Jetpack/kernel/kernel-4.9/arch/sh/include/asm/tlb.h

#ifndef __ASM_SH_TLB_H
#define __ASM_SH_TLB_H

#ifdef CONFIG_SUPERH64
# include <asm/tlb_64.h>
#endif

#ifndef __ASSEMBLY__
#include <linux/pagemap.h>

#ifdef CONFIG_MMU
#include <linux/swap.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>

/*
 * TLB handling.  This allows us to remove pages from the page
 * tables, and efficiently handle the TLB issues.
 */
struct mmu_gather {
	struct mm_struct	*mm;
	unsigned int		fullmm;
	unsigned long		start, end;
};

static inline void init_tlb_gather(struct mmu_gather *tlb)
{
	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 long start, unsigned long end)
{
	tlb->mm = mm;
	tlb->start = start;
	tlb->end = end;
	tlb->fullmm = !(start | (end+1));

	init_tlb_gather(tlb);
}

static inline void
tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
{
	if (tlb->fullmm)
		flush_tlb_mm(tlb->mm);

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

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;
}

/*
 * In the case of tlb vma handling, we can optimise these away in the
 * case where we're doing a full MM flush.  When we're doing a munmap,
 * the vmas are adjusted to only cover the region to be torn down.
 */
static inline void
tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
{
	if (!tlb->fullmm)
		flush_cache_range(vma, vma->vm_start, vma->vm_end);
}

static inline void
tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
{
	if (!tlb->fullmm && tlb->end) {
		flush_tlb_range(vma, tlb->start, tlb->end);
		init_tlb_gather(tlb);
	}
}

static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
{
}

static inline void tlb_flush_mmu_free(struct mmu_gather *tlb)
{
}

static inline void tlb_flush_mmu(struct mmu_gather *tlb)
{
}

static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
	free_page_and_swap_cache(page);
	return false; /* avoid calling tlb_flush_mmu */
}

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

static inline bool __tlb_remove_page_size(struct mmu_gather *tlb,
					  struct page *page, int page_size)
{
	return __tlb_remove_page(tlb, page);
}

static inline bool __tlb_remove_pte_page(struct mmu_gather *tlb,
					 struct page *page)
{
	return __tlb_remove_page(tlb, page);
}

static inline void tlb_remove_page_size(struct mmu_gather *tlb,
					struct page *page, int page_size)
{
	return tlb_remove_page(tlb, page);
}

#define pte_free_tlb(tlb, ptep, addr)	pte_free((tlb)->mm, ptep)
#define pmd_free_tlb(tlb, pmdp, addr)	pmd_free((tlb)->mm, pmdp)
#define pud_free_tlb(tlb, pudp, addr)	pud_free((tlb)->mm, pudp)

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

#if defined(CONFIG_CPU_SH4) || defined(CONFIG_SUPERH64)
extern void tlb_wire_entry(struct vm_area_struct *, unsigned long, pte_t);
extern void tlb_unwire_entry(void);
#else
static inline void tlb_wire_entry(struct vm_area_struct *vma ,
				  unsigned long addr, pte_t pte)
{
	BUG();
}

static inline void tlb_unwire_entry(void)
{
	BUG();
}
#endif

#else /* CONFIG_MMU */

#define tlb_start_vma(tlb, vma)				do { } while (0)
#define tlb_end_vma(tlb, vma)				do { } while (0)
#define __tlb_remove_tlb_entry(tlb, pte, address)	do { } while (0)
#define tlb_flush(tlb)					do { } while (0)

#include <asm-generic/tlb.h>

#endif /* CONFIG_MMU */
#endif /* __ASSEMBLY__ */
#endif /* __ASM_SH_TLB_H */