1#ifndef _ASM_GENERIC_HUGETLB_ENCODE_H_
2#define _ASM_GENERIC_HUGETLB_ENCODE_H_
3
4/*
5 * Several system calls take a flag to request "hugetlb" huge pages.
6 * Without further specification, these system calls will use the
7 * system's default huge page size. If a system supports multiple
8 * huge page sizes, the desired huge page size can be specified in
9 * bits [26:31] of the flag arguments. The value in these 6 bits
10 * will encode the log2 of the huge page size.
11 *
12 * The following definitions are associated with this huge page size
13 * encoding in flag arguments. System call specific header files
14 * that use this encoding should include this file. They can then
15 * provide definitions based on these with their own specific prefix.
16 * for example:
17 * #define MAP_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
18 */
19
20#define HUGETLB_FLAG_ENCODE_SHIFT 26
21#define HUGETLB_FLAG_ENCODE_MASK 0x3f
22
23#define HUGETLB_FLAG_ENCODE_64KB (16 << HUGETLB_FLAG_ENCODE_SHIFT)
24#define HUGETLB_FLAG_ENCODE_512KB (19 << HUGETLB_FLAG_ENCODE_SHIFT)
25#define HUGETLB_FLAG_ENCODE_1MB (20 << HUGETLB_FLAG_ENCODE_SHIFT)
26#define HUGETLB_FLAG_ENCODE_2MB (21 << HUGETLB_FLAG_ENCODE_SHIFT)
27#define HUGETLB_FLAG_ENCODE_8MB (23 << HUGETLB_FLAG_ENCODE_SHIFT)
28#define HUGETLB_FLAG_ENCODE_16MB (24 << HUGETLB_FLAG_ENCODE_SHIFT)
29#define HUGETLB_FLAG_ENCODE_32MB (25 << HUGETLB_FLAG_ENCODE_SHIFT)
30#define HUGETLB_FLAG_ENCODE_256MB (28 << HUGETLB_FLAG_ENCODE_SHIFT)
31#define HUGETLB_FLAG_ENCODE_512MB (29 << HUGETLB_FLAG_ENCODE_SHIFT)
32#define HUGETLB_FLAG_ENCODE_1GB (30 << HUGETLB_FLAG_ENCODE_SHIFT)
33#define HUGETLB_FLAG_ENCODE_2GB (31 << HUGETLB_FLAG_ENCODE_SHIFT)
34#define HUGETLB_FLAG_ENCODE_16GB (34 << HUGETLB_FLAG_ENCODE_SHIFT)
35
36#endif /* _ASM_GENERIC_HUGETLB_ENCODE_H_ */
37