3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
5 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
6 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
7 * Copyright (C) 1996 Paul Mackerras
8 * Amiga/APUS changes by Jesper Skov (jskov@cygnus.co.uk).
9 * PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
11 * Derived from "arch/i386/mm/init.c"
12 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
14 * This program is free software; you can redistribute it and/or
15 * modify it under the terms of the GNU General Public License
16 * as published by the Free Software Foundation; either version
17 * 2 of the License, or (at your option) any later version.
21 #include <linux/config.h>
22 #include <linux/module.h>
23 #include <linux/sched.h>
24 #include <linux/kernel.h>
25 #include <linux/errno.h>
26 #include <linux/string.h>
27 #include <linux/types.h>
29 #include <linux/stddef.h>
30 #include <linux/init.h>
31 #include <linux/bootmem.h>
32 #include <linux/highmem.h>
33 #include <linux/initrd.h>
34 #include <linux/pagemap.h>
36 #include <asm/pgalloc.h>
39 #include <asm/mmu_context.h>
40 #include <asm/pgtable.h>
43 #include <asm/machdep.h>
44 #include <asm/btext.h>
46 #include <asm/bootinfo.h>
49 #include <asm/sections.h>
53 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
54 /* The ammount of lowmem must be within 0xF0000000 - KERNELBASE. */
55 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - KERNELBASE))
56 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
59 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
61 DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
63 unsigned long total_memory;
64 unsigned long total_lowmem;
66 unsigned long ppc_memstart;
67 unsigned long ppc_memoffset = PAGE_OFFSET;
70 #ifdef CONFIG_PPC_PMAC
71 unsigned long agp_special_page;
78 EXPORT_SYMBOL(kmap_prot);
79 EXPORT_SYMBOL(kmap_pte);
84 /* XXX should be in current.h -- paulus */
85 extern struct task_struct *current_set[NR_CPUS];
88 struct device_node *memory_node;
90 extern int init_bootmem_done;
93 * this tells the system to map all of ram with the segregs
94 * (i.e. page tables) instead of the bats.
97 int __map_without_bats;
98 int __map_without_ltlbs;
100 /* max amount of low RAM to map in */
101 unsigned long __max_low_memory = MAX_LOW_MEM;
104 * limit of what is accessible with initial MMU setup -
105 * 256MB usually, but only 16MB on 601.
107 unsigned long __initial_memory_limit = 0x10000000;
110 * Check for command-line options that affect what MMU_init will do.
114 /* Check for nobats option (used in mapin_ram). */
115 if (strstr(cmd_line, "nobats")) {
116 __map_without_bats = 1;
119 if (strstr(cmd_line, "noltlbs")) {
120 __map_without_ltlbs = 1;
125 * MMU_init sets up the basic memory mappings for the kernel,
126 * including both RAM and possibly some I/O regions,
127 * and sets up the page tables and the MMU hardware ready to go.
129 void __init MMU_init(void)
132 ppc_md.progress("MMU:enter", 0x111);
134 /* 601 can only access 16MB at the moment */
135 if (PVR_VER(mfspr(SPRN_PVR)) == 1)
136 __initial_memory_limit = 0x01000000;
138 /* parse args from command line */
141 if (lmb.memory.cnt > 1) {
144 printk(KERN_WARNING "Only using first contiguous memory region");
147 total_memory = lmb_end_of_DRAM();
148 total_lowmem = total_memory;
150 #ifdef CONFIG_FSL_BOOKE
151 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
152 * entries, so we need to adjust lowmem to match the amount we can map
153 * in the fixed entries */
154 adjust_total_lowmem();
155 #endif /* CONFIG_FSL_BOOKE */
156 if (total_lowmem > __max_low_memory) {
157 total_lowmem = __max_low_memory;
158 #ifndef CONFIG_HIGHMEM
159 total_memory = total_lowmem;
160 #endif /* CONFIG_HIGHMEM */
163 /* Initialize the MMU hardware */
165 ppc_md.progress("MMU:hw init", 0x300);
168 /* Map in all of RAM starting at KERNELBASE */
170 ppc_md.progress("MMU:mapin", 0x301);
173 #ifdef CONFIG_HIGHMEM
174 ioremap_base = PKMAP_BASE;
176 ioremap_base = 0xfe000000UL; /* for now, could be 0xfffff000 */
177 #endif /* CONFIG_HIGHMEM */
178 ioremap_bot = ioremap_base;
180 /* Map in I/O resources */
182 ppc_md.progress("MMU:setio", 0x302);
183 if (ppc_md.setup_io_mappings)
184 ppc_md.setup_io_mappings();
186 /* Initialize the context management stuff */
190 ppc_md.progress("MMU:exit", 0x211);
193 /* This is only called until mem_init is done. */
194 void __init *early_get_page(void)
198 if (init_bootmem_done) {
199 p = alloc_bootmem_pages(PAGE_SIZE);
201 p = __va(lmb_alloc_base(PAGE_SIZE, PAGE_SIZE,
202 __initial_memory_limit));
207 /* Free up now-unused memory */
208 static void free_sec(unsigned long start, unsigned long end, const char *name)
210 unsigned long cnt = 0;
212 while (start < end) {
213 ClearPageReserved(virt_to_page(start));
214 set_page_count(virt_to_page(start), 1);
220 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
221 totalram_pages += cnt;
225 void free_initmem(void)
227 #define FREESEC(TYPE) \
228 free_sec((unsigned long)(&__ ## TYPE ## _begin), \
229 (unsigned long)(&__ ## TYPE ## _end), \
232 printk ("Freeing unused kernel memory:");
235 ppc_md.progress = NULL;
239 #ifdef CONFIG_BLK_DEV_INITRD
240 void free_initrd_mem(unsigned long start, unsigned long end)
243 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
244 for (; start < end; start += PAGE_SIZE) {
245 ClearPageReserved(virt_to_page(start));
246 set_page_count(virt_to_page(start), 1);