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 */
56static unsigned long empty_bad_page_table;
57static unsigned long empty_bad_page;
58
59unsigned long empty_zero_page;
60EXPORT_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 */
69void __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 */
115void __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 */
141void 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
153void __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