1 files changed, 160 insertions, 0 deletions

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
new file mode 100644
index 000000000000..faff403e1061
--- /dev/null
+++ b/include/asm-generic/tlb.h
@@ -0,0 +1,160 @@
+/* asm-generic/tlb.h
+ *
+ *      Generic TLB shootdown code
+ *
+ * Copyright 2001 Red Hat, Inc.
+ * Based on code from mm/memory.c Copyright Linus Torvalds and others.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+#ifndef _ASM_GENERIC__TLB_H
+#define _ASM_GENERIC__TLB_H
+
+#include <linux/config.h>
+#include <linux/swap.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+
+/*
+ * For UP we don't need to worry about TLB flush
+ * and page free order so much..
+ */
+#ifdef CONFIG_SMP
+  #define FREE_PTE_NR   506
+  #define tlb_fast_mode(tlb) ((tlb)->nr == ~0U)
+#else
+  #define FREE_PTE_NR   1
+  #define tlb_fast_mode(tlb) 1
+#endif
+
+/* 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.  This structure
+ * can be per-CPU or per-MM as the page table lock is held for the duration of
+ * TLB shootdown.
+ */
+struct mmu_gather {
+        struct mm_struct        *mm;
+        unsigned int            nr;     /* set to ~0U means fast mode */
+        unsigned int            need_flush;/* Really unmapped some ptes? */
+        unsigned int            fullmm; /* non-zero means full mm flush */
+        unsigned long           freed;
+        struct page *           pages[FREE_PTE_NR];
+};
+
+/* Users of the generic TLB shootdown code must declare this storage space. */
+DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+/* tlb_gather_mmu
+ *      Return a pointer to an initialized struct mmu_gather.
+ */
+static inline struct mmu_gather *
+tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
+{
+        struct mmu_gather *tlb = &per_cpu(mmu_gathers, smp_processor_id());
+
+        tlb->mm = mm;
+
+        /* Use fast mode if only one CPU is online */
+        tlb->nr = num_online_cpus() > 1 ? 0U : ~0U;
+
+        tlb->fullmm = full_mm_flush;
+        tlb->freed = 0;
+
+        return tlb;
+}
+
+static inline void
+tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+        if (!tlb->need_flush)
+                return;
+        tlb->need_flush = 0;
+        tlb_flush(tlb);
+        if (!tlb_fast_mode(tlb)) {
+                free_pages_and_swap_cache(tlb->pages, tlb->nr);
+                tlb->nr = 0;
+        }
+}
+
+/* tlb_finish_mmu
+ *      Called at the end of the shootdown operation to free up any resources
+ *      that were required.  The page table lock is still held at this point.
+ */
+static inline void
+tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+        int freed = tlb->freed;
+        struct mm_struct *mm = tlb->mm;
+        int rss = get_mm_counter(mm, rss);
+
+        if (rss < freed)
+                freed = rss;
+        add_mm_counter(mm, rss, -freed);
+        tlb_flush_mmu(tlb, start, end);
+
+        /* keep the page table cache within bounds */
+        check_pgt_cache();
+}
+
+static inline unsigned int
+tlb_is_full_mm(struct mmu_gather *tlb)
+{
+        return tlb->fullmm;
+}
+
+/* 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 void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+        tlb->need_flush = 1;
+        if (tlb_fast_mode(tlb)) {
+                free_page_and_swap_cache(page);
+                return;
+        }
+        tlb->pages[tlb->nr++] = page;
+        if (tlb->nr >= FREE_PTE_NR)
+                tlb_flush_mmu(tlb, 0, 0);
+}
+
+/**
+ * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
+ *
+ * Record the fact that pte's were really umapped in ->need_flush, so we can
+ * later optimise away the tlb invalidate.   This helps when userspace is
+ * unmapping already-unmapped pages, which happens quite a lot.
+ */
+#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)                                 \
+        do {                                                    \
+                tlb->need_flush = 1;                            \
+                __pte_free_tlb(tlb, ptep);                      \
+        } while (0)
+
+#ifndef __ARCH_HAS_4LEVEL_HACK
+#define pud_free_tlb(tlb, pudp)                                 \
+        do {                                                    \
+                tlb->need_flush = 1;                            \
+                __pud_free_tlb(tlb, pudp);                      \
+        } while (0)
+#endif
+
+#define pmd_free_tlb(tlb, pmdp)                                 \
+        do {                                                    \
+                tlb->need_flush = 1;                            \
+                __pmd_free_tlb(tlb, pmdp);                      \
+        } while (0)
+
+#define tlb_migrate_finish(mm) do {} while (0)
+
+#endif /* _ASM_GENERIC__TLB_H */