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Linux kernel mirror (for testing)
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linux
1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * PowerPC version
4 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
5 *
6 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
7 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
8 * Copyright (C) 1996 Paul Mackerras
9 * PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
10 *
11 * Derived from "arch/i386/mm/init.c"
12 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
13 */
14
15#include <linux/module.h>
16#include <linux/sched.h>
17#include <linux/kernel.h>
18#include <linux/errno.h>
19#include <linux/string.h>
20#include <linux/types.h>
21#include <linux/mm.h>
22#include <linux/stddef.h>
23#include <linux/init.h>
24#include <linux/highmem.h>
25#include <linux/initrd.h>
26#include <linux/pagemap.h>
27#include <linux/memblock.h>
28#include <linux/gfp.h>
29#include <linux/slab.h>
30#include <linux/hugetlb.h>
31
32#include <asm/pgalloc.h>
33#include <asm/prom.h>
34#include <asm/io.h>
35#include <asm/pgtable.h>
36#include <asm/mmu.h>
37#include <asm/smp.h>
38#include <asm/machdep.h>
39#include <asm/btext.h>
40#include <asm/tlb.h>
41#include <asm/sections.h>
42#include <asm/hugetlb.h>
43#include <asm/kup.h>
44#include <asm/kasan.h>
45
46#include <mm/mmu_decl.h>
47
48#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
49/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
50#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
51#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
52#endif
53#endif
54#define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
55
56phys_addr_t total_memory;
57phys_addr_t total_lowmem;
58
59phys_addr_t memstart_addr = (phys_addr_t)~0ull;
60EXPORT_SYMBOL(memstart_addr);
61phys_addr_t kernstart_addr;
62EXPORT_SYMBOL(kernstart_addr);
63
64#ifdef CONFIG_RELOCATABLE
65/* Used in __va()/__pa() */
66long long virt_phys_offset;
67EXPORT_SYMBOL(virt_phys_offset);
68#endif
69
70phys_addr_t lowmem_end_addr;
71
72int boot_mapsize;
73#ifdef CONFIG_PPC_PMAC
74unsigned long agp_special_page;
75EXPORT_SYMBOL(agp_special_page);
76#endif
77
78void MMU_init(void);
79
80/*
81 * this tells the system to map all of ram with the segregs
82 * (i.e. page tables) instead of the bats.
83 * -- Cort
84 */
85int __map_without_bats;
86int __map_without_ltlbs;
87
88/* max amount of low RAM to map in */
89unsigned long __max_low_memory = MAX_LOW_MEM;
90
91/*
92 * Check for command-line options that affect what MMU_init will do.
93 */
94static void __init MMU_setup(void)
95{
96 /* Check for nobats option (used in mapin_ram). */
97 if (strstr(boot_command_line, "nobats")) {
98 __map_without_bats = 1;
99 }
100
101 if (strstr(boot_command_line, "noltlbs")) {
102 __map_without_ltlbs = 1;
103 }
104 if (debug_pagealloc_enabled()) {
105 __map_without_bats = 1;
106 __map_without_ltlbs = 1;
107 }
108 if (strict_kernel_rwx_enabled() && !IS_ENABLED(CONFIG_PPC_8xx))
109 __map_without_ltlbs = 1;
110}
111
112/*
113 * MMU_init sets up the basic memory mappings for the kernel,
114 * including both RAM and possibly some I/O regions,
115 * and sets up the page tables and the MMU hardware ready to go.
116 */
117void __init MMU_init(void)
118{
119 if (ppc_md.progress)
120 ppc_md.progress("MMU:enter", 0x111);
121
122 /* parse args from command line */
123 MMU_setup();
124
125 /*
126 * Reserve gigantic pages for hugetlb. This MUST occur before
127 * lowmem_end_addr is initialized below.
128 */
129 if (memblock.memory.cnt > 1) {
130#ifndef CONFIG_WII
131 memblock_enforce_memory_limit(memblock.memory.regions[0].size);
132 pr_warn("Only using first contiguous memory region\n");
133#else
134 wii_memory_fixups();
135#endif
136 }
137
138 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
139 lowmem_end_addr = memstart_addr + total_lowmem;
140
141#ifdef CONFIG_FSL_BOOKE
142 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
143 * entries, so we need to adjust lowmem to match the amount we can map
144 * in the fixed entries */
145 adjust_total_lowmem();
146#endif /* CONFIG_FSL_BOOKE */
147
148 if (total_lowmem > __max_low_memory) {
149 total_lowmem = __max_low_memory;
150 lowmem_end_addr = memstart_addr + total_lowmem;
151#ifndef CONFIG_HIGHMEM
152 total_memory = total_lowmem;
153 memblock_enforce_memory_limit(total_lowmem);
154#endif /* CONFIG_HIGHMEM */
155 }
156
157 /* Initialize the MMU hardware */
158 if (ppc_md.progress)
159 ppc_md.progress("MMU:hw init", 0x300);
160 MMU_init_hw();
161
162 /* Map in all of RAM starting at KERNELBASE */
163 if (ppc_md.progress)
164 ppc_md.progress("MMU:mapin", 0x301);
165 mapin_ram();
166
167 /* Initialize early top-down ioremap allocator */
168 ioremap_bot = IOREMAP_TOP;
169
170 if (ppc_md.progress)
171 ppc_md.progress("MMU:exit", 0x211);
172
173 /* From now on, btext is no longer BAT mapped if it was at all */
174#ifdef CONFIG_BOOTX_TEXT
175 btext_unmap();
176#endif
177
178 kasan_mmu_init();
179
180 setup_kup();
181
182 /* Shortly after that, the entire linear mapping will be available */
183 memblock_set_current_limit(lowmem_end_addr);
184}