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/highmem.h>
30 #include <linux/initrd.h>
31 #include <linux/pagemap.h>
32 #include <linux/memblock.h>
33 #include <linux/gfp.h>
34 #include <linux/slab.h>
35 #include <linux/hugetlb.h>
36
37 #include <asm/pgalloc.h>
38 #include <asm/prom.h>
39 #include <asm/io.h>
40 #include <asm/pgtable.h>
41 #include <asm/mmu.h>
42 #include <asm/smp.h>
43 #include <asm/machdep.h>
44 #include <asm/btext.h>
45 #include <asm/tlb.h>
46 #include <asm/sections.h>
47 #include <asm/hugetlb.h>
48
49 #include "mmu_decl.h"
50
51 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
52 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
53 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
54 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
55 #endif
56 #endif
57 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
58
59 phys_addr_t total_memory;
60 phys_addr_t total_lowmem;
61
62 phys_addr_t memstart_addr = (phys_addr_t)~0ull;
63 EXPORT_SYMBOL(memstart_addr);
64 phys_addr_t kernstart_addr;
65 EXPORT_SYMBOL(kernstart_addr);
66
67 #ifdef CONFIG_RELOCATABLE_PPC32
68 /* Used in __va()/__pa() */
69 long long virt_phys_offset;
70 EXPORT_SYMBOL(virt_phys_offset);
71 #endif
72
73 phys_addr_t lowmem_end_addr;
74
75 int boot_mapsize;
76 #ifdef CONFIG_PPC_PMAC
77 unsigned long agp_special_page;
78 EXPORT_SYMBOL(agp_special_page);
79 #endif
80
81 void MMU_init(void);
82
83 /* XXX should be in current.h -- paulus */
84 extern struct task_struct *current_set[NR_CPUS];
85
86 /*
87 * this tells the system to map all of ram with the segregs
88 * (i.e. page tables) instead of the bats.
89 * -- Cort
90 */
91 int __map_without_bats;
92 int __map_without_ltlbs;
93
94 /*
95 * This tells the system to allow ioremapping memory marked as reserved.
96 */
97 int __allow_ioremap_reserved;
98
99 /* max amount of low RAM to map in */
100 unsigned long __max_low_memory = MAX_LOW_MEM;
101
102 /*
103 * Check for command-line options that affect what MMU_init will do.
104 */
MMU_setup(void)105 void __init MMU_setup(void)
106 {
107 /* Check for nobats option (used in mapin_ram). */
108 if (strstr(boot_command_line, "nobats")) {
109 __map_without_bats = 1;
110 }
111
112 if (strstr(boot_command_line, "noltlbs")) {
113 __map_without_ltlbs = 1;
114 }
115 #ifdef CONFIG_DEBUG_PAGEALLOC
116 __map_without_bats = 1;
117 __map_without_ltlbs = 1;
118 #endif
119 }
120
121 /*
122 * MMU_init sets up the basic memory mappings for the kernel,
123 * including both RAM and possibly some I/O regions,
124 * and sets up the page tables and the MMU hardware ready to go.
125 */
MMU_init(void)126 void __init MMU_init(void)
127 {
128 if (ppc_md.progress)
129 ppc_md.progress("MMU:enter", 0x111);
130
131 /* parse args from command line */
132 MMU_setup();
133
134 /*
135 * Reserve gigantic pages for hugetlb. This MUST occur before
136 * lowmem_end_addr is initialized below.
137 */
138 reserve_hugetlb_gpages();
139
140 if (memblock.memory.cnt > 1) {
141 #ifndef CONFIG_WII
142 memblock_enforce_memory_limit(memblock.memory.regions[0].size);
143 printk(KERN_WARNING "Only using first contiguous memory region");
144 #else
145 wii_memory_fixups();
146 #endif
147 }
148
149 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
150 lowmem_end_addr = memstart_addr + total_lowmem;
151
152 #ifdef CONFIG_FSL_BOOKE
153 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
154 * entries, so we need to adjust lowmem to match the amount we can map
155 * in the fixed entries */
156 adjust_total_lowmem();
157 #endif /* CONFIG_FSL_BOOKE */
158
159 if (total_lowmem > __max_low_memory) {
160 total_lowmem = __max_low_memory;
161 lowmem_end_addr = memstart_addr + total_lowmem;
162 #ifndef CONFIG_HIGHMEM
163 total_memory = total_lowmem;
164 memblock_enforce_memory_limit(total_lowmem);
165 #endif /* CONFIG_HIGHMEM */
166 }
167
168 /* Initialize the MMU hardware */
169 if (ppc_md.progress)
170 ppc_md.progress("MMU:hw init", 0x300);
171 MMU_init_hw();
172
173 /* Map in all of RAM starting at KERNELBASE */
174 if (ppc_md.progress)
175 ppc_md.progress("MMU:mapin", 0x301);
176 mapin_ram();
177
178 /* Initialize early top-down ioremap allocator */
179 ioremap_bot = IOREMAP_TOP;
180
181 /* Map in I/O resources */
182 if (ppc_md.progress)
183 ppc_md.progress("MMU:setio", 0x302);
184
185 if (ppc_md.progress)
186 ppc_md.progress("MMU:exit", 0x211);
187
188 /* From now on, btext is no longer BAT mapped if it was at all */
189 #ifdef CONFIG_BOOTX_TEXT
190 btext_unmap();
191 #endif
192
193 /* Shortly after that, the entire linear mapping will be available */
194 memblock_set_current_limit(lowmem_end_addr);
195 }
196
197 #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)198 void setup_initial_memory_limit(phys_addr_t first_memblock_base,
199 phys_addr_t first_memblock_size)
200 {
201 /* We don't currently support the first MEMBLOCK not mapping 0
202 * physical on those processors
203 */
204 BUG_ON(first_memblock_base != 0);
205
206 #ifdef CONFIG_PIN_TLB
207 /* 8xx can only access 24MB at the moment */
208 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x01800000));
209 #else
210 /* 8xx can only access 8MB at the moment */
211 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
212 #endif
213 }
214 #endif /* CONFIG_8xx */
215