linux-kernel - [PATCH v2 01/11] asm-generic/tlb: Fix MMU_GATHER_TABLE

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Date:   Fri, 17 Jul 2020 13:10:06 +0200
From:   Peter Zijlstra <peterz@...radead.org>
To:     Will Deacon <will@...nel.org>,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.ibm.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Nick Piggin <npiggin@...il.com>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     linux-arch@...r.kernel.org, linux-sh@...r.kernel.org,
        linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Rich Felker <dalias@...c.org>,
        "David S. Miller" <davem@...emloft.net>,
        Helge Deller <deller@....de>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Paul Burton <paulburton@...nel.org>,
        Tony Luck <tony.luck@...el.com>,
        Richard Henderson <rth@...ddle.net>,
        Nick Hu <nickhu@...estech.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        John Paul Adrian Glaubitz <glaubitz@...sik.fu-berlin.de>,
        Christoph Hellwig <hch@....de>
Subject: [PATCH v2 01/11] asm-generic/tlb: Fix MMU_GATHER_TABLE_FREE

The first MMU_GATHER_TABLE_FREE user showed a logic error in the
tlb_needs_table_invalidate() definition. Make sure any TABLE_FREE has
it defined.

Fixes: 0d6e24d430ef ("asm-generic/tlb: provide MMU_GATHER_TABLE_FREE")
Signed-off-by: Peter Zijlstra (Intel) <peterz@...radead.org>
---
 include/asm-generic/tlb.h |   35 +++++++++++++++++++----------------
 1 file changed, 19 insertions(+), 16 deletions(-)

--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -172,6 +172,18 @@
  *  various ptep_get_and_clear() functions.
  */
 
+#ifndef CONFIG_MMU_GATHER_RCU_TABLE_FREE
+
+/*
+ * Only RCU table free can override this; otherwise the TLBI is needed to
+ * provide existence guarantees for software walkers.
+ */
+#ifdef tlb_needs_table_invalidate
+#error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE
+#endif
+
+#endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */
+
 #ifdef CONFIG_MMU_GATHER_TABLE_FREE
 
 struct mmu_table_batch {
@@ -187,17 +199,6 @@ struct mmu_table_batch {
 
 extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
 
-#else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */
-
-/*
- * Without MMU_GATHER_TABLE_FREE the architecture is assumed to have page based
- * page directories and we can use the normal page batching to free them.
- */
-#define tlb_remove_table(tlb, page) tlb_remove_page((tlb), (page))
-
-#endif /* CONFIG_MMU_GATHER_TABLE_FREE */
-
-#ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE
 /*
  * This allows an architecture that does not use the linux page-tables for
  * hardware to skip the TLBI when freeing page tables.
@@ -206,13 +207,15 @@ extern void tlb_remove_table(struct mmu_
 #define tlb_needs_table_invalidate() (true)
 #endif
 
-#else
+#else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */
 
-#ifdef tlb_needs_table_invalidate
-#error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE
-#endif
+/*
+ * Without MMU_GATHER_TABLE_FREE the architecture is assumed to have page based
+ * page directories and we can use the normal page batching to free them.
+ */
+#define tlb_remove_table(tlb, page) tlb_remove_page((tlb), (page))
 
-#endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */
+#endif /* CONFIG_MMU_GATHER_TABLE_FREE */
 
 
 #ifndef CONFIG_MMU_GATHER_NO_GATHER