tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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#include <linux/slab.h>
36#include <linux/hugetlb.h>
37
38#include <asm/pgalloc.h>
39#include <asm/prom.h>
40#include <asm/io.h>
41#include <asm/pgtable.h>
42#include <asm/mmu.h>
43#include <asm/smp.h>
44#include <asm/machdep.h>
45#include <asm/btext.h>
46#include <asm/tlb.h>
47#include <asm/sections.h>
48#include <asm/hugetlb.h>
49
50#include "mmu_decl.h"
51
52#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
53/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
54#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
55#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
56#endif
57#endif
58#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
59
60phys_addr_t total_memory;
61phys_addr_t total_lowmem;
62
63phys_addr_t memstart_addr = (phys_addr_t)~0ull;
64EXPORT_SYMBOL(memstart_addr);
65phys_addr_t kernstart_addr;
66EXPORT_SYMBOL(kernstart_addr);
67
68#ifdef CONFIG_RELOCATABLE_PPC32
69/* Used in __va()/__pa() */
70long long virt_phys_offset;
71EXPORT_SYMBOL(virt_phys_offset);
72#endif
73
74phys_addr_t lowmem_end_addr;
75
76int boot_mapsize;
77#ifdef CONFIG_PPC_PMAC
78unsigned long agp_special_page;
79EXPORT_SYMBOL(agp_special_page);
80#endif
81
82void MMU_init(void);
83
84/* XXX should be in current.h -- paulus */
85extern struct task_struct *current_set[NR_CPUS];
86
87/*
88 * this tells the system to map all of ram with the segregs
89 * (i.e. page tables) instead of the bats.
90 * -- Cort
91 */
92int __map_without_bats;
93int __map_without_ltlbs;
94
95/*
96 * This tells the system to allow ioremapping memory marked as reserved.
97 */
98int __allow_ioremap_reserved;
99
100/* max amount of low RAM to map in */
101unsigned long __max_low_memory = MAX_LOW_MEM;
102
103/*
104 * Check for command-line options that affect what MMU_init will do.
105 */
106void MMU_setup(void)
107{
108 /* Check for nobats option (used in mapin_ram). */
109 if (strstr(cmd_line, "nobats")) {
110 __map_without_bats = 1;
111 }
112
113 if (strstr(cmd_line, "noltlbs")) {
114 __map_without_ltlbs = 1;
115 }
116#ifdef CONFIG_DEBUG_PAGEALLOC
117 __map_without_bats = 1;
118 __map_without_ltlbs = 1;
119#endif
120}
121
122/*
123 * MMU_init sets up the basic memory mappings for the kernel,
124 * including both RAM and possibly some I/O regions,
125 * and sets up the page tables and the MMU hardware ready to go.
126 */
127void __init MMU_init(void)
128{
129 if (ppc_md.progress)
130 ppc_md.progress("MMU:enter", 0x111);
131
132 /* parse args from command line */
133 MMU_setup();
134
135 /*
136 * Reserve gigantic pages for hugetlb. This MUST occur before
137 * lowmem_end_addr is initialized below.
138 */
139 reserve_hugetlb_gpages();
140
141 if (memblock.memory.cnt > 1) {
142#ifndef CONFIG_WII
143 memblock_enforce_memory_limit(memblock.memory.regions[0].size);
144 printk(KERN_WARNING "Only using first contiguous memory region");
145#else
146 wii_memory_fixups();
147#endif
148 }
149
150 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
151 lowmem_end_addr = memstart_addr + total_lowmem;
152
153#ifdef CONFIG_FSL_BOOKE
154 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
155 * entries, so we need to adjust lowmem to match the amount we can map
156 * in the fixed entries */
157 adjust_total_lowmem();
158#endif /* CONFIG_FSL_BOOKE */
159
160 if (total_lowmem > __max_low_memory) {
161 total_lowmem = __max_low_memory;
162 lowmem_end_addr = memstart_addr + total_lowmem;
163#ifndef CONFIG_HIGHMEM
164 total_memory = total_lowmem;
165 memblock_enforce_memory_limit(total_lowmem);
166#endif /* CONFIG_HIGHMEM */
167 }
168
169 /* Initialize the MMU hardware */
170 if (ppc_md.progress)
171 ppc_md.progress("MMU:hw init", 0x300);
172 MMU_init_hw();
173
174 /* Map in all of RAM starting at KERNELBASE */
175 if (ppc_md.progress)
176 ppc_md.progress("MMU:mapin", 0x301);
177 mapin_ram();
178
179 /* Initialize early top-down ioremap allocator */
180 ioremap_bot = IOREMAP_TOP;
181
182 /* Map in I/O resources */
183 if (ppc_md.progress)
184 ppc_md.progress("MMU:setio", 0x302);
185
186 if (ppc_md.progress)
187 ppc_md.progress("MMU:exit", 0x211);
188
189 /* From now on, btext is no longer BAT mapped if it was at all */
190#ifdef CONFIG_BOOTX_TEXT
191 btext_unmap();
192#endif
193
194 /* Shortly after that, the entire linear mapping will be available */
195 memblock_set_current_limit(lowmem_end_addr);
196}
197
198/* This is only called until mem_init is done. */
199void __init *early_get_page(void)
200{
201 if (init_bootmem_done)
202 return alloc_bootmem_pages(PAGE_SIZE);
203 else
204 return __va(memblock_alloc(PAGE_SIZE, PAGE_SIZE));
205}
206
207#ifdef CONFIG_8xx /* No 8xx specific .c file to put that in ... */
208void setup_initial_memory_limit(phys_addr_t first_memblock_base,
209 phys_addr_t first_memblock_size)
210{
211 /* We don't currently support the first MEMBLOCK not mapping 0
212 * physical on those processors
213 */
214 BUG_ON(first_memblock_base != 0);
215
216 /* 8xx can only access 8MB at the moment */
217 memblock_set_current_limit(min_t(u64, first_memblock_size, 0x00800000));
218}
219#endif /* CONFIG_8xx */