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Diffstat (limited to 'include/asm-generic/tlb.h')
| -rw-r--r-- | include/asm-generic/tlb.h | 160 |
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 */ |