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 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 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 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 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 */ 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 } 120 121 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 } 135 136 void mark_initmem_nx(void) 137 { 138 unsigned long numpages = PFN_UP((unsigned long)_einittext) - 139 PFN_DOWN((unsigned long)_sinittext); 140 141 if (v_block_mapped((unsigned long)_sinittext)) 142 mmu_mark_initmem_nx(); 143 else 144 set_memory_attr((unsigned long)_sinittext, numpages, PAGE_KERNEL); 145 } 146 147 #ifdef CONFIG_STRICT_KERNEL_RWX 148 void mark_rodata_ro(void) 149 { 150 unsigned long numpages; 151 152 if (v_block_mapped((unsigned long)_stext + 1)) { 153 mmu_mark_rodata_ro(); 154 ptdump_check_wx(); 155 return; 156 } 157 158 numpages = PFN_UP((unsigned long)_etext) - 159 PFN_DOWN((unsigned long)_stext); 160 161 set_memory_attr((unsigned long)_stext, numpages, PAGE_KERNEL_ROX); 162 /* 163 * mark .rodata as read only. Use __init_begin rather than __end_rodata 164 * to cover NOTES and EXCEPTION_TABLE. 165 */ 166 numpages = PFN_UP((unsigned long)__init_begin) - 167 PFN_DOWN((unsigned long)__start_rodata); 168 169 set_memory_attr((unsigned long)__start_rodata, numpages, PAGE_KERNEL_RO); 170 171 // mark_initmem_nx() should have already run by now 172 ptdump_check_wx(); 173 } 174 #endif 175 176 #ifdef CONFIG_DEBUG_PAGEALLOC 177 void __kernel_map_pages(struct page *page, int numpages, int enable) 178 { 179 unsigned long addr = (unsigned long)page_address(page); 180 181 if (PageHighMem(page)) 182 return; 183 184 if (enable) 185 set_memory_attr(addr, numpages, PAGE_KERNEL); 186 else 187 set_memory_attr(addr, numpages, __pgprot(0)); 188 } 189 #endif /* CONFIG_DEBUG_PAGEALLOC */ 190