| 1 | #ifndef _ASM_GENERIC_HUGETLB_ENCODE_H_
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| 2 | #define _ASM_GENERIC_HUGETLB_ENCODE_H_
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| 3 |
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| 4 | |
| 5 | * Several system calls take a flag to request "hugetlb" huge pages.
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| 6 | * Without further specification, these system calls will use the
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| 7 | * system's default huge page size. If a system supports multiple
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| 8 | * huge page sizes, the desired huge page size can be specified in
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| 9 | * bits [26:31] of the flag arguments. The value in these 6 bits
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| 10 | * will encode the log2 of the huge page size.
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| 11 | *
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| 12 | * The following definitions are associated with this huge page size
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| 13 | * encoding in flag arguments. System call specific header files
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| 14 | * that use this encoding should include this file. They can then
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| 15 | * provide definitions based on these with their own specific prefix.
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| 16 | * for example:
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| 17 | * #define MAP_HUGE_SHIFT HUGETLB_FLAG_ENCODE_SHIFT
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| 18 |
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| 19 |
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| 20 | #define HUGETLB_FLAG_ENCODE_SHIFT 26
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| 21 | #define HUGETLB_FLAG_ENCODE_MASK 0x3f
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| 22 |
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| 23 | #define HUGETLB_FLAG_ENCODE_16KB (14U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 24 | #define HUGETLB_FLAG_ENCODE_64KB (16U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 25 | #define HUGETLB_FLAG_ENCODE_512KB (19U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 26 | #define HUGETLB_FLAG_ENCODE_1MB (20U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 27 | #define HUGETLB_FLAG_ENCODE_2MB (21U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 28 | #define HUGETLB_FLAG_ENCODE_8MB (23U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 29 | #define HUGETLB_FLAG_ENCODE_16MB (24U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 30 | #define HUGETLB_FLAG_ENCODE_32MB (25U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 31 | #define HUGETLB_FLAG_ENCODE_256MB (28U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 32 | #define HUGETLB_FLAG_ENCODE_512MB (29U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 33 | #define HUGETLB_FLAG_ENCODE_1GB (30U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 34 | #define HUGETLB_FLAG_ENCODE_2GB (31U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 35 | #define HUGETLB_FLAG_ENCODE_16GB (34U << HUGETLB_FLAG_ENCODE_SHIFT)
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| 36 |
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| 37 | #endif
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