1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * This file contains the routines setting up the linux page tables.
4 * -- paulus
5 *
6 * Derived from arch/ppc/mm/init.c:
7 * Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
8 *
9 * Modifications by Paul Mackerras (PowerMac) (paulus@cs.anu.edu.au)
10 * and Cort Dougan (PReP) (cort@cs.nmt.edu)
11 * Copyright (C) 1996 Paul Mackerras
12 *
13 * Derived from "arch/i386/mm/init.c"
14 * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
15 */
16
17 #include <linux/kernel.h>
18 #include <linux/module.h>
19 #include <linux/types.h>
20 #include <linux/mm.h>
21 #include <linux/vmalloc.h>
22 #include <linux/init.h>
23 #include <linux/highmem.h>
24 #include <linux/memblock.h>
25 #include <linux/slab.h>
26 #include <linux/set_memory.h>
27
28 #include <asm/pgalloc.h>
29 #include <asm/fixmap.h>
30 #include <asm/setup.h>
31 #include <asm/sections.h>
32 #include <asm/early_ioremap.h>
33
34 #include <mm/mmu_decl.h>
35
36 extern char etext[], _stext[], _sinittext[], _einittext[];
37
38 static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data;
39
early_ioremap_init(void)40 notrace void __init early_ioremap_init(void)
41 {
42 unsigned long addr = ALIGN_DOWN(FIXADDR_START, PGDIR_SIZE);
43 pte_t *ptep = (pte_t *)early_fixmap_pagetable;
44 pmd_t *pmdp = pmd_off_k(addr);
45
46 for (; (s32)(FIXADDR_TOP - addr) > 0;
47 addr += PGDIR_SIZE, ptep += PTRS_PER_PTE, pmdp++)
48 pmd_populate_kernel(&init_mm, pmdp, ptep);
49
50 early_ioremap_setup();
51 }
52
early_alloc_pgtable(unsigned long size)53 static void __init *early_alloc_pgtable(unsigned long size)
54 {
55 void *ptr = memblock_alloc(size, size);
56
57 if (!ptr)
58 panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
59 __func__, size, size);
60
61 return ptr;
62 }
63
early_pte_alloc_kernel(pmd_t * pmdp,unsigned long va)64 pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va)
65 {
66 if (pmd_none(*pmdp)) {
67 pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE);
68
69 pmd_populate_kernel(&init_mm, pmdp, ptep);
70 }
71 return pte_offset_kernel(pmdp, va);
72 }
73
74
map_kernel_page(unsigned long va,phys_addr_t pa,pgprot_t prot)75 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot)
76 {
77 pmd_t *pd;
78 pte_t *pg;
79 int err = -ENOMEM;
80
81 /* Use upper 10 bits of VA to index the first level map */
82 pd = pmd_off_k(va);
83 /* Use middle 10 bits of VA to index the second-level map */
84 if (likely(slab_is_available()))
85 pg = pte_alloc_kernel(pd, va);
86 else
87 pg = early_pte_alloc_kernel(pd, va);
88 if (pg) {
89 err = 0;
90 /* The PTE should never be already set nor present in the
91 * hash table
92 */
93 BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot));
94 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot));
95 }
96 smp_wmb();
97 return err;
98 }
99
100 /*
101 * Map in a chunk of physical memory starting at start.
102 */
__mapin_ram_chunk(unsigned long offset,unsigned long top)103 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top)
104 {
105 unsigned long v, s;
106 phys_addr_t p;
107 int ktext;
108
109 s = offset;
110 v = PAGE_OFFSET + s;
111 p = memstart_addr + s;
112 for (; s < top; s += PAGE_SIZE) {
113 ktext = ((char *)v >= _stext && (char *)v < etext) ||
114 ((char *)v >= _sinittext && (char *)v < _einittext);
115 map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL);
116 v += PAGE_SIZE;
117 p += PAGE_SIZE;
118 }
119 }
120
mapin_ram(void)121 void __init mapin_ram(void)
122 {
123 phys_addr_t base, end;
124 u64 i;
125
126 for_each_mem_range(i, &base, &end) {
127 phys_addr_t top = min(end, total_lowmem);
128
129 if (base >= top)
130 continue;
131 base = mmu_mapin_ram(base, top);
132 __mapin_ram_chunk(base, top);
133 }
134 }
135
mark_initmem_nx(void)136 void mark_initmem_nx(void)
137 {
138 unsigned long numpages = PFN_UP((unsigned long)_einittext) -
139 PFN_DOWN((unsigned long)_sinittext);
140
141 mmu_mark_initmem_nx();
142
143 if (!v_block_mapped((unsigned long)_sinittext)) {
144 set_memory_nx((unsigned long)_sinittext, numpages);
145 set_memory_rw((unsigned long)_sinittext, numpages);
146 }
147 }
148
149 #ifdef CONFIG_STRICT_KERNEL_RWX
mark_rodata_ro(void)150 void mark_rodata_ro(void)
151 {
152 unsigned long numpages;
153
154 if (v_block_mapped((unsigned long)_stext + 1)) {
155 mmu_mark_rodata_ro();
156 ptdump_check_wx();
157 return;
158 }
159
160 /*
161 * mark .text and .rodata as read only. Use __init_begin rather than
162 * __end_rodata to cover NOTES and EXCEPTION_TABLE.
163 */
164 numpages = PFN_UP((unsigned long)__init_begin) -
165 PFN_DOWN((unsigned long)_stext);
166
167 set_memory_ro((unsigned long)_stext, numpages);
168
169 // mark_initmem_nx() should have already run by now
170 ptdump_check_wx();
171 }
172 #endif
173
174 #if defined(CONFIG_ARCH_SUPPORTS_DEBUG_PAGEALLOC) && defined(CONFIG_DEBUG_PAGEALLOC)
__kernel_map_pages(struct page * page,int numpages,int enable)175 void __kernel_map_pages(struct page *page, int numpages, int enable)
176 {
177 unsigned long addr = (unsigned long)page_address(page);
178
179 if (PageHighMem(page))
180 return;
181
182 if (enable)
183 set_memory_p(addr, numpages);
184 else
185 set_memory_np(addr, numpages);
186 }
187 #endif /* CONFIG_DEBUG_PAGEALLOC */
188