mm: declare VMA flags by bit

Patch series "initial work on making VMA flags a bitmap", v3.

We are in the rather silly situation that we are running out of VMA flags
as they are currently limited to a system word in size.

This leads to absurd situations where we limit features to 64-bit
architectures only because we simply do not have the ability to add a flag
for 32-bit ones.

This is very constraining and leads to hacks or, in the worst case, simply
an inability to implement features we want for entirely arbitrary reasons.

This also of course gives us something of a Y2K type situation in mm where
we might eventually exhaust all of the VMA flags even on 64-bit systems.

This series lays the groundwork for getting away from this limitation by
establishing VMA flags as a bitmap whose size we can increase in future
beyond 64 bits if required.

This is necessarily a highly iterative process given the extensive use of
VMA flags throughout the kernel, so we start by performing basic steps.

Firstly, we declare VMA flags by bit number rather than by value,
retaining the VM_xxx fields but in terms of these newly introduced
VMA_xxx_BIT fields.

While we are here, we use sparse annotations to ensure that, when dealing
with VMA bit number parameters, we cannot be passed values which are not
declared as such - providing some useful type safety.

We then introduce an opaque VMA flag type, much like the opaque mm_struct
flag type introduced in commit bb6525f2f8c4 ("mm: add bitmap mm->flags
field"), which we establish in union with vma->vm_flags (but still set at
system word size meaning there is no functional or data type size change).

We update the vm_flags_xxx() helpers to use this new bitmap, introducing
sensible helpers to do so.

This series lays the foundation for further work to expand the use of
bitmap VMA flags and eventually eliminate these arbitrary restrictions.


This patch (of 4):

In order to lay the groundwork for VMA flags being a bitmap rather than a
system word in size, we need to be able to consistently refer to VMA flags
by bit number rather than value.

Take this opportunity to do so in an enum which we which is additionally
useful for tooling to extract metadata from.

This additionally makes it very clear which bits are being used for what
at a glance.

We use the VMA_ prefix for the bit values as it is logical to do so since
these reference VMAs.  We consistently suffix with _BIT to make it clear
what the values refer to.

We declare bit values even when the flags that use them would not be
enabled by config options as this is simply clearer and clearly defines
what bit numbers are used for what, at no additional cost.

We declare a sparse-bitwise type vma_flag_t which ensures that users can't
pass around invalid VMA flags by accident and prepares for future work
towards VMA flags being a bitmap where we want to ensure bit values are
type safe.

To make life easier, we declare some macro helpers - DECLARE_VMA_BIT()
allows us to avoid duplication in the enum bit number declarations (and
maintaining the sparse __bitwise attribute), and INIT_VM_FLAG() is used to
assist with declaration of flags.

Unfortunately we can't declare both in the enum, as we run into issue with
logic in the kernel requiring that flags are preprocessor definitions, and
additionally we cannot have a macro which declares another macro so we
must define each flag macro directly.

Additionally, update the VMA userland testing vma_internal.h header to
include these changes.

We also have to fix the parameters to the vma_flag_*_atomic() functions
since VMA_MAYBE_GUARD_BIT is now of type vma_flag_t and sparse will
complain otherwise.

We have to update some rather silly if-deffery found in mm/task_mmu.c
which would otherwise break.

Finally, we update the rust binding helper as now it cannot auto-detect
the flags at all.

Link: https://lkml.kernel.org/r/cover.1764064556.git.lorenzo.stoakes@oracle.com
Link: https://lkml.kernel.org/r/3a35e5a0bcfa00e84af24cbafc0653e74deda64a.1764064556.git.lorenzo.stoakes@oracle.com
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Pedro Falcato <pfalcato@suse.de>
Acked-by: Alice Ryhl <aliceryhl@google.com>	[rust]
Cc: Alex Gaynor <alex.gaynor@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andreas Hindborg <a.hindborg@kernel.org>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Ben Segall <bsegall@google.com>
Cc: Björn Roy Baron <bjorn3_gh@protonmail.com>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul@sk.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Cc: Chris Li <chrisl@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Gary Guo <gary@garyguo.net>
Cc: Gregory Price <gourry@gourry.net>
Cc: "Huang, Ying" <ying.huang@linux.alibaba.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joshua Hahn <joshua.hahnjy@gmail.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Kairui Song <kasong@tencent.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Lance Yang <lance.yang@linux.dev>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mathew Brost <matthew.brost@intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Rakie Kim <rakie.kim@sk.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Trevor Gross <tmgross@umich.edu>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Wei Xu <weixugc@google.com>
Cc: xu xin <xu.xin16@zte.com.cn>
Cc: Yuanchu Xie <yuanchu@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 259 insertions, 45 deletions

diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
index 8c2ac301a00e..b7e8fc9ccdf4 100644
--- a/tools/testing/vma/vma_internal.h
+++ b/tools/testing/vma/vma_internal.h
@@ -46,42 +46,271 @@ extern unsigned long dac_mmap_min_addr;
 
 #define MMF_HAS_MDWE	28
 
+/*
+ * vm_flags in vm_area_struct, see mm_types.h.
+ * When changing, update also include/trace/events/mmflags.h
+ */
+
 #define VM_NONE		0x00000000
-#define VM_READ		0x00000001
-#define VM_WRITE	0x00000002
-#define VM_EXEC		0x00000004
-#define VM_SHARED	0x00000008
-#define VM_MAYREAD	0x00000010
-#define VM_MAYWRITE	0x00000020
-#define VM_MAYEXEC	0x00000040
-#define VM_GROWSDOWN	0x00000100
-#define VM_PFNMAP	0x00000400
-#define VM_MAYBE_GUARD	0x00000800
-#define VM_LOCKED	0x00002000
-#define VM_IO           0x00004000
-#define VM_SEQ_READ	0x00008000	/* App will access data sequentially */
-#define VM_RAND_READ	0x00010000	/* App will not benefit from clustered reads */
-#define VM_DONTEXPAND	0x00040000
-#define VM_LOCKONFAULT	0x00080000
-#define VM_ACCOUNT	0x00100000
-#define VM_NORESERVE	0x00200000
-#define VM_MIXEDMAP	0x10000000
-#define VM_STACK	VM_GROWSDOWN
-#define VM_SHADOW_STACK	VM_NONE
-#define VM_SOFTDIRTY	0
-#define VM_ARCH_1	0x01000000	/* Architecture-specific flag */
-#define VM_GROWSUP	VM_NONE
 
-#define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC)
-#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
+/**
+ * typedef vma_flag_t - specifies an individual VMA flag by bit number.
+ *
+ * This value is made type safe by sparse to avoid passing invalid flag values
+ * around.
+ */
+typedef int __bitwise vma_flag_t;
 
+#define DECLARE_VMA_BIT(name, bitnum) \
+	VMA_ ## name ## _BIT = ((__force vma_flag_t)bitnum)
+#define DECLARE_VMA_BIT_ALIAS(name, aliased) \
+	VMA_ ## name ## _BIT = VMA_ ## aliased ## _BIT
+enum {
+	DECLARE_VMA_BIT(READ, 0),
+	DECLARE_VMA_BIT(WRITE, 1),
+	DECLARE_VMA_BIT(EXEC, 2),
+	DECLARE_VMA_BIT(SHARED, 3),
+	/* mprotect() hardcodes VM_MAYREAD >> 4 == VM_READ, and so for r/w/x bits. */
+	DECLARE_VMA_BIT(MAYREAD, 4),	/* limits for mprotect() etc. */
+	DECLARE_VMA_BIT(MAYWRITE, 5),
+	DECLARE_VMA_BIT(MAYEXEC, 6),
+	DECLARE_VMA_BIT(MAYSHARE, 7),
+	DECLARE_VMA_BIT(GROWSDOWN, 8),	/* general info on the segment */
+#ifdef CONFIG_MMU
+	DECLARE_VMA_BIT(UFFD_MISSING, 9),/* missing pages tracking */
+#else
+	/* nommu: R/O MAP_PRIVATE mapping that might overlay a file mapping */
+	DECLARE_VMA_BIT(MAYOVERLAY, 9),
+#endif /* CONFIG_MMU */
+	/* Page-ranges managed without "struct page", just pure PFN */
+	DECLARE_VMA_BIT(PFNMAP, 10),
+	DECLARE_VMA_BIT(MAYBE_GUARD, 11),
+	DECLARE_VMA_BIT(UFFD_WP, 12),	/* wrprotect pages tracking */
+	DECLARE_VMA_BIT(LOCKED, 13),
+	DECLARE_VMA_BIT(IO, 14),	/* Memory mapped I/O or similar */
+	DECLARE_VMA_BIT(SEQ_READ, 15),	/* App will access data sequentially */
+	DECLARE_VMA_BIT(RAND_READ, 16),	/* App will not benefit from clustered reads */
+	DECLARE_VMA_BIT(DONTCOPY, 17),	/* Do not copy this vma on fork */
+	DECLARE_VMA_BIT(DONTEXPAND, 18),/* Cannot expand with mremap() */
+	DECLARE_VMA_BIT(LOCKONFAULT, 19),/* Lock pages covered when faulted in */
+	DECLARE_VMA_BIT(ACCOUNT, 20),	/* Is a VM accounted object */
+	DECLARE_VMA_BIT(NORESERVE, 21),	/* should the VM suppress accounting */
+	DECLARE_VMA_BIT(HUGETLB, 22),	/* Huge TLB Page VM */
+	DECLARE_VMA_BIT(SYNC, 23),	/* Synchronous page faults */
+	DECLARE_VMA_BIT(ARCH_1, 24),	/* Architecture-specific flag */
+	DECLARE_VMA_BIT(WIPEONFORK, 25),/* Wipe VMA contents in child. */
+	DECLARE_VMA_BIT(DONTDUMP, 26),	/* Do not include in the core dump */
+	DECLARE_VMA_BIT(SOFTDIRTY, 27),	/* NOT soft dirty clean area */
+	DECLARE_VMA_BIT(MIXEDMAP, 28),	/* Can contain struct page and pure PFN pages */
+	DECLARE_VMA_BIT(HUGEPAGE, 29),	/* MADV_HUGEPAGE marked this vma */
+	DECLARE_VMA_BIT(NOHUGEPAGE, 30),/* MADV_NOHUGEPAGE marked this vma */
+	DECLARE_VMA_BIT(MERGEABLE, 31),	/* KSM may merge identical pages */
+	/* These bits are reused, we define specific uses below. */
+	DECLARE_VMA_BIT(HIGH_ARCH_0, 32),
+	DECLARE_VMA_BIT(HIGH_ARCH_1, 33),
+	DECLARE_VMA_BIT(HIGH_ARCH_2, 34),
+	DECLARE_VMA_BIT(HIGH_ARCH_3, 35),
+	DECLARE_VMA_BIT(HIGH_ARCH_4, 36),
+	DECLARE_VMA_BIT(HIGH_ARCH_5, 37),
+	DECLARE_VMA_BIT(HIGH_ARCH_6, 38),
+	/*
+	 * This flag is used to connect VFIO to arch specific KVM code. It
+	 * indicates that the memory under this VMA is safe for use with any
+	 * non-cachable memory type inside KVM. Some VFIO devices, on some
+	 * platforms, are thought to be unsafe and can cause machine crashes
+	 * if KVM does not lock down the memory type.
+	 */
+	DECLARE_VMA_BIT(ALLOW_ANY_UNCACHED, 39),
+#ifdef CONFIG_PPC32
+	DECLARE_VMA_BIT_ALIAS(DROPPABLE, ARCH_1),
+#else
+	DECLARE_VMA_BIT(DROPPABLE, 40),
+#endif
+	DECLARE_VMA_BIT(UFFD_MINOR, 41),
+	DECLARE_VMA_BIT(SEALED, 42),
+	/* Flags that reuse flags above. */
+	DECLARE_VMA_BIT_ALIAS(PKEY_BIT0, HIGH_ARCH_0),
+	DECLARE_VMA_BIT_ALIAS(PKEY_BIT1, HIGH_ARCH_1),
+	DECLARE_VMA_BIT_ALIAS(PKEY_BIT2, HIGH_ARCH_2),
+	DECLARE_VMA_BIT_ALIAS(PKEY_BIT3, HIGH_ARCH_3),
+	DECLARE_VMA_BIT_ALIAS(PKEY_BIT4, HIGH_ARCH_4),
+#if defined(CONFIG_X86_USER_SHADOW_STACK)
+	/*
+	 * VM_SHADOW_STACK should not be set with VM_SHARED because of lack of
+	 * support core mm.
+	 *
+	 * These VMAs will get a single end guard page. This helps userspace
+	 * protect itself from attacks. A single page is enough for current
+	 * shadow stack archs (x86). See the comments near alloc_shstk() in
+	 * arch/x86/kernel/shstk.c for more details on the guard size.
+	 */
+	DECLARE_VMA_BIT_ALIAS(SHADOW_STACK, HIGH_ARCH_5),
+#elif defined(CONFIG_ARM64_GCS)
+	/*
+	 * arm64's Guarded Control Stack implements similar functionality and
+	 * has similar constraints to shadow stacks.
+	 */
+	DECLARE_VMA_BIT_ALIAS(SHADOW_STACK, HIGH_ARCH_6),
+#endif
+	DECLARE_VMA_BIT_ALIAS(SAO, ARCH_1),		/* Strong Access Ordering (powerpc) */
+	DECLARE_VMA_BIT_ALIAS(GROWSUP, ARCH_1),		/* parisc */
+	DECLARE_VMA_BIT_ALIAS(SPARC_ADI, ARCH_1),	/* sparc64 */
+	DECLARE_VMA_BIT_ALIAS(ARM64_BTI, ARCH_1),	/* arm64 */
+	DECLARE_VMA_BIT_ALIAS(ARCH_CLEAR, ARCH_1),	/* sparc64, arm64 */
+	DECLARE_VMA_BIT_ALIAS(MAPPED_COPY, ARCH_1),	/* !CONFIG_MMU */
+	DECLARE_VMA_BIT_ALIAS(MTE, HIGH_ARCH_4),	/* arm64 */
+	DECLARE_VMA_BIT_ALIAS(MTE_ALLOWED, HIGH_ARCH_5),/* arm64 */
 #ifdef CONFIG_STACK_GROWSUP
-#define VM_STACK	VM_GROWSUP
-#define VM_STACK_EARLY	VM_GROWSDOWN
+	DECLARE_VMA_BIT_ALIAS(STACK, GROWSUP),
+	DECLARE_VMA_BIT_ALIAS(STACK_EARLY, GROWSDOWN),
 #else
-#define VM_STACK	VM_GROWSDOWN
-#define VM_STACK_EARLY	0
+	DECLARE_VMA_BIT_ALIAS(STACK, GROWSDOWN),
 #endif
+};
+
+#define INIT_VM_FLAG(name) BIT((__force int) VMA_ ## name ## _BIT)
+#define VM_READ		INIT_VM_FLAG(READ)
+#define VM_WRITE	INIT_VM_FLAG(WRITE)
+#define VM_EXEC		INIT_VM_FLAG(EXEC)
+#define VM_SHARED	INIT_VM_FLAG(SHARED)
+#define VM_MAYREAD	INIT_VM_FLAG(MAYREAD)
+#define VM_MAYWRITE	INIT_VM_FLAG(MAYWRITE)
+#define VM_MAYEXEC	INIT_VM_FLAG(MAYEXEC)
+#define VM_MAYSHARE	INIT_VM_FLAG(MAYSHARE)
+#define VM_GROWSDOWN	INIT_VM_FLAG(GROWSDOWN)
+#ifdef CONFIG_MMU
+#define VM_UFFD_MISSING	INIT_VM_FLAG(UFFD_MISSING)
+#else
+#define VM_UFFD_MISSING	VM_NONE
+#define VM_MAYOVERLAY	INIT_VM_FLAG(MAYOVERLAY)
+#endif
+#define VM_PFNMAP	INIT_VM_FLAG(PFNMAP)
+#define VM_MAYBE_GUARD	INIT_VM_FLAG(MAYBE_GUARD)
+#define VM_UFFD_WP	INIT_VM_FLAG(UFFD_WP)
+#define VM_LOCKED	INIT_VM_FLAG(LOCKED)
+#define VM_IO		INIT_VM_FLAG(IO)
+#define VM_SEQ_READ	INIT_VM_FLAG(SEQ_READ)
+#define VM_RAND_READ	INIT_VM_FLAG(RAND_READ)
+#define VM_DONTCOPY	INIT_VM_FLAG(DONTCOPY)
+#define VM_DONTEXPAND	INIT_VM_FLAG(DONTEXPAND)
+#define VM_LOCKONFAULT	INIT_VM_FLAG(LOCKONFAULT)
+#define VM_ACCOUNT	INIT_VM_FLAG(ACCOUNT)
+#define VM_NORESERVE	INIT_VM_FLAG(NORESERVE)
+#define VM_HUGETLB	INIT_VM_FLAG(HUGETLB)
+#define VM_SYNC		INIT_VM_FLAG(SYNC)
+#define VM_ARCH_1	INIT_VM_FLAG(ARCH_1)
+#define VM_WIPEONFORK	INIT_VM_FLAG(WIPEONFORK)
+#define VM_DONTDUMP	INIT_VM_FLAG(DONTDUMP)
+#ifdef CONFIG_MEM_SOFT_DIRTY
+#define VM_SOFTDIRTY	INIT_VM_FLAG(SOFTDIRTY)
+#else
+#define VM_SOFTDIRTY	VM_NONE
+#endif
+#define VM_MIXEDMAP	INIT_VM_FLAG(MIXEDMAP)
+#define VM_HUGEPAGE	INIT_VM_FLAG(HUGEPAGE)
+#define VM_NOHUGEPAGE	INIT_VM_FLAG(NOHUGEPAGE)
+#define VM_MERGEABLE	INIT_VM_FLAG(MERGEABLE)
+#define VM_STACK	INIT_VM_FLAG(STACK)
+#ifdef CONFIG_STACK_GROWS_UP
+#define VM_STACK_EARLY	INIT_VM_FLAG(STACK_EARLY)
+#else
+#define VM_STACK_EARLY	VM_NONE
+#endif
+#ifdef CONFIG_ARCH_HAS_PKEYS
+#define VM_PKEY_SHIFT ((__force int)VMA_HIGH_ARCH_0_BIT)
+/* Despite the naming, these are FLAGS not bits. */
+#define VM_PKEY_BIT0 INIT_VM_FLAG(PKEY_BIT0)
+#define VM_PKEY_BIT1 INIT_VM_FLAG(PKEY_BIT1)
+#define VM_PKEY_BIT2 INIT_VM_FLAG(PKEY_BIT2)
+#if CONFIG_ARCH_PKEY_BITS > 3
+#define VM_PKEY_BIT3 INIT_VM_FLAG(PKEY_BIT3)
+#else
+#define VM_PKEY_BIT3  VM_NONE
+#endif /* CONFIG_ARCH_PKEY_BITS > 3 */
+#if CONFIG_ARCH_PKEY_BITS > 4
+#define VM_PKEY_BIT4 INIT_VM_FLAG(PKEY_BIT4)
+#else
+#define VM_PKEY_BIT4  VM_NONE
+#endif /* CONFIG_ARCH_PKEY_BITS > 4 */
+#endif /* CONFIG_ARCH_HAS_PKEYS */
+#if defined(CONFIG_X86_USER_SHADOW_STACK) || defined(CONFIG_ARM64_GCS)
+#define VM_SHADOW_STACK	INIT_VM_FLAG(SHADOW_STACK)
+#else
+#define VM_SHADOW_STACK	VM_NONE
+#endif
+#if defined(CONFIG_PPC64)
+#define VM_SAO		INIT_VM_FLAG(SAO)
+#elif defined(CONFIG_PARISC)
+#define VM_GROWSUP	INIT_VM_FLAG(GROWSUP)
+#elif defined(CONFIG_SPARC64)
+#define VM_SPARC_ADI	INIT_VM_FLAG(SPARC_ADI)
+#define VM_ARCH_CLEAR	INIT_VM_FLAG(ARCH_CLEAR)
+#elif defined(CONFIG_ARM64)
+#define VM_ARM64_BTI	INIT_VM_FLAG(ARM64_BTI)
+#define VM_ARCH_CLEAR	INIT_VM_FLAG(ARCH_CLEAR)
+#elif !defined(CONFIG_MMU)
+#define VM_MAPPED_COPY	INIT_VM_FLAG(MAPPED_COPY)
+#endif
+#ifndef VM_GROWSUP
+#define VM_GROWSUP	VM_NONE
+#endif
+#ifdef CONFIG_ARM64_MTE
+#define VM_MTE		INIT_VM_FLAG(MTE)
+#define VM_MTE_ALLOWED	INIT_VM_FLAG(MTE_ALLOWED)
+#else
+#define VM_MTE		VM_NONE
+#define VM_MTE_ALLOWED	VM_NONE
+#endif
+#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
+#define VM_UFFD_MINOR	INIT_VM_FLAG(UFFD_MINOR)
+#else
+#define VM_UFFD_MINOR	VM_NONE
+#endif
+#ifdef CONFIG_64BIT
+#define VM_ALLOW_ANY_UNCACHED	INIT_VM_FLAG(ALLOW_ANY_UNCACHED)
+#define VM_SEALED		INIT_VM_FLAG(SEALED)
+#else
+#define VM_ALLOW_ANY_UNCACHED	VM_NONE
+#define VM_SEALED		VM_NONE
+#endif
+#if defined(CONFIG_64BIT) || defined(CONFIG_PPC32)
+#define VM_DROPPABLE		INIT_VM_FLAG(DROPPABLE)
+#else
+#define VM_DROPPABLE		VM_NONE
+#endif
+
+/* Bits set in the VMA until the stack is in its final location */
+#define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEQ_READ | VM_STACK_EARLY)
+
+#define TASK_EXEC ((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0)
+
+/* Common data flag combinations */
+#define VM_DATA_FLAGS_TSK_EXEC	(VM_READ | VM_WRITE | TASK_EXEC | \
+				 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+#define VM_DATA_FLAGS_NON_EXEC	(VM_READ | VM_WRITE | VM_MAYREAD | \
+				 VM_MAYWRITE | VM_MAYEXEC)
+#define VM_DATA_FLAGS_EXEC	(VM_READ | VM_WRITE | VM_EXEC | \
+				 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
+
+#ifndef VM_DATA_DEFAULT_FLAGS		/* arch can override this */
+#define VM_DATA_DEFAULT_FLAGS  VM_DATA_FLAGS_EXEC
+#endif
+
+#ifndef VM_STACK_DEFAULT_FLAGS		/* arch can override this */
+#define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
+#endif
+
+#define VM_STARTGAP_FLAGS (VM_GROWSDOWN | VM_SHADOW_STACK)
+
+#define VM_STACK_FLAGS	(VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
+
+/* VMA basic access permission flags */
+#define VM_ACCESS_FLAGS (VM_READ | VM_WRITE | VM_EXEC)
+
+/*
+ * Special vmas that are non-mergable, non-mlock()able.
+ */
+#define VM_SPECIAL (VM_IO | VM_DONTEXPAND | VM_PFNMAP | VM_MIXEDMAP)
 
 #define DEFAULT_MAP_WINDOW	((1UL << 47) - PAGE_SIZE)
 #define TASK_SIZE_LOW		DEFAULT_MAP_WINDOW
@@ -97,26 +326,11 @@ extern unsigned long dac_mmap_min_addr;
 #define VM_DATA_FLAGS_TSK_EXEC	(VM_READ | VM_WRITE | TASK_EXEC | \
 				 VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
 
-#define VM_DATA_DEFAULT_FLAGS	VM_DATA_FLAGS_TSK_EXEC
-
-#define VM_STARTGAP_FLAGS (VM_GROWSDOWN | VM_SHADOW_STACK)
-
-#define VM_STACK_DEFAULT_FLAGS VM_DATA_DEFAULT_FLAGS
-#define VM_STACK_FLAGS	(VM_STACK | VM_STACK_DEFAULT_FLAGS | VM_ACCOUNT)
-#define VM_STACK_INCOMPLETE_SETUP (VM_RAND_READ | VM_SEQ_READ | VM_STACK_EARLY)
-
 #define RLIMIT_STACK		3	/* max stack size */
 #define RLIMIT_MEMLOCK		8	/* max locked-in-memory address space */
 
 #define CAP_IPC_LOCK         14
 
-#ifdef CONFIG_64BIT
-#define VM_SEALED_BIT	42
-#define VM_SEALED	BIT(VM_SEALED_BIT)
-#else
-#define VM_SEALED	VM_NONE
-#endif
-
 /*
  * Flags which should be 'sticky' on merge - that is, flags which, when one VMA
  * possesses it but the other does not, the merged VMA should nonetheless have