[PATCH 1/2] mips/mm: Guard SOFT_DIRTY bit with config option

[Jiaxun Yang]

After guarding SOFT_DIRTY with config option, it won't occupy
precious page table bit on systems that didn't enable SOFT_DIRTY.

It can prevent page btis overflow on MIPS32R2 systems with RIXI
enabled.

Signed-off-by: Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
Reported-by: Thomas Bogendoerfer <tsbogend@xxxxxxxxxxxxxxxx>
---
 arch/mips/include/asm/pgtable-bits.h | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/mips/include/asm/pgtable-bits.h b/arch/mips/include/asm/pgtable-bits.h
index d43fb6f8af14..e26dc41a8a68 100644
--- a/arch/mips/include/asm/pgtable-bits.h
+++ b/arch/mips/include/asm/pgtable-bits.h
@@ -55,7 +55,9 @@ enum pgtable_bits {
 #if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
 	_PAGE_SPECIAL_SHIFT,
 #endif
+#if defined(CONFIG_HAVE_ARCH_SOFT_DIRTY)
 	_PAGE_SOFT_DIRTY_SHIFT,
+#endif
 };
 
 /*
@@ -85,7 +87,9 @@ enum pgtable_bits {
 #if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
 	_PAGE_SPECIAL_SHIFT,
 #endif
+#if defined(CONFIG_HAVE_ARCH_SOFT_DIRTY)
 	_PAGE_SOFT_DIRTY_SHIFT,
+#endif
 };
 
 #elif defined(CONFIG_CPU_R3K_TLB)
@@ -101,7 +105,9 @@ enum pgtable_bits {
 #if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
 	_PAGE_SPECIAL_SHIFT,
 #endif
+#if defined(CONFIG_HAVE_ARCH_SOFT_DIRTY)
 	_PAGE_SOFT_DIRTY_SHIFT,
+#endif
 
 	/* Used by TLB hardware (placed in EntryLo) */
 	_PAGE_GLOBAL_SHIFT = 8,
@@ -128,7 +134,9 @@ enum pgtable_bits {
 #if defined(CONFIG_ARCH_HAS_PTE_SPECIAL)
 	_PAGE_SPECIAL_SHIFT,
 #endif
+#if defined(CONFIG_HAVE_ARCH_SOFT_DIRTY)
 	_PAGE_SOFT_DIRTY_SHIFT,
+#endif
 	/* Used by TLB hardware (placed in EntryLo*) */
 #if defined(CONFIG_CPU_HAS_RIXI)
 	_PAGE_NO_EXEC_SHIFT,
@@ -155,7 +163,11 @@ enum pgtable_bits {
 #else
 # define _PAGE_SPECIAL		0
 #endif
-#define _PAGE_SOFT_DIRTY	(1 << _PAGE_SOFT_DIRTY_SHIFT)
+#if defined(CONFIG_HAVE_ARCH_SOFT_DIRTY)
+# define _PAGE_SOFT_DIRTY	(1 << _PAGE_SOFT_DIRTY_SHIFT)
+#else
+# define _PAGE_SOFT_DIRTY	0
+#endif
 
 /* Used by TLB hardware (placed in EntryLo*) */
 #if defined(CONFIG_XPA)
-- 
2.26.0.rc2