From: Yu-cheng Yu Date: Tue, 13 Jun 2023 00:10:31 +0000 (-0700) Subject: mm: Move VM_UFFD_MINOR_BIT from 37 to 38 X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=fb47a799cc5ccc469c63e9174f2ad555a21ba2a1;p=linux.git mm: Move VM_UFFD_MINOR_BIT from 37 to 38 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. Future patches will introduce a new VM flag VM_SHADOW_STACK that will be VM_HIGH_ARCH_BIT_5. VM_HIGH_ARCH_BIT_1 through VM_HIGH_ARCH_BIT_4 are bits 32-36, and bit 37 is the unrelated VM_UFFD_MINOR_BIT. For the sake of order, make all VM_HIGH_ARCH_BITs stay together by moving VM_UFFD_MINOR_BIT from 37 to 38. This will allow VM_SHADOW_STACK to be introduced as 37. Co-developed-by: Rick Edgecombe Signed-off-by: Yu-cheng Yu Signed-off-by: Rick Edgecombe Signed-off-by: Dave Hansen Reviewed-by: Borislav Petkov (AMD) Reviewed-by: Kees Cook Reviewed-by: Axel Rasmussen Acked-by: Mike Rapoport (IBM) Acked-by: Peter Xu Tested-by: Pengfei Xu Tested-by: John Allen Tested-by: Kees Cook Link: https://lore.kernel.org/all/20230613001108.3040476-6-rick.p.edgecombe%40intel.com --- diff --git a/include/linux/mm.h b/include/linux/mm.h index f9a627c492f29..82990f3390f6c 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -370,7 +370,7 @@ extern unsigned int kobjsize(const void *objp); #endif #ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR -# define VM_UFFD_MINOR_BIT 37 +# define VM_UFFD_MINOR_BIT 38 # define VM_UFFD_MINOR BIT(VM_UFFD_MINOR_BIT) /* UFFD minor faults */ #else /* !CONFIG_HAVE_ARCH_USERFAULTFD_MINOR */ # define VM_UFFD_MINOR VM_NONE