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author | Steve Capper <steve.capper@linaro.org> | 2014-10-09 15:29:18 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-09 22:26:01 -0400 |
commit | a0ad5496b2b3accf09ab9485ad0170e3b4b1cb27 (patch) | |
tree | abb991c729c6ff57357f5e5d358b9d2967efe42f /arch/arm/include | |
parent | bd951303be5b4df578c7f30ef78839f1a9d6658c (diff) | |
download | op-kernel-dev-a0ad5496b2b3accf09ab9485ad0170e3b4b1cb27.zip op-kernel-dev-a0ad5496b2b3accf09ab9485ad0170e3b4b1cb27.tar.gz |
arm: mm: enable HAVE_RCU_TABLE_FREE logic
In order to implement fast_get_user_pages we need to ensure that the page
table walker is protected from page table pages being freed from under it.
This patch enables HAVE_RCU_TABLE_FREE, any page table pages belonging to
address spaces with multiple users will be call_rcu_sched freed. Meaning
that disabling interrupts will block the free and protect the fast gup
page walker.
Signed-off-by: Steve Capper <steve.capper@linaro.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Dann Frazier <dann.frazier@canonical.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/arm/include')
-rw-r--r-- | arch/arm/include/asm/tlb.h | 38 |
1 files changed, 36 insertions, 2 deletions
diff --git a/arch/arm/include/asm/tlb.h b/arch/arm/include/asm/tlb.h index f1a0dac..3cadb72 100644 --- a/arch/arm/include/asm/tlb.h +++ b/arch/arm/include/asm/tlb.h @@ -35,12 +35,39 @@ #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; @@ -101,6 +128,9 @@ static inline void __tlb_alloc_page(struct mmu_gather *tlb) 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) @@ -129,6 +159,10 @@ tlb_gather_mmu(struct mmu_gather *tlb, struct mm_struct *mm, unsigned long start tlb->pages = tlb->local; tlb->nr = 0; __tlb_alloc_page(tlb); + +#ifdef CONFIG_HAVE_RCU_TABLE_FREE + tlb->batch = NULL; +#endif } static inline void @@ -205,7 +239,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, tlb_add_flush(tlb, addr + SZ_1M); #endif - tlb_remove_page(tlb, pte); + tlb_remove_entry(tlb, pte); } static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, @@ -213,7 +247,7 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, { #ifdef CONFIG_ARM_LPAE tlb_add_flush(tlb, addr); - tlb_remove_page(tlb, virt_to_page(pmdp)); + tlb_remove_entry(tlb, virt_to_page(pmdp)); #endif } |