xref: /openbmc/u-boot/include/zfs/zap_impl.h (revision 274bced8)
1 /*
2  *  GRUB  --  GRand Unified Bootloader
3  *  Copyright (C) 1999,2000,2001,2002,2003,2004  Free Software Foundation, Inc.
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 /*
8  * Copyright (c) 2008, 2011, Oracle and/or its affiliates. All rights reserved.
9  */
10 
11 #ifndef	_SYS_ZAP_IMPL_H
12 #define	_SYS_ZAP_IMPL_H
13 
14 #define	ZAP_MAGIC 0x2F52AB2ABULL
15 
16 #define	ZAP_HASHBITS		28
17 #define	MZAP_ENT_LEN		64
18 #define	MZAP_NAME_LEN		(MZAP_ENT_LEN - 8 - 4 - 2)
19 #define	MZAP_MAX_BLKSHIFT	SPA_MAXBLOCKSHIFT
20 #define	MZAP_MAX_BLKSZ		(1 << MZAP_MAX_BLKSHIFT)
21 
22 typedef struct mzap_ent_phys {
23 	uint64_t mze_value;
24 	uint32_t mze_cd;
25 	uint16_t mze_pad;	/* in case we want to chain them someday */
26 	char mze_name[MZAP_NAME_LEN];
27 } mzap_ent_phys_t;
28 
29 typedef struct mzap_phys {
30 	uint64_t mz_block_type;	/* ZBT_MICRO */
31 	uint64_t mz_salt;
32 	uint64_t mz_pad[6];
33 	mzap_ent_phys_t mz_chunk[1];
34 	/* actually variable size depending on block size */
35 } mzap_phys_t;
36 
37 /*
38  * The (fat) zap is stored in one object. It is an array of
39  * 1<<FZAP_BLOCK_SHIFT byte blocks. The layout looks like one of:
40  *
41  * ptrtbl fits in first block:
42  *	[zap_phys_t zap_ptrtbl_shift < 6] [zap_leaf_t] ...
43  *
44  * ptrtbl too big for first block:
45  *	[zap_phys_t zap_ptrtbl_shift >= 6] [zap_leaf_t] [ptrtbl] ...
46  *
47  */
48 
49 #define	ZBT_LEAF		((1ULL << 63) + 0)
50 #define	ZBT_HEADER		((1ULL << 63) + 1)
51 #define	ZBT_MICRO		((1ULL << 63) + 3)
52 /* any other values are ptrtbl blocks */
53 
54 /*
55  * the embedded pointer table takes up half a block:
56  * block size / entry size (2^3) / 2
57  */
58 #define	ZAP_EMBEDDED_PTRTBL_SHIFT(zap) (FZAP_BLOCK_SHIFT(zap) - 3 - 1)
59 
60 /*
61  * The embedded pointer table starts half-way through the block.  Since
62  * the pointer table itself is half the block, it starts at (64-bit)
63  * word number (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap)).
64  */
65 #define	ZAP_EMBEDDED_PTRTBL_ENT(zap, idx) \
66 	((uint64_t *)(zap)->zap_f.zap_phys) \
67 	[(idx) + (1<<ZAP_EMBEDDED_PTRTBL_SHIFT(zap))]
68 
69 /*
70  * TAKE NOTE:
71  * If zap_phys_t is modified, zap_byteswap() must be modified.
72  */
73 typedef struct zap_phys {
74 	uint64_t zap_block_type;	/* ZBT_HEADER */
75 	uint64_t zap_magic;		/* ZAP_MAGIC */
76 
77 	struct zap_table_phys {
78 		uint64_t zt_blk;	/* starting block number */
79 		uint64_t zt_numblks;	/* number of blocks */
80 		uint64_t zt_shift;	/* bits to index it */
81 		uint64_t zt_nextblk;	/* next (larger) copy start block */
82 		uint64_t zt_blks_copied; /* number source blocks copied */
83 	} zap_ptrtbl;
84 
85 	uint64_t zap_freeblk;		/* the next free block */
86 	uint64_t zap_num_leafs;		/* number of leafs */
87 	uint64_t zap_num_entries;	/* number of entries */
88 	uint64_t zap_salt;		/* salt to stir into hash function */
89 	uint64_t zap_normflags;		/* flags for u8_textprep_str() */
90 	uint64_t zap_flags;		/* zap_flag_t */
91 	/*
92 	 * This structure is followed by padding, and then the embedded
93 	 * pointer table.  The embedded pointer table takes up second
94 	 * half of the block.  It is accessed using the
95 	 * ZAP_EMBEDDED_PTRTBL_ENT() macro.
96 	 */
97 } zap_phys_t;
98 
99 #endif /* _SYS_ZAP_IMPL_H */
100