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 27mm_context_t next_mmu_context; 28unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; 29atomic_t nr_free_contexts; 30struct mm_struct *context_mm[LAST_CONTEXT+1]; 31unsigned long num_pages; 32 33/* 34 * ColdFire paging_init derived from sun3. 35 */ 36void __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, bootmem_end; 42 unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 }; 43 int i; 44 45 empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE); 46 if (!empty_zero_page) 47 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 48 __func__, PAGE_SIZE, PAGE_SIZE); 49 50 pg_dir = swapper_pg_dir; 51 memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir)); 52 53 size = num_pages * sizeof(pte_t); 54 size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1); 55 next_pgtable = (unsigned long) memblock_alloc(size, PAGE_SIZE); 56 if (!next_pgtable) 57 panic("%s: Failed to allocate %lu bytes align=0x%lx\n", 58 __func__, size, PAGE_SIZE); 59 60 bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK; 61 pg_dir += PAGE_OFFSET >> PGDIR_SHIFT; 62 63 address = PAGE_OFFSET; 64 while (address < (unsigned long)high_memory) { 65 pg_table = (pte_t *) next_pgtable; 66 next_pgtable += PTRS_PER_PTE * sizeof(pte_t); 67 pgd_val(*pg_dir) = (unsigned long) pg_table; 68 pg_dir++; 69 70 /* now change pg_table to kernel virtual addresses */ 71 for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) { 72 pte_t pte = pfn_pte(virt_to_pfn((void *)address), 73 PAGE_INIT); 74 if (address >= (unsigned long) high_memory) 75 pte_val(pte) = 0; 76 77 set_pte(pg_table, pte); 78 address += PAGE_SIZE; 79 } 80 } 81 82 current->mm = NULL; 83 max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend); 84 free_area_init(max_zone_pfn); 85} 86 87int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word) 88{ 89 unsigned long flags, mmuar, mmutr; 90 struct mm_struct *mm; 91 pgd_t *pgd; 92 p4d_t *p4d; 93 pud_t *pud; 94 pmd_t *pmd; 95 pte_t *pte = NULL; 96 int ret = -1; 97 int asid; 98 99 local_irq_save(flags); 100 101 mmuar = (dtlb) ? mmu_read(MMUAR) : 102 regs->pc + (extension_word * sizeof(long)); 103 104 mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm; 105 if (!mm) 106 goto out; 107 108 pgd = pgd_offset(mm, mmuar); 109 if (pgd_none(*pgd)) 110 goto out; 111 112 p4d = p4d_offset(pgd, mmuar); 113 if (p4d_none(*p4d)) 114 goto out; 115 116 pud = pud_offset(p4d, mmuar); 117 if (pud_none(*pud)) 118 goto out; 119 120 pmd = pmd_offset(pud, mmuar); 121 if (pmd_none(*pmd)) 122 goto out; 123 124 pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar) 125 : pte_offset_map(pmd, mmuar); 126 if (!pte || pte_none(*pte) || !pte_present(*pte)) 127 goto out; 128 129 if (write) { 130 if (!pte_write(*pte)) 131 goto out; 132 set_pte(pte, pte_mkdirty(*pte)); 133 } 134 135 set_pte(pte, pte_mkyoung(*pte)); 136 asid = mm->context & 0xff; 137 if (!pte_dirty(*pte) && !KMAPAREA(mmuar)) 138 set_pte(pte, pte_wrprotect(*pte)); 139 140 mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V; 141 if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE)) 142 mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT; 143 mmu_write(MMUTR, mmutr); 144 145 mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | 146 ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); 147 148 if (dtlb) 149 mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); 150 else 151 mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); 152 ret = 0; 153out: 154 if (pte && !KMAPAREA(mmuar)) 155 pte_unmap(pte); 156 local_irq_restore(flags); 157 return ret; 158} 159 160void __init cf_bootmem_alloc(void) 161{ 162 unsigned long memstart; 163 164 /* _rambase and _ramend will be naturally page aligned */ 165 m68k_memory[0].addr = _rambase; 166 m68k_memory[0].size = _ramend - _rambase; 167 168 memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0, 169 MEMBLOCK_NONE); 170 171 /* compute total pages in system */ 172 num_pages = PFN_DOWN(_ramend - _rambase); 173 174 /* page numbers */ 175 memstart = PAGE_ALIGN(_ramstart); 176 min_low_pfn = PFN_DOWN(_rambase); 177 max_pfn = max_low_pfn = PFN_DOWN(_ramend); 178 high_memory = (void *)_ramend; 179 180 /* Reserve kernel text/data/bss */ 181 memblock_reserve(_rambase, memstart - _rambase); 182 183 m68k_virt_to_node_shift = fls(_ramend - 1) - 6; 184 module_fixup(NULL, __start_fixup, __stop_fixup); 185 186 /* setup node data */ 187 m68k_setup_node(0); 188} 189 190/* 191 * Initialize the context management stuff. 192 * The following was taken from arch/ppc/mmu_context.c 193 */ 194void __init cf_mmu_context_init(void) 195{ 196 /* 197 * Some processors have too few contexts to reserve one for 198 * init_mm, and require using context 0 for a normal task. 199 * Other processors reserve the use of context zero for the kernel. 200 * This code assumes FIRST_CONTEXT < 32. 201 */ 202 context_map[0] = (1 << FIRST_CONTEXT) - 1; 203 next_mmu_context = FIRST_CONTEXT; 204 atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1); 205} 206 207/* 208 * Steal a context from a task that has one at the moment. 209 * This isn't an LRU system, it just frees up each context in 210 * turn (sort-of pseudo-random replacement :). This would be the 211 * place to implement an LRU scheme if anyone was motivated to do it. 212 * -- paulus 213 */ 214void steal_context(void) 215{ 216 struct mm_struct *mm; 217 /* 218 * free up context `next_mmu_context' 219 * if we shouldn't free context 0, don't... 220 */ 221 if (next_mmu_context < FIRST_CONTEXT) 222 next_mmu_context = FIRST_CONTEXT; 223 mm = context_mm[next_mmu_context]; 224 flush_tlb_mm(mm); 225 destroy_context(mm); 226} 227 228static const pgprot_t protection_map[16] = { 229 [VM_NONE] = PAGE_NONE, 230 [VM_READ] = __pgprot(CF_PAGE_VALID | 231 CF_PAGE_ACCESSED | 232 CF_PAGE_READABLE), 233 [VM_WRITE] = __pgprot(CF_PAGE_VALID | 234 CF_PAGE_ACCESSED | 235 CF_PAGE_WRITABLE), 236 [VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 237 CF_PAGE_ACCESSED | 238 CF_PAGE_READABLE | 239 CF_PAGE_WRITABLE), 240 [VM_EXEC] = __pgprot(CF_PAGE_VALID | 241 CF_PAGE_ACCESSED | 242 CF_PAGE_EXEC), 243 [VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID | 244 CF_PAGE_ACCESSED | 245 CF_PAGE_READABLE | 246 CF_PAGE_EXEC), 247 [VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID | 248 CF_PAGE_ACCESSED | 249 CF_PAGE_WRITABLE | 250 CF_PAGE_EXEC), 251 [VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 252 CF_PAGE_ACCESSED | 253 CF_PAGE_READABLE | 254 CF_PAGE_WRITABLE | 255 CF_PAGE_EXEC), 256 [VM_SHARED] = PAGE_NONE, 257 [VM_SHARED | VM_READ] = __pgprot(CF_PAGE_VALID | 258 CF_PAGE_ACCESSED | 259 CF_PAGE_READABLE), 260 [VM_SHARED | VM_WRITE] = PAGE_SHARED, 261 [VM_SHARED | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 262 CF_PAGE_ACCESSED | 263 CF_PAGE_READABLE | 264 CF_PAGE_SHARED), 265 [VM_SHARED | VM_EXEC] = __pgprot(CF_PAGE_VALID | 266 CF_PAGE_ACCESSED | 267 CF_PAGE_EXEC), 268 [VM_SHARED | VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID | 269 CF_PAGE_ACCESSED | 270 CF_PAGE_READABLE | 271 CF_PAGE_EXEC), 272 [VM_SHARED | VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID | 273 CF_PAGE_ACCESSED | 274 CF_PAGE_SHARED | 275 CF_PAGE_EXEC), 276 [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID | 277 CF_PAGE_ACCESSED | 278 CF_PAGE_READABLE | 279 CF_PAGE_SHARED | 280 CF_PAGE_EXEC) 281}; 282DECLARE_VM_GET_PAGE_PROT 283