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arm64: mm: enable HAVE_RCU_TABLE_FREE logic

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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 <[email protected]>
Tested-by: Dann Frazier <[email protected]>
Acked-by: Catalin Marinas <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Russell King <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Christoffer Dall <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
Steve Capper authored and Linus Torvalds committed 2014-10-09 22:26:01 -04:00
1 parent b8cd51afe0
commit 5e5f6dc105
2 files changed
+18 -3
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arch/arm64/Kconfig
+1
View File
@@ -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
arch/arm64/include/asm/tlb.h
+17 -3
View File
@@ -23,6 +23,20 @@
#include <asm-generic/tlb.h>
#include <linux/pagemap.h>
#include <linux/swap.h>
#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