tlb.h

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#ifndef __UM_TLB_H
#define __UM_TLB_H

#include <linux/pagemap.h>
#include <linux/swap.h>
#include <asm/percpu.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>

#define tlb_start_vma(tlb, vma) do { } while (0)
#define tlb_end_vma(tlb, vma) do { } while (0)
#define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)

/* struct mmu_gather is an opaque type used by the mm code for passing around
 * any data needed by arch specific code for tlb_remove_page.
 */
struct mmu_gather {
    struct mm_struct    *mm;
    unsigned int        need_flush; /* Really unmapped some ptes? */
    unsigned long       start;
    unsigned long       end;
    unsigned int        fullmm; /* non-zero means full mm flush */
};

static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
                      unsigned long address)
{
    if (tlb->start > address)
        tlb->start = address;
    if (tlb->end < address + PAGE_SIZE)
        tlb->end = address + PAGE_SIZE;
}

static inline void init_tlb_gather(struct mmu_gather *tlb)
{
    tlb->need_flush = 0;

    tlb->start = TASK_SIZE;
    tlb->end = 0;

    if (tlb->fullmm) {
        tlb->start = 0;
        tlb->end = TASK_SIZE;
    }
}

static inline void
tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned int full_mm_flush)
{
    tlb->mm = mm;
    tlb->fullmm = full_mm_flush;

    init_tlb_gather(tlb);
}

extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
                   unsigned long end);

static inline void
tlb_flush_mmu(struct mmu_gather *tlb)
{
    if (!tlb->need_flush)
        return;

    flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
    init_tlb_gather(tlb);
}

/* tlb_finish_mmu
 *  Called at the end of the shootdown operation to free up any resources
 *  that were required.
 */
static inline void
tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
    tlb_flush_mmu(tlb);

    /* keep the page table cache within bounds */
    check_pgt_cache();
}

/* tlb_remove_page
 *  Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
 *  while handling the additional races in SMP caused by other CPUs
 *  caching valid mappings in their TLBs.
 */
static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
    tlb->need_flush = 1;
    free_page_and_swap_cache(page);
    return 1; /* avoid calling tlb_flush_mmu */
}

static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
    __tlb_remove_page(tlb, page);
}

#define tlb_remove_tlb_entry(tlb, ptep, address)        \
    do {                            \
        tlb->need_flush = 1;                \
        __tlb_remove_tlb_entry(tlb, ptep, address); \
    } while (0)

#define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)

#define pud_free_tlb(tlb, pudp, addr) __pud_free_tlb(tlb, pudp, addr)

#define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr)

#define tlb_migrate_finish(mm) do {} while (0)

#endif