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-rw-r--r--arch/m68k/mm/mcfmmu.c291
1 files changed, 291 insertions, 0 deletions
diff --git a/arch/m68k/mm/mcfmmu.c b/arch/m68k/mm/mcfmmu.c
new file mode 100644
index 000000000..70aa0979e
--- /dev/null
+++ b/arch/m68k/mm/mcfmmu.c
@@ -0,0 +1,291 @@
+// 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/memblock.h>
+
+#include <asm/setup.h>
+#include <asm/page.h>
+#include <asm/mmu_context.h>
+#include <asm/mcf_pgalloc.h>
+#include <asm/tlbflush.h>
+#include <asm/pgalloc.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 max_zone_pfn[MAX_NR_ZONES] = { 0 };
+ int i;
+
+ empty_zero_page = memblock_alloc(PAGE_SIZE, PAGE_SIZE);
+ if (!empty_zero_page)
+ panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+ __func__, PAGE_SIZE, 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) memblock_alloc(size, PAGE_SIZE);
+ if (!next_pgtable)
+ panic("%s: Failed to allocate %lu bytes align=0x%lx\n",
+ __func__, size, PAGE_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;
+ max_zone_pfn[ZONE_DMA] = PFN_DOWN(_ramend);
+ free_area_init(max_zone_pfn);
+}
+
+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;
+ p4d_t *p4d;
+ pud_t *pud;
+ 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;
+ }
+
+ p4d = p4d_offset(pgd, mmuar);
+ if (p4d_none(*p4d)) {
+ local_irq_restore(flags);
+ return -1;
+ }
+
+ pud = pud_offset(p4d, mmuar);
+ if (pud_none(*pud)) {
+ local_irq_restore(flags);
+ return -1;
+ }
+
+ pmd = pmd_offset(pud, 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,
+ MEMBLOCK_NONE);
+
+ /* 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 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);
+}
+
+static const pgprot_t protection_map[16] = {
+ [VM_NONE] = PAGE_NONE,
+ [VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE),
+ [VM_WRITE] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_WRITABLE),
+ [VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE |
+ CF_PAGE_WRITABLE),
+ [VM_EXEC] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_EXEC),
+ [VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE |
+ CF_PAGE_EXEC),
+ [VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_WRITABLE |
+ CF_PAGE_EXEC),
+ [VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE |
+ CF_PAGE_WRITABLE |
+ CF_PAGE_EXEC),
+ [VM_SHARED] = PAGE_NONE,
+ [VM_SHARED | VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE),
+ [VM_SHARED | VM_WRITE] = PAGE_SHARED,
+ [VM_SHARED | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE |
+ CF_PAGE_SHARED),
+ [VM_SHARED | VM_EXEC] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_EXEC),
+ [VM_SHARED | VM_EXEC | VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE |
+ CF_PAGE_EXEC),
+ [VM_SHARED | VM_EXEC | VM_WRITE] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_SHARED |
+ CF_PAGE_EXEC),
+ [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = __pgprot(CF_PAGE_VALID |
+ CF_PAGE_ACCESSED |
+ CF_PAGE_READABLE |
+ CF_PAGE_SHARED |
+ CF_PAGE_EXEC)
+};
+DECLARE_VM_GET_PAGE_PROT