/* * Based upon linux/arch/m68k/mm/sun3mmu.c * Based upon linux/arch/ppc/mm/mmu_context.c * * Implementations of mm routines specific to the Coldfire MMU. * * Copyright (c) 2008 Freescale Semiconductor, Inc. */ #include <linux/kernel.h> #include <linux/types.h> #include <linux/mm.h> #include <linux/init.h> #include <linux/string.h> #include <linux/bootmem.h> #include <asm/setup.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/mmu_context.h> #include <asm/mcf_pgalloc.h> #include <asm/tlbflush.h> #define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END)) mm_context_t next_mmu_context; unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1]; atomic_t nr_free_contexts; struct mm_struct *context_mm[LAST_CONTEXT+1]; extern unsigned long num_pages; void free_initmem(void) { } /* * ColdFire paging_init derived from sun3. */ void __init paging_init(void) { pgd_t *pg_dir; pte_t *pg_table; unsigned long address, size; unsigned long next_pgtable, bootmem_end; unsigned long zones_size[MAX_NR_ZONES]; enum zone_type zone; int i; empty_zero_page = (void *) alloc_bootmem_pages(PAGE_SIZE); memset((void *) empty_zero_page, 0, PAGE_SIZE); pg_dir = swapper_pg_dir; memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir)); size = num_pages * sizeof(pte_t); size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1); next_pgtable = (unsigned long) alloc_bootmem_pages(size); bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK; pg_dir += PAGE_OFFSET >> PGDIR_SHIFT; address = PAGE_OFFSET; while (address < (unsigned long)high_memory) { pg_table = (pte_t *) next_pgtable; next_pgtable += PTRS_PER_PTE * sizeof(pte_t); pgd_val(*pg_dir) = (unsigned long) pg_table; pg_dir++; /* now change pg_table to kernel virtual addresses */ for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) { pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT); if (address >= (unsigned long) high_memory) pte_val(pte) = 0; set_pte(pg_table, pte); address += PAGE_SIZE; } } current->mm = NULL; for (zone = 0; zone < MAX_NR_ZONES; zone++) zones_size[zone] = 0x0; zones_size[ZONE_DMA] = num_pages; free_area_init(zones_size); } int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word) { unsigned long flags, mmuar; struct mm_struct *mm; pgd_t *pgd; pmd_t *pmd; pte_t *pte; int asid; local_irq_save(flags); mmuar = (dtlb) ? mmu_read(MMUAR) : regs->pc + (extension_word * sizeof(long)); mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm; if (!mm) { local_irq_restore(flags); return -1; } pgd = pgd_offset(mm, mmuar); if (pgd_none(*pgd)) { local_irq_restore(flags); return -1; } pmd = pmd_offset(pgd, mmuar); if (pmd_none(*pmd)) { local_irq_restore(flags); return -1; } pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar) : pte_offset_map(pmd, mmuar); if (pte_none(*pte) || !pte_present(*pte)) { local_irq_restore(flags); return -1; } if (write) { if (!pte_write(*pte)) { local_irq_restore(flags); return -1; } set_pte(pte, pte_mkdirty(*pte)); } set_pte(pte, pte_mkyoung(*pte)); asid = mm->context & 0xff; if (!pte_dirty(*pte) && !KMAPAREA(mmuar)) set_pte(pte, pte_wrprotect(*pte)); mmu_write(MMUTR, (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT) | MMUTR_V); mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) | ((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X); if (dtlb) mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA); else mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA); local_irq_restore(flags); return 0; } /* * Initialize the context management stuff. * The following was taken from arch/ppc/mmu_context.c */ void __init mmu_context_init(void) { /* * Some processors have too few contexts to reserve one for * init_mm, and require using context 0 for a normal task. * Other processors reserve the use of context zero for the kernel. * This code assumes FIRST_CONTEXT < 32. */ context_map[0] = (1 << FIRST_CONTEXT) - 1; next_mmu_context = FIRST_CONTEXT; atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1); } /* * Steal a context from a task that has one at the moment. * This is only used on 8xx and 4xx and we presently assume that * they don't do SMP. If they do then thicfpgalloc.hs will have to check * whether the MM we steal is in use. * We also assume that this is only used on systems that don't * use an MMU hash table - this is true for 8xx and 4xx. * This isn't an LRU system, it just frees up each context in * turn (sort-of pseudo-random replacement :). This would be the * place to implement an LRU scheme if anyone was motivated to do it. * -- paulus */ void steal_context(void) { struct mm_struct *mm; /* * free up context `next_mmu_context' * if we shouldn't free context 0, don't... */ if (next_mmu_context < FIRST_CONTEXT) next_mmu_context = FIRST_CONTEXT; mm = context_mm[next_mmu_context]; flush_tlb_mm(mm); destroy_context(mm); }