2 * Copyright (C) 1997 Massachusetts Institute of Technology
4 * This software is being provided by the copyright holders under the
5 * following license. By obtaining, using and/or copying this software,
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15 * THIS SOFTWARE IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE NO
16 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED. BY WAY OF EXAMPLE,
17 * BUT NOT LIMITATION, COPYRIGHT HOLDERS MAKE NO REPRESENTATIONS OR
18 * WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR
19 * THAT THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY
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21 * HOLDERS WILL BEAR NO LIABILITY FOR ANY USE OF THIS SOFTWARE OR
24 * The name and trademarks of copyright holders may NOT be used in
25 * advertising or publicity pertaining to the software without specific,
26 * written prior permission. Title to copyright in this software and any
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28 * holders. See the file AUTHORS which should have accompanied this software
29 * for a list of all copyright holders.
31 * This file may be derived from previously copyrighted software. This
32 * copyright applies only to those changes made by the copyright
33 * holders listed in the AUTHORS file. The rest of this file is covered by
34 * the copyright notices, if any, listed below.
48 #define MASK(SHIFT, CNT) (((1ul << (CNT)) - 1) << (SHIFT))
50 /* Page offset (bits 0:11). */
51 #define PGSHIFT 0 /* First offset bit. */
52 #define PGBITS 12 /* Number of offset bits. */
53 #define PGMASK MASK(PGSHIFT, PGBITS)
54 #define PGSIZE (1 << PGBITS)
56 /* Page table (bits 12:21). */
57 #define PTSHIFT PGBITS /* First page table bit. */
58 #define PTBITS 10 /* Number of page table bits. */
59 #define PTMASK MASK(PTSHIFT, PTBITS)
61 /* Page directory (bits 22:31). */
62 #define PDSHIFT (PTSHIFT + PTBITS) /* First page dir bit. */
63 #define PDBITS 10 /* Number of page dir bits. */
64 #define PDMASK MASK(PDSHIFT, PDBITS)
67 /* Offset within a page. */
68 static inline unsigned pg_ofs (void *va) { return (uintptr_t) va & PGMASK; }
71 static inline uintptr_t pg_no (void *va) { return (uintptr_t) va >> PTSHIFT; }
73 /* Page table number. */
74 static inline unsigned pt_no (void *va) {
75 return ((uintptr_t) va & PTMASK) >> PTSHIFT;
78 /* Page directory number. */
79 static inline uintptr_t pd_no (void *va) { return (uintptr_t) va >> PDSHIFT; }
81 /* Round up to nearest page boundary. */
82 static inline void *pg_round_up (void *va) {
83 return (void *) (((uintptr_t) va + PGSIZE - 1) & ~PGMASK);
86 /* Round down to nearest page boundary. */
87 static inline void *pg_round_down (void *va) {
88 return (void *) ((uintptr_t) va & ~PGMASK);
91 #define PHYS_BASE ((void *) LOADER_PHYS_BASE)
93 /* Returns kernel virtual address at which physical address PADDR
96 ptov (uintptr_t paddr)
98 ASSERT ((void *) paddr < PHYS_BASE);
100 return (void *) (paddr + PHYS_BASE);
103 /* Returns physical address at which kernel virtual address VADDR
105 static inline uintptr_t
108 ASSERT (vaddr >= PHYS_BASE);
110 return (uintptr_t) vaddr - (uintptr_t) PHYS_BASE;
114 /* Page Table/Directory Entry flags
115 * these are defined by the hardware
117 #define PG_P 0x1 /* Present */
118 #define PG_W 0x2 /* Writeable */
119 #define PG_U 0x4 /* User */
120 #define PG_A 0x20 /* Accessed */
121 #define PG_D 0x40 /* Dirty */
123 /* EFLAGS Register. */
124 #define FLAG_MBS 0x00000002 /* Must be set. */
125 #define FLAG_IF 0x00000200 /* Interrupt Flag. */
127 /* Page fault error codes */
128 #define FEC_PR 0x1 /* Page fault caused by protection violation */
129 #define FEC_WR 0x2 /* Page fault caused by a write */
130 #define FEC_U 0x4 /* Page fault occured while in user mode */
133 /* Application segment type bits */
134 #define STA_X 0x8 /* Executable segment */
135 #define STA_A 0x1 /* Accessed */
137 #define STA_C 0x4 /* Conforming code segment (executable only) */
138 #define STA_R 0x2 /* Readable (executable segments) */
140 #define STA_E 0x4 /* Expand down (non-executable segments) */
141 #define STA_W 0x2 /* Writeable (non-executable segments) */
145 #endif /* !_MMU_H_ */