summaryrefslogtreecommitdiff
path: root/arch/powerpc/mm/init_32.c
blob: b04896a88d792eac665d6e239ccbe86c9f2364a4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  PowerPC version
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *
 *  Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
 *  and Cort Dougan (PReP) (cort@cs.nmt.edu)
 *    Copyright (C) 1996 Paul Mackerras
 *  PPC44x/36-bit changes by Matt Porter (mporter@mvista.com)
 *
 *  Derived from "arch/i386/mm/init.c"
 *    Copyright (C) 1991, 1992, 1993, 1994  Linus Torvalds
 */

#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/stddef.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/initrd.h>
#include <linux/pagemap.h>
#include <linux/memblock.h>
#include <linux/gfp.h>
#include <linux/slab.h>
#include <linux/hugetlb.h>

#include <asm/pgalloc.h>
#include <asm/prom.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/mmu.h>
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/btext.h>
#include <asm/tlb.h>
#include <asm/sections.h>
#include <asm/hugetlb.h>
#include <asm/kup.h>
#include <asm/kasan.h>

#include <mm/mmu_decl.h>

#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
#endif
#endif
#define MAX_LOW_MEM	CONFIG_LOWMEM_SIZE

phys_addr_t total_memory;
phys_addr_t total_lowmem;

phys_addr_t memstart_addr = (phys_addr_t)~0ull;
EXPORT_SYMBOL(memstart_addr);
phys_addr_t kernstart_addr;
EXPORT_SYMBOL(kernstart_addr);

#ifdef CONFIG_RELOCATABLE
/* Used in __va()/__pa() */
long long virt_phys_offset;
EXPORT_SYMBOL(virt_phys_offset);
#endif

phys_addr_t lowmem_end_addr;

int boot_mapsize;
#ifdef CONFIG_PPC_PMAC
unsigned long agp_special_page;
EXPORT_SYMBOL(agp_special_page);
#endif

void MMU_init(void);

/*
 * this tells the system to map all of ram with the segregs
 * (i.e. page tables) instead of the bats.
 * -- Cort
 */
int __map_without_bats;
int __map_without_ltlbs;

/* max amount of low RAM to map in */
unsigned long __max_low_memory = MAX_LOW_MEM;

/*
 * Check for command-line options that affect what MMU_init will do.
 */
static void __init MMU_setup(void)
{
	/* Check for nobats option (used in mapin_ram). */
	if (strstr(boot_command_line, "nobats")) {
		__map_without_bats = 1;
	}

	if (strstr(boot_command_line, "noltlbs")) {
		__map_without_ltlbs = 1;
	}
	if (debug_pagealloc_enabled()) {
		__map_without_bats = 1;
		__map_without_ltlbs = 1;
	}
	if (strict_kernel_rwx_enabled() && !IS_ENABLED(CONFIG_PPC_8xx))
		__map_without_ltlbs = 1;
}

/*
 * MMU_init sets up the basic memory mappings for the kernel,
 * including both RAM and possibly some I/O regions,
 * and sets up the page tables and the MMU hardware ready to go.
 */
void __init MMU_init(void)
{
	if (ppc_md.progress)
		ppc_md.progress("MMU:enter", 0x111);

	/* parse args from command line */
	MMU_setup();

	/*
	 * Reserve gigantic pages for hugetlb.  This MUST occur before
	 * lowmem_end_addr is initialized below.
	 */
	if (memblock.memory.cnt > 1) {
#ifndef CONFIG_WII
		memblock_enforce_memory_limit(memblock.memory.regions[0].size);
		pr_warn("Only using first contiguous memory region\n");
#else
		wii_memory_fixups();
#endif
	}

	total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
	lowmem_end_addr = memstart_addr + total_lowmem;

#ifdef CONFIG_FSL_BOOKE
	/* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
	 * entries, so we need to adjust lowmem to match the amount we can map
	 * in the fixed entries */
	adjust_total_lowmem();
#endif /* CONFIG_FSL_BOOKE */

	if (total_lowmem > __max_low_memory) {
		total_lowmem = __max_low_memory;
		lowmem_end_addr = memstart_addr + total_lowmem;
#ifndef CONFIG_HIGHMEM
		total_memory = total_lowmem;
		memblock_enforce_memory_limit(total_lowmem);
#endif /* CONFIG_HIGHMEM */
	}

	/* Initialize the MMU hardware */
	if (ppc_md.progress)
		ppc_md.progress("MMU:hw init", 0x300);
	MMU_init_hw();

	/* Map in all of RAM starting at KERNELBASE */
	if (ppc_md.progress)
		ppc_md.progress("MMU:mapin", 0x301);
	mapin_ram();

	/* Initialize early top-down ioremap allocator */
	ioremap_bot = IOREMAP_TOP;

	if (ppc_md.progress)
		ppc_md.progress("MMU:exit", 0x211);

	/* From now on, btext is no longer BAT mapped if it was at all */
#ifdef CONFIG_BOOTX_TEXT
	btext_unmap();
#endif

	kasan_mmu_init();

	setup_kup();

	/* Shortly after that, the entire linear mapping will be available */
	memblock_set_current_limit(lowmem_end_addr);
}