Commit 00547ef7 authored by Rick Edgecombe's avatar Rick Edgecombe
Browse files

mm/mmap: Add shadow stack pages to memory accounting 



The x86 Control-flow Enforcement Technology (CET) feature includes a new
type of memory called shadow stack. This shadow stack memory has some
unusual properties, which requires some core mm changes to function
properly.

Co-developed-by: default avatarYu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: default avatarYu-cheng Yu <yu-cheng.yu@intel.com>
Signed-off-by: default avatarRick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: default avatarDave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarKees Cook <keescook@chromium.org>
Acked-by: default avatarMike Rapoport (IBM) <rppt@kernel.org>
Acked-by: default avatarDavid Hildenbrand <david@redhat.com>
Tested-by: default avatarPengfei Xu <pengfei.xu@intel.com>
Tested-by: default avatarJohn Allen <john.allen@amd.com>
Tested-by: default avatarKees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/all/20230613001108.3040476-20-rick.p.edgecombe%40intel.com
parent ae1f05a6

mm/internal.h

+2 −2
Original line number Diff line number Diff line
@@ -538,14 +538,14 @@ static inline bool is_exec_mapping(vm_flags_t flags) 
}



/*

 * Stack area - automatically grows in one direction

 * Stack area (including shadow stacks)

 *

 * VM_GROWSUP / VM_GROWSDOWN VMAs are always private anonymous:

 * do_mmap() forbids all other combinations.

 */

static inline bool is_stack_mapping(vm_flags_t flags)

{

	return (flags & VM_STACK) == VM_STACK;

	return ((flags & VM_STACK) == VM_STACK) || (flags & VM_SHADOW_STACK);

}



/*