tlb.c

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/*
 * arch/xtensa/mm/tlb.c
 *
 * Logic that manipulates the Xtensa MMU.  Derived from MIPS.
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2001 - 2003 Tensilica Inc.
 *
 * Joe Taylor
 * Chris Zankel <[email protected]>
 * Marc Gauthier
 */

#include <linux/mm.h>
#include <asm/processor.h>
#include <asm/mmu_context.h>
#include <asm/tlbflush.h>
#include <asm/cacheflush.h>


static inline void __flush_itlb_all (void)
{
    int w, i;

    for (w = 0; w < ITLB_ARF_WAYS; w++) {
        for (i = 0; i < (1 << XCHAL_ITLB_ARF_ENTRIES_LOG2); i++) {
            int e = w + (i << PAGE_SHIFT);
            invalidate_itlb_entry_no_isync(e);
        }
    }
    asm volatile ("isync\n");
}

static inline void __flush_dtlb_all (void)
{
    int w, i;

    for (w = 0; w < DTLB_ARF_WAYS; w++) {
        for (i = 0; i < (1 << XCHAL_DTLB_ARF_ENTRIES_LOG2); i++) {
            int e = w + (i << PAGE_SHIFT);
            invalidate_dtlb_entry_no_isync(e);
        }
    }
    asm volatile ("isync\n");
}


void flush_tlb_all (void)
{
    __flush_itlb_all();
    __flush_dtlb_all();
}

/* If mm is current, we simply assign the current task a new ASID, thus,
 * invalidating all previous tlb entries. If mm is someone else's user mapping,
 * wie invalidate the context, thus, when that user mapping is swapped in,
 * a new context will be assigned to it.
 */

void flush_tlb_mm(struct mm_struct *mm)
{
    if (mm == current->active_mm) {
        int flags;
        local_save_flags(flags);
        __get_new_mmu_context(mm);
        __load_mmu_context(mm);
        local_irq_restore(flags);
    }
    else
        mm->context = 0;
}

#define _ITLB_ENTRIES (ITLB_ARF_WAYS << XCHAL_ITLB_ARF_ENTRIES_LOG2)
#define _DTLB_ENTRIES (DTLB_ARF_WAYS << XCHAL_DTLB_ARF_ENTRIES_LOG2)
#if _ITLB_ENTRIES > _DTLB_ENTRIES
# define _TLB_ENTRIES _ITLB_ENTRIES
#else
# define _TLB_ENTRIES _DTLB_ENTRIES
#endif

void flush_tlb_range (struct vm_area_struct *vma,
                  unsigned long start, unsigned long end)
{
    struct mm_struct *mm = vma->vm_mm;
    unsigned long flags;

    if (mm->context == NO_CONTEXT)
        return;

#if 0
    printk("[tlbrange<%02lx,%08lx,%08lx>]\n",
            (unsigned long)mm->context, start, end);
#endif
    local_save_flags(flags);

    if (end-start + (PAGE_SIZE-1) <= _TLB_ENTRIES << PAGE_SHIFT) {
        int oldpid = get_rasid_register();
        set_rasid_register (ASID_INSERT(mm->context));
        start &= PAGE_MASK;
        if (vma->vm_flags & VM_EXEC)
            while(start < end) {
                invalidate_itlb_mapping(start);
                invalidate_dtlb_mapping(start);
                start += PAGE_SIZE;
            }
        else
            while(start < end) {
                invalidate_dtlb_mapping(start);
                start += PAGE_SIZE;
            }

        set_rasid_register(oldpid);
    } else {
        flush_tlb_mm(mm);
    }
    local_irq_restore(flags);
}

void flush_tlb_page (struct vm_area_struct *vma, unsigned long page)
{
    struct mm_struct* mm = vma->vm_mm;
    unsigned long flags;
    int oldpid;

    if(mm->context == NO_CONTEXT)
        return;

    local_save_flags(flags);

        oldpid = get_rasid_register();

    if (vma->vm_flags & VM_EXEC)
        invalidate_itlb_mapping(page);
    invalidate_dtlb_mapping(page);

    set_rasid_register(oldpid);

    local_irq_restore(flags);
}