asm-generic/tlb, arch: Provide CONFIG_HAVE_MMU_GATHER_PAGE_SIZE

Move the mmu_gather::page_size things into the generic code instead of
PowerPC specific bits.

No change in behavior intended.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 19 insertions, 13 deletions

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index f1594ba8b2de..e75620e41ba4 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -61,7 +61,7 @@
  *    tlb_remove_page() and tlb_remove_page_size() imply the call to
  *    tlb_flush_mmu() when required and has no return value.
  *
- *  - tlb_remove_check_page_size_change()
+ *  - tlb_change_page_size()
  *
  *    call before __tlb_remove_page*() to set the current page-size; implies a
  *    possible tlb_flush_mmu() call.
@@ -114,6 +114,11 @@
  *
  * Additionally there are a few opt-in features:
  *
+ *  HAVE_MMU_GATHER_PAGE_SIZE
+ *
+ *  This ensures we call tlb_flush() every time tlb_change_page_size() actually
+ *  changes the size and provides mmu_gather::page_size to tlb_flush().
+ *
  *  HAVE_RCU_TABLE_FREE
  *
  *  This provides tlb_remove_table(), to be used instead of tlb_remove_page()
@@ -239,11 +244,15 @@ struct mmu_gather {
         unsigned int            cleared_puds : 1;
         unsigned int            cleared_p4ds : 1;
 
+        unsigned int            batch_count;
+
         struct mmu_gather_batch *active;
         struct mmu_gather_batch local;
         struct page             *__pages[MMU_GATHER_BUNDLE];
-        unsigned int            batch_count;
-        int page_size;
+
+#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
+        unsigned int page_size;
+#endif
 };
 
 void arch_tlb_gather_mmu(struct mmu_gather *tlb,
@@ -309,21 +318,18 @@ static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
         return tlb_remove_page_size(tlb, page, PAGE_SIZE);
 }
 
-#ifndef tlb_remove_check_page_size_change
-#define tlb_remove_check_page_size_change tlb_remove_check_page_size_change
-static inline void tlb_remove_check_page_size_change(struct mmu_gather *tlb,
+static inline void tlb_change_page_size(struct mmu_gather *tlb,
                                                      unsigned int page_size)
 {
-        /*
-         * We don't care about page size change, just update
-         * mmu_gather page size here so that debug checks
-         * doesn't throw false warning.
-         */
-#ifdef CONFIG_DEBUG_VM
+#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
+        if (tlb->page_size && tlb->page_size != page_size) {
+                if (!tlb->fullmm)
+                        tlb_flush_mmu(tlb);
+        }
+
         tlb->page_size = page_size;
 #endif
 }
-#endif
 
 static inline unsigned long tlb_get_unmap_shift(struct mmu_gather *tlb)
 {