Now we have updated all users of mm->flags to use the bitmap accessors,
repalce it with the bitmap version entirely.
We are then able to move to having 64 bits of mm->flags on both 32-bit and
64-bit architectures.
We also update the VMA userland tests to ensure that everything remains
functional there.
No functional changes intended, other than there now being 64 bits of
available mm_struct flags.
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
---
include/linux/mm.h | 12 ++++++------
include/linux/mm_types.h | 14 +++++---------
include/linux/sched/coredump.h | 2 +-
tools/testing/vma/vma_internal.h | 19 +++++++++++++++++--
4 files changed, 29 insertions(+), 18 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 34311ebe62cc..b61e2d4858cf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -724,32 +724,32 @@ static inline void assert_fault_locked(struct vm_fault *vmf)
static inline bool mm_flags_test(int flag, const struct mm_struct *mm)
{
- return test_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
+ return test_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
}
static inline bool mm_flags_test_and_set(int flag, struct mm_struct *mm)
{
- return test_and_set_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
+ return test_and_set_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
}
static inline bool mm_flags_test_and_clear(int flag, struct mm_struct *mm)
{
- return test_and_clear_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
+ return test_and_clear_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
}
static inline void mm_flags_set(int flag, struct mm_struct *mm)
{
- set_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
+ set_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
}
static inline void mm_flags_clear(int flag, struct mm_struct *mm)
{
- clear_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
+ clear_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
}
static inline void mm_flags_clear_all(struct mm_struct *mm)
{
- bitmap_zero(ACCESS_PRIVATE(&mm->_flags, __mm_flags), NUM_MM_FLAG_BITS);
+ bitmap_zero(ACCESS_PRIVATE(&mm->flags, __mm_flags), NUM_MM_FLAG_BITS);
}
extern const struct vm_operations_struct vma_dummy_vm_ops;
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 25577ab39094..47d2e4598acd 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -932,7 +932,7 @@ struct mm_cid {
* Opaque type representing current mm_struct flag state. Must be accessed via
* mm_flags_xxx() helper functions.
*/
-#define NUM_MM_FLAG_BITS BITS_PER_LONG
+#define NUM_MM_FLAG_BITS (64)
typedef struct {
__private DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
} mm_flags_t;
@@ -1119,11 +1119,7 @@ struct mm_struct {
/* Architecture-specific MM context */
mm_context_t context;
- /* Temporary union while we convert users to mm_flags_t. */
- union {
- unsigned long flags; /* Must use atomic bitops to access */
- mm_flags_t _flags; /* Must use mm_flags_* helpers to access */
- };
+ mm_flags_t flags; /* Must use mm_flags_* hlpers to access */
#ifdef CONFIG_AIO
spinlock_t ioctx_lock;
@@ -1236,7 +1232,7 @@ struct mm_struct {
/* Read the first system word of mm flags, non-atomically. */
static inline unsigned long __mm_flags_get_word(struct mm_struct *mm)
{
- unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
+ unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
return bitmap_read(bitmap, 0, BITS_PER_LONG);
}
@@ -1245,7 +1241,7 @@ static inline unsigned long __mm_flags_get_word(struct mm_struct *mm)
static inline void __mm_flags_set_word(struct mm_struct *mm,
unsigned long value)
{
- unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
+ unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
bitmap_copy(bitmap, &value, BITS_PER_LONG);
}
@@ -1253,7 +1249,7 @@ static inline void __mm_flags_set_word(struct mm_struct *mm,
/* Obtain a read-only view of the bitmap. */
static inline const unsigned long *__mm_flags_get_bitmap(const struct mm_struct *mm)
{
- return (const unsigned long *)ACCESS_PRIVATE(&mm->_flags, __mm_flags);
+ return (const unsigned long *)ACCESS_PRIVATE(&mm->flags, __mm_flags);
}
#define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \
diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
index 19ecfcceb27a..079ae5a97480 100644
--- a/include/linux/sched/coredump.h
+++ b/include/linux/sched/coredump.h
@@ -20,7 +20,7 @@ static inline unsigned long __mm_flags_get_dumpable(struct mm_struct *mm)
static inline void __mm_flags_set_mask_dumpable(struct mm_struct *mm, int value)
{
- unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
+ unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
set_mask_bits(bitmap, MMF_DUMPABLE_MASK, value);
}
diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
index cb1c2a8afe26..f13354bf0a1e 100644
--- a/tools/testing/vma/vma_internal.h
+++ b/tools/testing/vma/vma_internal.h
@@ -249,6 +249,14 @@ struct mutex {};
#define DEFINE_MUTEX(mutexname) \
struct mutex mutexname = {}
+#define DECLARE_BITMAP(name, bits) \
+ unsigned long name[BITS_TO_LONGS(bits)]
+
+#define NUM_MM_FLAG_BITS (64)
+typedef struct {
+ __private DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
+} mm_flags_t;
+
struct mm_struct {
struct maple_tree mm_mt;
int map_count; /* number of VMAs */
@@ -260,7 +268,7 @@ struct mm_struct {
unsigned long def_flags;
- unsigned long flags; /* Must use atomic bitops to access */
+ mm_flags_t flags; /* Must use mm_flags_* helpers to access */
};
struct vm_area_struct;
@@ -1333,6 +1341,13 @@ static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
{
}
+# define ACCESS_PRIVATE(p, member) ((p)->member)
+
+static inline bool mm_flags_test(int flag, const struct mm_struct *mm)
+{
+ return test_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
+}
+
/*
* Denies creating a writable executable mapping or gaining executable permissions.
*
@@ -1363,7 +1378,7 @@ static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
static inline bool map_deny_write_exec(unsigned long old, unsigned long new)
{
/* If MDWE is disabled, we have nothing to deny. */
- if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags))
+ if (mm_flags_test(MMF_HAS_MDWE, current->mm))
return false;
/* If the new VMA is not executable, we have nothing to deny. */
--
2.50.1On 12.08.25 17:44, Lorenzo Stoakes wrote: > Now we have updated all users of mm->flags to use the bitmap accessors, > repalce it with the bitmap version entirely. > > We are then able to move to having 64 bits of mm->flags on both 32-bit and > 64-bit architectures. > > We also update the VMA userland tests to ensure that everything remains > functional there. > > No functional changes intended, other than there now being 64 bits of > available mm_struct flags. > > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> > --- > include/linux/mm.h | 12 ++++++------ > include/linux/mm_types.h | 14 +++++--------- > include/linux/sched/coredump.h | 2 +- > tools/testing/vma/vma_internal.h | 19 +++++++++++++++++-- > 4 files changed, 29 insertions(+), 18 deletions(-) The vma test code duplication is still making me sad ... but I'll get over it I'm sure. Acked-by: David Hildenbrand <david@redhat.com> -- Cheers David / dhildenb
On Tue, Aug 26, 2025 at 03:14:46PM +0200, David Hildenbrand wrote: > On 12.08.25 17:44, Lorenzo Stoakes wrote: > > Now we have updated all users of mm->flags to use the bitmap accessors, > > repalce it with the bitmap version entirely. > > > > We are then able to move to having 64 bits of mm->flags on both 32-bit and > > 64-bit architectures. > > > > We also update the VMA userland tests to ensure that everything remains > > functional there. > > > > No functional changes intended, other than there now being 64 bits of > > available mm_struct flags. > > > > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com> > > --- > > include/linux/mm.h | 12 ++++++------ > > include/linux/mm_types.h | 14 +++++--------- > > include/linux/sched/coredump.h | 2 +- > > tools/testing/vma/vma_internal.h | 19 +++++++++++++++++-- > > 4 files changed, 29 insertions(+), 18 deletions(-) > > The vma test code duplication is still making me sad ... but I'll get over > it I'm sure. Yeah ;) I do want to work on seeing if I can do something more about this in future as I intend to do more with those tests but all time-dependent obviously! > > Acked-by: David Hildenbrand <david@redhat.com> Cheers! > > -- > Cheers > > David / dhildenb >
On Tue, Aug 12, 2025 at 04:44:19PM +0100, Lorenzo Stoakes wrote:
> Now we have updated all users of mm->flags to use the bitmap accessors,
> repalce it with the bitmap version entirely.
>
> We are then able to move to having 64 bits of mm->flags on both 32-bit and
> 64-bit architectures.
>
> We also update the VMA userland tests to ensure that everything remains
> functional there.
>
> No functional changes intended, other than there now being 64 bits of
> available mm_struct flags.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> ---
> include/linux/mm.h | 12 ++++++------
> include/linux/mm_types.h | 14 +++++---------
> include/linux/sched/coredump.h | 2 +-
> tools/testing/vma/vma_internal.h | 19 +++++++++++++++++--
> 4 files changed, 29 insertions(+), 18 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 34311ebe62cc..b61e2d4858cf 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -724,32 +724,32 @@ static inline void assert_fault_locked(struct vm_fault *vmf)
>
> static inline bool mm_flags_test(int flag, const struct mm_struct *mm)
> {
> - return test_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + return test_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline bool mm_flags_test_and_set(int flag, struct mm_struct *mm)
> {
> - return test_and_set_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + return test_and_set_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline bool mm_flags_test_and_clear(int flag, struct mm_struct *mm)
> {
> - return test_and_clear_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + return test_and_clear_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline void mm_flags_set(int flag, struct mm_struct *mm)
> {
> - set_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + set_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline void mm_flags_clear(int flag, struct mm_struct *mm)
> {
> - clear_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + clear_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline void mm_flags_clear_all(struct mm_struct *mm)
> {
> - bitmap_zero(ACCESS_PRIVATE(&mm->_flags, __mm_flags), NUM_MM_FLAG_BITS);
> + bitmap_zero(ACCESS_PRIVATE(&mm->flags, __mm_flags), NUM_MM_FLAG_BITS);
> }
>
> extern const struct vm_operations_struct vma_dummy_vm_ops;
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 25577ab39094..47d2e4598acd 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -932,7 +932,7 @@ struct mm_cid {
> * Opaque type representing current mm_struct flag state. Must be accessed via
> * mm_flags_xxx() helper functions.
> */
> -#define NUM_MM_FLAG_BITS BITS_PER_LONG
> +#define NUM_MM_FLAG_BITS (64)
> typedef struct {
> __private DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
> } mm_flags_t;
> @@ -1119,11 +1119,7 @@ struct mm_struct {
> /* Architecture-specific MM context */
> mm_context_t context;
>
> - /* Temporary union while we convert users to mm_flags_t. */
> - union {
> - unsigned long flags; /* Must use atomic bitops to access */
> - mm_flags_t _flags; /* Must use mm_flags_* helpers to access */
> - };
> + mm_flags_t flags; /* Must use mm_flags_* hlpers to access */
>
> #ifdef CONFIG_AIO
> spinlock_t ioctx_lock;
> @@ -1236,7 +1232,7 @@ struct mm_struct {
> /* Read the first system word of mm flags, non-atomically. */
> static inline unsigned long __mm_flags_get_word(struct mm_struct *mm)
> {
> - unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
>
> return bitmap_read(bitmap, 0, BITS_PER_LONG);
> }
> @@ -1245,7 +1241,7 @@ static inline unsigned long __mm_flags_get_word(struct mm_struct *mm)
> static inline void __mm_flags_set_word(struct mm_struct *mm,
> unsigned long value)
> {
> - unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
>
> bitmap_copy(bitmap, &value, BITS_PER_LONG);
> }
> @@ -1253,7 +1249,7 @@ static inline void __mm_flags_set_word(struct mm_struct *mm,
> /* Obtain a read-only view of the bitmap. */
> static inline const unsigned long *__mm_flags_get_bitmap(const struct mm_struct *mm)
> {
> - return (const unsigned long *)ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + return (const unsigned long *)ACCESS_PRIVATE(&mm->flags, __mm_flags);
> }
>
> #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \
> diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
> index 19ecfcceb27a..079ae5a97480 100644
> --- a/include/linux/sched/coredump.h
> +++ b/include/linux/sched/coredump.h
> @@ -20,7 +20,7 @@ static inline unsigned long __mm_flags_get_dumpable(struct mm_struct *mm)
>
> static inline void __mm_flags_set_mask_dumpable(struct mm_struct *mm, int value)
> {
> - unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
>
> set_mask_bits(bitmap, MMF_DUMPABLE_MASK, value);
> }
> diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
> index cb1c2a8afe26..f13354bf0a1e 100644
> --- a/tools/testing/vma/vma_internal.h
> +++ b/tools/testing/vma/vma_internal.h
> @@ -249,6 +249,14 @@ struct mutex {};
> #define DEFINE_MUTEX(mutexname) \
> struct mutex mutexname = {}
>
> +#define DECLARE_BITMAP(name, bits) \
> + unsigned long name[BITS_TO_LONGS(bits)]
> +
> +#define NUM_MM_FLAG_BITS (64)
> +typedef struct {
> + __private DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
> +} mm_flags_t;
> +
> struct mm_struct {
> struct maple_tree mm_mt;
> int map_count; /* number of VMAs */
> @@ -260,7 +268,7 @@ struct mm_struct {
>
> unsigned long def_flags;
>
> - unsigned long flags; /* Must use atomic bitops to access */
> + mm_flags_t flags; /* Must use mm_flags_* helpers to access */
> };
>
> struct vm_area_struct;
> @@ -1333,6 +1341,13 @@ static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
> {
> }
>
> +# define ACCESS_PRIVATE(p, member) ((p)->member)
> +
> +static inline bool mm_flags_test(int flag, const struct mm_struct *mm)
> +{
> + return test_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> +}
> +
> /*
> * Denies creating a writable executable mapping or gaining executable permissions.
> *
> @@ -1363,7 +1378,7 @@ static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
> static inline bool map_deny_write_exec(unsigned long old, unsigned long new)
> {
> /* If MDWE is disabled, we have nothing to deny. */
> - if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags))
> + if (mm_flags_test(MMF_HAS_MDWE, current->mm))
> return false;
>
> /* If the new VMA is not executable, we have nothing to deny. */
> --
> 2.50.1
>
--
Sincerely yours,
Mike.
* Lorenzo Stoakes <lorenzo.stoakes@oracle.com> [250812 11:48]:
> Now we have updated all users of mm->flags to use the bitmap accessors,
> repalce it with the bitmap version entirely.
>
> We are then able to move to having 64 bits of mm->flags on both 32-bit and
> 64-bit architectures.
>
> We also update the VMA userland tests to ensure that everything remains
> functional there.
>
> No functional changes intended, other than there now being 64 bits of
> available mm_struct flags.
>
> Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
A nit below, but..
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
> ---
> include/linux/mm.h | 12 ++++++------
> include/linux/mm_types.h | 14 +++++---------
> include/linux/sched/coredump.h | 2 +-
> tools/testing/vma/vma_internal.h | 19 +++++++++++++++++--
> 4 files changed, 29 insertions(+), 18 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 34311ebe62cc..b61e2d4858cf 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -724,32 +724,32 @@ static inline void assert_fault_locked(struct vm_fault *vmf)
>
> static inline bool mm_flags_test(int flag, const struct mm_struct *mm)
> {
> - return test_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + return test_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline bool mm_flags_test_and_set(int flag, struct mm_struct *mm)
> {
> - return test_and_set_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + return test_and_set_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline bool mm_flags_test_and_clear(int flag, struct mm_struct *mm)
> {
> - return test_and_clear_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + return test_and_clear_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline void mm_flags_set(int flag, struct mm_struct *mm)
> {
> - set_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + set_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline void mm_flags_clear(int flag, struct mm_struct *mm)
> {
> - clear_bit(flag, ACCESS_PRIVATE(&mm->_flags, __mm_flags));
> + clear_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> }
>
> static inline void mm_flags_clear_all(struct mm_struct *mm)
> {
> - bitmap_zero(ACCESS_PRIVATE(&mm->_flags, __mm_flags), NUM_MM_FLAG_BITS);
> + bitmap_zero(ACCESS_PRIVATE(&mm->flags, __mm_flags), NUM_MM_FLAG_BITS);
> }
>
> extern const struct vm_operations_struct vma_dummy_vm_ops;
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 25577ab39094..47d2e4598acd 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -932,7 +932,7 @@ struct mm_cid {
> * Opaque type representing current mm_struct flag state. Must be accessed via
> * mm_flags_xxx() helper functions.
> */
> -#define NUM_MM_FLAG_BITS BITS_PER_LONG
> +#define NUM_MM_FLAG_BITS (64)
> typedef struct {
> __private DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
> } mm_flags_t;
> @@ -1119,11 +1119,7 @@ struct mm_struct {
> /* Architecture-specific MM context */
> mm_context_t context;
>
> - /* Temporary union while we convert users to mm_flags_t. */
> - union {
> - unsigned long flags; /* Must use atomic bitops to access */
> - mm_flags_t _flags; /* Must use mm_flags_* helpers to access */
> - };
> + mm_flags_t flags; /* Must use mm_flags_* hlpers to access */
>
> #ifdef CONFIG_AIO
> spinlock_t ioctx_lock;
> @@ -1236,7 +1232,7 @@ struct mm_struct {
> /* Read the first system word of mm flags, non-atomically. */
> static inline unsigned long __mm_flags_get_word(struct mm_struct *mm)
> {
> - unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
>
> return bitmap_read(bitmap, 0, BITS_PER_LONG);
> }
> @@ -1245,7 +1241,7 @@ static inline unsigned long __mm_flags_get_word(struct mm_struct *mm)
> static inline void __mm_flags_set_word(struct mm_struct *mm,
> unsigned long value)
> {
> - unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
>
> bitmap_copy(bitmap, &value, BITS_PER_LONG);
> }
> @@ -1253,7 +1249,7 @@ static inline void __mm_flags_set_word(struct mm_struct *mm,
> /* Obtain a read-only view of the bitmap. */
> static inline const unsigned long *__mm_flags_get_bitmap(const struct mm_struct *mm)
> {
> - return (const unsigned long *)ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + return (const unsigned long *)ACCESS_PRIVATE(&mm->flags, __mm_flags);
> }
>
> #define MM_MT_FLAGS (MT_FLAGS_ALLOC_RANGE | MT_FLAGS_LOCK_EXTERN | \
> diff --git a/include/linux/sched/coredump.h b/include/linux/sched/coredump.h
> index 19ecfcceb27a..079ae5a97480 100644
> --- a/include/linux/sched/coredump.h
> +++ b/include/linux/sched/coredump.h
> @@ -20,7 +20,7 @@ static inline unsigned long __mm_flags_get_dumpable(struct mm_struct *mm)
>
> static inline void __mm_flags_set_mask_dumpable(struct mm_struct *mm, int value)
> {
> - unsigned long *bitmap = ACCESS_PRIVATE(&mm->_flags, __mm_flags);
> + unsigned long *bitmap = ACCESS_PRIVATE(&mm->flags, __mm_flags);
>
> set_mask_bits(bitmap, MMF_DUMPABLE_MASK, value);
> }
> diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
> index cb1c2a8afe26..f13354bf0a1e 100644
> --- a/tools/testing/vma/vma_internal.h
> +++ b/tools/testing/vma/vma_internal.h
> @@ -249,6 +249,14 @@ struct mutex {};
> #define DEFINE_MUTEX(mutexname) \
> struct mutex mutexname = {}
>
> +#define DECLARE_BITMAP(name, bits) \
> + unsigned long name[BITS_TO_LONGS(bits)]
> +
> +#define NUM_MM_FLAG_BITS (64)
> +typedef struct {
> + __private DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
> +} mm_flags_t;
> +
nit, This might be better in common test code? Probably just leave it
here until it's needed elsewhere.
> struct mm_struct {
> struct maple_tree mm_mt;
> int map_count; /* number of VMAs */
> @@ -260,7 +268,7 @@ struct mm_struct {
>
> unsigned long def_flags;
>
> - unsigned long flags; /* Must use atomic bitops to access */
> + mm_flags_t flags; /* Must use mm_flags_* helpers to access */
> };
>
> struct vm_area_struct;
> @@ -1333,6 +1341,13 @@ static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
> {
> }
>
> +# define ACCESS_PRIVATE(p, member) ((p)->member)
> +
> +static inline bool mm_flags_test(int flag, const struct mm_struct *mm)
> +{
> + return test_bit(flag, ACCESS_PRIVATE(&mm->flags, __mm_flags));
> +}
> +
> /*
> * Denies creating a writable executable mapping or gaining executable permissions.
> *
> @@ -1363,7 +1378,7 @@ static inline void userfaultfd_unmap_complete(struct mm_struct *mm,
> static inline bool map_deny_write_exec(unsigned long old, unsigned long new)
> {
> /* If MDWE is disabled, we have nothing to deny. */
> - if (!test_bit(MMF_HAS_MDWE, ¤t->mm->flags))
> + if (mm_flags_test(MMF_HAS_MDWE, current->mm))
> return false;
>
> /* If the new VMA is not executable, we have nothing to deny. */
> --
> 2.50.1
>
On Tue, Aug 12, 2025 at 01:35:18PM -0400, Liam R. Howlett wrote:
> * Lorenzo Stoakes <lorenzo.stoakes@oracle.com> [250812 11:48]:
> > Now we have updated all users of mm->flags to use the bitmap accessors,
> > repalce it with the bitmap version entirely.
> >
> > We are then able to move to having 64 bits of mm->flags on both 32-bit and
> > 64-bit architectures.
> >
> > We also update the VMA userland tests to ensure that everything remains
> > functional there.
> >
> > No functional changes intended, other than there now being 64 bits of
> > available mm_struct flags.
> >
> > Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
>
> A nit below, but..
>
> Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Thanks!
[snip]
> > diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h
> > index cb1c2a8afe26..f13354bf0a1e 100644
> > --- a/tools/testing/vma/vma_internal.h
> > +++ b/tools/testing/vma/vma_internal.h
> > @@ -249,6 +249,14 @@ struct mutex {};
> > #define DEFINE_MUTEX(mutexname) \
> > struct mutex mutexname = {}
> >
> > +#define DECLARE_BITMAP(name, bits) \
> > + unsigned long name[BITS_TO_LONGS(bits)]
> > +
> > +#define NUM_MM_FLAG_BITS (64)
> > +typedef struct {
> > + __private DECLARE_BITMAP(__mm_flags, NUM_MM_FLAG_BITS);
> > +} mm_flags_t;
> > +
>
> nit, This might be better in common test code? Probably just leave it
> here until it's needed elsewhere.
Yeah, I think we need to figure this out in a more sensible way so we keep
things vaguely synced for this stuff more generally. I'll add a todo for
this!
I think fine for now, key point here is keeping the tests working.
Cheers, Lorenzo
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