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authorPeter Zijlstra <peterz@infradead.org>2020-02-03 17:36:49 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-02-04 03:05:26 +0000
commit0ed1325967ab5f7a4549a2641c6ebe115f76e228 (patch)
treed8374c4245c4aa0faff50b5e9fae4ec55bcfce13 /arch/sparc
parent12e4d53f3f04e81f9e83d6fc10edc7314ab9f6b9 (diff)
downloadlinux-0ed1325967ab5f7a4549a2641c6ebe115f76e228.tar.gz
mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush
Architectures for which we have hardware walkers of Linux page table
should flush TLB on mmu gather batch allocation failures and batch flush.
Some architectures like POWER supports multiple translation modes (hash
and radix) and in the case of POWER only radix translation mode needs the
above TLBI.  This is because for hash translation mode kernel wants to
avoid this extra flush since there are no hardware walkers of linux page
table.  With radix translation, the hardware also walks linux page table
and with that, kernel needs to make sure to TLB invalidate page walk cache
before page table pages are freed.

More details in commit d86564a2f085 ("mm/tlb, x86/mm: Support invalidating
TLB caches for RCU_TABLE_FREE")

The changes to sparc are to make sure we keep the old behavior since we
are now removing HAVE_RCU_TABLE_NO_INVALIDATE.  The default value for
tlb_needs_table_invalidate is to always force an invalidate and sparc can
avoid the table invalidate.  Hence we define tlb_needs_table_invalidate to
false for sparc architecture.

Link: http://lkml.kernel.org/r/20200116064531.483522-3-aneesh.kumar@linux.ibm.com
Fixes: a46cc7a90fd8 ("powerpc/mm/radix: Improve TLB/PWC flushes")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>	[powerpc]
Cc: <stable@vger.kernel.org>	[4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/sparc')
-rw-r--r--arch/sparc/Kconfig1
-rw-r--r--arch/sparc/include/asm/tlb_64.h9
2 files changed, 9 insertions, 1 deletions
diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
index e8c3ea01c12f..7b9b3a954a76 100644
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -65,7 +65,6 @@ config SPARC64
 	select HAVE_KRETPROBES
 	select HAVE_KPROBES
 	select HAVE_RCU_TABLE_FREE if SMP
-	select HAVE_RCU_TABLE_NO_INVALIDATE if HAVE_RCU_TABLE_FREE
 	select HAVE_MEMBLOCK_NODE_MAP
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_DYNAMIC_FTRACE
diff --git a/arch/sparc/include/asm/tlb_64.h b/arch/sparc/include/asm/tlb_64.h
index a2f3fa61ee36..8cb8f3833239 100644
--- a/arch/sparc/include/asm/tlb_64.h
+++ b/arch/sparc/include/asm/tlb_64.h
@@ -28,6 +28,15 @@ void flush_tlb_pending(void);
 #define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
 #define tlb_flush(tlb)	flush_tlb_pending()
 
+/*
+ * SPARC64's hardware TLB fill does not use the Linux page-tables
+ * and therefore we don't need a TLBI when freeing page-table pages.
+ */
+
+#ifdef CONFIG_HAVE_RCU_TABLE_FREE
+#define tlb_needs_table_invalidate()	(false)
+#endif
+
 #include <asm-generic/tlb.h>
 
 #endif /* _SPARC64_TLB_H */