1 /*
2 * linux/arch/m68knommu/mm/init.c
3 *
4 * Copyright (C) 1998 D. Jeff Dionne <jeff@lineo.ca>,
5 * Kenneth Albanowski <kjahds@kjahds.com>,
6 * Copyright (C) 2000 Lineo, Inc. (www.lineo.com)
7 *
8 * Based on:
9 *
10 * linux/arch/m68k/mm/init.c
11 *
12 * Copyright (C) 1995 Hamish Macdonald
13 *
14 * JAN/1999 -- hacked to support ColdFire (gerg@snapgear.com)
15 * DEC/2000 -- linux 2.4 support <davidm@snapgear.com>
16 */
17
18 #include <linux/signal.h>
19 #include <linux/sched.h>
20 #include <linux/kernel.h>
21 #include <linux/errno.h>
22 #include <linux/string.h>
23 #include <linux/types.h>
24 #include <linux/ptrace.h>
25 #include <linux/mman.h>
26 #include <linux/mm.h>
27 #include <linux/swap.h>
28 #include <linux/init.h>
29 #include <linux/highmem.h>
30 #include <linux/pagemap.h>
31 #include <linux/bootmem.h>
32 #include <linux/slab.h>
33
34 #include <asm/setup.h>
35 #include <asm/segment.h>
36 #include <asm/page.h>
37 #include <asm/pgtable.h>
38 #include <asm/system.h>
39 #include <asm/machdep.h>
40
41 #undef DEBUG
42
43 extern void die_if_kernel(char *,struct pt_regs *,long);
44 extern void free_initmem(void);
45
46 /*
47 * BAD_PAGE is the page that is used for page faults when linux
48 * is out-of-memory. Older versions of linux just did a
49 * do_exit(), but using this instead means there is less risk
50 * for a process dying in kernel mode, possibly leaving a inode
51 * unused etc..
52 *
53 * BAD_PAGETABLE is the accompanying page-table: it is initialized
54 * to point to BAD_PAGE entries.
55 *
56 * ZERO_PAGE is a special page that is used for zero-initialized
57 * data and COW.
58 */
59 static unsigned long empty_bad_page_table;
60
61 static unsigned long empty_bad_page;
62
63 unsigned long empty_zero_page;
64
65 extern unsigned long memory_start;
66 extern unsigned long memory_end;
67
68 /*
69 * paging_init() continues the virtual memory environment setup which
70 * was begun by the code in arch/head.S.
71 * The parameters are pointers to where to stick the starting and ending
72 * addresses of available kernel virtual memory.
73 */
paging_init(void)74 void __init paging_init(void)
75 {
76 /*
77 * Make sure start_mem is page aligned, otherwise bootmem and
78 * page_alloc get different views of the world.
79 */
80 #ifdef DEBUG
81 unsigned long start_mem = PAGE_ALIGN(memory_start);
82 #endif
83 unsigned long end_mem = memory_end & PAGE_MASK;
84
85 #ifdef DEBUG
86 printk (KERN_DEBUG "start_mem is %#lx\nvirtual_end is %#lx\n",
87 start_mem, end_mem);
88 #endif
89
90 /*
91 * Initialize the bad page table and bad page to point
92 * to a couple of allocated pages.
93 */
94 empty_bad_page_table = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
95 empty_bad_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
96 empty_zero_page = (unsigned long)alloc_bootmem_pages(PAGE_SIZE);
97 memset((void *)empty_zero_page, 0, PAGE_SIZE);
98
99 /*
100 * Set up SFC/DFC registers (user data space).
101 */
102 set_fs (USER_DS);
103
104 #ifdef DEBUG
105 printk (KERN_DEBUG "before free_area_init\n");
106
107 printk (KERN_DEBUG "free_area_init -> start_mem is %#lx\nvirtual_end is %#lx\n",
108 start_mem, end_mem);
109 #endif
110
111 {
112 unsigned long zones_size[MAX_NR_ZONES] = {0, };
113
114 zones_size[ZONE_DMA] = 0 >> PAGE_SHIFT;
115 zones_size[ZONE_NORMAL] = (end_mem - PAGE_OFFSET) >> PAGE_SHIFT;
116 #ifdef CONFIG_HIGHMEM
117 zones_size[ZONE_HIGHMEM] = 0;
118 #endif
119 free_area_init(zones_size);
120 }
121 }
122
mem_init(void)123 void __init mem_init(void)
124 {
125 int codek = 0, datak = 0, initk = 0;
126 unsigned long tmp;
127 extern char _etext, _stext, _sdata, _ebss, __init_begin, __init_end;
128 extern unsigned int _ramend, _rambase;
129 unsigned long len = _ramend - _rambase;
130 unsigned long start_mem = memory_start; /* DAVIDM - these must start at end of kernel */
131 unsigned long end_mem = memory_end; /* DAVIDM - this must not include kernel stack at top */
132
133 #ifdef DEBUG
134 printk(KERN_DEBUG "Mem_init: start=%lx, end=%lx\n", start_mem, end_mem);
135 #endif
136
137 end_mem &= PAGE_MASK;
138 high_memory = (void *) end_mem;
139
140 start_mem = PAGE_ALIGN(start_mem);
141 max_mapnr = num_physpages = (((unsigned long) high_memory) - PAGE_OFFSET) >> PAGE_SHIFT;
142
143 /* this will put all memory onto the freelists */
144 totalram_pages = free_all_bootmem();
145
146 codek = (&_etext - &_stext) >> 10;
147 datak = (&_ebss - &_sdata) >> 10;
148 initk = (&__init_begin - &__init_end) >> 10;
149
150 tmp = nr_free_pages() << PAGE_SHIFT;
151 printk(KERN_INFO "Memory available: %luk/%luk RAM, (%dk kernel code, %dk data)\n",
152 tmp >> 10,
153 len >> 10,
154 codek,
155 datak
156 );
157 }
158
159
160 #ifdef CONFIG_BLK_DEV_INITRD
free_initrd_mem(unsigned long start,unsigned long end)161 void free_initrd_mem(unsigned long start, unsigned long end)
162 {
163 int pages = 0;
164 for (; start < end; start += PAGE_SIZE) {
165 ClearPageReserved(virt_to_page(start));
166 init_page_count(virt_to_page(start));
167 free_page(start);
168 totalram_pages++;
169 pages++;
170 }
171 printk (KERN_NOTICE "Freeing initrd memory: %dk freed\n", pages);
172 }
173 #endif
174
175 void
free_initmem()176 free_initmem()
177 {
178 #ifdef CONFIG_RAMKERNEL
179 unsigned long addr;
180 extern char __init_begin, __init_end;
181 /*
182 * The following code should be cool even if these sections
183 * are not page aligned.
184 */
185 addr = PAGE_ALIGN((unsigned long)(&__init_begin));
186 /* next to check that the page we free is not a partial page */
187 for (; addr + PAGE_SIZE < (unsigned long)(&__init_end); addr +=PAGE_SIZE) {
188 ClearPageReserved(virt_to_page(addr));
189 init_page_count(virt_to_page(addr));
190 free_page(addr);
191 totalram_pages++;
192 }
193 printk(KERN_NOTICE "Freeing unused kernel memory: %ldk freed (0x%x - 0x%x)\n",
194 (addr - PAGE_ALIGN((long) &__init_begin)) >> 10,
195 (int)(PAGE_ALIGN((unsigned long)(&__init_begin))),
196 (int)(addr - PAGE_SIZE));
197 #endif
198 }
199
200