diff options
Diffstat (limited to 'arch/m68k/mm/mcfmmu.c')
| -rw-r--r-- | arch/m68k/mm/mcfmmu.c | 226 |
1 files changed, 226 insertions, 0 deletions
diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c new file mode 100644 index 000000000..c5e262229 --- /dev/null +++ b/arch/m68k/mm/mcfmmu.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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 <linux/memblock.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]; +unsigned long num_pages; + +/* + * 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, mmutr; + 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)); + + mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V; + if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE)) + mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT; + mmu_write(MMUTR, mmutr); + + 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; +} + +void __init cf_bootmem_alloc(void) +{ + unsigned long memstart; + + /* _rambase and _ramend will be naturally page aligned */ + m68k_memory[0].addr = _rambase; + m68k_memory[0].size = _ramend - _rambase; + + memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0); + + /* compute total pages in system */ + num_pages = PFN_DOWN(_ramend - _rambase); + + /* page numbers */ + memstart = PAGE_ALIGN(_ramstart); + min_low_pfn = PFN_DOWN(_rambase); + max_pfn = max_low_pfn = PFN_DOWN(_ramend); + high_memory = (void *)_ramend; + + /* Reserve kernel text/data/bss */ + memblock_reserve(_rambase, memstart - _rambase); + + m68k_virt_to_node_shift = fls(_ramend - 1) - 6; + module_fixup(NULL, __start_fixup, __stop_fixup); + + /* setup node data */ + m68k_setup_node(0); +} + +/* + * Initialize the context management stuff. + * The following was taken from arch/ppc/mmu_context.c + */ +void __init cf_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); +} + |