[S390] move include/asm-s390 to arch/s390/include/asm

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 156 insertions, 0 deletions

diff --git a/arch/s390/include/asm/tlb.h b/arch/s390/include/asm/tlb.h
new file mode 100644
index 000000000000..3d8a96d39d9d
--- /dev/null
+++ b/arch/s390/include/asm/tlb.h
@@ -0,0 +1,156 @@
+#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 */