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authorJames Morris <james.l.morris@oracle.com>2017-11-29 12:47:41 +1100
committerJames Morris <james.l.morris@oracle.com>2017-11-29 12:47:41 +1100
commitcf40a76e7d5874bb25f4404eecc58a2e033af885 (patch)
tree8fd81cbea03c87b3d41d7ae5b1d11eadd35d6ef5 /include/uapi/asm-generic/hugetlb_encode.h
parentab5348c9c23cd253f5902980d2d8fe067dc24c82 (diff)
parent4fbd8d194f06c8a3fd2af1ce560ddb31f7ec8323 (diff)
Merge tag 'v4.15-rc1' into next-seccomp
Linux 4.15-rc1
Diffstat (limited to 'include/uapi/asm-generic/hugetlb_encode.h')
-rw-r--r--include/uapi/asm-generic/hugetlb_encode.h34
1 files changed, 34 insertions, 0 deletions
diff --git a/include/uapi/asm-generic/hugetlb_encode.h b/include/uapi/asm-generic/hugetlb_encode.h
new file mode 100644
index 000000000000..e4732d3c2998
--- /dev/null
+++ b/include/uapi/asm-generic/hugetlb_encode.h
@@ -0,0 +1,34 @@
+#ifndef _ASM_GENERIC_HUGETLB_ENCODE_H_
+#define _ASM_GENERIC_HUGETLB_ENCODE_H_
+
+/*
+ * Several system calls take a flag to request "hugetlb" huge pages.
+ * Without further specification, these system calls will use the
+ * system's default huge page size. If a system supports multiple
+ * huge page sizes, the desired huge page size can be specified in
+ * bits [26:31] of the flag arguments. The value in these 6 bits
+ * will encode the log2 of the huge page size.
+ *
+ * The following definitions are associated with this huge page size
+ * encoding in flag arguments. System call specific header files
+ * that use this encoding should include this file. They can then
+ * provide definitions based on these with their own specific prefix.
+ * for example:
+ * #define MAP_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
+ */
+
+#define HUGETLB_FLAG_ENCODE_SHIFT 26
+#define HUGETLB_FLAG_ENCODE_MASK 0x3f
+
+#define HUGETLB_FLAG_ENCODE_64KB (16 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_512KB (19 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_1MB (20 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_2MB (21 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_8MB (23 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_16MB (24 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_256MB (28 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_1GB (30 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_2GB (31 << HUGETLB_FLAG_ENCODE_SHIFT)
+#define HUGETLB_FLAG_ENCODE_16GB (34 << HUGETLB_FLAG_ENCODE_SHIFT)
+
+#endif /* _ASM_GENERIC_HUGETLB_ENCODE_H_ */