2 * linux/arch/arm/mm/init.c
4 * Copyright (C) 1995-2002 Russell King
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.
10 #include <linux/config.h>
11 #include <linux/signal.h>
12 #include <linux/sched.h>
13 #include <linux/kernel.h>
14 #include <linux/errno.h>
15 #include <linux/string.h>
16 #include <linux/types.h>
17 #include <linux/ptrace.h>
18 #include <linux/mman.h>
20 #include <linux/swap.h>
21 #include <linux/smp.h>
22 #include <linux/init.h>
23 #include <linux/initrd.h>
24 #include <linux/bootmem.h>
25 #include <linux/blkdev.h>
27 #include <asm/segment.h>
28 #include <asm/mach-types.h>
29 #include <asm/pgalloc.h>
31 #include <asm/hardware.h>
32 #include <asm/setup.h>
38 #define TABLE_SIZE PTRS_PER_PTE * sizeof(pte_t))
40 struct mmu_gather mmu_gathers[NR_CPUS];
42 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
43 extern char _stext, _text, _etext, _end, __init_begin, __init_end;
44 #ifdef CONFIG_XIP_KERNEL
45 extern char _endtext, _sdata;
47 extern unsigned long phys_initrd_start;
48 extern unsigned long phys_initrd_size;
51 * The sole use of this is to pass memory configuration
52 * data from paging_init to mem_init.
54 static struct meminfo meminfo __initdata = { 0, };
57 * empty_zero_page is a special page that is used for
58 * zero-initialized data and COW.
60 struct page *empty_zero_page;
64 int free = 0, total = 0, reserved = 0;
65 int shared = 0, cached = 0, slab = 0;
66 struct page *page, *end;
68 printk("Mem-info:\n");
70 printk("Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10));
73 page = NODE_MEM_MAP(0);
74 end = page + NODE_DATA(0)->node_spanned_pages;
78 if (PageReserved(page))
80 else if (PageSwapCache(page))
82 else if (PageSlab(page))
84 else if (!page_count(page))
87 shared += atomic_read(&page->count) - 1;
91 printk("%d pages of RAM\n", total);
92 printk("%d free pages\n", free);
93 printk("%d reserved pages\n", reserved);
94 printk("%d slab pages\n", slab);
95 printk("%d pages shared\n", shared);
96 printk("%d pages swap cached\n", cached);
105 #define PFN_DOWN(x) ((x) >> PAGE_SHIFT)
106 #define PFN_UP(x) (PAGE_ALIGN(x) >> PAGE_SHIFT)
107 #define PFN_SIZE(x) ((x) >> PAGE_SHIFT)
108 #define PFN_RANGE(s,e) PFN_SIZE(PAGE_ALIGN((unsigned long)(e)) - \
109 (((unsigned long)(s)) & PAGE_MASK))
112 * FIXME: We really want to avoid allocating the bootmap bitmap
113 * over the top of the initrd. Hopefully, this is located towards
114 * the start of a bank, so if we allocate the bootmap bitmap at
115 * the end, we won't clash.
117 static unsigned int __init
118 find_bootmap_pfn(struct meminfo *mi, unsigned int bootmap_pages)
120 unsigned int start_pfn, bootmap_pfn;
121 unsigned int start, end;
123 start_pfn = PFN_UP((unsigned long)&_end);
126 /* ARM26 machines only have one node */
127 if (mi->bank->node != 0)
130 start = PFN_UP(mi->bank->start);
131 end = PFN_DOWN(mi->bank->size + mi->bank->start);
133 if (start < start_pfn)
139 if (end - start >= bootmap_pages)
148 * Scan the memory info structure and pull out:
149 * - the end of memory
150 * - the number of nodes
151 * - the pfn range of each node
152 * - the number of bootmem bitmap pages
155 find_memend_and_nodes(struct meminfo *mi, struct node_info *np)
157 unsigned int memend_pfn = 0;
161 np->bootmap_pages = 0;
163 if (mi->bank->size == 0) {
168 * Get the start and end pfns for this bank
170 np->start = PFN_UP(mi->bank->start);
171 np->end = PFN_DOWN(mi->bank->start + mi->bank->size);
173 if (memend_pfn < np->end)
174 memend_pfn = np->end;
177 * Calculate the number of pages we require to
178 * store the bootmem bitmaps.
180 np->bootmap_pages = bootmem_bootmap_pages(np->end - np->start);
183 * This doesn't seem to be used by the Linux memory
184 * manager any more. If we can get rid of it, we
185 * also get rid of some of the stuff above as well.
187 max_low_pfn = memend_pfn - PFN_DOWN(PHYS_OFFSET);
188 max_pfn = memend_pfn - PFN_DOWN(PHYS_OFFSET);
189 mi->end = memend_pfn << PAGE_SHIFT;
194 * Initialise the bootmem allocator for all nodes. This is called
195 * early during the architecture specific initialisation.
197 void __init bootmem_init(struct meminfo *mi)
199 struct node_info node_info;
200 unsigned int bootmap_pfn;
201 pg_data_t *pgdat = NODE_DATA(0);
203 find_memend_and_nodes(mi, &node_info);
205 bootmap_pfn = find_bootmap_pfn(mi, node_info.bootmap_pages);
208 * Note that node 0 must always have some pages.
210 if (node_info.end == 0)
214 * Initialise the bootmem allocator.
216 init_bootmem_node(pgdat, bootmap_pfn, node_info.start, node_info.end);
219 * Register all available RAM in this node with the bootmem allocator.
221 free_bootmem_node(pgdat, mi->bank->start, mi->bank->size);
224 * Register the kernel text and data with bootmem.
225 * Note: with XIP we dont register .text since
228 #ifdef CONFIG_XIP_KERNEL
229 reserve_bootmem_node(pgdat, __pa(&_sdata), &_end - &_sdata);
231 reserve_bootmem_node(pgdat, __pa(&_stext), &_end - &_stext);
235 * And don't forget to reserve the allocator bitmap,
236 * which will be freed later.
238 reserve_bootmem_node(pgdat, bootmap_pfn << PAGE_SHIFT,
239 node_info.bootmap_pages << PAGE_SHIFT);
242 * These should likewise go elsewhere. They pre-reserve
243 * the screen memory region at the start of main system
244 * memory. FIXME - screen RAM is not 512K!
246 reserve_bootmem_node(pgdat, 0x02000000, 0x00080000);
248 #ifdef CONFIG_BLK_DEV_INITRD
249 initrd_start = phys_initrd_start;
250 initrd_end = initrd_start + phys_initrd_size;
252 /* Achimedes machines only have one node, so initrd is in node 0 */
253 #ifdef CONFIG_XIP_KERNEL
254 /* Only reserve initrd space if it is in RAM */
255 if(initrd_start && initrd_start < 0x03000000){
259 reserve_bootmem_node(pgdat, __pa(initrd_start),
260 initrd_end - initrd_start);
262 #endif /* CONFIG_BLK_DEV_INITRD */
268 * paging_init() sets up the page tables, initialises the zone memory
269 * maps, and sets up the zero page, bad page and bad page tables.
271 void __init paging_init(struct meminfo *mi)
274 unsigned long zone_size[MAX_NR_ZONES];
275 unsigned long zhole_size[MAX_NR_ZONES];
276 struct bootmem_data *bdata;
280 memcpy(&meminfo, mi, sizeof(meminfo));
283 * allocate the zero page. Note that we count on this going ok.
285 zero_page = alloc_bootmem_low_pages(PAGE_SIZE);
288 * initialise the page tables.
294 * initialise the zones in node 0 (archimedes have only 1 node)
297 for (i = 0; i < MAX_NR_ZONES; i++) {
302 pgdat = NODE_DATA(0);
303 bdata = pgdat->bdata;
304 zone_size[0] = bdata->node_low_pfn -
305 (bdata->node_boot_start >> PAGE_SHIFT);
309 free_area_init_node(0, pgdat, 0, zone_size,
310 bdata->node_boot_start >> PAGE_SHIFT, zhole_size);
312 mem_map = NODE_DATA(0)->node_mem_map;
315 * finish off the bad pages once
316 * the mem_map is initialised
318 memzero(zero_page, PAGE_SIZE);
319 empty_zero_page = virt_to_page(zero_page);
322 static inline void free_area(unsigned long addr, unsigned long end, char *s)
324 unsigned int size = (end - addr) >> 10;
326 for (; addr < end; addr += PAGE_SIZE) {
327 struct page *page = virt_to_page(addr);
328 ClearPageReserved(page);
329 set_page_count(page, 1);
335 printk(KERN_INFO "Freeing %s memory: %dK\n", s, size);
339 * mem_init() marks the free areas in the mem_map and tells us how much
340 * memory is free. This is done after various parts of the system have
341 * claimed their memory after the kernel image.
343 void __init mem_init(void)
345 unsigned int codepages, datapages, initpages;
346 pg_data_t *pgdat = NODE_DATA(0);
347 extern int sysctl_overcommit_memory;
350 /* Note: data pages includes BSS */
351 #ifdef CONFIG_XIP_KERNEL
352 codepages = &_endtext - &_text;
353 datapages = &_end - &_sdata;
355 codepages = &_etext - &_text;
356 datapages = &_end - &_etext;
358 initpages = &__init_end - &__init_begin;
360 high_memory = (void *)__va(meminfo.end);
361 max_mapnr = virt_to_page(high_memory) - mem_map;
363 /* this will put all unused low memory onto the freelists */
364 if (pgdat->node_spanned_pages != 0)
365 totalram_pages += free_all_bootmem_node(pgdat);
367 num_physpages = meminfo.bank[0].size >> PAGE_SHIFT;
369 printk(KERN_INFO "Memory: %luMB total\n", num_physpages >> (20 - PAGE_SHIFT));
370 printk(KERN_NOTICE "Memory: %luKB available (%dK code, "
371 "%dK data, %dK init)\n",
372 (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
373 codepages >> 10, datapages >> 10, initpages >> 10);
376 * Turn on overcommit on tiny machines
378 if (PAGE_SIZE >= 16384 && num_physpages <= 128) {
379 sysctl_overcommit_memory = 1;
380 printk("Turning on overcommit\n");
384 void free_initmem(void){
385 #ifndef CONFIG_XIP_KERNEL
386 free_area((unsigned long)(&__init_begin),
387 (unsigned long)(&__init_end),
392 #ifdef CONFIG_BLK_DEV_INITRD
394 static int keep_initrd;
396 void free_initrd_mem(unsigned long start, unsigned long end)
398 #ifdef CONFIG_XIP_KERNEL
399 /* Only bin initrd if it is in RAM... */
400 if(!keep_initrd && start < 0x03000000)
404 free_area(start, end, "initrd");
407 static int __init keepinitrd_setup(char *__unused)
413 __setup("keepinitrd", keepinitrd_setup);