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_ */ 35