mm/vma: update do_mmap() to use vma_flags_t

The core do_mmap() function accepts a vm_flags_t parameter which it then
manipulates before passing to mmap_region() to do the heavy lifting of the
memory mapping.

Update do_mmap() to instead accept a vma_flags_t parameter, and adjust all
the logic within do_mmap() to manipulate this instead.

This is as part of the ongoing effort to convert VMA flags from a system
word size to a bitmap type which allows us to unrestrict the number of VMA
flags, as well as gain control over how VMA flag manipulation occurs.

We do not cascade these changes to all functions which accept vm_flags_t,
but rather use vma_flags_to_legacy() where necessary, specifically
deferring converting calc_vm_prot_bits(), calc_vm_flag_bits() and
__get_unmapped_area() to vma_flags_t.

Also utilise the new vma_flags_can_grow() predicate which correctly
handles the case of architectures without upward growing stacks.

As part of this change, introduce VMA_SHADOW_STACK so we can correctly
handle the case of the shadow stack not being defined.

No functional change intended.

Link: https://lore.kernel.org/20260711-b4-vma-flags-mm-v2-2-0fa2357d5431@kernel.org
Signed-off-by: Lorenzo Stoakes <ljs@kernel.org>
Reviewed-by: Lance Yang <lance.yang@linux.dev>
Reviewed-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Barry Song <baohua@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Airlie <airlied@gmail.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jann Horn <jannh@google.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nico Pache <npache@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pedro Falcato <pfalcato@suse.de>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c
index bd1fc17d3975..94873775fc0f 100644
--- a/arch/mips/kernel/vdso.c
+++ b/arch/mips/kernel/vdso.c
@@ -91,8 +91,8 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 		/* Map delay slot emulation page */
 		base = do_mmap(NULL, STACK_TOP, PAGE_SIZE, PROT_READ | PROT_EXEC,
-			       MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED, 0, 0, &unused,
-			       NULL);
+			       MAP_ANONYMOUS | MAP_PRIVATE | MAP_FIXED,
+			       EMPTY_VMA_FLAGS, 0, &unused, NULL);
 		if (IS_ERR_VALUE(base)) {
 			ret = base;
 			goto out;