There are two main use cases for mmu notifiers. One is by KVM which uses mmu_notifier_invalidate_range_start()/end() to manage a software TLB.
The other is to manage hardware TLBs which need to use the invalidate_range() callback because HW can establish new TLB entries at any time. Hence using start/end() can lead to memory corruption as these callbacks happen too soon/late during page unmap. mmu notifier users should therefore either use the start()/end() callbacks or the invalidate_range() callbacks. To make this usage clearer rename the invalidate_range() callback to arch_invalidate_secondary_tlbs() and update documention. Signed-off-by: Alistair Popple <apop...@nvidia.com> Suggested-by: Jason Gunthorpe <j...@nvidia.com> Acked-by: Catalin Marinas <catalin.mari...@arm.com> Reviewed-by: Jason Gunthorpe <j...@nvidia.com> --- arch/arm64/include/asm/tlbflush.h | 6 +- arch/powerpc/mm/book3s64/radix_hugetlbpage.c | 2 +- arch/powerpc/mm/book3s64/radix_tlb.c | 8 +-- arch/x86/include/asm/tlbflush.h | 2 +- arch/x86/mm/tlb.c | 2 +- drivers/iommu/amd/iommu_v2.c | 10 ++-- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 13 ++--- drivers/iommu/intel/svm.c | 8 +-- drivers/misc/ocxl/link.c | 8 +-- include/linux/mmu_notifier.h | 48 +++++++++--------- mm/huge_memory.c | 4 +- mm/hugetlb.c | 7 +-- mm/mmu_notifier.c | 21 ++++++-- 13 files changed, 76 insertions(+), 63 deletions(-) diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h index a99349d..84a05a0 100644 --- a/arch/arm64/include/asm/tlbflush.h +++ b/arch/arm64/include/asm/tlbflush.h @@ -253,7 +253,7 @@ static inline void flush_tlb_mm(struct mm_struct *mm) __tlbi(aside1is, asid); __tlbi_user(aside1is, asid); dsb(ish); - mmu_notifier_invalidate_range(mm, 0, -1UL); + mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL); } static inline void __flush_tlb_page_nosync(struct mm_struct *mm, @@ -265,7 +265,7 @@ static inline void __flush_tlb_page_nosync(struct mm_struct *mm, addr = __TLBI_VADDR(uaddr, ASID(mm)); __tlbi(vale1is, addr); __tlbi_user(vale1is, addr); - mmu_notifier_invalidate_range(mm, uaddr & PAGE_MASK, + mmu_notifier_arch_invalidate_secondary_tlbs(mm, uaddr & PAGE_MASK, (uaddr & PAGE_MASK) + PAGE_SIZE); } @@ -400,7 +400,7 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma, scale++; } dsb(ish); - mmu_notifier_invalidate_range(vma->vm_mm, start, end); + mmu_notifier_arch_invalidate_secondary_tlbs(vma->vm_mm, start, end); } static inline void flush_tlb_range(struct vm_area_struct *vma, diff --git a/arch/powerpc/mm/book3s64/radix_hugetlbpage.c b/arch/powerpc/mm/book3s64/radix_hugetlbpage.c index f3fb49f..17075c7 100644 --- a/arch/powerpc/mm/book3s64/radix_hugetlbpage.c +++ b/arch/powerpc/mm/book3s64/radix_hugetlbpage.c @@ -39,7 +39,7 @@ void radix__flush_hugetlb_tlb_range(struct vm_area_struct *vma, unsigned long st radix__flush_tlb_pwc_range_psize(vma->vm_mm, start, end, psize); else radix__flush_tlb_range_psize(vma->vm_mm, start, end, psize); - mmu_notifier_invalidate_range(vma->vm_mm, start, end); + mmu_notifier_arch_invalidate_secondary_tlbs(vma->vm_mm, start, end); } void radix__huge_ptep_modify_prot_commit(struct vm_area_struct *vma, diff --git a/arch/powerpc/mm/book3s64/radix_tlb.c b/arch/powerpc/mm/book3s64/radix_tlb.c index 4d44902..06e647e 100644 --- a/arch/powerpc/mm/book3s64/radix_tlb.c +++ b/arch/powerpc/mm/book3s64/radix_tlb.c @@ -987,7 +987,7 @@ void radix__flush_tlb_mm(struct mm_struct *mm) } } preempt_enable(); - mmu_notifier_invalidate_range(mm, 0, -1UL); + mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL); } EXPORT_SYMBOL(radix__flush_tlb_mm); @@ -1021,7 +1021,7 @@ static void __flush_all_mm(struct mm_struct *mm, bool fullmm) _tlbiel_pid_multicast(mm, pid, RIC_FLUSH_ALL); } preempt_enable(); - mmu_notifier_invalidate_range(mm, 0, -1UL); + mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL); } void radix__flush_all_mm(struct mm_struct *mm) @@ -1230,7 +1230,7 @@ static inline void __radix__flush_tlb_range(struct mm_struct *mm, } out: preempt_enable(); - mmu_notifier_invalidate_range(mm, start, end); + mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end); } void radix__flush_tlb_range(struct vm_area_struct *vma, unsigned long start, @@ -1395,7 +1395,7 @@ static void __radix__flush_tlb_range_psize(struct mm_struct *mm, } out: preempt_enable(); - mmu_notifier_invalidate_range(mm, start, end); + mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end); } void radix__flush_tlb_range_psize(struct mm_struct *mm, unsigned long start, diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h index 0a54323..6ab42ca 100644 --- a/arch/x86/include/asm/tlbflush.h +++ b/arch/x86/include/asm/tlbflush.h @@ -283,7 +283,7 @@ static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *b { inc_mm_tlb_gen(mm); cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm)); - mmu_notifier_invalidate_range(mm, 0, -1UL); + mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL); } static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm) diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c index 93b2f81..2d25391 100644 --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -1037,7 +1037,7 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start, put_flush_tlb_info(); put_cpu(); - mmu_notifier_invalidate_range(mm, start, end); + mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end); } diff --git a/drivers/iommu/amd/iommu_v2.c b/drivers/iommu/amd/iommu_v2.c index 261352a..2596466 100644 --- a/drivers/iommu/amd/iommu_v2.c +++ b/drivers/iommu/amd/iommu_v2.c @@ -355,9 +355,9 @@ static struct pasid_state *mn_to_state(struct mmu_notifier *mn) return container_of(mn, struct pasid_state, mn); } -static void mn_invalidate_range(struct mmu_notifier *mn, - struct mm_struct *mm, - unsigned long start, unsigned long end) +static void mn_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, unsigned long end) { struct pasid_state *pasid_state; struct device_state *dev_state; @@ -391,8 +391,8 @@ static void mn_release(struct mmu_notifier *mn, struct mm_struct *mm) } static const struct mmu_notifier_ops iommu_mn = { - .release = mn_release, - .invalidate_range = mn_invalidate_range, + .release = mn_release, + .arch_invalidate_secondary_tlbs = mn_arch_invalidate_secondary_tlbs, }; static void set_pri_tag_status(struct pasid_state *pasid_state, diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c index 2a19784..dbc812a 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c @@ -186,9 +186,10 @@ static void arm_smmu_free_shared_cd(struct arm_smmu_ctx_desc *cd) } } -static void arm_smmu_mm_invalidate_range(struct mmu_notifier *mn, - struct mm_struct *mm, - unsigned long start, unsigned long end) +static void arm_smmu_mm_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, + unsigned long end) { struct arm_smmu_mmu_notifier *smmu_mn = mn_to_smmu(mn); struct arm_smmu_domain *smmu_domain = smmu_mn->domain; @@ -247,9 +248,9 @@ static void arm_smmu_mmu_notifier_free(struct mmu_notifier *mn) } static const struct mmu_notifier_ops arm_smmu_mmu_notifier_ops = { - .invalidate_range = arm_smmu_mm_invalidate_range, - .release = arm_smmu_mm_release, - .free_notifier = arm_smmu_mmu_notifier_free, + .arch_invalidate_secondary_tlbs = arm_smmu_mm_arch_invalidate_secondary_tlbs, + .release = arm_smmu_mm_release, + .free_notifier = arm_smmu_mmu_notifier_free, }; /* Allocate or get existing MMU notifier for this {domain, mm} pair */ diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c index e95b339..8f6d680 100644 --- a/drivers/iommu/intel/svm.c +++ b/drivers/iommu/intel/svm.c @@ -219,9 +219,9 @@ static void intel_flush_svm_range(struct intel_svm *svm, unsigned long address, } /* Pages have been freed at this point */ -static void intel_invalidate_range(struct mmu_notifier *mn, - struct mm_struct *mm, - unsigned long start, unsigned long end) +static void intel_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, unsigned long end) { struct intel_svm *svm = container_of(mn, struct intel_svm, notifier); @@ -256,7 +256,7 @@ static void intel_mm_release(struct mmu_notifier *mn, struct mm_struct *mm) static const struct mmu_notifier_ops intel_mmuops = { .release = intel_mm_release, - .invalidate_range = intel_invalidate_range, + .arch_invalidate_secondary_tlbs = intel_arch_invalidate_secondary_tlbs, }; static DEFINE_MUTEX(pasid_mutex); diff --git a/drivers/misc/ocxl/link.c b/drivers/misc/ocxl/link.c index 4cf4c55..c06c699 100644 --- a/drivers/misc/ocxl/link.c +++ b/drivers/misc/ocxl/link.c @@ -491,9 +491,9 @@ void ocxl_link_release(struct pci_dev *dev, void *link_handle) } EXPORT_SYMBOL_GPL(ocxl_link_release); -static void invalidate_range(struct mmu_notifier *mn, - struct mm_struct *mm, - unsigned long start, unsigned long end) +static void arch_invalidate_secondary_tlbs(struct mmu_notifier *mn, + struct mm_struct *mm, + unsigned long start, unsigned long end) { struct pe_data *pe_data = container_of(mn, struct pe_data, mmu_notifier); struct ocxl_link *link = pe_data->link; @@ -509,7 +509,7 @@ static void invalidate_range(struct mmu_notifier *mn, } static const struct mmu_notifier_ops ocxl_mmu_notifier_ops = { - .invalidate_range = invalidate_range, + .arch_invalidate_secondary_tlbs = arch_invalidate_secondary_tlbs, }; static u64 calculate_cfg_state(bool kernel) diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h index f2e9edc..6e3c857 100644 --- a/include/linux/mmu_notifier.h +++ b/include/linux/mmu_notifier.h @@ -187,27 +187,27 @@ struct mmu_notifier_ops { const struct mmu_notifier_range *range); /* - * invalidate_range() is either called between - * invalidate_range_start() and invalidate_range_end() when the - * VM has to free pages that where unmapped, but before the - * pages are actually freed, or outside of _start()/_end() when - * a (remote) TLB is necessary. + * arch_invalidate_secondary_tlbs() is used to manage a non-CPU TLB + * which shares page-tables with the CPU. The + * invalidate_range_start()/end() callbacks should not be implemented as + * invalidate_secondary_tlbs() already catches the points in time when + * an external TLB needs to be flushed. * - * If invalidate_range() is used to manage a non-CPU TLB with - * shared page-tables, it not necessary to implement the - * invalidate_range_start()/end() notifiers, as - * invalidate_range() already catches the points in time when an - * external TLB range needs to be flushed. For more in depth - * discussion on this see Documentation/mm/mmu_notifier.rst + * This requires arch_invalidate_secondary_tlbs() to be called while + * holding the ptl spin-lock and therefore this callback is not allowed + * to sleep. * - * Note that this function might be called with just a sub-range - * of what was passed to invalidate_range_start()/end(), if - * called between those functions. + * This is called by architecture code whenever invalidating a TLB + * entry. It is assumed that any secondary TLB has the same rules for + * when invalidations are required. If this is not the case architecture + * code will need to call this explicitly when required for secondary + * TLB invalidation. */ - void (*invalidate_range)(struct mmu_notifier *subscription, - struct mm_struct *mm, - unsigned long start, - unsigned long end); + void (*arch_invalidate_secondary_tlbs)( + struct mmu_notifier *subscription, + struct mm_struct *mm, + unsigned long start, + unsigned long end); /* * These callbacks are used with the get/put interface to manage the @@ -396,8 +396,8 @@ extern void __mmu_notifier_change_pte(struct mm_struct *mm, unsigned long address, pte_t pte); extern int __mmu_notifier_invalidate_range_start(struct mmu_notifier_range *r); extern void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *r); -extern void __mmu_notifier_invalidate_range(struct mm_struct *mm, - unsigned long start, unsigned long end); +extern void __mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm, + unsigned long start, unsigned long end); extern bool mmu_notifier_range_update_to_read_only(const struct mmu_notifier_range *range); @@ -483,11 +483,11 @@ mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range) __mmu_notifier_invalidate_range_end(range); } -static inline void mmu_notifier_invalidate_range(struct mm_struct *mm, - unsigned long start, unsigned long end) +static inline void mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm, + unsigned long start, unsigned long end) { if (mm_has_notifiers(mm)) - __mmu_notifier_invalidate_range(mm, start, end); + __mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end); } static inline void mmu_notifier_subscriptions_init(struct mm_struct *mm) @@ -664,7 +664,7 @@ void mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range) { } -static inline void mmu_notifier_invalidate_range(struct mm_struct *mm, +static inline void mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm, unsigned long start, unsigned long end) { } diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 3ece117..e0420de 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2120,8 +2120,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, if (is_huge_zero_pmd(*pmd)) { /* * FIXME: Do we want to invalidate secondary mmu by calling - * mmu_notifier_invalidate_range() see comments below inside - * __split_huge_pmd() ? + * mmu_notifier_arch_invalidate_secondary_tlbs() see comments below + * inside __split_huge_pmd() ? * * We are going from a zero huge page write protected to zero * small page also write protected so it does not seems useful diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 9c6e431..e0028cb 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6676,8 +6676,9 @@ long hugetlb_change_protection(struct vm_area_struct *vma, else flush_hugetlb_tlb_range(vma, start, end); /* - * No need to call mmu_notifier_invalidate_range() we are downgrading - * page table protection not changing it to point to a new page. + * No need to call mmu_notifier_arch_invalidate_secondary_tlbs() we are + * downgrading page table protection not changing it to point to a new + * page. * * See Documentation/mm/mmu_notifier.rst */ @@ -7321,7 +7322,7 @@ static void hugetlb_unshare_pmds(struct vm_area_struct *vma, i_mmap_unlock_write(vma->vm_file->f_mapping); hugetlb_vma_unlock_write(vma); /* - * No need to call mmu_notifier_invalidate_range(), see + * No need to call mmu_notifier_arch_invalidate_secondary_tlbs(), see * Documentation/mm/mmu_notifier.rst. */ mmu_notifier_invalidate_range_end(&range); diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 453a156..ec3b068 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -585,8 +585,8 @@ void __mmu_notifier_invalidate_range_end(struct mmu_notifier_range *range) lock_map_release(&__mmu_notifier_invalidate_range_start_map); } -void __mmu_notifier_invalidate_range(struct mm_struct *mm, - unsigned long start, unsigned long end) +void __mmu_notifier_arch_invalidate_secondary_tlbs(struct mm_struct *mm, + unsigned long start, unsigned long end) { struct mmu_notifier *subscription; int id; @@ -595,9 +595,10 @@ void __mmu_notifier_invalidate_range(struct mm_struct *mm, hlist_for_each_entry_rcu(subscription, &mm->notifier_subscriptions->list, hlist, srcu_read_lock_held(&srcu)) { - if (subscription->ops->invalidate_range) - subscription->ops->invalidate_range(subscription, mm, - start, end); + if (subscription->ops->arch_invalidate_secondary_tlbs) + subscription->ops->arch_invalidate_secondary_tlbs( + subscription, mm, + start, end); } srcu_read_unlock(&srcu, id); } @@ -616,6 +617,16 @@ int __mmu_notifier_register(struct mmu_notifier *subscription, mmap_assert_write_locked(mm); BUG_ON(atomic_read(&mm->mm_users) <= 0); + /* + * Subsystems should only register for invalidate_secondary_tlbs() or + * invalidate_range_start()/end() callbacks, not both. + */ + if (WARN_ON_ONCE(subscription && + (subscription->ops->arch_invalidate_secondary_tlbs && + (subscription->ops->invalidate_range_start || + subscription->ops->invalidate_range_end)))) + return -EINVAL; + if (!mm->notifier_subscriptions) { /* * kmalloc cannot be called under mm_take_all_locks(), but we -- git-series 0.9.1