diff options
| -rw-r--r-- | arch/arm/include/asm/tlb.h | 102 |
1 files changed, 89 insertions, 13 deletions
diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h index f41a6f57cd12..e7690887b958 100644 --- a/arch/arm/include/asm/tlb.h +++ b/arch/arm/include/asm/tlb.h @@ -18,7 +18,6 @@ #define __ASMARM_TLB_H #include <asm/cacheflush.h> -#include <asm/tlbflush.h> #ifndef CONFIG_MMU @@ -27,7 +26,23 @@ #else /* !CONFIG_MMU */ +#include <linux/swap.h> #include <asm/pgalloc.h> +#include <asm/tlbflush.h> + +/* + * We need to delay page freeing for SMP as other CPUs can access pages + * which have been removed but not yet had their TLB entries invalidated. + * Also, as ARMv7 speculative prefetch can drag new entries into the TLB, + * we need to apply this same delaying tactic to ensure correct operation. + */ +#if defined(CONFIG_SMP) || defined(CONFIG_CPU_32v7) +#define tlb_fast_mode(tlb) 0 +#define FREE_PTE_NR 500 +#else +#define tlb_fast_mode(tlb) 1 +#define FREE_PTE_NR 0 +#endif /* * TLB handling. This allows us to remove pages from the page @@ -36,12 +51,58 @@ struct mmu_gather { struct mm_struct *mm; unsigned int fullmm; + struct vm_area_struct *vma; unsigned long range_start; unsigned long range_end; + unsigned int nr; + struct page *pages[FREE_PTE_NR]; }; 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_flush_mmu(struct mmu_gather *tlb) +{ + tlb_flush(tlb); + if (!tlb_fast_mode(tlb)) { + free_pages_and_swap_cache(tlb->pages, tlb->nr); + tlb->nr = 0; + } +} + static inline struct mmu_gather * tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush) { @@ -49,6 +110,8 @@ tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush) tlb->mm = mm; tlb->fullmm = full_mm_flush; + tlb->vma = NULL; + tlb->nr = 0; return tlb; } @@ -56,8 +119,7 @@ tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush) static inline void tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) { - if (tlb->fullmm) - flush_tlb_mm(tlb->mm); + tlb_flush_mmu(tlb); /* keep the page table cache within bounds */ check_pgt_cache(); @@ -71,12 +133,7 @@ tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end) static inline void tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, 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; - } + tlb_add_flush(tlb, addr); } /* @@ -89,6 +146,7 @@ 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; } @@ -97,12 +155,30 @@ tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { - if (!tlb->fullmm && tlb->range_end > 0) - flush_tlb_range(vma, tlb->range_start, tlb->range_end); + if (!tlb->fullmm) + tlb_flush(tlb); +} + +static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page) +{ + if (tlb_fast_mode(tlb)) { + free_page_and_swap_cache(page); + } else { + tlb->pages[tlb->nr++] = page; + if (tlb->nr >= FREE_PTE_NR) + tlb_flush_mmu(tlb); + } +} + +static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, + unsigned long addr) +{ + pgtable_page_dtor(pte); + tlb_add_flush(tlb, addr); + tlb_remove_page(tlb, pte); } -#define tlb_remove_page(tlb,page) free_page_and_swap_cache(page) -#define pte_free_tlb(tlb, ptep, addr) pte_free((tlb)->mm, ptep) +#define pte_free_tlb(tlb, ptep, addr) __pte_free_tlb(tlb, ptep, addr) #define pmd_free_tlb(tlb, pmdp, addr) pmd_free((tlb)->mm, pmdp) #define tlb_migrate_finish(mm) do { } while (0) |