292 lines
7.7 KiB
C
292 lines
7.7 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Based upon linux/arch/m68k/mm/sun3mmu.c
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* Based upon linux/arch/ppc/mm/mmu_context.c
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*
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* Implementations of mm routines specific to the Coldfire MMU.
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*
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* Copyright (c) 2008 Freescale Semiconductor, Inc.
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*/
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#include <linux/kernel.h>
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#include <linux/types.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/string.h>
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#include <linux/memblock.h>
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#include <asm/setup.h>
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#include <asm/page.h>
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#include <asm/mmu_context.h>
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#include <asm/mcf_pgalloc.h>
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#include <asm/tlbflush.h>
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#include <asm/pgalloc.h>
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#define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END))
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mm_context_t next_mmu_context;
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unsigned long context_map[LAST_CONTEXT / BITS_PER_LONG + 1];
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atomic_t nr_free_contexts;
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struct mm_struct *context_mm[LAST_CONTEXT+1];
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unsigned long num_pages;
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/*
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* ColdFire paging_init derived from sun3.
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*/
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void __init paging_init(void)
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{
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pgd_t *pg_dir;
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pte_t *pg_table;
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unsigned long address, size;
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unsigned long next_pgtable, bootmem_end;
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unsigned long max_zone_pfn[MAX_NR_ZONES] = { 0 };
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int i;
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empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
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if (!empty_zero_page)
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panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
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__func__, PAGE_SIZE, PAGE_SIZE);
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pg_dir = swapper_pg_dir;
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memset(swapper_pg_dir, 0, sizeof(swapper_pg_dir));
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size = num_pages * sizeof(pte_t);
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size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
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next_pgtable = (unsigned long) memblock_alloc(size, PAGE_SIZE);
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if (!next_pgtable)
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panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
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__func__, size, PAGE_SIZE);
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bootmem_end = (next_pgtable + size + PAGE_SIZE) & PAGE_MASK;
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pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
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address = PAGE_OFFSET;
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while (address < (unsigned long)high_memory) {
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pg_table = (pte_t *) next_pgtable;
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next_pgtable += PTRS_PER_PTE * sizeof(pte_t);
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pgd_val(*pg_dir) = (unsigned long) pg_table;
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pg_dir++;
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/* now change pg_table to kernel virtual addresses */
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for (i = 0; i < PTRS_PER_PTE; ++i, ++pg_table) {
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pte_t pte = pfn_pte(virt_to_pfn(address), PAGE_INIT);
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if (address >= (unsigned long) high_memory)
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pte_val(pte) = 0;
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set_pte(pg_table, pte);
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address += PAGE_SIZE;
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}
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}
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current->mm = NULL;
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max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend);
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free_area_init(max_zone_pfn);
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}
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int cf_tlb_miss(struct pt_regs *regs, int write, int dtlb, int extension_word)
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{
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unsigned long flags, mmuar, mmutr;
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struct mm_struct *mm;
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pgd_t *pgd;
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p4d_t *p4d;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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int asid;
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local_irq_save(flags);
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mmuar = (dtlb) ? mmu_read(MMUAR) :
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regs->pc + (extension_word * sizeof(long));
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mm = (!user_mode(regs) && KMAPAREA(mmuar)) ? &init_mm : current->mm;
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if (!mm) {
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local_irq_restore(flags);
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return -1;
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}
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pgd = pgd_offset(mm, mmuar);
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if (pgd_none(*pgd)) {
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local_irq_restore(flags);
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return -1;
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}
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p4d = p4d_offset(pgd, mmuar);
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if (p4d_none(*p4d)) {
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local_irq_restore(flags);
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return -1;
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}
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pud = pud_offset(p4d, mmuar);
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if (pud_none(*pud)) {
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local_irq_restore(flags);
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return -1;
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}
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pmd = pmd_offset(pud, mmuar);
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if (pmd_none(*pmd)) {
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local_irq_restore(flags);
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return -1;
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}
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pte = (KMAPAREA(mmuar)) ? pte_offset_kernel(pmd, mmuar)
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: pte_offset_map(pmd, mmuar);
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if (pte_none(*pte) || !pte_present(*pte)) {
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local_irq_restore(flags);
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return -1;
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}
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if (write) {
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if (!pte_write(*pte)) {
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local_irq_restore(flags);
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return -1;
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}
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set_pte(pte, pte_mkdirty(*pte));
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}
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set_pte(pte, pte_mkyoung(*pte));
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asid = mm->context & 0xff;
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if (!pte_dirty(*pte) && !KMAPAREA(mmuar))
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set_pte(pte, pte_wrprotect(*pte));
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mmutr = (mmuar & PAGE_MASK) | (asid << MMUTR_IDN) | MMUTR_V;
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if ((mmuar < TASK_UNMAPPED_BASE) || (mmuar >= TASK_SIZE))
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mmutr |= (pte->pte & CF_PAGE_MMUTR_MASK) >> CF_PAGE_MMUTR_SHIFT;
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mmu_write(MMUTR, mmutr);
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mmu_write(MMUDR, (pte_val(*pte) & PAGE_MASK) |
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((pte->pte) & CF_PAGE_MMUDR_MASK) | MMUDR_SZ_8KB | MMUDR_X);
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if (dtlb)
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mmu_write(MMUOR, MMUOR_ACC | MMUOR_UAA);
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else
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mmu_write(MMUOR, MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA);
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local_irq_restore(flags);
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return 0;
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}
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void __init cf_bootmem_alloc(void)
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{
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unsigned long memstart;
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/* _rambase and _ramend will be naturally page aligned */
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m68k_memory[0].addr = _rambase;
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m68k_memory[0].size = _ramend - _rambase;
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memblock_add_node(m68k_memory[0].addr, m68k_memory[0].size, 0,
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MEMBLOCK_NONE);
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/* compute total pages in system */
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num_pages = PFN_DOWN(_ramend - _rambase);
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/* page numbers */
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memstart = PAGE_ALIGN(_ramstart);
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min_low_pfn = PFN_DOWN(_rambase);
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max_pfn = max_low_pfn = PFN_DOWN(_ramend);
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high_memory = (void *)_ramend;
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/* Reserve kernel text/data/bss */
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memblock_reserve(_rambase, memstart - _rambase);
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m68k_virt_to_node_shift = fls(_ramend - 1) - 6;
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module_fixup(NULL, __start_fixup, __stop_fixup);
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/* setup node data */
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m68k_setup_node(0);
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}
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/*
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* Initialize the context management stuff.
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* The following was taken from arch/ppc/mmu_context.c
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*/
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void __init cf_mmu_context_init(void)
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{
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/*
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* Some processors have too few contexts to reserve one for
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* init_mm, and require using context 0 for a normal task.
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* Other processors reserve the use of context zero for the kernel.
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* This code assumes FIRST_CONTEXT < 32.
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*/
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context_map[0] = (1 << FIRST_CONTEXT) - 1;
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next_mmu_context = FIRST_CONTEXT;
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atomic_set(&nr_free_contexts, LAST_CONTEXT - FIRST_CONTEXT + 1);
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}
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/*
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* Steal a context from a task that has one at the moment.
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* This isn't an LRU system, it just frees up each context in
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* turn (sort-of pseudo-random replacement :). This would be the
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* place to implement an LRU scheme if anyone was motivated to do it.
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* -- paulus
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*/
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void steal_context(void)
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{
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struct mm_struct *mm;
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/*
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* free up context `next_mmu_context'
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* if we shouldn't free context 0, don't...
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*/
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if (next_mmu_context < FIRST_CONTEXT)
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next_mmu_context = FIRST_CONTEXT;
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mm = context_mm[next_mmu_context];
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flush_tlb_mm(mm);
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destroy_context(mm);
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}
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static const pgprot_t protection_map[16] = {
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[VM_NONE] = PAGE_NONE,
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[VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE),
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[VM_WRITE] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_WRITABLE),
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[VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE |
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CF_PAGE_WRITABLE),
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[VM_EXEC] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_EXEC),
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[VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE |
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CF_PAGE_EXEC),
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[VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_WRITABLE |
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CF_PAGE_EXEC),
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[VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE |
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CF_PAGE_WRITABLE |
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CF_PAGE_EXEC),
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[VM_SHARED] = PAGE_NONE,
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[VM_SHARED | VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE),
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[VM_SHARED | VM_WRITE] = PAGE_SHARED,
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[VM_SHARED | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE |
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CF_PAGE_SHARED),
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[VM_SHARED | VM_EXEC] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_EXEC),
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[VM_SHARED | VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE |
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CF_PAGE_EXEC),
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[VM_SHARED | VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_SHARED |
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CF_PAGE_EXEC),
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[VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
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CF_PAGE_ACCESSED |
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CF_PAGE_READABLE |
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CF_PAGE_SHARED |
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CF_PAGE_EXEC)
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};
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DECLARE_VM_GET_PAGE_PROT
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