diff --git a/include/linux/mm.h b/include/linux/mm.h index 0f2612a70fb1..485df9c2dbdd 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -496,6 +496,21 @@ enum { #else #define VM_UFFD_MINOR VM_NONE #endif + +/* + * vma_flags_t masks for the userfaultfd VMA flags. VMA_UFFD_MINOR is gated on + * the same config as VM_UFFD_MINOR -- which implies 64BIT, where the bit fits + * -- so an out-of-range bit is never fed to mk_vma_flags() on a build whose + * bitmap cannot hold it. + */ +#define VMA_UFFD_MISSING mk_vma_flags(VMA_UFFD_MISSING_BIT) +#define VMA_UFFD_WP mk_vma_flags(VMA_UFFD_WP_BIT) +#ifdef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR +#define VMA_UFFD_MINOR mk_vma_flags(VMA_UFFD_MINOR_BIT) +#else +#define VMA_UFFD_MINOR EMPTY_VMA_FLAGS +#endif + #ifdef CONFIG_64BIT #define VM_ALLOW_ANY_UNCACHED INIT_VM_FLAG(ALLOW_ANY_UNCACHED) #define VM_SEALED INIT_VM_FLAG(SEALED) @@ -1238,6 +1253,30 @@ static __always_inline void vma_flags_set_mask(vma_flags_t *flags, #define vma_flags_set(flags, ...) \ vma_flags_set_mask(flags, mk_vma_flags(__VA_ARGS__)) +static __always_inline vma_flags_t __mk_vma_flags_from_masks(size_t count, + const vma_flags_t *masks) +{ + vma_flags_t flags = EMPTY_VMA_FLAGS; + size_t i; + + for (i = 0; i < count; i++) + vma_flags_set_mask(&flags, masks[i]); + return flags; +} + +/* + * Combine pre-computed vma_flags_t masks into one value, e.g.: + * + * vma_flags_t flags = mk_vma_flags_from_masks(VMA_UFFD_WP, VMA_UFFD_MINOR); + * + * Unlike mk_vma_flags(), which takes bit numbers, this takes whole masks -- + * each of which may be EMPTY_VMA_FLAGS when its feature is unavailable -- so a + * bit that does not exist on the current build is never materialised. + */ +#define mk_vma_flags_from_masks(...) \ + __mk_vma_flags_from_masks(COUNT_ARGS(__VA_ARGS__), \ + (const vma_flags_t []){__VA_ARGS__}) + /* Clear all of the to-clear flags in flags, non-atomically. */ static __always_inline void vma_flags_clear_mask(vma_flags_t *flags, vma_flags_t to_clear) diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index 3ec8e1071673..68edac4dcd78 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -23,8 +23,8 @@ /* The set of all possible UFFD-related VM flags. */ #define __VM_UFFD_FLAGS (VM_UFFD_MISSING | VM_UFFD_WP | VM_UFFD_MINOR) -#define __VMA_UFFD_FLAGS mk_vma_flags(VMA_UFFD_MISSING_BIT, VMA_UFFD_WP_BIT, \ - VMA_UFFD_MINOR_BIT) +#define __VMA_UFFD_FLAGS mk_vma_flags_from_masks(VMA_UFFD_MISSING, VMA_UFFD_WP, \ + VMA_UFFD_MINOR) /* * CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining