                         pr_warn("Ignoring tag 0x%08x\n", tag->id);
174                 tag = (bp_tag_t*)((unsigned long)(tag + 1) + tag->size);
175         }
176
177         return 0;
178 }
179 #else
180 static int __init parse_bootparam(const bp_tag_t *tag)
181 {
182         pr_info("Ignoring boot parameters at %p\n", tag);
183         return 0;
184 }
185 #endif
186
187 #ifdef CONFIG_USE_OF
188
189 #if !XCHAL_HAVE_PTP_MMU || XCHAL_HAVE_SPANNING_WAY
190 unsigned long xtensa_kio_paddr = XCHAL_KIO_DEFAULT_PADDR;
191 EXPORT_SYMBOL(xtensa_kio_paddr);
192
193 static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
194                 int depth, void *data)
195 {
196         const __be32 *ranges;
197         int len;
198
199         if (depth > 1)
200                 return 0;
201
202         if (!of_flat_dt_is_compatible(node, "simple-bus"))
203                 return 0;
204
205         ranges = of_get_flat_dt_prop(node, "ranges", &len);
206         if (!ranges)
207                 return 1;
208         if (len == 0)
209                 return 1;
210
211         xtensa_kio_paddr = of_read_ulong(ranges+1, 1);
212         /* round down to nearest 256MB boundary */
213         xtensa_kio_paddr &= 0xf0000000;
214
215         init_kio();
216
217         return 1;
218 }
219 #else
220 static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
221                 int depth, void *data)
222 {
223         return 1;
224 }
225 #endif
226
227 void __init early_init_devtree(void *params)
228 {
229         early_init_dt_scan(params);
230         of_scan_flat_dt(xtensa_dt_io_area, NULL);
231
232         if (!command_line[0])
233                 strscpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
234 }
235
236 #endif /* CONFIG_USE_OF */
237
238 /*
239  * Initialize architecture. (Early stage)
240  */
241
242 void __init init_arch(bp_tag_t *bp_start)
243 {
244         /* Initialize MMU. */
245
246         init_mmu();
247
248         /* Initialize initial KASAN shadow map */
249
250         kasan_early_init();
251
252         /* Parse boot parameters */
253
254         if (bp_start)
255                 parse_bootparam(bp_start);
256
257 #ifdef CONFIG_USE_OF
258         early_init_devtree(dtb_start);
259 #endif
260
261 #ifdef CONFIG_CMDLINE_BOOL
262         if (!command_line[0])
263                 strscpy(command_line, default_command_line, COMMAND_LINE_SIZE);
264 #endif
265
266         /* Early hook for platforms */
267
268         platform_init(bp_start);
269 }
270
271 /*
272  * Initialize system. Setup memory and reserve regions.
273  */
274
275 static inline int __init_memblock mem_reserve(unsigned long start,
276                                               unsigned long end)
277 {
278         return memblock_reserve(start, end - start);
279 }
280
281 void __init setup_arch(char **cmdline_p)
282 {
283         pr_info("config ID: %08x:%08x\n",
284                 xtensa_get_sr(SREG_EPC), xtensa_get_sr(SREG_EXCSAVE));
285         if (xtensa_get_sr(SREG_EPC) != XCHAL_HW_CONFIGID0 ||
286             xtensa_get_sr(SREG_EXCSAVE) != XCHAL_HW_CONFIGID1)
287                 pr_info("built for config ID: %08x:%08x\n",
288                         XCHAL_HW_CONFIGID0, XCHAL_HW_CONFIGID1);
289
290         *cmdline_p = command_line;
291         platform_setup(cmdline_p);
292         strscpy(boot_command_line, *cmdline_p, COMMAND_LINE_SIZE);
293
294         /* Reserve some memory regions */
295
296 #ifdef CONFIG_BLK_DEV_INITRD
297         if (initrd_start < initrd_end &&
298             !mem_reserve(__pa(initrd_start), __pa(initrd_end)))
299                 initrd_below_start_ok = 1;
300         else
301                 initrd_start = 0;
302 #endif
303
304         mem_reserve(__pa(_stext), __pa(_end));
305 #ifdef CONFIG_XIP_KERNEL
306         mem_reserve(__pa(_xip_start), __pa(_xip_end));
307 #endif
308
309 #ifdef CONFIG_VECTORS_ADDR
310 #ifdef SUPPORT_WINDOWED
311         mem_reserve(__pa(_WindowVectors_text_start),
312                     __pa(_WindowVectors_text_end));
313 #endif
314
315         mem_reserve(__pa(_DebugInterruptVector_text_start),
316                     __pa(_DebugInterruptVector_text_end));
317
318         mem_reserve(__pa(_KernelExceptionVector_text_start),
319                     __pa(_KernelExceptionVector_text_end));
320
321         mem_reserve(__pa(_UserExceptionVector_text_start),
322                     __pa(_UserExceptionVector_text_end));
323
324         mem_reserve(__pa(_DoubleExceptionVector_text_start),
325                     __pa(_DoubleExceptionVector_text_end));
326
327         mem_reserve(__pa(_exception_text_start),
328                     __pa(_exception_text_end));
329 #if XCHAL_EXCM_LEVEL >= 2
330         mem_reserve(__pa(_Level2InterruptVector_text_start),
331                     __pa(_Level2InterruptVector_text_end));
332 #endif
333 #if XCHAL_EXCM_LEVEL >= 3
334         mem_reserve(__pa(_Level3InterruptVector_text_start),
335                     __pa(_Level3InterruptVector_text_end));
336 #endif
337 #if XCHAL_EXCM_LEVEL >= 4
338         mem_reserve(__pa(_Level4InterruptVector_text_start),
339                     __pa(_Level4InterruptVector_text_end));
340 #endif
341 #if XCHAL_EXCM_LEVEL >= 5
342         mem_reserve(__pa(_Level5InterruptVector_text_start),
343                     __pa(_Level5InterruptVector_text_end));
344 #endif
345 #if XCHAL_EXCM_LEVEL >= 6
346         mem_reserve(__pa(_Level6InterruptVector_text_start),
347                     __pa(_Level6InterruptVector_text_end));
348 #endif
349
350 #endif /* CONFIG_VECTORS_ADDR */
351
352 #ifdef CONFIG_SECONDARY_RESET_VECTOR
353         mem_reserve(__pa(_SecondaryResetVector_text_start),
354                     __pa(_SecondaryResetVector_text_end));
355 #endif
356         parse_early_param();
357         bootmem_init();
358         kasan_init();
359         unflatten_and_copy_device_tree();
360
361 #ifdef CONFIG_SMP
362         smp_init_cpus();
363 #endif
364
365         paging_init();
366         zones_init();
367
368 #ifdef CONFIG_VT
369 # if defined(CONFIG_VGA_CONSOLE)
370         conswitchp = &vga_con;
371 # endif
372 #endif
373 }
374
375 static DEFINE_PER_CPU(struct cpu, cpu_data);
376
377 static int __init topology_init(void)
378 {
379         int i;
380
381         for_each_possible_cpu(i) {
382                 struct cpu *cpu = &per_cpu(cpu_data, i);
383                 cpu->hotpluggable = !!i;
384                 register_cpu(cpu, i);
385         }
386
387         return 0;
388 }
389 subsys_initcall(topology_init);
390
391 void cpu_reset(void)
392 {
393 #if XCHAL_HAVE_PTP_MMU && IS_ENABLED(CONFIG_MMU)
394         local_irq_disable();
395         /*
396          * We have full MMU: all autoload ways, ways 7, 8 and 9 of DTLB must
397          * be flushed.
398          * Way 4 is not currently used by linux.
399          * Ways 5 and 6 shall not be touched on MMUv2 as they are hardwired.
400          * Way 5 shall be flushed and way 6 shall be set to identity mapping
401          * on MMUv3.
402          */
403         local_flush_tlb_all();
404         invalidate_page_directory();
405 #if XCHAL_HAVE_SPANNING_WAY
406         /* MMU v3 */
407         {
408                 unsigned long vaddr = (unsigned long)cpu_reset;
409                 unsigned long paddr = __pa(vaddr);
410                 unsigned long tmpaddr = vaddr + SZ_512M;
411                 unsigned long tmp0, tmp1, tmp2, tmp3;
412
413                 /*
414                  * Find a place for the temporary mapping. It must not be
415                  * in the same 512MB region with vaddr or paddr, otherwise
416                  * there may be multihit exception either on entry to the
417                  * temporary mapping, or on entry to the identity mapping.
418                  * (512MB is the biggest page size supported by TLB.)
419                  */
420                 while (((tmpaddr ^ paddr) & -SZ_512M) == 0)
421                         tmpaddr += SZ_512M;
422
423                 /* Invalidate mapping in the selected temporary area */
424                 if (itlb_probe(tmpaddr) & BIT(ITLB_HIT_BIT))
425                         invalidate_itlb_entry(itlb_probe(tmpaddr));
426                 if (itlb_probe(tmpaddr + PAGE_SIZE) & BIT(ITLB_HIT_BIT))
427                         invalidate_itlb_entry(itlb_probe(tmpaddr + PAGE_SIZE));
428
429                 /*
430                  * Map two consecutive pages starting at the physical address
431                  * of this function to the temporary mapping area.
432                  */
433                 write_itlb_entry(__pte((paddr & PAGE_MASK) |
434                                        _PAGE_HW_VALID |
435                                        _PAGE_HW_EXEC |
436                                        _PAGE_CA_BYPASS),
437                                  tmpaddr & PAGE_MASK);
438                 write_itlb_entry(__pte(((paddr & PAGE_MASK) + PAGE_SIZE) |
439                                        _PAGE_HW_VALID |
440                                        _PAGE_HW_EXEC |
441                                        _PAGE_CA_BYPASS),
442                                  (tmpaddr & PAGE_MASK) + PAGE_SIZE);
443
444                 /* Reinitialize TLB */
445                 __asm__ __volatile__ ("movi     %0, 1f\n\t"
446                                       "movi     %3, 2f\n\t"
447                                       "add      %0, %0, %4\n\t"
448                                       "add      %3, %3, %5\n\t"
449                                       "jx       %0\n"
450                                       /*
451                                        * No literal, data or stack access
452                                        * below this point
453                                        */
454                                       "1:\n\t"
455                                       /* Initialize *tlbcfg */
456                                       "movi     %0, 0\n\t"
457                                       "wsr      %0, itlbcfg\n\t"
458                                       "wsr      %0, dtlbcfg\n\t"
459                                       /* Invalidate TLB way 5 */
460                                       "movi     %0, 4\n\t"
461                                       "movi     %1, 5\n"
462                                       "1:\n\t"
463                                       "iitlb    %1\n\t"
464                                       "idtlb    %1\n\t"
465                                       "add      %1, %1, %6\n\t"
466                                       "addi     %0, %0, -1\n\t"
467                                       "bnez     %0, 1b\n\t"
468                                       /* Initialize TLB way 6 */
469                                       "movi     %0, 7\n\t"
470                                       "addi     %1, %9, 3\n\t"
471                                       "addi     %2, %9, 6\n"
472                                       "1:\n\t"
473                                       "witlb    %1, %2\n\t"
474                                       "wdtlb    %1, %2\n\t"
475                                       "add      %1, %1, %7\n\t"
476                                       "add      %2, %2, %7\n\t"
477                                       "addi     %0, %0, -1\n\t"
478                                       "bnez     %0, 1b\n\t"
479                                       "isync\n\t"
480                                       /* Jump to identity mapping */
481                                       "jx       %3\n"
482                                       "2:\n\t"
483                                       /* Complete way 6 initialization */
484                                       "witlb    %1, %2\n\t"
485                                       "wdtlb    %1, %2\n\t"
486                                       /* Invalidate temporary mapping */
487                                       "sub      %0, %9, %7\n\t"
488                                       "iitlb    %0\n\t"
489                                       "add      %0, %0, %8\n\t"
490                                       "iitlb    %0"
491                                       : "=&a"(tmp0), "=&a"(tmp1), "=&a"(tmp2),
492                                         "=&a"(tmp3)
493                                       : "a"(tmpaddr - vaddr),
494                                         "a"(paddr - vaddr),
495                                         "a"(SZ_128M), "a"(SZ_512M),
496                                         "a"(PAGE_SIZE),
497                                         "a"((tmpaddr + SZ_512M) & PAGE_MASK)
498                                       : "memory");
499         }
500 #endif
501 #endif
502         __asm__ __volatile__ ("movi     a2, 0\n\t"
503                               "wsr      a2, icountlevel\n\t"
504                               "movi     a2, 0\n\t"
505                               "wsr      a2, icount\n\t"
506 #if XCHAL_NUM_IBREAK > 0
507                               "wsr      a2, ibreakenable\n\t"
508 #endif
509 #if XCHAL_HAVE_LOOPS
510                               "wsr      a2, lcount\n\t"
511 #endif
512                               "movi     a2, 0x1f\n\t"
513                               "wsr      a2, ps\n\t"
514                               "isync\n\t"
515                               "jx       %0\n\t"
516                               :
517                               : "a" (XCHAL_RESET_VECTOR_VADDR)
518                               : "a2");
519         for (;;)
520                 ;
521 }
522
523 void machine_restart(char * cmd)
524 {
525         platform_restart();
526 }
527
528 void machine_halt(void)
529 {
530         platform_halt();
531         while (1);
532 }
533
534 void machine_power_off(void)
535 {
536         platform_power_off();
537         while (1);
538 }
539 #ifdef CONFIG_PROC_FS
540
541 /*
542  * Display some core information through /proc/cpuinfo.
543  */
544
545 static int
546 c_show(struct seq_file *f, void *slot)
547 {
548         /* high-level stuff */
549         seq_printf(f, "CPU count\t: %u\n"
550                       "CPU list\t: %*pbl\n"
551                       "vendor_id\t: Tensilica\n"
552                       "model\t\t: Xtensa " XCHAL_HW_VERSION_NAME "\n"
553                       "core ID\t\t: " XCHAL_CORE_ID "\n"
554                       "build ID\t: 0x%x\n"
555                       "config ID\t: %08x:%08x\n"
556                       "byte order\t: %s\n"
557                       "cpu MHz\t\t: %lu.%02lu\n"
558                       "bogomips\t: %lu.%02lu\n",
559                       num_online_cpus(),
560                       cpumask_pr_args(cpu_online_mask),
561                       XCHAL_BUILD_UNIQUE_ID,
562                       xtensa_get_sr(SREG_EPC), xtensa_get_sr(SREG_EXCSAVE),
563                       XCHAL_HAVE_BE ?  "big" : "little",
564                       ccount_freq/1000000,
565                       (ccount_freq/10000) % 100,
566                       loops_per_jiffy/(500000/HZ),
567                       (loops_per_jiffy/(5000/HZ)) % 100);
568         seq_puts(f, "flags\t\t: "
569 #if XCHAL_HAVE_NMI
570                      "nmi "
571 #endif
572 #if XCHAL_HAVE_DEBUG
573                      "debug "
574 # if XCHAL_HAVE_OCD
575                      "ocd "
576 # endif
577 #endif
578 #if XCHAL_HAVE_DENSITY
579                      "density "
580 #endif
581 #if XCHAL_HAVE_BOOLEANS
582                      "boolean "
583 #endif
584 #if XCHAL_HAVE_LOOPS
585                      "loop "
586 #endif
587 #if XCHAL_HAVE_NSA
588                      "nsa "
589 #endif
590 #if XCHAL_HAVE_MINMAX
591                      "minmax "
592 #endif
593 #if XCHAL_HAVE_SEXT
594                      "sext "
595 #endif
596 #if XCHAL_HAVE_CLAMPS
597                      "clamps "
598 #endif
599 #if XCHAL_HAVE_MAC16
600                      "mac16 "
601 #endif
602 #if XCHAL_HAVE_MUL16
603                      "mul16 "
604 #endif
605 #if XCHAL_HAVE_MUL32
606                      "mul32 "
607 #endif
608 #if XCHAL_HAVE_MUL32_HIGH
609                      "mul32h "
610 #endif
611 #if XCHAL_HAVE_FP
612                      "fpu "
613 #endif
614 #if XCHAL_HAVE_S32C1I
615                      "s32c1i "
616 #endif
617 #if XCHAL_HAVE_EXCLUSIVE
618                      "exclusive "
619 #endif
620                      "\n");
621
622         /* Registers. */
623         seq_printf(f,"physical aregs\t: %d\n"
624                      "misc regs\t: %d\n"
625                      "ibreak\t\t: %d\n"
626                      "dbreak\t\t: %d\n",
627                      XCHAL_NUM_AREGS,
628                      XCHAL_NUM_MISC_REGS,
629                      XCHAL_NUM_IBREAK,
630                      XCHAL_NUM_DBREAK);
631
632
633         /* Interrupt. */
634         seq_printf(f,"num ints\t: %d\n"
635                      "ext ints\t: %d\n"
636                      "int levels\t: %d\n"
637                      "timers\t\t: %d\n"
638                      "debug level\t: %d\n",
639                      XCHAL_NUM_INTERRUPTS,
640                      XCHAL_NUM_EXTINTERRUPTS,
641                      XCHAL_NUM_INTLEVELS,
642                      XCHAL_NUM_TIMERS,
643                      XCHAL_DEBUGLEVEL);
644
645         /* Cache */
646         seq_printf(f,"icache line size: %d\n"
647                      "icache ways\t: %d\n"
648                      "icache size\t: %d\n"
649                      "icache flags\t: "
650 #if XCHAL_ICACHE_LINE_LOCKABLE
651                      "lock "
652 #endif
653                      "\n"
654                      "dcache line size: %d\n"
655                      "dcache ways\t: %d\n"
656                      "dcache size\t: %d\n"
657                      "dcache flags\t: "
658 #if XCHAL_DCACHE_IS_WRITEBACK
659                      "writeback "
660 #endif
661 #if XCHAL_DCACHE_LINE_LOCKABLE
662                      "lock "
663 #endif
664                      "\n",
665                      XCHAL_ICACHE_LINESIZE,
666                      XCHAL_ICACHE_WAYS,
667                      XCHAL_ICACHE_SIZE,
668                      XCHAL_DCACHE_LINESIZE,
669                      XCHAL_DCACHE_WAYS,
670                      XCHAL_DCACHE_SIZE);
671
672         return 0;
673 }
674
675 /*
676  * We show only CPU #0 info.
677  */
678 static void *
679 c_start(struct seq_file *f, loff_t *pos)
680 {
681         return (*pos == 0) ? (void *)1 : NULL;
682 }
683
684 static void *
685 c_next(struct seq_file *f, void *v, loff_t *pos)
686 {
687         ++*pos;
688         return c_start(f, pos);
689 }
690
691 static void
692 c_stop(struct seq_file *f, void *v)
693 {
694 }
695
696 const struct seq_operations cpuinfo_op =
697 {
698         .start  = c_start,
699         .next   = c_next,
700         .stop   = c_stop,
701         .show   = c_show,
702 };
703
704 #endif /* CONFIG_PROC_FS */