Greg Ungerer | 066bf87 | 2011-10-18 16:24:19 +1000 | [diff] [blame] | 1 | /* |
| 2 | * Based upon linux/arch/m68k/mm/sun3mmu.c |
| 3 | * Based upon linux/arch/ppc/mm/mmu_context.c |
| 4 | * |
| 5 | * Implementations of mm routines specific to the Coldfire MMU. |
| 6 | * |
| 7 | * Copyright (c) 2008 Freescale Semiconductor, Inc. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/kernel.h> |
| 11 | #include <linux/types.h> |
| 12 | #include <linux/mm.h> |
| 13 | #include <linux/init.h> |
| 14 | #include <linux/string.h> |
| 15 | #include <linux/bootmem.h> |
| 16 | |
| 17 | #include <asm/setup.h> |
| 18 | #include <asm/page.h> |
| 19 | #include <asm/pgtable.h> |
| 20 | #include <asm/mmu_context.h> |
| 21 | #include <asm/mcf_pgalloc.h> |
| 22 | #include <asm/tlbflush.h> |
| 23 | |
| 24 | #define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END)) |
| 25 | |
| 26 | mm_context_t next_mmu_context; |
| 27 | unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; |
| 28 | atomic_t nr_free_contexts; |
| 29 | struct mm_struct *context_mm[LAST_CONTEXT+1]; |
| 30 | extern unsigned long num_pages; |
| 31 | |
Greg Ungerer | 066bf87 | 2011-10-18 16:24:19 +1000 | [diff] [blame] | 32 | /* |
| 33 | * ColdFire paging_init derived from sun3. |
| 34 | */ |
| 35 | void __init paging_init(void) |
| 36 | { |
| 37 | pgd_t *pg_dir; |
| 38 | pte_t *pg_table; |
| 39 | unsigned long address, size; |
| 40 | unsigned long next_pgtable, bootmem_end; |
| 41 | unsigned long zones_size[MAX_NR_ZONES]; |
| 42 | enum zone_type zone; |
| 43 | int i; |
| 44 | |
| 45 | empty_zero_page = (void *) alloc_bootmem_pages(PAGE_SIZE); |
| 46 | memset((void *) empty_zero_page, 0, PAGE_SIZE); |
| 47 | |
| 48 | pg_dir = swapper_pg_dir; |
| 49 | memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir)); |
| 50 | |
| 51 | size = num_pages * sizeof(pte_t); |
| 52 | size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1); |
| 53 | next_pgtable = (unsigned long) alloc_bootmem_pages(size); |
| 54 | |
| 55 | bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK; |
| 56 | pg_dir += PAGE_OFFSET >> PGDIR_SHIFT; |
| 57 | |
| 58 | address = PAGE_OFFSET; |
| 59 | while (address < (unsigned long)high_memory) { |
| 60 | pg_table = (pte_t *) next_pgtable; |
| 61 | next_pgtable += PTRS_PER_PTE * sizeof(pte_t); |
| 62 | pgd_val(*pg_dir) = (unsigned long) pg_table; |
| 63 | pg_dir++; |
| 64 | |
| 65 | /* now change pg_table to kernel virtual addresses */ |
| 66 | for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) { |
| 67 | pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT); |
| 68 | if (address >= (unsigned long) high_memory) |
| 69 | pte_val(pte) = 0; |
| 70 | |
| 71 | set_pte(pg_table, pte); |
| 72 | address += PAGE_SIZE; |
| 73 | } |
| 74 | } |
| 75 | |
| 76 | current->mm = NULL; |
| 77 | |
| 78 | for (zone = 0; zone < MAX_NR_ZONES; zone++) |
| 79 | zones_size[zone] = 0x0; |
| 80 | zones_size[ZONE_DMA] = num_pages; |
| 81 | free_area_init(zones_size); |
| 82 | } |
| 83 | |
| 84 | int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word) |
| 85 | { |
Alexander Stein | 3372f5a | 2012-01-23 15:45:56 +0100 | [diff] [blame] | 86 | unsigned long flags, mmuar, mmutr; |
Greg Ungerer | 066bf87 | 2011-10-18 16:24:19 +1000 | [diff] [blame] | 87 | struct mm_struct *mm; |
| 88 | pgd_t *pgd; |
| 89 | pmd_t *pmd; |
| 90 | pte_t *pte; |
| 91 | int asid; |
| 92 | |
| 93 | local_irq_save(flags); |
| 94 | |
| 95 | mmuar = (dtlb) ? mmu_read(MMUAR) : |
| 96 | regs->pc + (extension_word * sizeof(long)); |
| 97 | |
| 98 | mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm; |
| 99 | if (!mm) { |
| 100 | local_irq_restore(flags); |
| 101 | return -1; |
| 102 | } |
| 103 | |
| 104 | pgd = pgd_offset(mm, mmuar); |
| 105 | if (pgd_none(*pgd)) { |
| 106 | local_irq_restore(flags); |
| 107 | return -1; |
| 108 | } |
| 109 | |
| 110 | pmd = pmd_offset(pgd, mmuar); |
| 111 | if (pmd_none(*pmd)) { |
| 112 | local_irq_restore(flags); |
| 113 | return -1; |
| 114 | } |
| 115 | |
| 116 | pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar) |
| 117 | : pte_offset_map(pmd, mmuar); |
| 118 | if (pte_none(*pte) || !pte_present(*pte)) { |
| 119 | local_irq_restore(flags); |
| 120 | return -1; |
| 121 | } |
| 122 | |
| 123 | if (write) { |
| 124 | if (!pte_write(*pte)) { |
| 125 | local_irq_restore(flags); |
| 126 | return -1; |
| 127 | } |
| 128 | set_pte(pte, pte_mkdirty(*pte)); |
| 129 | } |
| 130 | |
| 131 | set_pte(pte, pte_mkyoung(*pte)); |
| 132 | asid = mm->context & 0xff; |
| 133 | if (!pte_dirty(*pte) && !KMAPAREA(mmuar)) |
| 134 | set_pte(pte, pte_wrprotect(*pte)); |
| 135 | |
Alexander Stein | 3372f5a | 2012-01-23 15:45:56 +0100 | [diff] [blame] | 136 | mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V; |
| 137 | if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE)) |
| 138 | mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT; |
| 139 | mmu_write(MMUTR, mmutr); |
Greg Ungerer | 066bf87 | 2011-10-18 16:24:19 +1000 | [diff] [blame] | 140 | |
| 141 | mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | |
| 142 | ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); |
| 143 | |
| 144 | if (dtlb) |
| 145 | mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); |
| 146 | else |
| 147 | mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); |
| 148 | |
| 149 | local_irq_restore(flags); |
| 150 | return 0; |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * Initialize the context management stuff. |
| 155 | * The following was taken from arch/ppc/mmu_context.c |
| 156 | */ |
| 157 | void __init mmu_context_init(void) |
| 158 | { |
| 159 | /* |
| 160 | * Some processors have too few contexts to reserve one for |
| 161 | * init_mm, and require using context 0 for a normal task. |
| 162 | * Other processors reserve the use of context zero for the kernel. |
| 163 | * This code assumes FIRST_CONTEXT < 32. |
| 164 | */ |
| 165 | context_map[0] = (1 << FIRST_CONTEXT) - 1; |
| 166 | next_mmu_context = FIRST_CONTEXT; |
| 167 | atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1); |
| 168 | } |
| 169 | |
| 170 | /* |
| 171 | * Steal a context from a task that has one at the moment. |
| 172 | * This is only used on 8xx and 4xx and we presently assume that |
| 173 | * they don't do SMP. If they do then thicfpgalloc.hs will have to check |
| 174 | * whether the MM we steal is in use. |
| 175 | * We also assume that this is only used on systems that don't |
| 176 | * use an MMU hash table - this is true for 8xx and 4xx. |
| 177 | * This isn't an LRU system, it just frees up each context in |
| 178 | * turn (sort-of pseudo-random replacement :). This would be the |
| 179 | * place to implement an LRU scheme if anyone was motivated to do it. |
| 180 | * -- paulus |
| 181 | */ |
| 182 | void steal_context(void) |
| 183 | { |
| 184 | struct mm_struct *mm; |
| 185 | /* |
| 186 | * free up context `next_mmu_context' |
| 187 | * if we shouldn't free context 0, don't... |
| 188 | */ |
| 189 | if (next_mmu_context < FIRST_CONTEXT) |
| 190 | next_mmu_context = FIRST_CONTEXT; |
| 191 | mm = context_mm[next_mmu_context]; |
| 192 | flush_tlb_mm(mm); |
| 193 | destroy_context(mm); |
| 194 | } |
| 195 | |