#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/swap.h>
#include <asm/processor.h>
#include <asm/pgalloc.h>
#include <asm/smp.h>
#include <asm/tlbflush.h>
#ifndef CONFIG_SMP
#define TLB_NR_PTRS 1
#else
#define TLB_NR_PTRS 508
#endif
struct mmu_gather {
struct mm_struct *mm;
unsigned int fullmm;
unsigned int nr_ptes;
unsigned int nr_pxds;
void *array[TLB_NR_PTRS];
};
DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
static inline struct mmu_gather *tlb_gather_mmu(struct mm_struct *mm,
unsigned int full_mm_flush)
{
struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
tlb->mm = mm;
tlb->fullmm = full_mm_flush || (num_online_cpus() == 1) ||
(atomic_read(&mm->mm_users) <= 1 && mm == current->active_mm);
tlb->nr_ptes = 0;
tlb->nr_pxds = TLB_NR_PTRS;
if (tlb->fullmm)
__tlb_flush_mm(mm);
return tlb;
}
static inline void tlb_flush_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end)
{
if (!tlb->fullmm && (tlb->nr_ptes > 0 || tlb->nr_pxds < TLB_NR_PTRS))
__tlb_flush_mm(tlb->mm);
while (tlb->nr_ptes > 0)
pte_free(tlb->mm, tlb->array[--tlb->nr_ptes]);
while (tlb->nr_pxds < TLB_NR_PTRS)
/* pgd_free frees the pointer as region or segment table */
pgd_free(tlb->mm, tlb->array[tlb->nr_pxds++]);
}
static inline void tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end)
{
tlb_flush_mmu(tlb, start, end);
/* keep the page table cache within bounds */
check_pgt_cache();
put_cpu_var(mmu_gathers);
}
/*
* Release the page cache reference for a pte removed by
* tlb_ptep_clear_flush. In both flush modes the tlb fo a page cache page
* has already been freed, so just do free_page_and_swap_cache.
*/
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)
{
if (!tlb->fullmm) {
tlb->array[tlb->nr_ptes++] = pte;
if (tlb->nr_ptes >= tlb->nr_pxds)
tlb_flush_mmu(tlb, 0, 0);
} else
pte_free(tlb->mm, 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)
{
#ifdef __s390x__
if (tlb->mm->context.asce_limit <= (1UL << 31))
return;
if (!tlb->fullmm) {
tlb->array[--tlb->nr_pxds] = pmd;
if (tlb->nr_ptes >= tlb->nr_pxds)
tlb_flush_mmu(tlb, 0, 0);
} else
pmd_free(tlb->mm, 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)
{
#ifdef __s390x__
if (tlb->mm->context.asce_limit <= (1UL << 42))
return;
if (!tlb->fullmm) {
tlb->array[--tlb->nr_pxds] = pud;
if (tlb->nr_ptes >= tlb->nr_pxds)
tlb_flush_mmu(tlb, 0, 0);
} else
pud_free(tlb->mm, 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_migrate_finish(mm) do { } while (0)
#endif /* _S390_TLB_H */
