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/io.h>
33 #include <asm/mmu.h>
34 #include <asm/smp.h>
35 #include <asm/machdep.h>
36 #include <asm/btext.h>
37 #include <asm/tlb.h>
38 #include <asm/sections.h>
39 #include <asm/hugetlb.h>
40 #include <asm/kup.h>
41 #include <asm/kasan.h>
42
43 #include <mm/mmu_decl.h>
44
45 #if defined(CONFIG_KERNEL_START_BOOL) || defined(CONFIG_LOWMEM_SIZE_BOOL)
46 /* The amount of lowmem must be within 0xF0000000 - KERNELBASE. */
47 #if (CONFIG_LOWMEM_SIZE > (0xF0000000 - PAGE_OFFSET))
48 #error "You must adjust CONFIG_LOWMEM_SIZE or CONFIG_KERNEL_START"
49 #endif
50 #endif
51 #define MAX_LOW_MEM CONFIG_LOWMEM_SIZE
52
53 phys_addr_t total_memory;
54 phys_addr_t total_lowmem;
55
56 #ifdef CONFIG_RELOCATABLE
57 /* Used in __va()/__pa() */
58 long long virt_phys_offset;
59 EXPORT_SYMBOL(virt_phys_offset);
60 #endif
61
62 phys_addr_t lowmem_end_addr;
63
64 int boot_mapsize;
65 #ifdef CONFIG_PPC_PMAC
66 unsigned long agp_special_page;
67 EXPORT_SYMBOL(agp_special_page);
68 #endif
69
70 void MMU_init(void);
71
72 /* max amount of low RAM to map in */
73 unsigned long __max_low_memory = MAX_LOW_MEM;
74
75 /*
76 * MMU_init sets up the basic memory mappings for the kernel,
77 * including both RAM and possibly some I/O regions,
78 * and sets up the page tables and the MMU hardware ready to go.
79 */
MMU_init(void)80 void __init MMU_init(void)
81 {
82 if (ppc_md.progress)
83 ppc_md.progress("MMU:enter", 0x111);
84
85 total_lowmem = total_memory = memblock_end_of_DRAM() - memstart_addr;
86 lowmem_end_addr = memstart_addr + total_lowmem;
87
88 #ifdef CONFIG_PPC_85xx
89 /* Freescale Book-E parts expect lowmem to be mapped by fixed TLB
90 * entries, so we need to adjust lowmem to match the amount we can map
91 * in the fixed entries */
92 adjust_total_lowmem();
93 #endif /* CONFIG_PPC_85xx */
94
95 if (total_lowmem > __max_low_memory) {
96 total_lowmem = __max_low_memory;
97 lowmem_end_addr = memstart_addr + total_lowmem;
98 #ifndef CONFIG_HIGHMEM
99 total_memory = total_lowmem;
100 memblock_enforce_memory_limit(total_lowmem);
101 #endif /* CONFIG_HIGHMEM */
102 }
103
104 /* Initialize the MMU hardware */
105 if (ppc_md.progress)
106 ppc_md.progress("MMU:hw init", 0x300);
107 MMU_init_hw();
108
109 /* Map in all of RAM starting at KERNELBASE */
110 if (ppc_md.progress)
111 ppc_md.progress("MMU:mapin", 0x301);
112 mapin_ram();
113
114 /* Initialize early top-down ioremap allocator */
115 ioremap_bot = IOREMAP_TOP;
116
117 if (ppc_md.progress)
118 ppc_md.progress("MMU:exit", 0x211);
119
120 /* From now on, btext is no longer BAT mapped if it was at all */
121 #ifdef CONFIG_BOOTX_TEXT
122 btext_unmap();
123 #endif
124
125 kasan_mmu_init();
126
127 setup_kup();
128
129 update_mmu_feature_fixups(MMU_FTR_KUAP);
130
131 /* Shortly after that, the entire linear mapping will be available */
132 memblock_set_current_limit(lowmem_end_addr);
133 }
134
