317 lines
7.9 KiB
C
317 lines
7.9 KiB
C
/*
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* linux/arch/m68k/mm/cf-mmu.c
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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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* Copyright Freescale Semiconductor, Inc. 2008-2009
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* Jason Jin Jason.Jin@freescale.com
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* Shrek Wu B16972@freescale.com
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*/
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#include <linux/signal.h>
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#include <linux/sched.h>
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#include <linux/mm.h>
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#include <linux/swap.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/types.h>
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#include <linux/init.h>
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#ifdef CONFIG_BLK_DEV_RAM
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#include <linux/blkdev.h>
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#endif
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#include <linux/bootmem.h>
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#include <asm/setup.h>
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#include <asm/uaccess.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/machdep.h>
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#include <asm/io.h>
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#include <asm/mmu_context.h>
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#include <asm/cf_pgalloc.h>
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#include <asm/coldfire.h>
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#include <asm/tlbflush.h>
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#define KMAPAREA(x) ((x >= VMALLOC_START) && (x < KMAP_END))
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#undef DEBUG
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#ifdef CONFIG_VDSO
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unsigned long next_mmu_context;
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#else
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mm_context_t next_mmu_context;
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#endif
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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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void steal_context(void);
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#ifdef CONFIG_M5445X
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void m68k_setup_node(int);
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#endif
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const char bad_pmd_string[] = "Bad pmd in pte_alloc: %08lx\n";
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extern unsigned long empty_bad_page_table;
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extern unsigned long empty_bad_page;
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extern unsigned long num_pages;
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#ifdef CONFIG_M5445X
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extern unsigned long availmem;
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#endif
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extern char __init_begin, __init_end;
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/*
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* Free memory used for system initialization.
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*/
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void free_initmem(void)
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{
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#if 0
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unsigned long addr;
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unsigned long start = (unsigned long)&__init_begin;
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unsigned long end = (unsigned long)&__init_end;
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printk(KERN_INFO "free_initmem: __init_begin = 0x%lx __init_end = 0x%lx\n", start, end);
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addr = (unsigned long)&__init_begin;
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for (; addr < (unsigned long)&__init_end; addr += PAGE_SIZE) {
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/* not currently used */
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virt_to_page(addr)->flags &= ~(1 << PG_reserved);
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init_page_count(virt_to_page(addr));
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free_page(addr);
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totalram_pages++;
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}
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#endif
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}
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/*
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* Initialize the paging system.
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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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int i;
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unsigned long address;
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unsigned long next_pgtable;
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unsigned long zones_size[MAX_NR_ZONES];
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unsigned long size;
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enum zone_type zone;
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/* allocate zero page */
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empty_zero_page = (void *)alloc_bootmem_pages(PAGE_SIZE);
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memset((void *)empty_zero_page, 0, PAGE_SIZE);
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/* zero kernel page directory */
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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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/*
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* setup page tables for PHYSRAM
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*/
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/* starting loc in page directory */
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pg_dir += PAGE_OFFSET >> PGDIR_SHIFT;
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/* allocate page tables */
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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)alloc_bootmem_pages(size);
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address = PAGE_OFFSET;
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while (address < (unsigned long)high_memory) {
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/* setup page table in page directory */
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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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/* create PTEs in page table */
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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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/*
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* setup page tables for DMA area
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*/
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/* starting loc in page directory */
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pg_dir = swapper_pg_dir;
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pg_dir += CONFIG_DMA_BASE >> PGDIR_SHIFT;
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/* allocate page tables */
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size = (CONFIG_DMA_SIZE >> PAGE_SHIFT) * sizeof(pte_t);
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size = (size + PAGE_SIZE) & ~(PAGE_SIZE-1);
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next_pgtable = (unsigned long)alloc_bootmem_pages(size);
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address = CONFIG_DMA_BASE;
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while (address < (CONFIG_DMA_BASE + CONFIG_DMA_SIZE)) {
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/* setup page table in page directory */
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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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/* create PTEs in page table */
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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 >= (CONFIG_DMA_BASE + CONFIG_DMA_SIZE))
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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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/*
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* setup zones
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*/
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current->mm = NULL;
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/* clear zones */
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for (zone = 0; zone < MAX_NR_ZONES; zone++)
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zones_size[zone] = 0x0;
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zones_size[ZONE_DMA] = CONFIG_DMA_SIZE >> PAGE_SHIFT;
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zones_size[ZONE_NORMAL] = (((unsigned long)high_memory -
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PAGE_OFFSET) >> PAGE_SHIFT) -
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zones_size[ZONE_DMA];
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free_area_init(zones_size);
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}
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/*
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* Handle a missed TLB
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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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struct mm_struct *mm;
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pgd_t *pgd;
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pmd_t *pmd;
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pte_t *pte;
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unsigned long mmuar;
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int asid;
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int flags;
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local_save_flags(flags);
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local_irq_disable();
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mmuar = ( dtlb ) ? regs->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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pmd = pmd_offset(pgd, 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 = cpu_context(mm) & 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 << CF_ASID_MMU_SHIFT)
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| (((int)(pte->pte) & (int)CF_PAGE_MMUTR_MASK ) >> CF_PAGE_MMUTR_SHIFT)
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| MMUTR_V;
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*MMUDR = (pte_val(*pte) & PAGE_MASK)
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| ((pte->pte) & CF_PAGE_MMUDR_MASK)
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| MMUDR_SZ8K | MMUDR_X;
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if ( dtlb )
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*MMUOR = MMUOR_ACC | MMUOR_UAA;
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else
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*MMUOR = MMUOR_ITLB | MMUOR_ACC | MMUOR_UAA;
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asm("nop");
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#ifdef DEBUG
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printk("cf_tlb_miss: va=%lx, pa=%lx\n", (mmuar & PAGE_MASK),
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(pte_val(*pte) & PAGE_MASK));
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#endif
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local_irq_restore(flags);
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return (0);
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}
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/*
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* Context Management
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*
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* Based on arch/ppc/mmu_context.c
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*/
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/*
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* Initialize the context management system.
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*/
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void __init 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 is only used on 8xx and 4xx and we presently assume that
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* they don't do SMP. If they do then thicfpgalloc.hs will have to check
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* whether the MM we steal is in use.
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* We also assume that this is only used on systems that don't
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* use an MMU hash table - this is true for 8xx and 4xx.
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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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/* free up context `next_mmu_context' */
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/* if we shouldn't free context 0, don't... */
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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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