[PATCH v2 07/17] mm/softdirty: Move VM_SOFTDIRTY into high bits

[Peter Zijlstra]

From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Only 64bit architectures (x86_64, s390, PPC_BOOK3S_64) have support for
HAVE_ARCH_SOFT_DIRTY, so ensure they all select ARCH_USES_HIGH_VMA_FLAGS
and move the VM_SOFTDIRTY flag into the high flags.

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
 arch/powerpc/platforms/Kconfig.cputype |    1 +
 arch/s390/Kconfig                      |    1 +
 include/linux/mm.h                     |   17 +++++++++++------
 3 files changed, 13 insertions(+), 6 deletions(-)

--- a/arch/powerpc/platforms/Kconfig.cputype
+++ b/arch/powerpc/platforms/Kconfig.cputype
@@ -76,6 +76,7 @@ config PPC_BOOK3S_64
 	select ARCH_SUPPORTS_NUMA_BALANCING
 	select IRQ_WORK
 	select HAVE_KERNEL_XZ
+	select ARCH_USES_HIGH_VMA_FLAGS
 
 config PPC_BOOK3E_64
 	bool "Embedded processors"
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -131,6 +131,7 @@ config S390
 	select CPU_NO_EFFICIENT_FFS if !HAVE_MARCH_Z9_109_FEATURES
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_SOFT_DIRTY
+	select ARCH_USES_HIGH_VMA_FLAGS
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_ARCH_TRANSPARENT_HUGEPAGE
 	select HAVE_EBPF_JIT if PACK_STACK && HAVE_MARCH_Z196_FEATURES
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -194,12 +194,6 @@ extern unsigned int kobjsize(const void
 #define VM_WIPEONFORK	0x02000000	/* Wipe VMA contents in child. */
 #define VM_DONTDUMP	0x04000000	/* Do not include in the core dump */
 
-#ifdef CONFIG_MEM_SOFT_DIRTY
-# define VM_SOFTDIRTY	0x08000000	/* Not soft dirty clean area */
-#else
-# define VM_SOFTDIRTY	0
-#endif
-
 #define VM_MIXEDMAP	0x10000000	/* Can contain "struct page" and pure PFN pages */
 #define VM_HUGEPAGE	0x20000000	/* MADV_HUGEPAGE marked this vma */
 #define VM_NOHUGEPAGE	0x40000000	/* MADV_NOHUGEPAGE marked this vma */
@@ -216,8 +210,19 @@ extern unsigned int kobjsize(const void
 #define VM_HIGH_ARCH_2	BIT(VM_HIGH_ARCH_BIT_2)
 #define VM_HIGH_ARCH_3	BIT(VM_HIGH_ARCH_BIT_3)
 #define VM_HIGH_ARCH_4	BIT(VM_HIGH_ARCH_BIT_4)
+
+#define VM_HIGH_SOFTDIRTY_BIT	37	/* bit only usable on 64-bit architectures */
 #endif /* CONFIG_ARCH_USES_HIGH_VMA_FLAGS */
 
+#ifdef CONFIG_MEM_SOFT_DIRTY
+# ifndef CONFIG_ARCH_USES_HIGH_VMA_FLAGS
+#  error MEM_SOFT_DIRTY depends on ARCH_USES_HIGH_VMA_FLAGS
+# endif
+# define VM_SOFTDIRTY		BIT(VM_HIGH_SOFTDIRTY_BIT) /* Not soft dirty clean area */
+#else
+# define VM_SOFTDIRTY		VM_NONE
+#endif
+
 #if defined(CONFIG_X86)
 # define VM_PAT		VM_ARCH_1	/* PAT reserves whole VMA at once (x86) */
 #if defined (CONFIG_X86_INTEL_MEMORY_PROTECTION_KEYS)