mm/vma: introduce [vma_flags,legacy]_to_[legacy,vma_flags]() helpers

While we are still converting VMA flags from vma_flags_t to vm_flags_t,
introduce helpers to convert between the two to allow for iterative
development without having to 'change the world' in a single commit'.

Also update VMA flags tests to reflect the change.

Finally, refresh vma_flags_overwrite_word(),
vma_flag_overwrite_word_once(), vma_flags_set_word() and
vma_flags_clear_word() in the VMA tests to reflect current kernel
implementations - this should make no functional difference, but keeps the
logic consistent between the two.

Link: https://lkml.kernel.org/r/d3569470dbb3ae79134ca7c3eb3fc4df7086e874.1774034900.git.ljs@kernel.org
Signed-off-by: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: "Borislav Petkov (AMD)" <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Ondrej Mosnacek <omosnace@redhat.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: xu xin <xu.xin16@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 32 insertions, 4 deletions

diff --git a/tools/testing/vma/include/dup.h b/tools/testing/vma/include/dup.h
index 65f630923461..f49af21319ba 100644
--- a/tools/testing/vma/include/dup.h
+++ b/tools/testing/vma/include/dup.h
@@ -766,7 +766,9 @@ static inline bool mm_flags_test(int flag, const struct mm_struct *mm)
  */
 static inline void vma_flags_overwrite_word(vma_flags_t *flags, unsigned long value)
 {
-	*ACCESS_PRIVATE(flags, __vma_flags) = value;
+	unsigned long *bitmap = flags->__vma_flags;
+
+	bitmap[0] = value;
 }
 
 /*
@@ -777,7 +779,7 @@ static inline void vma_flags_overwrite_word(vma_flags_t *flags, unsigned long va
  */
 static inline void vma_flags_overwrite_word_once(vma_flags_t *flags, unsigned long value)
 {
-	unsigned long *bitmap = ACCESS_PRIVATE(flags, __vma_flags);
+	unsigned long *bitmap = flags->__vma_flags;
 
 	WRITE_ONCE(*bitmap, value);
 }
@@ -785,7 +787,7 @@ static inline void vma_flags_overwrite_word_once(vma_flags_t *flags, unsigned lo
 /* Update the first system word of VMA flags setting bits, non-atomically. */
 static inline void vma_flags_set_word(vma_flags_t *flags, unsigned long value)
 {
-	unsigned long *bitmap = ACCESS_PRIVATE(flags, __vma_flags);
+	unsigned long *bitmap = flags->__vma_flags;
 
 	*bitmap |= value;
 }
@@ -793,7 +795,7 @@ static inline void vma_flags_set_word(vma_flags_t *flags, unsigned long value)
 /* Update the first system word of VMA flags clearing bits, non-atomically. */
 static inline void vma_flags_clear_word(vma_flags_t *flags, unsigned long value)
 {
-	unsigned long *bitmap = ACCESS_PRIVATE(flags, __vma_flags);
+	unsigned long *bitmap = flags->__vma_flags;
 
 	*bitmap &= ~value;
 }
@@ -803,6 +805,32 @@ static __always_inline void vma_flags_clear_all(vma_flags_t *flags)
 	bitmap_zero(ACCESS_PRIVATE(flags, __vma_flags), NUM_VMA_FLAG_BITS);
 }
 
+/*
+ * Helper function which converts a vma_flags_t value to a legacy vm_flags_t
+ * value. This is only valid if the input flags value can be expressed in a
+ * system word.
+ *
+ * Will be removed once the conversion to VMA flags is complete.
+ */
+static __always_inline vm_flags_t vma_flags_to_legacy(vma_flags_t flags)
+{
+	return (vm_flags_t)flags.__vma_flags[0];
+}
+
+/*
+ * Helper function which converts a legacy vm_flags_t value to a vma_flags_t
+ * value.
+ *
+ * Will be removed once the conversion to VMA flags is complete.
+ */
+static __always_inline vma_flags_t legacy_to_vma_flags(vm_flags_t flags)
+{
+	vma_flags_t ret = EMPTY_VMA_FLAGS;
+
+	vma_flags_overwrite_word(&ret, flags);
+	return ret;
+}
+
 static __always_inline void vma_flags_set_flag(vma_flags_t *flags,
 		vma_flag_t bit)
 {