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 27 #include <asm/pgalloc.h> 28 #include <asm/fixmap.h> 29 #include <asm/setup.h> 30 #include <asm/sections.h> 31 #include <asm/early_ioremap.h> 32 33 #include <mm/mmu_decl.h> 34 35 extern char etext[], _stext[], _sinittext[], _einittext[]; 36 37 static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data; 38 39 notrace void __init early_ioremap_init(void) 40 { 41 unsigned long addr = ALIGN_DOWN(FIXADDR_START, PGDIR_SIZE); 42 pte_t *ptep = (pte_t *)early_fixmap_pagetable; 43 pmd_t *pmdp = pmd_off_k(addr); 44 45 for (; (s32)(FIXADDR_TOP - addr) > 0; 46 addr += PGDIR_SIZE, ptep += PTRS_PER_PTE, pmdp++) 47 pmd_populate_kernel(&init_mm, pmdp, ptep); 48 49 early_ioremap_setup(); 50 } 51 52 static void __init *early_alloc_pgtable(unsigned long size) 53 { 54 void *ptr = memblock_alloc(size, size); 55 56 if (!ptr) 57 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 58 __func__, size, size); 59 60 return ptr; 61 } 62 63 pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va) 64 { 65 if (pmd_none(*pmdp)) { 66 pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE); 67 68 pmd_populate_kernel(&init_mm, pmdp, ptep); 69 } 70 return pte_offset_kernel(pmdp, va); 71 } 72 73 74 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot) 75 { 76 pmd_t *pd; 77 pte_t *pg; 78 int err = -ENOMEM; 79 80 /* Use upper 10 bits of VA to index the first level map */ 81 pd = pmd_off_k(va); 82 /* Use middle 10 bits of VA to index the second-level map */ 83 if (likely(slab_is_available())) 84 pg = pte_alloc_kernel(pd, va); 85 else 86 pg = early_pte_alloc_kernel(pd, va); 87 if (pg != 0) { 88 err = 0; 89 /* The PTE should never be already set nor present in the 90 * hash table 91 */ 92 BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot)); 93 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot)); 94 } 95 smp_wmb(); 96 return err; 97 } 98 99 /* 100 * Map in a chunk of physical memory starting at start. 101 */ 102 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top) 103 { 104 unsigned long v, s; 105 phys_addr_t p; 106 int ktext; 107 108 s = offset; 109 v = PAGE_OFFSET + s; 110 p = memstart_addr + s; 111 for (; s < top; s += PAGE_SIZE) { 112 ktext = ((char *)v >= _stext && (char *)v < etext) || 113 ((char *)v >= _sinittext && (char *)v < _einittext); 114 map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL); 115 #ifdef CONFIG_PPC_BOOK3S_32 116 if (ktext) 117 hash_preload(&init_mm, v); 118 #endif 119 v += PAGE_SIZE; 120 p += PAGE_SIZE; 121 } 122 } 123 124 void __init mapin_ram(void) 125 { 126 phys_addr_t base, end; 127 u64 i; 128 129 for_each_mem_range(i, &base, &end) { 130 phys_addr_t top = min(end, total_lowmem); 131 132 if (base >= top) 133 continue; 134 base = mmu_mapin_ram(base, top); 135 __mapin_ram_chunk(base, top); 136 } 137 } 138 139 static int __change_page_attr_noflush(struct page *page, pgprot_t prot) 140 { 141 pte_t *kpte; 142 unsigned long address; 143 144 BUG_ON(PageHighMem(page)); 145 address = (unsigned long)page_address(page); 146 147 if (v_block_mapped(address)) 148 return 0; 149 kpte = virt_to_kpte(address); 150 if (!kpte) 151 return -EINVAL; 152 __set_pte_at(&init_mm, address, kpte, mk_pte(page, prot), 0); 153 154 return 0; 155 } 156 157 /* 158 * Change the page attributes of an page in the linear mapping. 159 * 160 * THIS DOES NOTHING WITH BAT MAPPINGS, DEBUG USE ONLY 161 */ 162 static int change_page_attr(struct page *page, int numpages, pgprot_t prot) 163 { 164 int i, err = 0; 165 unsigned long flags; 166 struct page *start = page; 167 168 local_irq_save(flags); 169 for (i = 0; i < numpages; i++, page++) { 170 err = __change_page_attr_noflush(page, prot); 171 if (err) 172 break; 173 } 174 wmb(); 175 local_irq_restore(flags); 176 flush_tlb_kernel_range((unsigned long)page_address(start), 177 (unsigned long)page_address(page)); 178 return err; 179 } 180 181 void mark_initmem_nx(void) 182 { 183 struct page *page = virt_to_page(_sinittext); 184 unsigned long numpages = PFN_UP((unsigned long)_einittext) - 185 PFN_DOWN((unsigned long)_sinittext); 186 187 if (v_block_mapped((unsigned long)_sinittext)) 188 mmu_mark_initmem_nx(); 189 else 190 change_page_attr(page, numpages, PAGE_KERNEL); 191 } 192 193 #ifdef CONFIG_STRICT_KERNEL_RWX 194 void mark_rodata_ro(void) 195 { 196 struct page *page; 197 unsigned long numpages; 198 199 if (v_block_mapped((unsigned long)_stext + 1)) { 200 mmu_mark_rodata_ro(); 201 ptdump_check_wx(); 202 return; 203 } 204 205 page = virt_to_page(_stext); 206 numpages = PFN_UP((unsigned long)_etext) - 207 PFN_DOWN((unsigned long)_stext); 208 209 change_page_attr(page, numpages, PAGE_KERNEL_ROX); 210 /* 211 * mark .rodata as read only. Use __init_begin rather than __end_rodata 212 * to cover NOTES and EXCEPTION_TABLE. 213 */ 214 page = virt_to_page(__start_rodata); 215 numpages = PFN_UP((unsigned long)__init_begin) - 216 PFN_DOWN((unsigned long)__start_rodata); 217 218 change_page_attr(page, numpages, PAGE_KERNEL_RO); 219 220 // mark_initmem_nx() should have already run by now 221 ptdump_check_wx(); 222 } 223 #endif 224 225 #ifdef CONFIG_DEBUG_PAGEALLOC 226 void __kernel_map_pages(struct page *page, int numpages, int enable) 227 { 228 if (PageHighMem(page)) 229 return; 230 231 change_page_attr(page, numpages, enable ? PAGE_KERNEL : __pgprot(0)); 232 } 233 #endif /* CONFIG_DEBUG_PAGEALLOC */ 234