diff options
| -rw-r--r-- | arch/x86/include/asm/tlbflush.h | 5 | ||||
| -rw-r--r-- | arch/x86/mm/tlb.c | 27 | ||||
| -rw-r--r-- | include/asm-generic/tlb.h | 10 | ||||
| -rw-r--r-- | mm/memory.c | 22 |
4 files changed, 56 insertions, 8 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 6690cd3fc8b1..3aa3204b5dc0 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -554,4 +554,9 @@ extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch); native_flush_tlb_others(mask, info) #endif +extern void tlb_flush_remove_tables(struct mm_struct *mm); +extern void tlb_flush_remove_tables_local(void *arg); + +#define HAVE_TLB_FLUSH_REMOVE_TABLES + #endif /* _ASM_X86_TLBFLUSH_H */ diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 6eb1f34c3c85..9a893673c56b 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -646,6 +646,33 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, put_cpu(); } +void tlb_flush_remove_tables_local(void *arg) +{ + struct mm_struct *mm = arg; + + if (this_cpu_read(cpu_tlbstate.loaded_mm) == mm && + this_cpu_read(cpu_tlbstate.is_lazy)) { + /* + * We're in lazy mode. We need to at least flush our + * paging-structure cache to avoid speculatively reading + * garbage into our TLB. Since switching to init_mm is barely + * slower than a minimal flush, just switch to init_mm. + */ + switch_mm_irqs_off(NULL, &init_mm, NULL); + } +} + +void tlb_flush_remove_tables(struct mm_struct *mm) +{ + int cpu = get_cpu(); + /* + * XXX: this really only needs to be called for CPUs in lazy TLB mode. + */ + if (cpumask_any_but(mm_cpumask(mm), cpu) < nr_cpu_ids) + smp_call_function_many(mm_cpumask(mm), tlb_flush_remove_tables_local, (void *)mm, 1); + + put_cpu(); +} static void do_flush_tlb_all(void *info) { diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h index 3063125197ad..e811ef7b8350 100644 --- a/include/asm-generic/tlb.h +++ b/include/asm-generic/tlb.h @@ -303,4 +303,14 @@ static inline void tlb_remove_check_page_size_change(struct mmu_gather *tlb, #define tlb_migrate_finish(mm) do {} while (0) +/* + * Used to flush the TLB when page tables are removed, when lazy + * TLB mode may cause a CPU to retain intermediate translations + * pointing to about-to-be-freed page table memory. + */ +#ifndef HAVE_TLB_FLUSH_REMOVE_TABLES +#define tlb_flush_remove_tables(mm) do {} while (0) +#define tlb_flush_remove_tables_local(mm) do {} while (0) +#endif + #endif /* _ASM_GENERIC__TLB_H */ diff --git a/mm/memory.c b/mm/memory.c index 7206a634270b..18355e0b971a 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -326,16 +326,20 @@ bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_ #ifdef CONFIG_HAVE_RCU_TABLE_FREE -/* - * See the comment near struct mmu_table_batch. - */ - static void tlb_remove_table_smp_sync(void *arg) { - /* Simply deliver the interrupt */ + struct mm_struct __maybe_unused *mm = arg; + /* + * On most architectures this does nothing. Simply delivering the + * interrupt is enough to prevent races with software page table + * walking like that done in get_user_pages_fast. + * + * See the comment near struct mmu_table_batch. + */ + tlb_flush_remove_tables_local(mm); } -static void tlb_remove_table_one(void *table) +static void tlb_remove_table_one(void *table, struct mmu_gather *tlb) { /* * This isn't an RCU grace period and hence the page-tables cannot be @@ -344,7 +348,7 @@ static void tlb_remove_table_one(void *table) * It is however sufficient for software page-table walkers that rely on * IRQ disabling. See the comment near struct mmu_table_batch. */ - smp_call_function(tlb_remove_table_smp_sync, NULL, 1); + smp_call_function(tlb_remove_table_smp_sync, tlb->mm, 1); __tlb_remove_table(table); } @@ -365,6 +369,8 @@ void tlb_table_flush(struct mmu_gather *tlb) { struct mmu_table_batch **batch = &tlb->batch; + tlb_flush_remove_tables(tlb->mm); + if (*batch) { call_rcu_sched(&(*batch)->rcu, tlb_remove_table_rcu); *batch = NULL; @@ -387,7 +393,7 @@ void tlb_remove_table(struct mmu_gather *tlb, void *table) if (*batch == NULL) { *batch = (struct mmu_table_batch *)__get_free_page(GFP_NOWAIT | __GFP_NOWARN); if (*batch == NULL) { - tlb_remove_table_one(table); + tlb_remove_table_one(table, tlb); return; } (*batch)->nr = 0; |