[RFC][PATCH 04/11] asm-generic/tlb: Provide generic VIPT cache flush

[Peter Zijlstra]

The one obvious thing SH and ARM want is a sensible default for
tlb_start_vma(). (also: https://lkml.org/lkml/2004/1/15/6 )

Avoid all VIPT architectures providing their own tlb_start_vma()
implementation and rely on architectures to provide a no-op
flush_cache_range() when it is not relevant.

The below makes tlb_start_vma() default to flush_cache_range(), which
should be right and sufficient. The only exceptions that I found where
(oddly):

  - m68k-mmu
  - sparc64
  - unicore

Those architectures appear to have flush_cache_range(), but their
current tlb_start_vma() does not call it.

Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Nick Piggin <npiggin@xxxxxxxxx>
Cc: David Miller <davem@xxxxxxxxxxxxx>
Cc: Guan Xuetao <gxt@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 arch/arc/include/asm/tlb.h      |    9 ---------
 arch/mips/include/asm/tlb.h     |    9 ---------
 arch/nds32/include/asm/tlb.h    |    6 ------
 arch/nios2/include/asm/tlb.h    |   10 ----------
 arch/parisc/include/asm/tlb.h   |    5 -----
 arch/sparc/include/asm/tlb_32.h |    5 -----
 arch/xtensa/include/asm/tlb.h   |    9 ---------
 include/asm-generic/tlb.h       |   19 +++++++++++--------
 8 files changed, 11 insertions(+), 61 deletions(-)

--- a/arch/arc/include/asm/tlb.h
+++ b/arch/arc/include/asm/tlb.h
@@ -23,15 +23,6 @@ do {						\
  *
  * Note, read http://lkml.org/lkml/2004/1/15/6
  */
-#ifndef CONFIG_ARC_CACHE_VIPT_ALIASING
-#define tlb_start_vma(tlb, vma)
-#else
-#define tlb_start_vma(tlb, vma)						\
-do {									\
-	if (!tlb->fullmm)						\
-		flush_cache_range(vma, vma->vm_start, vma->vm_end);	\
-} while(0)
-#endif
 
 #define tlb_end_vma(tlb, vma)						\
 do {									\
--- a/arch/mips/include/asm/tlb.h
+++ b/arch/mips/include/asm/tlb.h
@@ -5,15 +5,6 @@
 #include <asm/cpu-features.h>
 #include <asm/mipsregs.h>
 
-/*
- * MIPS doesn't need any special per-pte or per-vma handling, except
- * we need to flush cache for area to be unmapped.
- */
-#define tlb_start_vma(tlb, vma)					\
-	do {							\
-		if (!tlb->fullmm)				\
-			flush_cache_range(vma, vma->vm_start, vma->vm_end); \
-	}  while (0)
 #define tlb_end_vma(tlb, vma) do { } while (0)
 #define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
 
--- a/arch/nds32/include/asm/tlb.h
+++ b/arch/nds32/include/asm/tlb.h
@@ -4,12 +4,6 @@
 #ifndef __ASMNDS32_TLB_H
 #define __ASMNDS32_TLB_H
 
-#define tlb_start_vma(tlb,vma)						\
-	do {								\
-		if (!tlb->fullmm)					\
-			flush_cache_range(vma, vma->vm_start, vma->vm_end); \
-	} while (0)
-
 #define tlb_end_vma(tlb,vma)				\
 	do { 						\
 		if(!tlb->fullmm)			\
--- a/arch/nios2/include/asm/tlb.h
+++ b/arch/nios2/include/asm/tlb.h
@@ -15,16 +15,6 @@
 
 extern void set_mmu_pid(unsigned long pid);
 
-/*
- * NiosII doesn't need any special per-pte or per-vma handling, except
- * we need to flush cache for the area to be unmapped.
- */
-#define tlb_start_vma(tlb, vma)					\
-	do {							\
-		if (!tlb->fullmm)				\
-			flush_cache_range(vma, vma->vm_start, vma->vm_end); \
-	}  while (0)
-
 #define tlb_end_vma(tlb, vma)	do { } while (0)
 #define __tlb_remove_tlb_entry(tlb, ptep, address)	do { } while (0)
 
--- a/arch/parisc/include/asm/tlb.h
+++ b/arch/parisc/include/asm/tlb.h
@@ -7,11 +7,6 @@ do {	if ((tlb)->fullmm)		\
 		flush_tlb_mm((tlb)->mm);\
 } while (0)
 
-#define tlb_start_vma(tlb, vma) \
-do {	if (!(tlb)->fullmm)	\
-		flush_cache_range(vma, vma->vm_start, vma->vm_end); \
-} while (0)
-
 #define tlb_end_vma(tlb, vma)	\
 do {	if (!(tlb)->fullmm)	\
 		flush_tlb_range(vma, vma->vm_start, vma->vm_end); \
--- a/arch/sparc/include/asm/tlb_32.h
+++ b/arch/sparc/include/asm/tlb_32.h
@@ -2,11 +2,6 @@
 #ifndef _SPARC_TLB_H
 #define _SPARC_TLB_H
 
-#define tlb_start_vma(tlb, vma) \
-do {								\
-	flush_cache_range(vma, vma->vm_start, vma->vm_end);	\
-} while (0)
-
 #define tlb_end_vma(tlb, vma) \
 do {								\
 	flush_tlb_range(vma, vma->vm_start, vma->vm_end);	\
--- a/arch/xtensa/include/asm/tlb.h
+++ b/arch/xtensa/include/asm/tlb.h
@@ -16,19 +16,10 @@
 
 #if (DCACHE_WAY_SIZE <= PAGE_SIZE)
 
-/* Note, read http://lkml.org/lkml/2004/1/15/6 */
-
-# define tlb_start_vma(tlb,vma)			do { } while (0)
 # define tlb_end_vma(tlb,vma)			do { } while (0)
 
 #else
 
-# define tlb_start_vma(tlb, vma)					      \
-	do {								      \
-		if (!tlb->fullmm)					      \
-			flush_cache_range(vma, vma->vm_start, vma->vm_end);   \
-	} while(0)
-
 # define tlb_end_vma(tlb, vma)						      \
 	do {								      \
 		if (!tlb->fullmm)					      \
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -19,6 +19,7 @@
 #include <linux/swap.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
 
 #ifdef CONFIG_MMU
 
@@ -351,17 +352,19 @@ static inline unsigned long tlb_get_unma
  * the vmas are adjusted to only cover the region to be torn down.
  */
 #ifndef tlb_start_vma
-#define tlb_start_vma(tlb, vma) do { } while (0)
+#define tlb_start_vma(tlb, vma)						\
+do {									\
+	if (!tlb->fullmm)						\
+		flush_cache_range(vma, vma->vm_start, vma->vm_end);	\
+} while (0)
 #endif
 
-#define __tlb_end_vma(tlb, vma)					\
-	do {							\
-		if (!tlb->fullmm)				\
-			tlb_flush_mmu_tlbonly(tlb);		\
-	} while (0)
-
 #ifndef tlb_end_vma
-#define tlb_end_vma	__tlb_end_vma
+#define tlb_end_vma(tlb, vma)						\
+do {									\
+	if (!tlb->fullmm)						\
+		tlb_flush_mmu_tlbonly(tlb);				\
+} while (0)
 #endif
 
 #ifndef __tlb_remove_tlb_entry