mm: Reserve asm-generic prot flags 0x10 and 0x20 for arch use

The asm-generic/mman.h definitions are used by a few architectures that
also define arch-specific PROT flags with value 0x10 and 0x20. This
currently applies to sparc and powerpc for 0x10, while arm64 will soon
join with 0x10 and 0x20.

To help future maintainers, document the use of this flag in the
asm-generic header too.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Dave Martin <Dave.Martin@arm.com>
[catalin.marinas@arm.com: reserve 0x20 as well]
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>

diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index c160a53..f94f65d 100644 (file)
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -11,6 +11,8 @@
 #define PROT_WRITE     0x2             /* page can be written */
 #define PROT_EXEC      0x4             /* page can be executed */
 #define PROT_SEM       0x8             /* page may be used for atomic ops */
+/*                     0x10               reserved for arch-specific use */
+/*                     0x20               reserved for arch-specific use */
 #define PROT_NONE      0x0             /* page can not be accessed */
 #define PROT_GROWSDOWN 0x01000000      /* mprotect flag: extend change to start of growsdown vma */
 #define PROT_GROWSUP   0x02000000      /* mprotect flag: extend change to end of growsup vma */