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Linux/arch/arm/mm/init.c

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  1 /*
  2  *  linux/arch/arm/mm/init.c
  3  *
  4  *  Copyright (C) 1995-2005 Russell King
  5  *
  6  * This program is free software; you can redistribute it and/or modify
  7  * it under the terms of the GNU General Public License version 2 as
  8  * published by the Free Software Foundation.
  9  */
 10 #include <linux/kernel.h>
 11 #include <linux/errno.h>
 12 #include <linux/swap.h>
 13 #include <linux/init.h>
 14 #include <linux/mman.h>
 15 #include <linux/sched/signal.h>
 16 #include <linux/sched/task.h>
 17 #include <linux/export.h>
 18 #include <linux/nodemask.h>
 19 #include <linux/initrd.h>
 20 #include <linux/of_fdt.h>
 21 #include <linux/highmem.h>
 22 #include <linux/gfp.h>
 23 #include <linux/memblock.h>
 24 #include <linux/dma-contiguous.h>
 25 #include <linux/sizes.h>
 26 #include <linux/stop_machine.h>
 27 
 28 #include <asm/cp15.h>
 29 #include <asm/mach-types.h>
 30 #include <asm/memblock.h>
 31 #include <asm/memory.h>
 32 #include <asm/prom.h>
 33 #include <asm/sections.h>
 34 #include <asm/setup.h>
 35 #include <asm/system_info.h>
 36 #include <asm/tlb.h>
 37 #include <asm/fixmap.h>
 38 #include <asm/ptdump.h>
 39 
 40 #include <asm/mach/arch.h>
 41 #include <asm/mach/map.h>
 42 
 43 #include "mm.h"
 44 
 45 #ifdef CONFIG_CPU_CP15_MMU
 46 unsigned long __init __clear_cr(unsigned long mask)
 47 {
 48         cr_alignment = cr_alignment & ~mask;
 49         return cr_alignment;
 50 }
 51 #endif
 52 
 53 #ifdef CONFIG_BLK_DEV_INITRD
 54 static int __init parse_tag_initrd(const struct tag *tag)
 55 {
 56         pr_warn("ATAG_INITRD is deprecated; "
 57                 "please update your bootloader.\n");
 58         phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
 59         phys_initrd_size = tag->u.initrd.size;
 60         return 0;
 61 }
 62 
 63 __tagtable(ATAG_INITRD, parse_tag_initrd);
 64 
 65 static int __init parse_tag_initrd2(const struct tag *tag)
 66 {
 67         phys_initrd_start = tag->u.initrd.start;
 68         phys_initrd_size = tag->u.initrd.size;
 69         return 0;
 70 }
 71 
 72 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
 73 #endif
 74 
 75 static void __init find_limits(unsigned long *min, unsigned long *max_low,
 76                                unsigned long *max_high)
 77 {
 78         *max_low = PFN_DOWN(memblock_get_current_limit());
 79         *min = PFN_UP(memblock_start_of_DRAM());
 80         *max_high = PFN_DOWN(memblock_end_of_DRAM());
 81 }
 82 
 83 #ifdef CONFIG_ZONE_DMA
 84 
 85 phys_addr_t arm_dma_zone_size __read_mostly;
 86 EXPORT_SYMBOL(arm_dma_zone_size);
 87 
 88 /*
 89  * The DMA mask corresponding to the maximum bus address allocatable
 90  * using GFP_DMA.  The default here places no restriction on DMA
 91  * allocations.  This must be the smallest DMA mask in the system,
 92  * so a successful GFP_DMA allocation will always satisfy this.
 93  */
 94 phys_addr_t arm_dma_limit;
 95 unsigned long arm_dma_pfn_limit;
 96 
 97 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
 98         unsigned long dma_size)
 99 {
100         if (size[0] <= dma_size)
101                 return;
102 
103         size[ZONE_NORMAL] = size[0] - dma_size;
104         size[ZONE_DMA] = dma_size;
105         hole[ZONE_NORMAL] = hole[0];
106         hole[ZONE_DMA] = 0;
107 }
108 #endif
109 
110 void __init setup_dma_zone(const struct machine_desc *mdesc)
111 {
112 #ifdef CONFIG_ZONE_DMA
113         if (mdesc->dma_zone_size) {
114                 arm_dma_zone_size = mdesc->dma_zone_size;
115                 arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
116         } else
117                 arm_dma_limit = 0xffffffff;
118         arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
119 #endif
120 }
121 
122 static void __init zone_sizes_init(unsigned long min, unsigned long max_low,
123         unsigned long max_high)
124 {
125         unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
126         struct memblock_region *reg;
127 
128         /*
129          * initialise the zones.
130          */
131         memset(zone_size, 0, sizeof(zone_size));
132 
133         /*
134          * The memory size has already been determined.  If we need
135          * to do anything fancy with the allocation of this memory
136          * to the zones, now is the time to do it.
137          */
138         zone_size[0] = max_low - min;
139 #ifdef CONFIG_HIGHMEM
140         zone_size[ZONE_HIGHMEM] = max_high - max_low;
141 #endif
142 
143         /*
144          * Calculate the size of the holes.
145          *  holes = node_size - sum(bank_sizes)
146          */
147         memcpy(zhole_size, zone_size, sizeof(zhole_size));
148         for_each_memblock(memory, reg) {
149                 unsigned long start = memblock_region_memory_base_pfn(reg);
150                 unsigned long end = memblock_region_memory_end_pfn(reg);
151 
152                 if (start < max_low) {
153                         unsigned long low_end = min(end, max_low);
154                         zhole_size[0] -= low_end - start;
155                 }
156 #ifdef CONFIG_HIGHMEM
157                 if (end > max_low) {
158                         unsigned long high_start = max(start, max_low);
159                         zhole_size[ZONE_HIGHMEM] -= end - high_start;
160                 }
161 #endif
162         }
163 
164 #ifdef CONFIG_ZONE_DMA
165         /*
166          * Adjust the sizes according to any special requirements for
167          * this machine type.
168          */
169         if (arm_dma_zone_size)
170                 arm_adjust_dma_zone(zone_size, zhole_size,
171                         arm_dma_zone_size >> PAGE_SHIFT);
172 #endif
173 
174         free_area_init_node(0, zone_size, min, zhole_size);
175 }
176 
177 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
178 int pfn_valid(unsigned long pfn)
179 {
180         return memblock_is_map_memory(__pfn_to_phys(pfn));
181 }
182 EXPORT_SYMBOL(pfn_valid);
183 #endif
184 
185 #ifndef CONFIG_SPARSEMEM
186 static void __init arm_memory_present(void)
187 {
188 }
189 #else
190 static void __init arm_memory_present(void)
191 {
192         struct memblock_region *reg;
193 
194         for_each_memblock(memory, reg)
195                 memory_present(0, memblock_region_memory_base_pfn(reg),
196                                memblock_region_memory_end_pfn(reg));
197 }
198 #endif
199 
200 static bool arm_memblock_steal_permitted = true;
201 
202 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
203 {
204         phys_addr_t phys;
205 
206         BUG_ON(!arm_memblock_steal_permitted);
207 
208         phys = memblock_phys_alloc(size, align);
209         if (!phys)
210                 panic("Failed to steal %pa bytes at %pS\n",
211                       &size, (void *)_RET_IP_);
212 
213         memblock_free(phys, size);
214         memblock_remove(phys, size);
215 
216         return phys;
217 }
218 
219 static void __init arm_initrd_init(void)
220 {
221 #ifdef CONFIG_BLK_DEV_INITRD
222         phys_addr_t start;
223         unsigned long size;
224 
225         initrd_start = initrd_end = 0;
226 
227         if (!phys_initrd_size)
228                 return;
229 
230         /*
231          * Round the memory region to page boundaries as per free_initrd_mem()
232          * This allows us to detect whether the pages overlapping the initrd
233          * are in use, but more importantly, reserves the entire set of pages
234          * as we don't want these pages allocated for other purposes.
235          */
236         start = round_down(phys_initrd_start, PAGE_SIZE);
237         size = phys_initrd_size + (phys_initrd_start - start);
238         size = round_up(size, PAGE_SIZE);
239 
240         if (!memblock_is_region_memory(start, size)) {
241                 pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
242                        (u64)start, size);
243                 return;
244         }
245 
246         if (memblock_is_region_reserved(start, size)) {
247                 pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
248                        (u64)start, size);
249                 return;
250         }
251 
252         memblock_reserve(start, size);
253 
254         /* Now convert initrd to virtual addresses */
255         initrd_start = __phys_to_virt(phys_initrd_start);
256         initrd_end = initrd_start + phys_initrd_size;
257 #endif
258 }
259 
260 void __init arm_memblock_init(const struct machine_desc *mdesc)
261 {
262         /* Register the kernel text, kernel data and initrd with memblock. */
263         memblock_reserve(__pa(KERNEL_START), KERNEL_END - KERNEL_START);
264 
265         arm_initrd_init();
266 
267         arm_mm_memblock_reserve();
268 
269         /* reserve any platform specific memblock areas */
270         if (mdesc->reserve)
271                 mdesc->reserve();
272 
273         early_init_fdt_reserve_self();
274         early_init_fdt_scan_reserved_mem();
275 
276         /* reserve memory for DMA contiguous allocations */
277         dma_contiguous_reserve(arm_dma_limit);
278 
279         arm_memblock_steal_permitted = false;
280         memblock_dump_all();
281 }
282 
283 void __init bootmem_init(void)
284 {
285         memblock_allow_resize();
286 
287         find_limits(&min_low_pfn, &max_low_pfn, &max_pfn);
288 
289         early_memtest((phys_addr_t)min_low_pfn << PAGE_SHIFT,
290                       (phys_addr_t)max_low_pfn << PAGE_SHIFT);
291 
292         /*
293          * Sparsemem tries to allocate bootmem in memory_present(),
294          * so must be done after the fixed reservations
295          */
296         arm_memory_present();
297 
298         /*
299          * sparse_init() needs the bootmem allocator up and running.
300          */
301         sparse_init();
302 
303         /*
304          * Now free the memory - free_area_init_node needs
305          * the sparse mem_map arrays initialized by sparse_init()
306          * for memmap_init_zone(), otherwise all PFNs are invalid.
307          */
308         zone_sizes_init(min_low_pfn, max_low_pfn, max_pfn);
309 }
310 
311 /*
312  * Poison init memory with an undefined instruction (ARM) or a branch to an
313  * undefined instruction (Thumb).
314  */
315 static inline void poison_init_mem(void *s, size_t count)
316 {
317         u32 *p = (u32 *)s;
318         for (; count != 0; count -= 4)
319                 *p++ = 0xe7fddef0;
320 }
321 
322 static inline void
323 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
324 {
325         struct page *start_pg, *end_pg;
326         phys_addr_t pg, pgend;
327 
328         /*
329          * Convert start_pfn/end_pfn to a struct page pointer.
330          */
331         start_pg = pfn_to_page(start_pfn - 1) + 1;
332         end_pg = pfn_to_page(end_pfn - 1) + 1;
333 
334         /*
335          * Convert to physical addresses, and
336          * round start upwards and end downwards.
337          */
338         pg = PAGE_ALIGN(__pa(start_pg));
339         pgend = __pa(end_pg) & PAGE_MASK;
340 
341         /*
342          * If there are free pages between these,
343          * free the section of the memmap array.
344          */
345         if (pg < pgend)
346                 memblock_free_early(pg, pgend - pg);
347 }
348 
349 /*
350  * The mem_map array can get very big.  Free the unused area of the memory map.
351  */
352 static void __init free_unused_memmap(void)
353 {
354         unsigned long start, prev_end = 0;
355         struct memblock_region *reg;
356 
357         /*
358          * This relies on each bank being in address order.
359          * The banks are sorted previously in bootmem_init().
360          */
361         for_each_memblock(memory, reg) {
362                 start = memblock_region_memory_base_pfn(reg);
363 
364 #ifdef CONFIG_SPARSEMEM
365                 /*
366                  * Take care not to free memmap entries that don't exist
367                  * due to SPARSEMEM sections which aren't present.
368                  */
369                 start = min(start,
370                                  ALIGN(prev_end, PAGES_PER_SECTION));
371 #else
372                 /*
373                  * Align down here since the VM subsystem insists that the
374                  * memmap entries are valid from the bank start aligned to
375                  * MAX_ORDER_NR_PAGES.
376                  */
377                 start = round_down(start, MAX_ORDER_NR_PAGES);
378 #endif
379                 /*
380                  * If we had a previous bank, and there is a space
381                  * between the current bank and the previous, free it.
382                  */
383                 if (prev_end && prev_end < start)
384                         free_memmap(prev_end, start);
385 
386                 /*
387                  * Align up here since the VM subsystem insists that the
388                  * memmap entries are valid from the bank end aligned to
389                  * MAX_ORDER_NR_PAGES.
390                  */
391                 prev_end = ALIGN(memblock_region_memory_end_pfn(reg),
392                                  MAX_ORDER_NR_PAGES);
393         }
394 
395 #ifdef CONFIG_SPARSEMEM
396         if (!IS_ALIGNED(prev_end, PAGES_PER_SECTION))
397                 free_memmap(prev_end,
398                             ALIGN(prev_end, PAGES_PER_SECTION));
399 #endif
400 }
401 
402 #ifdef CONFIG_HIGHMEM
403 static inline void free_area_high(unsigned long pfn, unsigned long end)
404 {
405         for (; pfn < end; pfn++)
406                 free_highmem_page(pfn_to_page(pfn));
407 }
408 #endif
409 
410 static void __init free_highpages(void)
411 {
412 #ifdef CONFIG_HIGHMEM
413         unsigned long max_low = max_low_pfn;
414         struct memblock_region *mem, *res;
415 
416         /* set highmem page free */
417         for_each_memblock(memory, mem) {
418                 unsigned long start = memblock_region_memory_base_pfn(mem);
419                 unsigned long end = memblock_region_memory_end_pfn(mem);
420 
421                 /* Ignore complete lowmem entries */
422                 if (end <= max_low)
423                         continue;
424 
425                 if (memblock_is_nomap(mem))
426                         continue;
427 
428                 /* Truncate partial highmem entries */
429                 if (start < max_low)
430                         start = max_low;
431 
432                 /* Find and exclude any reserved regions */
433                 for_each_memblock(reserved, res) {
434                         unsigned long res_start, res_end;
435 
436                         res_start = memblock_region_reserved_base_pfn(res);
437                         res_end = memblock_region_reserved_end_pfn(res);
438 
439                         if (res_end < start)
440                                 continue;
441                         if (res_start < start)
442                                 res_start = start;
443                         if (res_start > end)
444                                 res_start = end;
445                         if (res_end > end)
446                                 res_end = end;
447                         if (res_start != start)
448                                 free_area_high(start, res_start);
449                         start = res_end;
450                         if (start == end)
451                                 break;
452                 }
453 
454                 /* And now free anything which remains */
455                 if (start < end)
456                         free_area_high(start, end);
457         }
458 #endif
459 }
460 
461 /*
462  * mem_init() marks the free areas in the mem_map and tells us how much
463  * memory is free.  This is done after various parts of the system have
464  * claimed their memory after the kernel image.
465  */
466 void __init mem_init(void)
467 {
468 #ifdef CONFIG_HAVE_TCM
469         /* These pointers are filled in on TCM detection */
470         extern u32 dtcm_end;
471         extern u32 itcm_end;
472 #endif
473 
474         set_max_mapnr(pfn_to_page(max_pfn) - mem_map);
475 
476         /* this will put all unused low memory onto the freelists */
477         free_unused_memmap();
478         memblock_free_all();
479 
480 #ifdef CONFIG_SA1111
481         /* now that our DMA memory is actually so designated, we can free it */
482         free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
483 #endif
484 
485         free_highpages();
486 
487         mem_init_print_info(NULL);
488 
489         /*
490          * Check boundaries twice: Some fundamental inconsistencies can
491          * be detected at build time already.
492          */
493 #ifdef CONFIG_MMU
494         BUILD_BUG_ON(TASK_SIZE                          > MODULES_VADDR);
495         BUG_ON(TASK_SIZE                                > MODULES_VADDR);
496 #endif
497 
498 #ifdef CONFIG_HIGHMEM
499         BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
500         BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE      > PAGE_OFFSET);
501 #endif
502 }
503 
504 #ifdef CONFIG_STRICT_KERNEL_RWX
505 struct section_perm {
506         const char *name;
507         unsigned long start;
508         unsigned long end;
509         pmdval_t mask;
510         pmdval_t prot;
511         pmdval_t clear;
512 };
513 
514 /* First section-aligned location at or after __start_rodata. */
515 extern char __start_rodata_section_aligned[];
516 
517 static struct section_perm nx_perms[] = {
518         /* Make pages tables, etc before _stext RW (set NX). */
519         {
520                 .name   = "pre-text NX",
521                 .start  = PAGE_OFFSET,
522                 .end    = (unsigned long)_stext,
523                 .mask   = ~PMD_SECT_XN,
524                 .prot   = PMD_SECT_XN,
525         },
526         /* Make init RW (set NX). */
527         {
528                 .name   = "init NX",
529                 .start  = (unsigned long)__init_begin,
530                 .end    = (unsigned long)_sdata,
531                 .mask   = ~PMD_SECT_XN,
532                 .prot   = PMD_SECT_XN,
533         },
534         /* Make rodata NX (set RO in ro_perms below). */
535         {
536                 .name   = "rodata NX",
537                 .start  = (unsigned long)__start_rodata_section_aligned,
538                 .end    = (unsigned long)__init_begin,
539                 .mask   = ~PMD_SECT_XN,
540                 .prot   = PMD_SECT_XN,
541         },
542 };
543 
544 static struct section_perm ro_perms[] = {
545         /* Make kernel code and rodata RX (set RO). */
546         {
547                 .name   = "text/rodata RO",
548                 .start  = (unsigned long)_stext,
549                 .end    = (unsigned long)__init_begin,
550 #ifdef CONFIG_ARM_LPAE
551                 .mask   = ~(L_PMD_SECT_RDONLY | PMD_SECT_AP2),
552                 .prot   = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
553 #else
554                 .mask   = ~(PMD_SECT_APX | PMD_SECT_AP_WRITE),
555                 .prot   = PMD_SECT_APX | PMD_SECT_AP_WRITE,
556                 .clear  = PMD_SECT_AP_WRITE,
557 #endif
558         },
559 };
560 
561 /*
562  * Updates section permissions only for the current mm (sections are
563  * copied into each mm). During startup, this is the init_mm. Is only
564  * safe to be called with preemption disabled, as under stop_machine().
565  */
566 static inline void section_update(unsigned long addr, pmdval_t mask,
567                                   pmdval_t prot, struct mm_struct *mm)
568 {
569         pmd_t *pmd;
570 
571         pmd = pmd_offset(pud_offset(pgd_offset(mm, addr), addr), addr);
572 
573 #ifdef CONFIG_ARM_LPAE
574         pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
575 #else
576         if (addr & SECTION_SIZE)
577                 pmd[1] = __pmd((pmd_val(pmd[1]) & mask) | prot);
578         else
579                 pmd[0] = __pmd((pmd_val(pmd[0]) & mask) | prot);
580 #endif
581         flush_pmd_entry(pmd);
582         local_flush_tlb_kernel_range(addr, addr + SECTION_SIZE);
583 }
584 
585 /* Make sure extended page tables are in use. */
586 static inline bool arch_has_strict_perms(void)
587 {
588         if (cpu_architecture() < CPU_ARCH_ARMv6)
589                 return false;
590 
591         return !!(get_cr() & CR_XP);
592 }
593 
594 void set_section_perms(struct section_perm *perms, int n, bool set,
595                         struct mm_struct *mm)
596 {
597         size_t i;
598         unsigned long addr;
599 
600         if (!arch_has_strict_perms())
601                 return;
602 
603         for (i = 0; i < n; i++) {
604                 if (!IS_ALIGNED(perms[i].start, SECTION_SIZE) ||
605                     !IS_ALIGNED(perms[i].end, SECTION_SIZE)) {
606                         pr_err("BUG: %s section %lx-%lx not aligned to %lx\n",
607                                 perms[i].name, perms[i].start, perms[i].end,
608                                 SECTION_SIZE);
609                         continue;
610                 }
611 
612                 for (addr = perms[i].start;
613                      addr < perms[i].end;
614                      addr += SECTION_SIZE)
615                         section_update(addr, perms[i].mask,
616                                 set ? perms[i].prot : perms[i].clear, mm);
617         }
618 
619 }
620 
621 /**
622  * update_sections_early intended to be called only through stop_machine
623  * framework and executed by only one CPU while all other CPUs will spin and
624  * wait, so no locking is required in this function.
625  */
626 static void update_sections_early(struct section_perm perms[], int n)
627 {
628         struct task_struct *t, *s;
629 
630         for_each_process(t) {
631                 if (t->flags & PF_KTHREAD)
632                         continue;
633                 for_each_thread(t, s)
634                         set_section_perms(perms, n, true, s->mm);
635         }
636         set_section_perms(perms, n, true, current->active_mm);
637         set_section_perms(perms, n, true, &init_mm);
638 }
639 
640 static int __fix_kernmem_perms(void *unused)
641 {
642         update_sections_early(nx_perms, ARRAY_SIZE(nx_perms));
643         return 0;
644 }
645 
646 static void fix_kernmem_perms(void)
647 {
648         stop_machine(__fix_kernmem_perms, NULL, NULL);
649 }
650 
651 static int __mark_rodata_ro(void *unused)
652 {
653         update_sections_early(ro_perms, ARRAY_SIZE(ro_perms));
654         return 0;
655 }
656 
657 static int kernel_set_to_readonly __read_mostly;
658 
659 void mark_rodata_ro(void)
660 {
661         kernel_set_to_readonly = 1;
662         stop_machine(__mark_rodata_ro, NULL, NULL);
663         debug_checkwx();
664 }
665 
666 void set_kernel_text_rw(void)
667 {
668         if (!kernel_set_to_readonly)
669                 return;
670 
671         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), false,
672                                 current->active_mm);
673 }
674 
675 void set_kernel_text_ro(void)
676 {
677         if (!kernel_set_to_readonly)
678                 return;
679 
680         set_section_perms(ro_perms, ARRAY_SIZE(ro_perms), true,
681                                 current->active_mm);
682 }
683 
684 #else
685 static inline void fix_kernmem_perms(void) { }
686 #endif /* CONFIG_STRICT_KERNEL_RWX */
687 
688 void free_initmem(void)
689 {
690         fix_kernmem_perms();
691 
692         poison_init_mem(__init_begin, __init_end - __init_begin);
693         if (!machine_is_integrator() && !machine_is_cintegrator())
694                 free_initmem_default(-1);
695 }
696 
697 #ifdef CONFIG_BLK_DEV_INITRD
698 
699 static int keep_initrd;
700 
701 void free_initrd_mem(unsigned long start, unsigned long end)
702 {
703         if (!keep_initrd) {
704                 if (start == initrd_start)
705                         start = round_down(start, PAGE_SIZE);
706                 if (end == initrd_end)
707                         end = round_up(end, PAGE_SIZE);
708 
709                 poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
710                 free_reserved_area((void *)start, (void *)end, -1, "initrd");
711         }
712 }
713 
714 static int __init keepinitrd_setup(char *__unused)
715 {
716         keep_initrd = 1;
717         return 1;
718 }
719 
720 __setup("keepinitrd", keepinitrd_setup);
721 #endif
722 

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