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-rw-r--r--include/uapi/asm-generic/mman-common.h11
-rw-r--r--include/uapi/asm-generic/mman.h2
2 files changed, 13 insertions, 0 deletions
diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index d030d2c2647a..4164529a94f9 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -55,4 +55,15 @@
/* compatibility flags */
#define MAP_FILE 0
+/*
+ * When MAP_HUGETLB is set bits [26:31] encode the log2 of the huge page size.
+ * This gives us 6 bits, which is enough until someone invents 128 bit address
+ * spaces.
+ *
+ * Assume these are all power of twos.
+ * When 0 use the default page size.
+ */
+#define MAP_HUGE_SHIFT 26
+#define MAP_HUGE_MASK 0x3f
+
#endif /* __ASM_GENERIC_MMAN_COMMON_H */
diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index 32c8bd6a196d..e9fe6fd2a074 100644
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -13,6 +13,8 @@
#define MAP_STACK 0x20000 /* give out an address that is best suited for process/thread stacks */
#define MAP_HUGETLB 0x40000 /* create a huge page mapping */
+/* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */
+
#define MCL_CURRENT 1 /* lock all current mappings */
#define MCL_FUTURE 2 /* lock all future mappings */