sys/{mman,shm}.h: add {MAP,SHM}_HUGE_ macros from linux uapi
*_HUGE_SHIFT, *_HUGE_2MB, *_HUGE_1GB are documented in the man page,
so add all of the *_HUGE_* macros from linux uapi.
if MAP_HUGETLB is set, top bits of the mmap flags encode the page size.
see the linux commit aafd4562dfee81a40ba21b5ea3cf5e06664bc7f6
if SHM_HUGETLB is set, top bits of the shmget flags encode the page size.
see the linux commit 4da243ac1cf6aeb30b7c555d56208982d66d6d33
*_HUGE_16GB is defined unsigned to avoid signed left shift ub.
diff --git a/include/sys/mman.h b/include/sys/mman.h
index 1231878..d13d4ca 100644
--- a/include/sys/mman.h
+++ b/include/sys/mman.h
@@ -35,6 +35,19 @@
#define MAP_HUGETLB 0x40000
#define MAP_FILE 0
+#define MAP_HUGE_SHIFT 26
+#define MAP_HUGE_MASK 0x3f
+#define MAP_HUGE_64KB (16 << 26)
+#define MAP_HUGE_512KB (19 << 26)
+#define MAP_HUGE_1MB (20 << 26)
+#define MAP_HUGE_2MB (21 << 26)
+#define MAP_HUGE_8MB (23 << 26)
+#define MAP_HUGE_16MB (24 << 26)
+#define MAP_HUGE_256MB (28 << 26)
+#define MAP_HUGE_1GB (30 << 26)
+#define MAP_HUGE_2GB (31 << 26)
+#define MAP_HUGE_16GB (34U << 26)
+
#define PROT_NONE 0
#define PROT_READ 1
#define PROT_WRITE 2
diff --git a/include/sys/shm.h b/include/sys/shm.h
index 67be822..e7d39ff 100644
--- a/include/sys/shm.h
+++ b/include/sys/shm.h
@@ -40,6 +40,19 @@
#define SHM_HUGETLB 04000
#define SHM_NORESERVE 010000
+#define SHM_HUGE_SHIFT 26
+#define SHM_HUGE_MASK 0x3f
+#define SHM_HUGE_64KB (16 << 26)
+#define SHM_HUGE_512KB (19 << 26)
+#define SHM_HUGE_1MB (20 << 26)
+#define SHM_HUGE_2MB (21 << 26)
+#define SHM_HUGE_8MB (23 << 26)
+#define SHM_HUGE_16MB (24 << 26)
+#define SHM_HUGE_256MB (28 << 26)
+#define SHM_HUGE_1GB (30 << 26)
+#define SHM_HUGE_2GB (31 << 26)
+#define SHM_HUGE_16GB (34U << 26)
+
typedef unsigned long shmatt_t;
void *shmat(int, const void *, int);