1 /* init.c: memory initialisation for FRV
2 *
3 * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 *
11 * Derived from:
12 * - linux/arch/m68knommu/mm/init.c
13 * - Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>, Kenneth Albanowski <kjahds@kjahds.com>,
14 * - Copyright (C) 2000 Lineo, Inc. (www.lineo.com)
15 * - linux/arch/m68k/mm/init.c
16 * - Copyright (C) 1995 Hamish Macdonald
17 */
18
19 #include <linux/signal.h>
20 #include <linux/sched.h>
21 #include <linux/pagemap.h>
22 #include <linux/swap.h>
23 #include <linux/mm.h>
24 #include <linux/kernel.h>
25 #include <linux/string.h>
26 #include <linux/types.h>
27 #include <linux/bootmem.h>
28 #include <linux/highmem.h>
29 #include <linux/module.h>
30
31 #include <asm/setup.h>
32 #include <asm/segment.h>
33 #include <asm/page.h>
34 #include <asm/pgtable.h>
35 #include <asm/system.h>
36 #include <asm/mmu_context.h>
37 #include <asm/virtconvert.h>
38 #include <asm/sections.h>
39 #include <asm/tlb.h>
40
41 #undef DEBUG
42
43 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
44
45 /*
46 * BAD_PAGE is the page that is used for page faults when linux
47 * is out-of-memory. Older versions of linux just did a
48 * do_exit(), but using this instead means there is less risk
49 * for a process dying in kernel mode, possibly leaving a inode
50 * unused etc..
51 *
52 * BAD_PAGETABLE is the accompanying page-table: it is initialized
53 * to point to BAD_PAGE entries.
54 *
55 * ZERO_PAGE is a special page that is used for zero-initialized
56 * data and COW.
57 */
58 static unsigned long empty_bad_page_table;
59 static unsigned long empty_bad_page;
60
61 unsigned long empty_zero_page;
62 EXPORT_SYMBOL(empty_zero_page);
63
64 /*****************************************************************************/
65 /*
66 * paging_init() continues the virtual memory environment setup which
67 * was begun by the code in arch/head.S.
68 * The parameters are pointers to where to stick the starting and ending
69 * addresses of available kernel virtual memory.
70 */
paging_init(void)71 void __init paging_init(void)
72 {
73 unsigned long zones_size[MAX_NR_ZONES] = {0, };
74
75 /* allocate some pages for kernel housekeeping tasks */
76 empty_bad_page_table = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
77 empty_bad_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
78 empty_zero_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
79
80 memset((void *) empty_zero_page, 0, PAGE_SIZE);
81
82 #ifdef CONFIG_HIGHMEM
83 if (num_physpages - num_mappedpages) {
84 pgd_t *pge;
85 pud_t *pue;
86 pmd_t *pme;
87
88 pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
89
90 pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
91 pue = pud_offset(pge, PKMAP_BASE);
92 pme = pmd_offset(pue, PKMAP_BASE);
93 __set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
94 }
95 #endif
96
97 /* distribute the allocatable pages across the various zones and pass them to the allocator
98 */
99 zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
100 #ifdef CONFIG_HIGHMEM
101 zones_size[ZONE_HIGHMEM] = num_physpages - num_mappedpages;
102 #endif
103
104 free_area_init(zones_size);
105
106 #ifdef CONFIG_MMU
107 /* initialise init's MMU context */
108 init_new_context(&init_task, &init_mm);
109 #endif
110
111 } /* end paging_init() */
112
113 /*****************************************************************************/
114 /*
115 *
116 */
mem_init(void)117 void __init mem_init(void)
118 {
119 unsigned long npages = (memory_end - memory_start) >> PAGE_SHIFT;
120 unsigned long tmp;
121 #ifdef CONFIG_MMU
122 unsigned long loop, pfn;
123 int datapages = 0;
124 #endif
125 int codek = 0, datak = 0;
126
127 /* this will put all memory onto the freelists */
128 totalram_pages = free_all_bootmem();
129
130 #ifdef CONFIG_MMU
131 for (loop = 0 ; loop < npages ; loop++)
132 if (PageReserved(&mem_map[loop]))
133 datapages++;
134
135 #ifdef CONFIG_HIGHMEM
136 for (pfn = num_physpages - 1; pfn >= num_mappedpages; pfn--) {
137 struct page *page = &mem_map[pfn];
138
139 ClearPageReserved(page);
140 init_page_count(page);
141 __free_page(page);
142 totalram_pages++;
143 }
144 #endif
145
146 codek = ((unsigned long) &_etext - (unsigned long) &_stext) >> 10;
147 datak = datapages << (PAGE_SHIFT - 10);
148
149 #else
150 codek = (_etext - _stext) >> 10;
151 datak = 0; //(_ebss - _sdata) >> 10;
152 #endif
153
154 tmp = nr_free_pages() << PAGE_SHIFT;
155 printk("Memory available: %luKiB/%luKiB RAM, %luKiB/%luKiB ROM (%dKiB kernel code, %dKiB data)\n",
156 tmp >> 10,
157 npages << (PAGE_SHIFT - 10),
158 (rom_length > 0) ? ((rom_length >> 10) - codek) : 0,
159 rom_length >> 10,
160 codek,
161 datak
162 );
163
164 } /* end mem_init() */
165
166 /*****************************************************************************/
167 /*
168 * free the memory that was only required for initialisation
169 */
free_initmem(void)170 void free_initmem(void)
171 {
172 #if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
173 unsigned long start, end, addr;
174
175 start = PAGE_ALIGN((unsigned long) &__init_begin); /* round up */
176 end = ((unsigned long) &__init_end) & PAGE_MASK; /* round down */
177
178 /* next to check that the page we free is not a partial page */
179 for (addr = start; addr < end; addr += PAGE_SIZE) {
180 ClearPageReserved(virt_to_page(addr));
181 init_page_count(virt_to_page(addr));
182 free_page(addr);
183 totalram_pages++;
184 }
185
186 printk("Freeing unused kernel memory: %ldKiB freed (0x%lx - 0x%lx)\n",
187 (end - start) >> 10, start, end);
188 #endif
189 } /* end free_initmem() */
190
191 /*****************************************************************************/
192 /*
193 * free the initial ramdisk memory
194 */
195 #ifdef CONFIG_BLK_DEV_INITRD
free_initrd_mem(unsigned long start,unsigned long end)196 void __init free_initrd_mem(unsigned long start, unsigned long end)
197 {
198 int pages = 0;
199 for (; start < end; start += PAGE_SIZE) {
200 ClearPageReserved(virt_to_page(start));
201 init_page_count(virt_to_page(start));
202 free_page(start);
203 totalram_pages++;
204 pages++;
205 }
206 printk("Freeing initrd memory: %dKiB freed\n", (pages * PAGE_SIZE) >> 10);
207 } /* end free_initrd_mem() */
208 #endif
209