1 /*
2 * PowerPC version
3 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
4 *
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 * PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
9 *
10 * Derived from "arch/i386/mm/init.c"
11 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
12 *
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
17 *
18 */
19
20 #include <linux/module.h>
21 #include <linux/sched.h>
22 #include <linux/kernel.h>
23 #include <linux/errno.h>
24 #include <linux/string.h>
25 #include <linux/types.h>
26 #include <linux/mm.h>
27 #include <linux/stddef.h>
28 #include <linux/init.h>
29 #include <linux/bootmem.h>
30 #include <linux/highmem.h>
31 #include <linux/initrd.h>
32 #include <linux/pagemap.h>
33 #include <linux/memblock.h>
34 #include <linux/gfp.h>
35
36 #include <asm/pgalloc.h>
37 #include <asm/prom.h>
38 #include <asm/io.h>
39 #include <asm/pgtable.h>
40 #include <asm/mmu.h>
41 #include <asm/smp.h>
42 #include <asm/machdep.h>
43 #include <asm/btext.h>
44 #include <asm/tlb.h>
45 #include <asm/sections.h>
46 #include <asm/system.h>
47
48 #include "mmu_decl.h"
49
50 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
51 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
52 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
53 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_START_KERNEL"
54 #endif
55 #endif
56 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
57
58 phys_addr_t total_memory;
59 phys_addr_t total_lowmem;
60
61 phys_addr_t memstart_addr = (phys_addr_t)~0ull;
62 EXPORT_SYMBOL(memstart_addr);
63 phys_addr_t kernstart_addr;
64 EXPORT_SYMBOL(kernstart_addr);
65 phys_addr_t lowmem_end_addr;
66
67 int boot_mapsize;
68 #ifdef CONFIG_PPC_PMAC
69 unsigned long agp_special_page;
70 EXPORT_SYMBOL(agp_special_page);
71 #endif
72
73 void MMU_init(void);
74
75 /* XXX should be in current.h -- paulus */
76 extern struct task_struct *current_set[NR_CPUS];
77
78 /*
79 * this tells the system to map all of ram with the segregs
80 * (i.e. page tables) instead of the bats.
81 * -- Cort
82 */
83 int __map_without_bats;
84 int __map_without_ltlbs;
85
86 /*
87 * This tells the system to allow ioremapping memory marked as reserved.
88 */
89 int __allow_ioremap_reserved;
90
91 /* max amount of low RAM to map in */
92 unsigned long __max_low_memory = MAX_LOW_MEM;
93
94 /*
95 * Check for command-line options that affect what MMU_init will do.
96 */
MMU_setup(void)97 void MMU_setup(void)
98 {
99 /* Check for nobats option (used in mapin_ram). */
100 if (strstr(cmd_line, "nobats")) {
101 __map_without_bats = 1;
102 }
103
104 if (strstr(cmd_line, "noltlbs")) {
105 __map_without_ltlbs = 1;
106 }
107 #ifdef CONFIG_DEBUG_PAGEALLOC
108 __map_without_bats = 1;
109 __map_without_ltlbs = 1;
110 #endif
111 }
112
113 /*
114 * MMU_init sets up the basic memory mappings for the kernel,
115 * including both RAM and possibly some I/O regions,
116 * and sets up the page tables and the MMU hardware ready to go.
117 */
MMU_init(void)118 void __init MMU_init(void)
119 {
120 if (ppc_md.progress)
121 ppc_md.progress("MMU:enter", 0x111);
122
123 /* parse args from command line */
124 MMU_setup();
125
126 if (memblock.memory.cnt > 1) {
127 #ifndef CONFIG_WII
128 memblock.memory.cnt = 1;
129 memblock_analyze();
130 printk(KERN_WARNING "Only using first contiguous memory region");
131 #else
132 wii_memory_fixups();
133 #endif
134 }
135
136 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
137 lowmem_end_addr = memstart_addr + total_lowmem;
138
139 #ifdef CONFIG_FSL_BOOKE
140 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
141 * entries, so we need to adjust lowmem to match the amount we can map
142 * in the fixed entries */
143 adjust_total_lowmem();
144 #endif /* CONFIG_FSL_BOOKE */
145
146 if (total_lowmem > __max_low_memory) {
147 total_lowmem = __max_low_memory;
148 lowmem_end_addr = memstart_addr + total_lowmem;
149 #ifndef CONFIG_HIGHMEM
150 total_memory = total_lowmem;
151 memblock_enforce_memory_limit(total_lowmem);
152 memblock_analyze();
153 #endif /* CONFIG_HIGHMEM */
154 }
155
156 /* Initialize the MMU hardware */
157 if (ppc_md.progress)
158 ppc_md.progress("MMU:hw init", 0x300);
159 MMU_init_hw();
160
161 /* Map in all of RAM starting at KERNELBASE */
162 if (ppc_md.progress)
163 ppc_md.progress("MMU:mapin", 0x301);
164 mapin_ram();
165
166 /* Initialize early top-down ioremap allocator */
167 ioremap_bot = IOREMAP_TOP;
168
169 /* Map in I/O resources */
170 if (ppc_md.progress)
171 ppc_md.progress("MMU:setio", 0x302);
172
173 if (ppc_md.progress)
174 ppc_md.progress("MMU:exit", 0x211);
175
176 /* From now on, btext is no longer BAT mapped if it was at all */
177 #ifdef CONFIG_BOOTX_TEXT
178 btext_unmap();
179 #endif
180
181 /* Shortly after that, the entire linear mapping will be available */
182 memblock_set_current_limit(lowmem_end_addr);
183 }
184
185 /* This is only called until mem_init is done. */
early_get_page(void)186 void __init *early_get_page(void)
187 {
188 if (init_bootmem_done)
189 return alloc_bootmem_pages(PAGE_SIZE);
190 else
191 return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
192 }
193
194 /* Free up now-unused memory */
free_sec(unsigned long start,unsigned long end,const char * name)195 static void free_sec(unsigned long start, unsigned long end, const char *name)
196 {
197 unsigned long cnt = 0;
198
199 while (start < end) {
200 ClearPageReserved(virt_to_page(start));
201 init_page_count(virt_to_page(start));
202 free_page(start);
203 cnt++;
204 start += PAGE_SIZE;
205 }
206 if (cnt) {
207 printk(" %ldk %s", cnt << (PAGE_SHIFT - 10), name);
208 totalram_pages += cnt;
209 }
210 }
211
free_initmem(void)212 void free_initmem(void)
213 {
214 #define FREESEC(TYPE) \
215 free_sec((unsigned long)(&__ ## TYPE ## _begin), \
216 (unsigned long)(&__ ## TYPE ## _end), \
217 #TYPE);
218
219 printk ("Freeing unused kernel memory:");
220 FREESEC(init);
221 printk("\n");
222 ppc_md.progress = NULL;
223 #undef FREESEC
224 }
225
226 #ifdef CONFIG_BLK_DEV_INITRD
free_initrd_mem(unsigned long start,unsigned long end)227 void free_initrd_mem(unsigned long start, unsigned long end)
228 {
229 if (start < end)
230 printk ("Freeing initrd memory: %ldk freed\n", (end - start) >> 10);
231 for (; start < end; start += PAGE_SIZE) {
232 ClearPageReserved(virt_to_page(start));
233 init_page_count(virt_to_page(start));
234 free_page(start);
235 totalram_pages++;
236 }
237 }
238 #endif
239
240
241 #ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
setup_initial_memory_limit(phys_addr_t first_memblock_base,phys_addr_t first_memblock_size)242 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
243 phys_addr_t first_memblock_size)
244 {
245 /* We don't currently support the first MEMBLOCK not mapping 0
246 * physical on those processors
247 */
248 BUG_ON(first_memblock_base != 0);
249
250 /* 8xx can only access 8MB at the moment */
251 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
252 }
253 #endif /* CONFIG_8xx */
254