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 static u8 early_fixmap_pagetable[FIXMAP_PTE_SIZE] __page_aligned_data; 37 38 notrace void __init early_ioremap_init(void) 39 { 40 unsigned long addr = ALIGN_DOWN(FIXADDR_START, PGDIR_SIZE); 41 pte_t *ptep = (pte_t *)early_fixmap_pagetable; 42 pmd_t *pmdp = pmd_off_k(addr); 43 44 for (; (s32)(FIXADDR_TOP - addr) > 0; 45 addr += PGDIR_SIZE, ptep += PTRS_PER_PTE, pmdp++) 46 pmd_populate_kernel(&init_mm, pmdp, ptep); 47 48 early_ioremap_setup(); 49 } 50 51 static void __init *early_alloc_pgtable(unsigned long size) 52 { 53 void *ptr = memblock_alloc(size, size); 54 55 if (!ptr) 56 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 57 __func__, size, size); 58 59 return ptr; 60 } 61 62 pte_t __init *early_pte_alloc_kernel(pmd_t *pmdp, unsigned long va) 63 { 64 if (pmd_none(*pmdp)) { 65 pte_t *ptep = early_alloc_pgtable(PTE_FRAG_SIZE); 66 67 pmd_populate_kernel(&init_mm, pmdp, ptep); 68 } 69 return pte_offset_kernel(pmdp, va); 70 } 71 72 73 int __ref map_kernel_page(unsigned long va, phys_addr_t pa, pgprot_t prot) 74 { 75 pmd_t *pd; 76 pte_t *pg; 77 int err = -ENOMEM; 78 79 /* Use upper 10 bits of VA to index the first level map */ 80 pd = pmd_off_k(va); 81 /* Use middle 10 bits of VA to index the second-level map */ 82 if (likely(slab_is_available())) 83 pg = pte_alloc_kernel(pd, va); 84 else 85 pg = early_pte_alloc_kernel(pd, va); 86 if (pg) { 87 err = 0; 88 /* The PTE should never be already set nor present in the 89 * hash table 90 */ 91 BUG_ON((pte_present(*pg) | pte_hashpte(*pg)) && pgprot_val(prot)); 92 set_pte_at(&init_mm, va, pg, pfn_pte(pa >> PAGE_SHIFT, prot)); 93 } 94 smp_wmb(); 95 return err; 96 } 97 98 /* 99 * Map in a chunk of physical memory starting at start. 100 */ 101 static void __init __mapin_ram_chunk(unsigned long offset, unsigned long top) 102 { 103 unsigned long v, s; 104 phys_addr_t p; 105 bool ktext; 106 107 s = offset; 108 v = PAGE_OFFSET + s; 109 p = memstart_addr + s; 110 for (; s < top; s += PAGE_SIZE) { 111 ktext = core_kernel_text(v); 112 map_kernel_page(v, p, ktext ? PAGE_KERNEL_TEXT : PAGE_KERNEL); 113 v += PAGE_SIZE; 114 p += PAGE_SIZE; 115 } 116 } 117 118 void __init mapin_ram(void) 119 { 120 phys_addr_t base, end; 121 u64 i; 122 123 for_each_mem_range(i, &base, &end) { 124 phys_addr_t top = min(end, total_lowmem); 125 126 if (base >= top) 127 continue; 128 base = mmu_mapin_ram(base, top); 129 __mapin_ram_chunk(base, top); 130 } 131 } 132 133 static int __mark_initmem_nx(void) 134 { 135 unsigned long numpages = PFN_UP((unsigned long)_einittext) - 136 PFN_DOWN((unsigned long)_sinittext); 137 int err; 138 139 err = mmu_mark_initmem_nx(); 140 141 if (!v_block_mapped((unsigned long)_sinittext)) { 142 err = set_memory_nx((unsigned long)_sinittext, numpages); 143 if (err) 144 return err; 145 err = set_memory_rw((unsigned long)_sinittext, numpages); 146 } 147 return err; 148 } 149 150 void mark_initmem_nx(void) 151 { 152 int err = __mark_initmem_nx(); 153 154 if (err) 155 panic("%s() failed, err = %d\n", __func__, err); 156 } 157 158 #ifdef CONFIG_STRICT_KERNEL_RWX 159 static int __mark_rodata_ro(void) 160 { 161 unsigned long numpages; 162 163 if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX) && mmu_has_feature(MMU_FTR_HPTE_TABLE)) 164 pr_warn("This platform has HASH MMU, STRICT_MODULE_RWX won't work\n"); 165 166 if (v_block_mapped((unsigned long)_stext + 1)) 167 return mmu_mark_rodata_ro(); 168 169 /* 170 * mark text and rodata as read only. __end_rodata is set by 171 * powerpc's linker script and includes tables and data 172 * requiring relocation which are not put in RO_DATA. 173 */ 174 numpages = PFN_UP((unsigned long)__end_rodata) - 175 PFN_DOWN((unsigned long)_stext); 176 177 return set_memory_ro((unsigned long)_stext, numpages); 178 } 179 180 void mark_rodata_ro(void) 181 { 182 int err = __mark_rodata_ro(); 183 184 if (err) 185 panic("%s() failed, err = %d\n", __func__, err); 186 } 187 #endif 188