1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Based upon linux/arch/m68k/mm/sun3mmu.c 4 * Based upon linux/arch/ppc/mm/mmu_context.c 5 * 6 * Implementations of mm routines specific to the Coldfire MMU. 7 * 8 * Copyright (c) 2008 Freescale Semiconductor, Inc. 9 */ 10 11 #include <linux/kernel.h> 12 #include <linux/types.h> 13 #include <linux/mm.h> 14 #include <linux/init.h> 15 #include <linux/string.h> 16 #include <linux/memblock.h> 17 18 #include <asm/setup.h> 19 #include <asm/page.h> 20 #include <asm/mmu_context.h> 21 #include <asm/mcf_pgalloc.h> 22 #include <asm/tlbflush.h> 23 #include <asm/pgalloc.h> 24 25 #define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END)) 26 27 mm_context_t next_mmu_context; 28 unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; 29 atomic_t nr_free_contexts; 30 struct mm_struct *context_mm[LAST_CONTEXT+1]; 31 unsigned long num_pages; 32 33 /* 34 * ColdFire paging_init derived from sun3. 35 */ 36 void __init paging_init(void) 37 { 38 pgd_t *pg_dir; 39 pte_t *pg_table; 40 unsigned long address, size; 41 unsigned long next_pgtable; 42 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 43 int i; 44 45 empty_zero_page = memblock_alloc_or_panic(PAGE_SIZE, PAGE_SIZE); 46 47 pg_dir = swapper_pg_dir; 48 memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir)); 49 50 size = num_pages * sizeof(pte_t); 51 size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1); 52 next_pgtable = (unsigned long) memblock_alloc_or_panic(size, PAGE_SIZE); 53 54 pg_dir += PAGE_OFFSET >> PGDIR_SHIFT; 55 56 address = PAGE_OFFSET; 57 while (address < (unsigned long)high_memory) { 58 pg_table = (pte_t *) next_pgtable; 59 next_pgtable += PTRS_PER_PTE * sizeof(pte_t); 60 pgd_val(*pg_dir) = (unsigned long) pg_table; 61 pg_dir++; 62 63 /* now change pg_table to kernel virtual addresses */ 64 for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) { 65 pte_t pte = pfn_pte(virt_to_pfn((void *)address), 66 PAGE_INIT); 67 if (address >= (unsigned long) high_memory) 68 pte_val(pte) = 0; 69 70 set_pte(pg_table, pte); 71 address += PAGE_SIZE; 72 } 73 } 74 75 current->mm = NULL; 76 max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend); 77 free_area_init(max_zone_pfn); 78 } 79 80 int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word) 81 { 82 unsigned long flags, mmuar, mmutr; 83 struct mm_struct *mm; 84 pgd_t *pgd; 85 p4d_t *p4d; 86 pud_t *pud; 87 pmd_t *pmd; 88 pte_t *pte = NULL; 89 int ret = -1; 90 int asid; 91 92 local_irq_save(flags); 93 94 mmuar = (dtlb) ? mmu_read(MMUAR) : 95 regs->pc + (extension_word * sizeof(long)); 96 97 mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm; 98 if (!mm) 99 goto out; 100 101 pgd = pgd_offset(mm, mmuar); 102 if (pgd_none(*pgd)) 103 goto out; 104 105 p4d = p4d_offset(pgd, mmuar); 106 if (p4d_none(*p4d)) 107 goto out; 108 109 pud = pud_offset(p4d, mmuar); 110 if (pud_none(*pud)) 111 goto out; 112 113 pmd = pmd_offset(pud, mmuar); 114 if (pmd_none(*pmd)) 115 goto out; 116 117 pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar) 118 : pte_offset_map(pmd, mmuar); 119 if (!pte || pte_none(*pte) || !pte_present(*pte)) 120 goto out; 121 122 if (write) { 123 if (!pte_write(*pte)) 124 goto out; 125 set_pte(pte, pte_mkdirty(*pte)); 126 } 127 128 set_pte(pte, pte_mkyoung(*pte)); 129 asid = mm->context & 0xff; 130 if (!pte_dirty(*pte) && !KMAPAREA(mmuar)) 131 set_pte(pte, pte_wrprotect(*pte)); 132 133 mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V; 134 if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE)) 135 mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT; 136 mmu_write(MMUTR, mmutr); 137 138 mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | 139 ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); 140 141 if (dtlb) 142 mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); 143 else 144 mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); 145 ret = 0; 146 out: 147 if (pte && !KMAPAREA(mmuar)) 148 pte_unmap(pte); 149 local_irq_restore(flags); 150 return ret; 151 } 152 153 void __init cf_bootmem_alloc(void) 154 { 155 unsigned long memstart; 156 157 /* _rambase and _ramend will be naturally page aligned */ 158 m68k_memory[0].addr = _rambase; 159 m68k_memory[0].size = _ramend - _rambase; 160 161 memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0, 162 MEMBLOCK_NONE); 163 164 /* compute total pages in system */ 165 num_pages = PFN_DOWN(_ramend - _rambase); 166 167 /* page numbers */ 168 memstart = PAGE_ALIGN(_ramstart); 169 min_low_pfn = PFN_DOWN(_rambase); 170 max_pfn = max_low_pfn = PFN_DOWN(_ramend); 171 high_memory = (void *)_ramend; 172 173 /* Reserve kernel text/data/bss */ 174 memblock_reserve(_rambase, memstart - _rambase); 175 176 m68k_virt_to_node_shift = fls(_ramend - 1) - 6; 177 module_fixup(NULL, __start_fixup, __stop_fixup); 178 179 /* setup node data */ 180 m68k_setup_node(0); 181 } 182 183 /* 184 * Initialize the context management stuff. 185 * The following was taken from arch/ppc/mmu_context.c 186 */ 187 void __init cf_mmu_context_init(void) 188 { 189 /* 190 * Some processors have too few contexts to reserve one for 191 * init_mm, and require using context 0 for a normal task. 192 * Other processors reserve the use of context zero for the kernel. 193 * This code assumes FIRST_CONTEXT < 32. 194 */ 195 context_map[0] = (1 << FIRST_CONTEXT) - 1; 196 next_mmu_context = FIRST_CONTEXT; 197 atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1); 198 } 199 200 /* 201 * Steal a context from a task that has one at the moment. 202 * This isn't an LRU system, it just frees up each context in 203 * turn (sort-of pseudo-random replacement :). This would be the 204 * place to implement an LRU scheme if anyone was motivated to do it. 205 * -- paulus 206 */ 207 void steal_context(void) 208 { 209 struct mm_struct *mm; 210 /* 211 * free up context `next_mmu_context' 212 * if we shouldn't free context 0, don't... 213 */ 214 if (next_mmu_context < FIRST_CONTEXT) 215 next_mmu_context = FIRST_CONTEXT; 216 mm = context_mm[next_mmu_context]; 217 flush_tlb_mm(mm); 218 destroy_context(mm); 219 } 220 221 static const pgprot_t protection_map[16] = { 222 [VM_NONE] = PAGE_NONE, 223 [VM_READ] = __pgprot(CF_PAGE_VALID | 224 CF_PAGE_ACCESSED | 225 CF_PAGE_READABLE), 226 [VM_WRITE] = __pgprot(CF_PAGE_VALID | 227 CF_PAGE_ACCESSED | 228 CF_PAGE_WRITABLE), 229 [VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 230 CF_PAGE_ACCESSED | 231 CF_PAGE_READABLE | 232 CF_PAGE_WRITABLE), 233 [VM_EXEC] = __pgprot(CF_PAGE_VALID | 234 CF_PAGE_ACCESSED | 235 CF_PAGE_EXEC), 236 [VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID | 237 CF_PAGE_ACCESSED | 238 CF_PAGE_READABLE | 239 CF_PAGE_EXEC), 240 [VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID | 241 CF_PAGE_ACCESSED | 242 CF_PAGE_WRITABLE | 243 CF_PAGE_EXEC), 244 [VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 245 CF_PAGE_ACCESSED | 246 CF_PAGE_READABLE | 247 CF_PAGE_WRITABLE | 248 CF_PAGE_EXEC), 249 [VM_SHARED] = PAGE_NONE, 250 [VM_SHARED | VM_READ] = __pgprot(CF_PAGE_VALID | 251 CF_PAGE_ACCESSED | 252 CF_PAGE_READABLE), 253 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 254 [VM_SHARED | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 255 CF_PAGE_ACCESSED | 256 CF_PAGE_READABLE | 257 CF_PAGE_SHARED), 258 [VM_SHARED | VM_EXEC] = __pgprot(CF_PAGE_VALID | 259 CF_PAGE_ACCESSED | 260 CF_PAGE_EXEC), 261 [VM_SHARED | VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID | 262 CF_PAGE_ACCESSED | 263 CF_PAGE_READABLE | 264 CF_PAGE_EXEC), 265 [VM_SHARED | VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID | 266 CF_PAGE_ACCESSED | 267 CF_PAGE_SHARED | 268 CF_PAGE_EXEC), 269 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 270 CF_PAGE_ACCESSED | 271 CF_PAGE_READABLE | 272 CF_PAGE_SHARED | 273 CF_PAGE_EXEC) 274 }; 275 DECLARE_VM_GET_PAGE_PROT 276