init.c revision 264da9f708b130122d881fa4570d1cd618440a73 
1/*
2 * arch/xtensa/mm/init.c
3 *
4 * Derived from MIPS, PPC.
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License.  See the file "COPYING" in the main directory of this archive
8 * for more details.
9 *
10 * Copyright (C) 2001 - 2005 Tensilica Inc.
11 *
12 * Chris Zankel	<chris@zankel.net>
13 * Joe Taylor	<joe@tensilica.com, joetylr@yahoo.com>
14 * Marc Gauthier
15 * Kevin Chea
16 */
17
18#include <linux/kernel.h>
19#include <linux/errno.h>
20#include <linux/bootmem.h>
21#include <linux/swap.h>
22#include <linux/mman.h>
23#include <linux/nodemask.h>
24#include <linux/mm.h>
25#include <linux/slab.h>
26
27#include <asm/pgtable.h>
28#include <asm/bootparam.h>
29#include <asm/mmu_context.h>
30#include <asm/tlb.h>
31#include <asm/page.h>
32#include <asm/pgalloc.h>
33
34
35DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
36
37/* References to section boundaries */
38
39extern char _ftext, _etext, _fdata, _edata, _rodata_end;
40extern char __init_begin, __init_end;
41
42/*
43 * mem_reserve(start, end, must_exist)
44 *
45 * Reserve some memory from the memory pool.
46 *
47 * Parameters:
48 *  start	Start of region,
49 *  end		End of region,
50 *  must_exist	Must exist in memory pool.
51 *
52 * Returns:
53 *  0 (memory area couldn't be mapped)
54 * -1 (success)
55 */
56
57int __init mem_reserve(unsigned long start, unsigned long end, int must_exist)
58{
59	int i;
60
61	if (start == end)
62		return 0;
63
64	start = start & PAGE_MASK;
65	end = PAGE_ALIGN(end);
66
67	for (i = 0; i < sysmem.nr_banks; i++)
68		if (start < sysmem.bank[i].end
69		    && end >= sysmem.bank[i].start)
70			break;
71
72	if (i == sysmem.nr_banks) {
73		if (must_exist)
74			printk (KERN_WARNING "mem_reserve: [0x%0lx, 0x%0lx) "
75				"not in any region!\n", start, end);
76		return 0;
77	}
78
79	if (start > sysmem.bank[i].start) {
80		if (end < sysmem.bank[i].end) {
81			/* split entry */
82			if (sysmem.nr_banks >= SYSMEM_BANKS_MAX)
83				panic("meminfo overflow\n");
84			sysmem.bank[sysmem.nr_banks].start = end;
85			sysmem.bank[sysmem.nr_banks].end = sysmem.bank[i].end;
86			sysmem.nr_banks++;
87		}
88		sysmem.bank[i].end = start;
89	} else {
90		if (end < sysmem.bank[i].end)
91			sysmem.bank[i].start = end;
92		else {
93			/* remove entry */
94			sysmem.nr_banks--;
95			sysmem.bank[i].start = sysmem.bank[sysmem.nr_banks].start;
96			sysmem.bank[i].end   = sysmem.bank[sysmem.nr_banks].end;
97		}
98	}
99	return -1;
100}
101
102
103/*
104 * Initialize the bootmem system and give it all the memory we have available.
105 */
106
107void __init bootmem_init(void)
108{
109	unsigned long pfn;
110	unsigned long bootmap_start, bootmap_size;
111	int i;
112
113	max_low_pfn = max_pfn = 0;
114	min_low_pfn = ~0;
115
116	for (i=0; i < sysmem.nr_banks; i++) {
117		pfn = PAGE_ALIGN(sysmem.bank[i].start) >> PAGE_SHIFT;
118		if (pfn < min_low_pfn)
119			min_low_pfn = pfn;
120		pfn = PAGE_ALIGN(sysmem.bank[i].end - 1) >> PAGE_SHIFT;
121		if (pfn > max_pfn)
122			max_pfn = pfn;
123	}
124
125	if (min_low_pfn > max_pfn)
126		panic("No memory found!\n");
127
128	max_low_pfn = max_pfn < MAX_MEM_PFN >> PAGE_SHIFT ?
129		max_pfn : MAX_MEM_PFN >> PAGE_SHIFT;
130
131	/* Find an area to use for the bootmem bitmap. */
132
133	bootmap_size = bootmem_bootmap_pages(max_low_pfn - min_low_pfn);
134	bootmap_size <<= PAGE_SHIFT;
135	bootmap_start = ~0;
136
137	for (i=0; i<sysmem.nr_banks; i++)
138		if (sysmem.bank[i].end - sysmem.bank[i].start >= bootmap_size) {
139			bootmap_start = sysmem.bank[i].start;
140			break;
141		}
142
143	if (bootmap_start == ~0UL)
144		panic("Cannot find %ld bytes for bootmap\n", bootmap_size);
145
146	/* Reserve the bootmem bitmap area */
147
148	mem_reserve(bootmap_start, bootmap_start + bootmap_size, 1);
149	bootmap_size = init_bootmem_node(NODE_DATA(0),
150					 bootmap_start >> PAGE_SHIFT,
151					 min_low_pfn,
152					 max_low_pfn);
153
154	/* Add all remaining memory pieces into the bootmem map */
155
156	for (i=0; i<sysmem.nr_banks; i++)
157		free_bootmem(sysmem.bank[i].start,
158			     sysmem.bank[i].end - sysmem.bank[i].start);
159
160}
161
162
163void __init paging_init(void)
164{
165	unsigned long zones_size[MAX_NR_ZONES];
166	int i;
167
168	/* All pages are DMA-able, so we put them all in the DMA zone. */
169
170	zones_size[ZONE_DMA] = max_low_pfn;
171	for (i = 1; i < MAX_NR_ZONES; i++)
172		zones_size[i] = 0;
173
174#ifdef CONFIG_HIGHMEM
175	zones_size[ZONE_HIGHMEM] = max_pfn - max_low_pfn;
176#endif
177
178	/* Initialize the kernel's page tables. */
179
180	memset(swapper_pg_dir, 0, PAGE_SIZE);
181
182	free_area_init(zones_size);
183}
184
185/*
186 * Flush the mmu and reset associated register to default values.
187 */
188
189void __init init_mmu (void)
190{
191	/* Writing zeros to the <t>TLBCFG special registers ensure
192	 * that valid values exist in the register.  For existing
193	 * PGSZID<w> fields, zero selects the first element of the
194	 * page-size array.  For nonexistent PGSZID<w> fields, zero is
195	 * the best value to write.  Also, when changing PGSZID<w>
196	 * fields, the corresponding TLB must be flushed.
197	 */
198	set_itlbcfg_register (0);
199	set_dtlbcfg_register (0);
200	flush_tlb_all ();
201
202	/* Set rasid register to a known value. */
203
204	set_rasid_register (ASID_USER_FIRST);
205
206	/* Set PTEVADDR special register to the start of the page
207	 * table, which is in kernel mappable space (ie. not
208	 * statically mapped).  This register's value is undefined on
209	 * reset.
210	 */
211	set_ptevaddr_register (PGTABLE_START);
212}
213
214/*
215 * Initialize memory pages.
216 */
217
218void __init mem_init(void)
219{
220	unsigned long codesize, reservedpages, datasize, initsize;
221	unsigned long highmemsize, tmp, ram;
222
223	max_mapnr = num_physpages = max_low_pfn;
224	high_memory = (void *) __va(max_mapnr << PAGE_SHIFT);
225	highmemsize = 0;
226
227#ifdef CONFIG_HIGHMEM
228#error HIGHGMEM not implemented in init.c
229#endif
230
231	totalram_pages += free_all_bootmem();
232
233	reservedpages = ram = 0;
234	for (tmp = 0; tmp < max_low_pfn; tmp++) {
235		ram++;
236		if (PageReserved(mem_map+tmp))
237			reservedpages++;
238	}
239
240	codesize =  (unsigned long) &_etext - (unsigned long) &_ftext;
241	datasize =  (unsigned long) &_edata - (unsigned long) &_fdata;
242	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
243
244	printk("Memory: %luk/%luk available (%ldk kernel code, %ldk reserved, "
245	       "%ldk data, %ldk init %ldk highmem)\n",
246	       (unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
247	       ram << (PAGE_SHIFT-10),
248	       codesize >> 10,
249	       reservedpages << (PAGE_SHIFT-10),
250	       datasize >> 10,
251	       initsize >> 10,
252	       highmemsize >> 10);
253}
254
255void
256free_reserved_mem(void *start, void *end)
257{
258	for (; start < end; start += PAGE_SIZE) {
259		ClearPageReserved(virt_to_page(start));
260		init_page_count(virt_to_page(start));
261		free_page((unsigned long)start);
262		totalram_pages++;
263	}
264}
265
266#ifdef CONFIG_BLK_DEV_INITRD
267extern int initrd_is_mapped;
268
269void free_initrd_mem(unsigned long start, unsigned long end)
270{
271	if (initrd_is_mapped) {
272		free_reserved_mem((void*)start, (void*)end);
273		printk ("Freeing initrd memory: %ldk freed\n",(end-start)>>10);
274	}
275}
276#endif
277
278void free_initmem(void)
279{
280	free_reserved_mem(&__init_begin, &__init_end);
281	printk("Freeing unused kernel memory: %dk freed\n",
282	       (&__init_end - &__init_begin) >> 10);
283}
284
285struct kmem_cache *pgtable_cache __read_mostly;
286
287static void pgd_ctor(void* addr)
288{
289	pte_t* ptep = (pte_t*)addr;
290	int i;
291
292	for (i = 0; i < 1024; i++, ptep++)
293		pte_clear(NULL, 0, ptep);
294
295}
296
297void __init pgtable_cache_init(void)
298{
299	pgtable_cache = kmem_cache_create("pgd",
300			PAGE_SIZE, PAGE_SIZE,
301			SLAB_HWCACHE_ALIGN,
302			pgd_ctor);
303}
304