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/gfp.h>
23 #include <linux/swap.h>
24 #include <linux/mm.h>
25 #include <linux/kernel.h>
26 #include <linux/string.h>
27 #include <linux/types.h>
28 #include <linux/bootmem.h>
29 #include <linux/highmem.h>
30 #include <linux/module.h>
31
32 #include <asm/setup.h>
33 #include <asm/segment.h>
34 #include <asm/page.h>
35 #include <asm/pgtable.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 /*
44 * BAD_PAGE is the page that is used for page faults when linux
45 * is out-of-memory. Older versions of linux just did a
46 * do_exit(), but using this instead means there is less risk
47 * for a process dying in kernel mode, possibly leaving a inode
48 * unused etc..
49 *
50 * BAD_PAGETABLE is the accompanying page-table: it is initialized
51 * to point to BAD_PAGE entries.
52 *
53 * ZERO_PAGE is a special page that is used for zero-initialized
54 * data and COW.
55 */
56 static unsigned long empty_bad_page_table;
57 static unsigned long empty_bad_page;
58
59 unsigned long empty_zero_page;
60 EXPORT_SYMBOL(empty_zero_page);
61
62 /*****************************************************************************/
63 /*
64 * paging_init() continues the virtual memory environment setup which
65 * was begun by the code in arch/head.S.
66 * The parameters are pointers to where to stick the starting and ending
67 * addresses of available kernel virtual memory.
68 */
paging_init(void)69 void __init paging_init(void)
70 {
71 unsigned long zones_size[MAX_NR_ZONES] = {0, };
72
73 /* allocate some pages for kernel housekeeping tasks */
74 empty_bad_page_table = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
75 empty_bad_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
76 empty_zero_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
77
78 memset((void *) empty_zero_page, 0, PAGE_SIZE);
79
80 #ifdef CONFIG_HIGHMEM
81 if (get_num_physpages() - num_mappedpages) {
82 pgd_t *pge;
83 pud_t *pue;
84 pmd_t *pme;
85
86 pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
87
88 pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
89 pue = pud_offset(pge, PKMAP_BASE);
90 pme = pmd_offset(pue, PKMAP_BASE);
91 __set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
92 }
93 #endif
94
95 /* distribute the allocatable pages across the various zones and pass them to the allocator
96 */
97 zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
98 #ifdef CONFIG_HIGHMEM
99 zones_size[ZONE_HIGHMEM] = get_num_physpages() - num_mappedpages;
100 #endif
101
102 free_area_init(zones_size);
103
104 #ifdef CONFIG_MMU
105 /* initialise init's MMU context */
106 init_new_context(&init_task, &init_mm);
107 #endif
108
109 } /* end paging_init() */
110
111 /*****************************************************************************/
112 /*
113 *
114 */
mem_init(void)115 void __init mem_init(void)
116 {
117 unsigned long code_size = _etext - _stext;
118
119 /* this will put all low memory onto the freelists */
120 free_all_bootmem();
121 #if defined(CONFIG_MMU) && defined(CONFIG_HIGHMEM)
122 {
123 unsigned long pfn;
124
125 for (pfn = get_num_physpages() - 1;
126 pfn >= num_mappedpages; pfn--)
127 free_highmem_page(&mem_map[pfn]);
128 }
129 #endif
130
131 mem_init_print_info(NULL);
132 if (rom_length > 0 && rom_length >= code_size)
133 printk("Memory available: %luKiB/%luKiB ROM\n",
134 (rom_length - code_size) >> 10, rom_length >> 10);
135 } /* end mem_init() */
136
137 /*****************************************************************************/
138 /*
139 * free the memory that was only required for initialisation
140 */
free_initmem(void)141 void free_initmem(void)
142 {
143 #if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
144 free_initmem_default(-1);
145 #endif
146 } /* end free_initmem() */
147
148 /*****************************************************************************/
149 /*
150 * free the initial ramdisk memory
151 */
152 #ifdef CONFIG_BLK_DEV_INITRD
free_initrd_mem(unsigned long start,unsigned long end)153 void __init free_initrd_mem(unsigned long start, unsigned long end)
154 {
155 free_reserved_area((void *)start, (void *)end, -1, "initrd");
156 } /* end free_initrd_mem() */
157 #endif
158