#ifndef _S390_TLB_H
#define _S390_TLB_H
/*
* TLB flushing on s390 is complicated. The following requirement
* from the principles of operation is the most arduous:
*
* "A valid table entry must not be changed while it is attached
* to any CPU and may be used for translation by that CPU except to
* (1) invalidate the entry by using INVALIDATE PAGE TABLE ENTRY,
* or INVALIDATE DAT TABLE ENTRY, (2) alter bits 56-63 of a page
* table entry, or (3) make a change by means of a COMPARE AND SWAP
* AND PURGE instruction that purges the TLB."
*
* The modification of a pte of an active mm struct therefore is
* a two step process: i) invalidate the pte, ii) store the new pte.
* This is true for the page protection bit as well.
* The only possible optimization is to flush at the beginning of
* a tlb_gather_mmu cycle if the mm_struct is currently not in use.
*
* Pages used for the page tables is a different story. FIXME: more
*/
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#include <asm/processor.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
struct mmu_gather {
struct mm_struct *mm;
struct mmu_table_batch *batch;
unsigned int fullmm;
};
struct mmu_table_batch {
struct rcu_head rcu;
unsigned int nr;
void *tables[0];
};
#define MAX_TABLE_BATCH \
((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
extern void tlb_table_flush(struct mmu_gather *tlb);
extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
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;
tlb->batch = NULL;
if (tlb->fullmm)
__tlb_flush_mm(mm);
}
static inline void tlb_flush_mmu(struct mmu_gather *tlb)
{
tlb_table_flush(tlb);
}
static inline void tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end)
{
tlb_table_flush(tlb);
}
/*
* Release the page cache reference for a pte removed by
* tlb_ptep_clear_flush. In both flush modes the tlb for a page cache page
* has already been freed, so just do free_page_and_swap_cache.
*/
static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
{
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)
{
free_page_and_swap_cache(page);
}
/*
* pte_free_tlb frees a pte table and clears the CRSTE for the
* page table from the tlb.
*/
static inline void pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
unsigned long address)
{
if (!tlb->fullmm)
return page_table_free_rcu(tlb, (unsigned long *) pte);
page_table_free(tlb->mm, (unsigned long *) pte);
}
/*
* pmd_free_tlb frees a pmd table and clears the CRSTE for the
* segment table entry from the tlb.
* If the mm uses a two level page table the single pmd is freed
* as the pgd. pmd_free_tlb checks the asce_limit against 2GB
* to avoid the double free of the pmd in this case.
*/
static inline void pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd,
unsigned long address)
{
#ifdef CONFIG_64BIT
if (tlb->mm->context.asce_limit <= (1UL << 31))
return;
if (!tlb->fullmm)
return tlb_remove_table(tlb, pmd);
crst_table_free(tlb->mm, (unsigned long *) pmd);
#endif
}
/*
* pud_free_tlb frees a pud table and clears the CRSTE for the
* region third table entry from the tlb.
* If the mm uses a three level page table the single pud is freed
* as the pgd. pud_free_tlb checks the asce_limit against 4TB
* to avoid the double free of the pud in this case.
*/
static inline void pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
unsigned long address)
{
#ifdef CONFIG_64BIT
if (tlb->mm->context.asce_limit <= (1UL << 42))
return;
if (!tlb->fullmm)
return tlb_remove_table(tlb, pud);
crst_table_free(tlb->mm, (unsigned long *) pud);
#endif
}
#define tlb_start_vma(tlb, vma) do { } while (0)
#define tlb_end_vma(tlb, vma) do { } while (0)
#define tlb_remove_tlb_entry(tlb, ptep, addr) do { } while (0)
#define tlb_remove_pmd_tlb_entry(tlb, pmdp, addr) do { } while (0)
#define tlb_migrate_finish(mm) do { } while (0)
#endif /* _S390_TLB_H */
