1 files changed, 50 insertions, 41 deletions

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index e402aef79c93..1fff717cae51 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -58,6 +58,11 @@
  *    Defaults to flushing at tlb_end_vma() to reset the range; helps when
  *    there's large holes between the VMAs.
  *
+ *  - tlb_free_vmas()
+ *
+ *    tlb_free_vmas() marks the start of unlinking of one or more vmas
+ *    and freeing page-tables.
+ *
  *  - tlb_remove_table()
  *
  *    tlb_remove_table() is the basic primitive to free page-table directories
@@ -67,22 +72,21 @@
  *
  *    See also MMU_GATHER_TABLE_FREE and MMU_GATHER_RCU_TABLE_FREE.
  *
- *  - tlb_remove_page() / __tlb_remove_page()
- *  - tlb_remove_page_size() / __tlb_remove_page_size()
- *  - __tlb_remove_folio_pages()
+ *  - tlb_remove_page() / tlb_remove_page_size()
+ *  - __tlb_remove_folio_pages() / __tlb_remove_page_size()
+ *  - __tlb_remove_folio_pages_size()
  *
- *    __tlb_remove_page_size() is the basic primitive that queues a page for
- *    freeing. __tlb_remove_page() assumes PAGE_SIZE. Both will return a
- *    boolean indicating if the queue is (now) full and a call to
- *    tlb_flush_mmu() is required.
+ *    __tlb_remove_folio_pages_size() is the basic primitive that queues pages
+ *    for freeing. It will return a boolean indicating if the queue is (now)
+ *    full and a call to tlb_flush_mmu() is required.
  *
  *    tlb_remove_page() and tlb_remove_page_size() imply the call to
  *    tlb_flush_mmu() when required and has no return value.
  *
- *    __tlb_remove_folio_pages() is similar to __tlb_remove_page(), however,
- *    instead of removing a single page, remove the given number of consecutive
- *    pages that are all part of the same (large) folio: just like calling
- *    __tlb_remove_page() on each page individually.
+ *    __tlb_remove_folio_pages() is similar to __tlb_remove_page_size(),
+ *    however, instead of removing a single page, assume PAGE_SIZE and remove
+ *    the given number of consecutive pages that are all part of the
+ *    same (large) folio.
  *
  *  - tlb_change_page_size()
  *
@@ -228,10 +232,10 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page);
  */
 static inline void tlb_remove_table(struct mmu_gather *tlb, void *table)
 {
-	struct page *page = (struct page *)table;
+	struct ptdesc *ptdesc = (struct ptdesc *)table;
 
-	pagetable_dtor(page_ptdesc(page));
-	tlb_remove_page(tlb, page);
+	pagetable_dtor(ptdesc);
+	tlb_remove_page(tlb, ptdesc_page(ptdesc));
 }
 #endif /* CONFIG_MMU_GATHER_TABLE_FREE */
 
@@ -465,7 +469,12 @@ tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma)
 	 */
 	tlb->vma_huge = is_vm_hugetlb_page(vma);
 	tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);
-	tlb->vma_pfn  = !!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP));
+
+	/*
+	 * Track if there's at least one VM_PFNMAP/VM_MIXEDMAP vma
+	 * in the tracked range, see tlb_free_vmas().
+	 */
+	tlb->vma_pfn |= !!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP));
 }
 
 static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
@@ -489,32 +498,16 @@ static inline void tlb_remove_page_size(struct mmu_gather *tlb,
 		tlb_flush_mmu(tlb);
 }
 
-static __always_inline bool __tlb_remove_page(struct mmu_gather *tlb,
-		struct page *page, bool delay_rmap)
-{
-	return __tlb_remove_page_size(tlb, page, delay_rmap, PAGE_SIZE);
-}
-
-/* tlb_remove_page
- *	Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
- *	required.
- */
 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
 {
 	return tlb_remove_page_size(tlb, page, PAGE_SIZE);
 }
 
-static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, void *pt)
+static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt)
 {
 	tlb_remove_table(tlb, pt);
 }
 
-/* Like tlb_remove_ptdesc, but for page-like page directories. */
-static inline void tlb_remove_page_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt)
-{
-	tlb_remove_page(tlb, ptdesc_page(pt));
-}
-
 static inline void tlb_change_page_size(struct mmu_gather *tlb,
 						     unsigned int page_size)
 {
@@ -565,22 +558,38 @@ static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *
 
 static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
 {
+	if (tlb->fullmm || IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS))
+		return;
+
+	/*
+	 * Do a TLB flush and reset the range at VMA boundaries; this avoids
+	 * the ranges growing with the unused space between consecutive VMAs,
+	 * but also the mmu_gather::vma_* flags from tlb_start_vma() rely on
+	 * this.
+	 */
+	tlb_flush_mmu_tlbonly(tlb);
+}
+
+static inline void tlb_free_vmas(struct mmu_gather *tlb)
+{
 	if (tlb->fullmm)
 		return;
 
 	/*
 	 * VM_PFNMAP is more fragile because the core mm will not track the
-	 * page mapcount -- there might not be page-frames for these PFNs after
-	 * all. Force flush TLBs for such ranges to avoid munmap() vs
-	 * unmap_mapping_range() races.
+	 * page mapcount -- there might not be page-frames for these PFNs
+	 * after all.
+	 *
+	 * Specifically() there is a race between munmap() and
+	 * unmap_mapping_range(), where munmap() will unlink the VMA, such
+	 * that unmap_mapping_range() will no longer observe the VMA and
+	 * no-op, without observing the TLBI, returning prematurely.
+	 *
+	 * So if we're about to unlink such a VMA, and we have pending
+	 * TLBI for such a vma, flush things now.
 	 */
-	if (tlb->vma_pfn || !IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS)) {
-		/*
-		 * Do a TLB flush and reset the range at VMA boundaries; this avoids
-		 * the ranges growing with the unused space between consecutive VMAs.
-		 */
+	if (tlb->vma_pfn)
 		tlb_flush_mmu_tlbonly(tlb);
-	}
 }
 
 /*