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_256MB	(28 << HUGETLB_FLAG_ENCODE_SHIFT)
30#define HUGETLB_FLAG_ENCODE_1GB		(30 << HUGETLB_FLAG_ENCODE_SHIFT)
31#define HUGETLB_FLAG_ENCODE_2GB		(31 << HUGETLB_FLAG_ENCODE_SHIFT)
32#define HUGETLB_FLAG_ENCODE_16GB	(34 << HUGETLB_FLAG_ENCODE_SHIFT)
33
34#endif /* _ASM_GENERIC_HUGETLB_ENCODE_H_ */