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/prom.h>
33#include <asm/io.h>
34#include <asm/mmu.h>
35#include <asm/smp.h>
36#include <asm/machdep.h>
37#include <asm/btext.h>
38#include <asm/tlb.h>
39#include <asm/sections.h>
40#include <asm/hugetlb.h>
41#include <asm/kup.h>
42#include <asm/kasan.h>
43
44#include <mm/mmu_decl.h>
45
46#if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
47/* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
48#if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
49#error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
50#endif
51#endif
52#define MAX_LOW_MEM	CONFIG_LOWMEM_SIZE
53
54phys_addr_t total_memory;
55phys_addr_t total_lowmem;
56
57#ifdef CONFIG_RELOCATABLE
58/* Used in __va()/__pa() */
59long long virt_phys_offset;
60EXPORT_SYMBOL(virt_phys_offset);
61#endif
62
63phys_addr_t lowmem_end_addr;
64
65int boot_mapsize;
66#ifdef CONFIG_PPC_PMAC
67unsigned long agp_special_page;
68EXPORT_SYMBOL(agp_special_page);
69#endif
70
71void MMU_init(void);
72
73/*
74 * this tells the system to map all of ram with the segregs
75 * (i.e. page tables) instead of the bats.
76 * -- Cort
77 */
78int __map_without_bats;
79int __map_without_ltlbs;
80
81/* max amount of low RAM to map in */
82unsigned long __max_low_memory = MAX_LOW_MEM;
83
84/*
85 * Check for command-line options that affect what MMU_init will do.
86 */
87static void __init MMU_setup(void)
88{
89	/* Check for nobats option (used in mapin_ram). */
90	if (strstr(boot_command_line, "nobats")) {
91		__map_without_bats = 1;
92	}
93
94	if (strstr(boot_command_line, "noltlbs")) {
95		__map_without_ltlbs = 1;
96	}
97	if (IS_ENABLED(CONFIG_PPC_8xx))
98		return;
99
100	if (debug_pagealloc_enabled())
101		__map_without_ltlbs = 1;
102
103	if (strict_kernel_rwx_enabled())
104		__map_without_ltlbs = 1;
105}
106
107/*
108 * MMU_init sets up the basic memory mappings for the kernel,
109 * including both RAM and possibly some I/O regions,
110 * and sets up the page tables and the MMU hardware ready to go.
111 */
112void __init MMU_init(void)
113{
114	if (ppc_md.progress)
115		ppc_md.progress("MMU:enter", 0x111);
116
117	/* parse args from command line */
118	MMU_setup();
119
120	/*
121	 * Reserve gigantic pages for hugetlb.  This MUST occur before
122	 * lowmem_end_addr is initialized below.
123	 */
124	if (memblock.memory.cnt > 1) {
125#ifndef CONFIG_WII
126		memblock_enforce_memory_limit(memblock.memory.regions[0].size);
127		pr_warn("Only using first contiguous memory region\n");
128#else
129		wii_memory_fixups();
130#endif
131	}
132
133	total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
134	lowmem_end_addr = memstart_addr + total_lowmem;
135
136#ifdef CONFIG_FSL_BOOKE
137	/* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
138	 * entries, so we need to adjust lowmem to match the amount we can map
139	 * in the fixed entries */
140	adjust_total_lowmem();
141#endif /* CONFIG_FSL_BOOKE */
142
143	if (total_lowmem > __max_low_memory) {
144		total_lowmem = __max_low_memory;
145		lowmem_end_addr = memstart_addr + total_lowmem;
146#ifndef CONFIG_HIGHMEM
147		total_memory = total_lowmem;
148		memblock_enforce_memory_limit(total_lowmem);
149#endif /* CONFIG_HIGHMEM */
150	}
151
152	/* Initialize the MMU hardware */
153	if (ppc_md.progress)
154		ppc_md.progress("MMU:hw init", 0x300);
155	MMU_init_hw();
156
157	/* Map in all of RAM starting at KERNELBASE */
158	if (ppc_md.progress)
159		ppc_md.progress("MMU:mapin", 0x301);
160	mapin_ram();
161
162	/* Initialize early top-down ioremap allocator */
163	ioremap_bot = IOREMAP_TOP;
164
165	if (ppc_md.progress)
166		ppc_md.progress("MMU:exit", 0x211);
167
168	/* From now on, btext is no longer BAT mapped if it was at all */
169#ifdef CONFIG_BOOTX_TEXT
170	btext_unmap();
171#endif
172
173	kasan_mmu_init();
174
175	setup_kup();
176
177	/* Shortly after that, the entire linear mapping will be available */
178	memblock_set_current_limit(lowmem_end_addr);
179}
180