--- /dev/null
+/*
+ * arch/arm/include/asm/tlb.h
+ *
+ * Copyright (C) 2002 Russell King
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Experimentation shows that on a StrongARM, it appears to be faster
+ * to use the "invalidate whole tlb" rather than "invalidate single
+ * tlb" for this.
+ *
+ * This appears true for both the process fork+exit case, as well as
+ * the munmap-large-area case.
+ */
+#ifndef __ASMARM_TLB_H
+#define __ASMARM_TLB_H
+
+#include <asm/cacheflush.h>
+
+#ifndef CONFIG_MMU
+
+#include <linux/pagemap.h>
+
+#define tlb_flush(tlb) ((void) tlb)
+
+#include <asm-generic/tlb.h>
+
+#else /* !CONFIG_MMU */
+
+#include <linux/swap.h>
+#include <asm/pgalloc.h>
+#include <asm/tlbflush.h>
+
+#define MMU_GATHER_BUNDLE 8
+
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+static inline void __tlb_remove_table(void *_table)
+{
+ free_page_and_swap_cache((struct page *)_table);
+}
+
+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);
+
+#define tlb_remove_entry(tlb, entry) tlb_remove_table(tlb, entry)
+#else
+#define tlb_remove_entry(tlb, entry) tlb_remove_page(tlb, entry)
+#endif /* CONFIG_HAVE_RCU_TABLE_FREE */
+
+/*
+ * 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;
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+ struct mmu_table_batch *batch;
+ unsigned int need_flush;
+#endif
+ unsigned int fullmm;
+ struct vm_area_struct *vma;
+ unsigned long start, end;
+ unsigned long range_start;
+ unsigned long range_end;
+ unsigned int nr;
+ unsigned int max;
+ struct page **pages;
+ struct page *local[MMU_GATHER_BUNDLE];
+};
+
+DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
+
+/*
+ * This is unnecessarily complex. There's three ways the TLB shootdown
+ * code is used:
+ * 1. Unmapping a range of vmas. See zap_page_range(), unmap_region().
+ * tlb->fullmm = 0, and tlb_start_vma/tlb_end_vma will be called.
+ * tlb->vma will be non-NULL.
+ * 2. Unmapping all vmas. See exit_mmap().
+ * tlb->fullmm = 1, and tlb_start_vma/tlb_end_vma will be called.
+ * tlb->vma will be non-NULL. Additionally, page tables will be freed.
+ * 3. Unmapping argument pages. See shift_arg_pages().
+ * tlb->fullmm = 0, but tlb_start_vma/tlb_end_vma will not be called.
+ * tlb->vma will be NULL.
+ */
+static inline void tlb_flush(struct mmu_gather *tlb)
+{
+ if (tlb->fullmm || !tlb->vma)
+ flush_tlb_mm(tlb->mm);
+ else if (tlb->range_end > 0) {
+ flush_tlb_range(tlb->vma, tlb->range_start, tlb->range_end);
+ tlb->range_start = TASK_SIZE;
+ tlb->range_end = 0;
+ }
+}
+
+static inline void tlb_add_flush(struct mmu_gather *tlb, unsigned long addr)
+{
+ if (!tlb->fullmm) {
+ if (addr < tlb->range_start)
+ tlb->range_start = addr;
+ if (addr + PAGE_SIZE > tlb->range_end)
+ tlb->range_end = addr + PAGE_SIZE;
+ }
+}
+
+static inline void __tlb_alloc_page(struct mmu_gather *tlb)
+{
+ unsigned long addr = __get_free_pages(GFP_NOWAIT | __GFP_NOWARN, 0);
+
+ if (addr) {
+ tlb->pages = (void *)addr;
+ tlb->max = PAGE_SIZE / sizeof(struct page *);
+ }
+}
+
+static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
+{
+ tlb_flush(tlb);
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+ tlb_table_flush(tlb);
+#endif
+}
+
+static inline void tlb_flush_mmu_free(struct mmu_gather *tlb)
+{
+ free_pages_and_swap_cache(tlb->pages, tlb->nr);
+ tlb->nr = 0;
+ if (tlb->pages == tlb->local)
+ __tlb_alloc_page(tlb);
+}
+
+static inline void tlb_flush_mmu(struct mmu_gather *tlb)
+{
+ tlb_flush_mmu_tlbonly(tlb);
+ tlb_flush_mmu_free(tlb);
+}
+
+static inline void
+tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start, unsigned long end)
+{
+ tlb->mm = mm;
+ tlb->fullmm = !(start | (end+1));
+ tlb->start = start;
+ tlb->end = end;
+ tlb->vma = NULL;
+ tlb->max = ARRAY_SIZE(tlb->local);
+ tlb->pages = tlb->local;
+ tlb->nr = 0;
+ __tlb_alloc_page(tlb);
+
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+ tlb->batch = NULL;
+#endif
+}
+
+static inline void
+tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
+{
+ tlb_flush_mmu(tlb);
+
+ /* keep the page table cache within bounds */
+ check_pgt_cache();
+
+ if (tlb->pages != tlb->local)
+ free_pages((unsigned long)tlb->pages, 0);
+}
+
+/*
+ * Memorize the range for the TLB flush.
+ */
+static inline void
+tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)
+{
+ tlb_add_flush(tlb, addr);
+}
+
+/*
+ * 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);
+ tlb->vma = vma;
+ tlb->range_start = TASK_SIZE;
+ tlb->range_end = 0;
+ }
+}
+
+static inline void
+tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+ if (!tlb->fullmm)
+ tlb_flush(tlb);
+}
+
+static inline int __tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+ tlb->pages[tlb->nr++] = page;
+ VM_BUG_ON(tlb->nr > tlb->max);
+ return tlb->max - tlb->nr;
+}
+
+static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+ if (!__tlb_remove_page(tlb, page))
+ tlb_flush_mmu(tlb);
+}
+
+static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
+ unsigned long addr)
+{
+ pgtable_page_dtor(pte);
+
+#ifdef CONFIG_ARM_LPAE
+ tlb_add_flush(tlb, addr);
+#else
+ /*
+ * With the classic ARM MMU, a pte page has two corresponding pmd
+ * entries, each covering 1MB.
+ */
+ addr &= PMD_MASK;
+ tlb_add_flush(tlb, addr + SZ_1M - PAGE_SIZE);
+ tlb_add_flush(tlb, addr + SZ_1M);
+#endif
+
+ tlb_remove_entry(tlb, pte);
+}
+
+static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp,
+ unsigned long addr)
+{
+#ifdef CONFIG_ARM_LPAE
+ tlb_add_flush(tlb, addr);
+ tlb_remove_entry(tlb, virt_to_page(pmdp));
+#endif
+}
+
+static inline void
+tlb_remove_pmd_tlb_entry(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr)
+{
+ tlb_add_flush(tlb, addr);
+}
+
+#define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr)
+#define pmd_free_tlb(tlb, pmdp, addr) __pmd_free_tlb(tlb, pmdp, addr)
+#define pud_free_tlb(tlb, pudp, addr) pud_free((tlb)->mm, pudp)
+
+#define tlb_migrate_finish(mm) do { } while (0)
+
+#endif /* CONFIG_MMU */
+#endif
Code Review / kvmfornfv.git / blobdiff