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/sched/task.h>
22 #include <linux/pagemap.h>
23 #include <linux/gfp.h>
24 #include <linux/swap.h>
25 #include <linux/mm.h>
26 #include <linux/kernel.h>
27 #include <linux/string.h>
28 #include <linux/types.h>
29 #include <linux/bootmem.h>
30 #include <linux/highmem.h>
31 #include <linux/module.h>
32
33 #include <asm/setup.h>
34 #include <asm/segment.h>
35 #include <asm/page.h>
36 #include <asm/pgtable.h>
37 #include <asm/mmu_context.h>
38 #include <asm/virtconvert.h>
39 #include <asm/sections.h>
40 #include <asm/tlb.h>
41
42 #undef DEBUG
43
44 /*
45 * BAD_PAGE is the page that is used for page faults when linux
46 * is out-of-memory. Older versions of linux just did a
47 * do_exit(), but using this instead means there is less risk
48 * for a process dying in kernel mode, possibly leaving a inode
49 * unused etc..
50 *
51 * BAD_PAGETABLE is the accompanying page-table: it is initialized
52 * to point to BAD_PAGE entries.
53 *
54 * ZERO_PAGE is a special page that is used for zero-initialized
55 * data and COW.
56 */
57 static unsigned long empty_bad_page_table;
58 static unsigned long empty_bad_page;
59
60 unsigned long empty_zero_page;
61 EXPORT_SYMBOL(empty_zero_page);
62
63 /*****************************************************************************/
64 /*
65 * paging_init() continues the virtual memory environment setup which
66 * was begun by the code in arch/head.S.
67 * The parameters are pointers to where to stick the starting and ending
68 * addresses of available kernel virtual memory.
69 */
paging_init(void)70 void __init paging_init(void)
71 {
72 unsigned long zones_size[MAX_NR_ZONES] = {0, };
73
74 /* allocate some pages for kernel housekeeping tasks */
75 empty_bad_page_table = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
76 empty_bad_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
77 empty_zero_page = (unsigned long) alloc_bootmem_pages(PAGE_SIZE);
78
79 memset((void *) empty_zero_page, 0, PAGE_SIZE);
80
81 #ifdef CONFIG_HIGHMEM
82 if (get_num_physpages() - num_mappedpages) {
83 pgd_t *pge;
84 pud_t *pue;
85 pmd_t *pme;
86
87 pkmap_page_table = alloc_bootmem_pages(PAGE_SIZE);
88
89 pge = swapper_pg_dir + pgd_index_k(PKMAP_BASE);
90 pue = pud_offset(pge, PKMAP_BASE);
91 pme = pmd_offset(pue, PKMAP_BASE);
92 __set_pmd(pme, virt_to_phys(pkmap_page_table) | _PAGE_TABLE);
93 }
94 #endif
95
96 /* distribute the allocatable pages across the various zones and pass them to the allocator
97 */
98 zones_size[ZONE_NORMAL] = max_low_pfn - min_low_pfn;
99 #ifdef CONFIG_HIGHMEM
100 zones_size[ZONE_HIGHMEM] = get_num_physpages() - num_mappedpages;
101 #endif
102
103 free_area_init(zones_size);
104
105 #ifdef CONFIG_MMU
106 /* initialise init's MMU context */
107 init_new_context(&init_task, &init_mm);
108 #endif
109
110 } /* end paging_init() */
111
112 /*****************************************************************************/
113 /*
114 *
115 */
mem_init(void)116 void __init mem_init(void)
117 {
118 unsigned long code_size = _etext - _stext;
119
120 /* this will put all low memory onto the freelists */
121 free_all_bootmem();
122 #if defined(CONFIG_MMU) && defined(CONFIG_HIGHMEM)
123 {
124 unsigned long pfn;
125
126 for (pfn = get_num_physpages() - 1;
127 pfn >= num_mappedpages; pfn--)
128 free_highmem_page(&mem_map[pfn]);
129 }
130 #endif
131
132 mem_init_print_info(NULL);
133 if (rom_length > 0 && rom_length >= code_size)
134 printk("Memory available: %luKiB/%luKiB ROM\n",
135 (rom_length - code_size) >> 10, rom_length >> 10);
136 } /* end mem_init() */
137
138 /*****************************************************************************/
139 /*
140 * free the memory that was only required for initialisation
141 */
free_initmem(void)142 void free_initmem(void)
143 {
144 #if defined(CONFIG_RAMKERNEL) && !defined(CONFIG_PROTECT_KERNEL)
145 free_initmem_default(-1);
146 #endif
147 } /* end free_initmem() */
148
149 /*****************************************************************************/
150 /*
151 * free the initial ramdisk memory
152 */
153 #ifdef CONFIG_BLK_DEV_INITRD
free_initrd_mem(unsigned long start,unsigned long end)154 void __init free_initrd_mem(unsigned long start, unsigned long end)
155 {
156 free_reserved_area((void *)start, (void *)end, -1, "initrd");
157 } /* end free_initrd_mem() */
158 #endif
159