From 5e5f6dc10546f5c03bc572e3ba3089af30c66e2d Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Thu, 9 Oct 2014 15:29:23 -0700 Subject: [PATCH] arm64: 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 Tested-by: Dann Frazier Acked-by: Catalin Marinas Cc: Hugh Dickins Cc: Russell King Cc: Mark Rutland Cc: Mel Gorman Cc: Will Deacon Cc: Christoffer Dall Cc: Andrea Arcangeli Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/arm64/Kconfig | 1 + arch/arm64/include/asm/tlb.h | 20 +++++++++++++++++--- 2 files changed, 18 insertions(+), 3 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index e96cbe84d5ae..1ffd9a05206b 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -57,6 +57,7 @@ config ARM64 select HAVE_PERF_EVENTS select HAVE_PERF_REGS select HAVE_PERF_USER_STACK_DUMP + select HAVE_RCU_TABLE_FREE select HAVE_SYSCALL_TRACEPOINTS select IRQ_DOMAIN select MODULES_USE_ELF_RELA diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h index 62731ef9749a..a82c0c5c8b52 100644 --- a/arch/arm64/include/asm/tlb.h +++ b/arch/arm64/include/asm/tlb.h @@ -23,6 +23,20 @@ #include +#include +#include + +#ifdef CONFIG_HAVE_RCU_TABLE_FREE + +#define tlb_remove_entry(tlb, entry) tlb_remove_table(tlb, entry) +static inline void __tlb_remove_table(void *_table) +{ + free_page_and_swap_cache((struct page *)_table); +} +#else +#define tlb_remove_entry(tlb, entry) tlb_remove_page(tlb, entry) +#endif /* CONFIG_HAVE_RCU_TABLE_FREE */ + /* * There's three ways the TLB shootdown code is used: * 1. Unmapping a range of vmas. See zap_page_range(), unmap_region(). @@ -88,7 +102,7 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, { pgtable_page_dtor(pte); tlb_add_flush(tlb, addr); - tlb_remove_page(tlb, pte); + tlb_remove_entry(tlb, pte); } #if CONFIG_ARM64_PGTABLE_LEVELS > 2 @@ -96,7 +110,7 @@ static inline void __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr) { tlb_add_flush(tlb, addr); - tlb_remove_page(tlb, virt_to_page(pmdp)); + tlb_remove_entry(tlb, virt_to_page(pmdp)); } #endif @@ -105,7 +119,7 @@ static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pudp, unsigned long addr) { tlb_add_flush(tlb, addr); - tlb_remove_page(tlb, virt_to_page(pudp)); + tlb_remove_entry(tlb, virt_to_page(pudp)); } #endif -- 2.20.1