xref: /openbmc/linux/arch/arm/mm/init.c (revision 77d84ff8)
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/bootmem.h>
15 #include <linux/mman.h>
16 #include <linux/export.h>
17 #include <linux/nodemask.h>
18 #include <linux/initrd.h>
19 #include <linux/of_fdt.h>
20 #include <linux/highmem.h>
21 #include <linux/gfp.h>
22 #include <linux/memblock.h>
23 #include <linux/dma-contiguous.h>
24 #include <linux/sizes.h>
25 
26 #include <asm/mach-types.h>
27 #include <asm/memblock.h>
28 #include <asm/prom.h>
29 #include <asm/sections.h>
30 #include <asm/setup.h>
31 #include <asm/tlb.h>
32 #include <asm/fixmap.h>
33 
34 #include <asm/mach/arch.h>
35 #include <asm/mach/map.h>
36 
37 #include "mm.h"
38 
39 static phys_addr_t phys_initrd_start __initdata = 0;
40 static unsigned long phys_initrd_size __initdata = 0;
41 
42 static int __init early_initrd(char *p)
43 {
44 	phys_addr_t start;
45 	unsigned long size;
46 	char *endp;
47 
48 	start = memparse(p, &endp);
49 	if (*endp == ',') {
50 		size = memparse(endp + 1, NULL);
51 
52 		phys_initrd_start = start;
53 		phys_initrd_size = size;
54 	}
55 	return 0;
56 }
57 early_param("initrd", early_initrd);
58 
59 static int __init parse_tag_initrd(const struct tag *tag)
60 {
61 	printk(KERN_WARNING "ATAG_INITRD is deprecated; "
62 		"please update your bootloader.\n");
63 	phys_initrd_start = __virt_to_phys(tag->u.initrd.start);
64 	phys_initrd_size = tag->u.initrd.size;
65 	return 0;
66 }
67 
68 __tagtable(ATAG_INITRD, parse_tag_initrd);
69 
70 static int __init parse_tag_initrd2(const struct tag *tag)
71 {
72 	phys_initrd_start = tag->u.initrd.start;
73 	phys_initrd_size = tag->u.initrd.size;
74 	return 0;
75 }
76 
77 __tagtable(ATAG_INITRD2, parse_tag_initrd2);
78 
79 /*
80  * This keeps memory configuration data used by a couple memory
81  * initialization functions, as well as show_mem() for the skipping
82  * of holes in the memory map.  It is populated by arm_add_memory().
83  */
84 struct meminfo meminfo;
85 
86 void show_mem(unsigned int filter)
87 {
88 	int free = 0, total = 0, reserved = 0;
89 	int shared = 0, cached = 0, slab = 0, i;
90 	struct meminfo * mi = &meminfo;
91 
92 	printk("Mem-info:\n");
93 	show_free_areas(filter);
94 
95 	if (filter & SHOW_MEM_FILTER_PAGE_COUNT)
96 		return;
97 
98 	for_each_bank (i, mi) {
99 		struct membank *bank = &mi->bank[i];
100 		unsigned int pfn1, pfn2;
101 		struct page *page, *end;
102 
103 		pfn1 = bank_pfn_start(bank);
104 		pfn2 = bank_pfn_end(bank);
105 
106 		page = pfn_to_page(pfn1);
107 		end  = pfn_to_page(pfn2 - 1) + 1;
108 
109 		do {
110 			total++;
111 			if (PageReserved(page))
112 				reserved++;
113 			else if (PageSwapCache(page))
114 				cached++;
115 			else if (PageSlab(page))
116 				slab++;
117 			else if (!page_count(page))
118 				free++;
119 			else
120 				shared += page_count(page) - 1;
121 			page++;
122 		} while (page < end);
123 	}
124 
125 	printk("%d pages of RAM\n", total);
126 	printk("%d free pages\n", free);
127 	printk("%d reserved pages\n", reserved);
128 	printk("%d slab pages\n", slab);
129 	printk("%d pages shared\n", shared);
130 	printk("%d pages swap cached\n", cached);
131 }
132 
133 static void __init find_limits(unsigned long *min, unsigned long *max_low,
134 			       unsigned long *max_high)
135 {
136 	struct meminfo *mi = &meminfo;
137 	int i;
138 
139 	/* This assumes the meminfo array is properly sorted */
140 	*min = bank_pfn_start(&mi->bank[0]);
141 	for_each_bank (i, mi)
142 		if (mi->bank[i].highmem)
143 				break;
144 	*max_low = bank_pfn_end(&mi->bank[i - 1]);
145 	*max_high = bank_pfn_end(&mi->bank[mi->nr_banks - 1]);
146 }
147 
148 static void __init arm_bootmem_init(unsigned long start_pfn,
149 	unsigned long end_pfn)
150 {
151 	struct memblock_region *reg;
152 	unsigned int boot_pages;
153 	phys_addr_t bitmap;
154 	pg_data_t *pgdat;
155 
156 	/*
157 	 * Allocate the bootmem bitmap page.  This must be in a region
158 	 * of memory which has already been mapped.
159 	 */
160 	boot_pages = bootmem_bootmap_pages(end_pfn - start_pfn);
161 	bitmap = memblock_alloc_base(boot_pages << PAGE_SHIFT, L1_CACHE_BYTES,
162 				__pfn_to_phys(end_pfn));
163 
164 	/*
165 	 * Initialise the bootmem allocator, handing the
166 	 * memory banks over to bootmem.
167 	 */
168 	node_set_online(0);
169 	pgdat = NODE_DATA(0);
170 	init_bootmem_node(pgdat, __phys_to_pfn(bitmap), start_pfn, end_pfn);
171 
172 	/* Free the lowmem regions from memblock into bootmem. */
173 	for_each_memblock(memory, reg) {
174 		unsigned long start = memblock_region_memory_base_pfn(reg);
175 		unsigned long end = memblock_region_memory_end_pfn(reg);
176 
177 		if (end >= end_pfn)
178 			end = end_pfn;
179 		if (start >= end)
180 			break;
181 
182 		free_bootmem(__pfn_to_phys(start), (end - start) << PAGE_SHIFT);
183 	}
184 
185 	/* Reserve the lowmem memblock reserved regions in bootmem. */
186 	for_each_memblock(reserved, reg) {
187 		unsigned long start = memblock_region_reserved_base_pfn(reg);
188 		unsigned long end = memblock_region_reserved_end_pfn(reg);
189 
190 		if (end >= end_pfn)
191 			end = end_pfn;
192 		if (start >= end)
193 			break;
194 
195 		reserve_bootmem(__pfn_to_phys(start),
196 			        (end - start) << PAGE_SHIFT, BOOTMEM_DEFAULT);
197 	}
198 }
199 
200 #ifdef CONFIG_ZONE_DMA
201 
202 phys_addr_t arm_dma_zone_size __read_mostly;
203 EXPORT_SYMBOL(arm_dma_zone_size);
204 
205 /*
206  * The DMA mask corresponding to the maximum bus address allocatable
207  * using GFP_DMA.  The default here places no restriction on DMA
208  * allocations.  This must be the smallest DMA mask in the system,
209  * so a successful GFP_DMA allocation will always satisfy this.
210  */
211 phys_addr_t arm_dma_limit;
212 unsigned long arm_dma_pfn_limit;
213 
214 static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
215 	unsigned long dma_size)
216 {
217 	if (size[0] <= dma_size)
218 		return;
219 
220 	size[ZONE_NORMAL] = size[0] - dma_size;
221 	size[ZONE_DMA] = dma_size;
222 	hole[ZONE_NORMAL] = hole[0];
223 	hole[ZONE_DMA] = 0;
224 }
225 #endif
226 
227 void __init setup_dma_zone(const struct machine_desc *mdesc)
228 {
229 #ifdef CONFIG_ZONE_DMA
230 	if (mdesc->dma_zone_size) {
231 		arm_dma_zone_size = mdesc->dma_zone_size;
232 		arm_dma_limit = __pv_phys_offset + arm_dma_zone_size - 1;
233 	} else
234 		arm_dma_limit = 0xffffffff;
235 	arm_dma_pfn_limit = arm_dma_limit >> PAGE_SHIFT;
236 #endif
237 }
238 
239 static void __init arm_bootmem_free(unsigned long min, unsigned long max_low,
240 	unsigned long max_high)
241 {
242 	unsigned long zone_size[MAX_NR_ZONES], zhole_size[MAX_NR_ZONES];
243 	struct memblock_region *reg;
244 
245 	/*
246 	 * initialise the zones.
247 	 */
248 	memset(zone_size, 0, sizeof(zone_size));
249 
250 	/*
251 	 * The memory size has already been determined.  If we need
252 	 * to do anything fancy with the allocation of this memory
253 	 * to the zones, now is the time to do it.
254 	 */
255 	zone_size[0] = max_low - min;
256 #ifdef CONFIG_HIGHMEM
257 	zone_size[ZONE_HIGHMEM] = max_high - max_low;
258 #endif
259 
260 	/*
261 	 * Calculate the size of the holes.
262 	 *  holes = node_size - sum(bank_sizes)
263 	 */
264 	memcpy(zhole_size, zone_size, sizeof(zhole_size));
265 	for_each_memblock(memory, reg) {
266 		unsigned long start = memblock_region_memory_base_pfn(reg);
267 		unsigned long end = memblock_region_memory_end_pfn(reg);
268 
269 		if (start < max_low) {
270 			unsigned long low_end = min(end, max_low);
271 			zhole_size[0] -= low_end - start;
272 		}
273 #ifdef CONFIG_HIGHMEM
274 		if (end > max_low) {
275 			unsigned long high_start = max(start, max_low);
276 			zhole_size[ZONE_HIGHMEM] -= end - high_start;
277 		}
278 #endif
279 	}
280 
281 #ifdef CONFIG_ZONE_DMA
282 	/*
283 	 * Adjust the sizes according to any special requirements for
284 	 * this machine type.
285 	 */
286 	if (arm_dma_zone_size)
287 		arm_adjust_dma_zone(zone_size, zhole_size,
288 			arm_dma_zone_size >> PAGE_SHIFT);
289 #endif
290 
291 	free_area_init_node(0, zone_size, min, zhole_size);
292 }
293 
294 #ifdef CONFIG_HAVE_ARCH_PFN_VALID
295 int pfn_valid(unsigned long pfn)
296 {
297 	return memblock_is_memory(__pfn_to_phys(pfn));
298 }
299 EXPORT_SYMBOL(pfn_valid);
300 #endif
301 
302 #ifndef CONFIG_SPARSEMEM
303 static void __init arm_memory_present(void)
304 {
305 }
306 #else
307 static void __init arm_memory_present(void)
308 {
309 	struct memblock_region *reg;
310 
311 	for_each_memblock(memory, reg)
312 		memory_present(0, memblock_region_memory_base_pfn(reg),
313 			       memblock_region_memory_end_pfn(reg));
314 }
315 #endif
316 
317 static bool arm_memblock_steal_permitted = true;
318 
319 phys_addr_t __init arm_memblock_steal(phys_addr_t size, phys_addr_t align)
320 {
321 	phys_addr_t phys;
322 
323 	BUG_ON(!arm_memblock_steal_permitted);
324 
325 	phys = memblock_alloc_base(size, align, MEMBLOCK_ALLOC_ANYWHERE);
326 	memblock_free(phys, size);
327 	memblock_remove(phys, size);
328 
329 	return phys;
330 }
331 
332 void __init arm_memblock_init(struct meminfo *mi,
333 	const struct machine_desc *mdesc)
334 {
335 	int i;
336 
337 	for (i = 0; i < mi->nr_banks; i++)
338 		memblock_add(mi->bank[i].start, mi->bank[i].size);
339 
340 	/* Register the kernel text, kernel data and initrd with memblock. */
341 #ifdef CONFIG_XIP_KERNEL
342 	memblock_reserve(__pa(_sdata), _end - _sdata);
343 #else
344 	memblock_reserve(__pa(_stext), _end - _stext);
345 #endif
346 #ifdef CONFIG_BLK_DEV_INITRD
347 	/* FDT scan will populate initrd_start */
348 	if (initrd_start) {
349 		phys_initrd_start = __virt_to_phys(initrd_start);
350 		phys_initrd_size = initrd_end - initrd_start;
351 	}
352 	if (phys_initrd_size &&
353 	    !memblock_is_region_memory(phys_initrd_start, phys_initrd_size)) {
354 		pr_err("INITRD: 0x%08llx+0x%08lx is not a memory region - disabling initrd\n",
355 		       (u64)phys_initrd_start, phys_initrd_size);
356 		phys_initrd_start = phys_initrd_size = 0;
357 	}
358 	if (phys_initrd_size &&
359 	    memblock_is_region_reserved(phys_initrd_start, phys_initrd_size)) {
360 		pr_err("INITRD: 0x%08llx+0x%08lx overlaps in-use memory region - disabling initrd\n",
361 		       (u64)phys_initrd_start, phys_initrd_size);
362 		phys_initrd_start = phys_initrd_size = 0;
363 	}
364 	if (phys_initrd_size) {
365 		memblock_reserve(phys_initrd_start, phys_initrd_size);
366 
367 		/* Now convert initrd to virtual addresses */
368 		initrd_start = __phys_to_virt(phys_initrd_start);
369 		initrd_end = initrd_start + phys_initrd_size;
370 	}
371 #endif
372 
373 	arm_mm_memblock_reserve();
374 	arm_dt_memblock_reserve();
375 
376 	/* reserve any platform specific memblock areas */
377 	if (mdesc->reserve)
378 		mdesc->reserve();
379 
380 	/*
381 	 * reserve memory for DMA contigouos allocations,
382 	 * must come from DMA area inside low memory
383 	 */
384 	dma_contiguous_reserve(min(arm_dma_limit, arm_lowmem_limit));
385 
386 	arm_memblock_steal_permitted = false;
387 	memblock_allow_resize();
388 	memblock_dump_all();
389 }
390 
391 void __init bootmem_init(void)
392 {
393 	unsigned long min, max_low, max_high;
394 
395 	max_low = max_high = 0;
396 
397 	find_limits(&min, &max_low, &max_high);
398 
399 	arm_bootmem_init(min, max_low);
400 
401 	/*
402 	 * Sparsemem tries to allocate bootmem in memory_present(),
403 	 * so must be done after the fixed reservations
404 	 */
405 	arm_memory_present();
406 
407 	/*
408 	 * sparse_init() needs the bootmem allocator up and running.
409 	 */
410 	sparse_init();
411 
412 	/*
413 	 * Now free the memory - free_area_init_node needs
414 	 * the sparse mem_map arrays initialized by sparse_init()
415 	 * for memmap_init_zone(), otherwise all PFNs are invalid.
416 	 */
417 	arm_bootmem_free(min, max_low, max_high);
418 
419 	/*
420 	 * This doesn't seem to be used by the Linux memory manager any
421 	 * more, but is used by ll_rw_block.  If we can get rid of it, we
422 	 * also get rid of some of the stuff above as well.
423 	 */
424 	min_low_pfn = min;
425 	max_low_pfn = max_low;
426 	max_pfn = max_high;
427 }
428 
429 /*
430  * Poison init memory with an undefined instruction (ARM) or a branch to an
431  * undefined instruction (Thumb).
432  */
433 static inline void poison_init_mem(void *s, size_t count)
434 {
435 	u32 *p = (u32 *)s;
436 	for (; count != 0; count -= 4)
437 		*p++ = 0xe7fddef0;
438 }
439 
440 static inline void
441 free_memmap(unsigned long start_pfn, unsigned long end_pfn)
442 {
443 	struct page *start_pg, *end_pg;
444 	phys_addr_t pg, pgend;
445 
446 	/*
447 	 * Convert start_pfn/end_pfn to a struct page pointer.
448 	 */
449 	start_pg = pfn_to_page(start_pfn - 1) + 1;
450 	end_pg = pfn_to_page(end_pfn - 1) + 1;
451 
452 	/*
453 	 * Convert to physical addresses, and
454 	 * round start upwards and end downwards.
455 	 */
456 	pg = PAGE_ALIGN(__pa(start_pg));
457 	pgend = __pa(end_pg) & PAGE_MASK;
458 
459 	/*
460 	 * If there are free pages between these,
461 	 * free the section of the memmap array.
462 	 */
463 	if (pg < pgend)
464 		free_bootmem(pg, pgend - pg);
465 }
466 
467 /*
468  * The mem_map array can get very big.  Free the unused area of the memory map.
469  */
470 static void __init free_unused_memmap(struct meminfo *mi)
471 {
472 	unsigned long bank_start, prev_bank_end = 0;
473 	unsigned int i;
474 
475 	/*
476 	 * This relies on each bank being in address order.
477 	 * The banks are sorted previously in bootmem_init().
478 	 */
479 	for_each_bank(i, mi) {
480 		struct membank *bank = &mi->bank[i];
481 
482 		bank_start = bank_pfn_start(bank);
483 
484 #ifdef CONFIG_SPARSEMEM
485 		/*
486 		 * Take care not to free memmap entries that don't exist
487 		 * due to SPARSEMEM sections which aren't present.
488 		 */
489 		bank_start = min(bank_start,
490 				 ALIGN(prev_bank_end, PAGES_PER_SECTION));
491 #else
492 		/*
493 		 * Align down here since the VM subsystem insists that the
494 		 * memmap entries are valid from the bank start aligned to
495 		 * MAX_ORDER_NR_PAGES.
496 		 */
497 		bank_start = round_down(bank_start, MAX_ORDER_NR_PAGES);
498 #endif
499 		/*
500 		 * If we had a previous bank, and there is a space
501 		 * between the current bank and the previous, free it.
502 		 */
503 		if (prev_bank_end && prev_bank_end < bank_start)
504 			free_memmap(prev_bank_end, bank_start);
505 
506 		/*
507 		 * Align up here since the VM subsystem insists that the
508 		 * memmap entries are valid from the bank end aligned to
509 		 * MAX_ORDER_NR_PAGES.
510 		 */
511 		prev_bank_end = ALIGN(bank_pfn_end(bank), MAX_ORDER_NR_PAGES);
512 	}
513 
514 #ifdef CONFIG_SPARSEMEM
515 	if (!IS_ALIGNED(prev_bank_end, PAGES_PER_SECTION))
516 		free_memmap(prev_bank_end,
517 			    ALIGN(prev_bank_end, PAGES_PER_SECTION));
518 #endif
519 }
520 
521 #ifdef CONFIG_HIGHMEM
522 static inline void free_area_high(unsigned long pfn, unsigned long end)
523 {
524 	for (; pfn < end; pfn++)
525 		free_highmem_page(pfn_to_page(pfn));
526 }
527 #endif
528 
529 static void __init free_highpages(void)
530 {
531 #ifdef CONFIG_HIGHMEM
532 	unsigned long max_low = max_low_pfn;
533 	struct memblock_region *mem, *res;
534 
535 	/* set highmem page free */
536 	for_each_memblock(memory, mem) {
537 		unsigned long start = memblock_region_memory_base_pfn(mem);
538 		unsigned long end = memblock_region_memory_end_pfn(mem);
539 
540 		/* Ignore complete lowmem entries */
541 		if (end <= max_low)
542 			continue;
543 
544 		/* Truncate partial highmem entries */
545 		if (start < max_low)
546 			start = max_low;
547 
548 		/* Find and exclude any reserved regions */
549 		for_each_memblock(reserved, res) {
550 			unsigned long res_start, res_end;
551 
552 			res_start = memblock_region_reserved_base_pfn(res);
553 			res_end = memblock_region_reserved_end_pfn(res);
554 
555 			if (res_end < start)
556 				continue;
557 			if (res_start < start)
558 				res_start = start;
559 			if (res_start > end)
560 				res_start = end;
561 			if (res_end > end)
562 				res_end = end;
563 			if (res_start != start)
564 				free_area_high(start, res_start);
565 			start = res_end;
566 			if (start == end)
567 				break;
568 		}
569 
570 		/* And now free anything which remains */
571 		if (start < end)
572 			free_area_high(start, end);
573 	}
574 #endif
575 }
576 
577 /*
578  * mem_init() marks the free areas in the mem_map and tells us how much
579  * memory is free.  This is done after various parts of the system have
580  * claimed their memory after the kernel image.
581  */
582 void __init mem_init(void)
583 {
584 #ifdef CONFIG_HAVE_TCM
585 	/* These pointers are filled in on TCM detection */
586 	extern u32 dtcm_end;
587 	extern u32 itcm_end;
588 #endif
589 
590 	max_mapnr   = pfn_to_page(max_pfn + PHYS_PFN_OFFSET) - mem_map;
591 
592 	/* this will put all unused low memory onto the freelists */
593 	free_unused_memmap(&meminfo);
594 	free_all_bootmem();
595 
596 #ifdef CONFIG_SA1111
597 	/* now that our DMA memory is actually so designated, we can free it */
598 	free_reserved_area(__va(PHYS_OFFSET), swapper_pg_dir, -1, NULL);
599 #endif
600 
601 	free_highpages();
602 
603 	mem_init_print_info(NULL);
604 
605 #define MLK(b, t) b, t, ((t) - (b)) >> 10
606 #define MLM(b, t) b, t, ((t) - (b)) >> 20
607 #define MLK_ROUNDUP(b, t) b, t, DIV_ROUND_UP(((t) - (b)), SZ_1K)
608 
609 	printk(KERN_NOTICE "Virtual kernel memory layout:\n"
610 			"    vector  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
611 #ifdef CONFIG_HAVE_TCM
612 			"    DTCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
613 			"    ITCM    : 0x%08lx - 0x%08lx   (%4ld kB)\n"
614 #endif
615 			"    fixmap  : 0x%08lx - 0x%08lx   (%4ld kB)\n"
616 			"    vmalloc : 0x%08lx - 0x%08lx   (%4ld MB)\n"
617 			"    lowmem  : 0x%08lx - 0x%08lx   (%4ld MB)\n"
618 #ifdef CONFIG_HIGHMEM
619 			"    pkmap   : 0x%08lx - 0x%08lx   (%4ld MB)\n"
620 #endif
621 #ifdef CONFIG_MODULES
622 			"    modules : 0x%08lx - 0x%08lx   (%4ld MB)\n"
623 #endif
624 			"      .text : 0x%p" " - 0x%p" "   (%4d kB)\n"
625 			"      .init : 0x%p" " - 0x%p" "   (%4d kB)\n"
626 			"      .data : 0x%p" " - 0x%p" "   (%4d kB)\n"
627 			"       .bss : 0x%p" " - 0x%p" "   (%4d kB)\n",
628 
629 			MLK(UL(CONFIG_VECTORS_BASE), UL(CONFIG_VECTORS_BASE) +
630 				(PAGE_SIZE)),
631 #ifdef CONFIG_HAVE_TCM
632 			MLK(DTCM_OFFSET, (unsigned long) dtcm_end),
633 			MLK(ITCM_OFFSET, (unsigned long) itcm_end),
634 #endif
635 			MLK(FIXADDR_START, FIXADDR_TOP),
636 			MLM(VMALLOC_START, VMALLOC_END),
637 			MLM(PAGE_OFFSET, (unsigned long)high_memory),
638 #ifdef CONFIG_HIGHMEM
639 			MLM(PKMAP_BASE, (PKMAP_BASE) + (LAST_PKMAP) *
640 				(PAGE_SIZE)),
641 #endif
642 #ifdef CONFIG_MODULES
643 			MLM(MODULES_VADDR, MODULES_END),
644 #endif
645 
646 			MLK_ROUNDUP(_text, _etext),
647 			MLK_ROUNDUP(__init_begin, __init_end),
648 			MLK_ROUNDUP(_sdata, _edata),
649 			MLK_ROUNDUP(__bss_start, __bss_stop));
650 
651 #undef MLK
652 #undef MLM
653 #undef MLK_ROUNDUP
654 
655 	/*
656 	 * Check boundaries twice: Some fundamental inconsistencies can
657 	 * be detected at build time already.
658 	 */
659 #ifdef CONFIG_MMU
660 	BUILD_BUG_ON(TASK_SIZE				> MODULES_VADDR);
661 	BUG_ON(TASK_SIZE 				> MODULES_VADDR);
662 #endif
663 
664 #ifdef CONFIG_HIGHMEM
665 	BUILD_BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE > PAGE_OFFSET);
666 	BUG_ON(PKMAP_BASE + LAST_PKMAP * PAGE_SIZE	> PAGE_OFFSET);
667 #endif
668 
669 	if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) {
670 		extern int sysctl_overcommit_memory;
671 		/*
672 		 * On a machine this small we won't get
673 		 * anywhere without overcommit, so turn
674 		 * it on by default.
675 		 */
676 		sysctl_overcommit_memory = OVERCOMMIT_ALWAYS;
677 	}
678 }
679 
680 void free_initmem(void)
681 {
682 #ifdef CONFIG_HAVE_TCM
683 	extern char __tcm_start, __tcm_end;
684 
685 	poison_init_mem(&__tcm_start, &__tcm_end - &__tcm_start);
686 	free_reserved_area(&__tcm_start, &__tcm_end, -1, "TCM link");
687 #endif
688 
689 	poison_init_mem(__init_begin, __init_end - __init_begin);
690 	if (!machine_is_integrator() && !machine_is_cintegrator())
691 		free_initmem_default(-1);
692 }
693 
694 #ifdef CONFIG_BLK_DEV_INITRD
695 
696 static int keep_initrd;
697 
698 void free_initrd_mem(unsigned long start, unsigned long end)
699 {
700 	if (!keep_initrd) {
701 		poison_init_mem((void *)start, PAGE_ALIGN(end) - start);
702 		free_reserved_area((void *)start, (void *)end, -1, "initrd");
703 	}
704 }
705 
706 static int __init keepinitrd_setup(char *__unused)
707 {
708 	keep_initrd = 1;
709 	return 1;
710 }
711 
712 __setup("keepinitrd", keepinitrd_setup);
713 #endif
714