Annotation of sys/arch/i386/include/segments.h, Revision 1.1.1.1
1.1 nbrk 1: /* $OpenBSD: segments.h,v 1.14 2006/01/12 22:39:21 weingart Exp $ */
2: /* $NetBSD: segments.h,v 1.23 1996/02/01 22:31:03 mycroft Exp $ */
3:
4: /*-
5: * Copyright (c) 1995 Charles M. Hannum. All rights reserved.
6: * Copyright (c) 1989, 1990 William F. Jolitz
7: * Copyright (c) 1990 The Regents of the University of California.
8: * All rights reserved.
9: *
10: * This code is derived from software contributed to Berkeley by
11: * William Jolitz.
12: *
13: * Redistribution and use in source and binary forms, with or without
14: * modification, are permitted provided that the following conditions
15: * are met:
16: * 1. Redistributions of source code must retain the above copyright
17: * notice, this list of conditions and the following disclaimer.
18: * 2. Redistributions in binary form must reproduce the above copyright
19: * notice, this list of conditions and the following disclaimer in the
20: * documentation and/or other materials provided with the distribution.
21: * 3. Neither the name of the University nor the names of its contributors
22: * may be used to endorse or promote products derived from this software
23: * without specific prior written permission.
24: *
25: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35: * SUCH DAMAGE.
36: *
37: * @(#)segments.h 7.1 (Berkeley) 5/9/91
38: */
39:
40: /*
41: * 386 Segmentation Data Structures and definitions
42: * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
43: */
44:
45: #ifndef _I386_SEGMENTS_H_
46: #define _I386_SEGMENTS_H_
47:
48: /*
49: * Selectors
50: */
51:
52: #define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */
53: #define SEL_KPL 0 /* kernel privilege level */
54: #define SEL_UPL 3 /* user privilege level */
55: #define SEL_RPL 3 /* requester's privilege level mask */
56: #define ISLDT(s) ((s) & SEL_LDT) /* is it local or global */
57: #define SEL_LDT 4 /* local descriptor table */
58: #define IDXSEL(s) (((s) >> 3) & 0x1fff) /* index of selector */
59: #define GSEL(s,r) (((s) << 3) | r) /* a global selector */
60: #define LSEL(s,r) (((s) << 3) | r | SEL_LDT) /* a local selector */
61:
62: #ifdef VM86
63: #define USERMODE(c, f) (ISPL(c) == SEL_UPL || ((f) & PSL_VM) != 0)
64: #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL && ((f) & PSL_VM) == 0)
65: #else
66: #define USERMODE(c, f) (ISPL(c) == SEL_UPL)
67: #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL)
68: #endif
69:
70: #ifndef _LOCORE
71:
72: #if __GNUC__ == 2 && __GNUC_MINOR__ < 7
73: #pragma pack(1)
74: #endif
75:
76: /*
77: * Memory and System segment descriptors
78: */
79: struct segment_descriptor {
80: unsigned sd_lolimit:16; /* segment extent (lsb) */
81: unsigned sd_lobase:24; /* segment base address (lsb) */
82: unsigned sd_type:5; /* segment type */
83: unsigned sd_dpl:2; /* segment descriptor priority level */
84: unsigned sd_p:1; /* segment descriptor present */
85: unsigned sd_hilimit:4; /* segment extent (msb) */
86: unsigned sd_xx:2; /* unused */
87: unsigned sd_def32:1; /* default 32 vs 16 bit size */
88: unsigned sd_gran:1; /* limit granularity (byte/page) */
89: unsigned sd_hibase:8; /* segment base address (msb) */
90: } __packed;
91:
92: /*
93: * Gate descriptors (e.g. indirect descriptors)
94: */
95: struct gate_descriptor {
96: unsigned gd_looffset:16; /* gate offset (lsb) */
97: unsigned gd_selector:16; /* gate segment selector */
98: unsigned gd_stkcpy:5; /* number of stack wds to cpy */
99: unsigned gd_xx:3; /* unused */
100: unsigned gd_type:5; /* segment type */
101: unsigned gd_dpl:2; /* segment descriptor priority level */
102: unsigned gd_p:1; /* segment descriptor present */
103: unsigned gd_hioffset:16; /* gate offset (msb) */
104: } __packed;
105:
106: /*
107: * Generic descriptor
108: */
109: union descriptor {
110: struct segment_descriptor sd;
111: struct gate_descriptor gd;
112: } __packed;
113:
114: /*
115: * region descriptors, used to load gdt/idt tables before segments yet exist.
116: */
117: struct region_descriptor {
118: unsigned rd_limit:16; /* segment extent */
119: unsigned rd_base:32; /* base address */
120: } __packed;
121:
122: #if __GNUC__ == 2 && __GNUC_MINOR__ < 7
123: #pragma pack(4)
124: #endif
125:
126: #ifdef _KERNEL
127: extern union descriptor *gdt, ldt[];
128: extern struct gate_descriptor idt_region[];
129: extern struct gate_descriptor *idt;
130:
131: void setgate(struct gate_descriptor *, void *, int, int, int, int);
132: void setregion(struct region_descriptor *, void *, size_t);
133: void setsegment(struct segment_descriptor *, void *, size_t, int, int,
134: int, int);
135: void unsetgate(struct gate_descriptor *);
136: void cpu_init_idt(void);
137: void cpu_default_ldt(struct cpu_info *);
138: void cpu_alloc_ldt(struct cpu_info *);
139: void cpu_init_ldt(struct cpu_info *);
140:
141: int idt_vec_alloc(int, int);
142: void idt_vec_set(int, void (*)(void));
143: void idt_vec_free(int);
144:
145: #endif /* _KERNEL */
146:
147: #endif /* !_LOCORE */
148:
149: /* system segments and gate types */
150: #define SDT_SYSNULL 0 /* system null */
151: #define SDT_SYS286TSS 1 /* system 286 TSS available */
152: #define SDT_SYSLDT 2 /* system local descriptor table */
153: #define SDT_SYS286BSY 3 /* system 286 TSS busy */
154: #define SDT_SYS286CGT 4 /* system 286 call gate */
155: #define SDT_SYSTASKGT 5 /* system task gate */
156: #define SDT_SYS286IGT 6 /* system 286 interrupt gate */
157: #define SDT_SYS286TGT 7 /* system 286 trap gate */
158: #define SDT_SYSNULL2 8 /* system null again */
159: #define SDT_SYS386TSS 9 /* system 386 TSS available */
160: #define SDT_SYSNULL3 10 /* system null again */
161: #define SDT_SYS386BSY 11 /* system 386 TSS busy */
162: #define SDT_SYS386CGT 12 /* system 386 call gate */
163: #define SDT_SYSNULL4 13 /* system null again */
164: #define SDT_SYS386IGT 14 /* system 386 interrupt gate */
165: #define SDT_SYS386TGT 15 /* system 386 trap gate */
166:
167: /* memory segment types */
168: #define SDT_MEMRO 16 /* memory read only */
169: #define SDT_MEMROA 17 /* memory read only accessed */
170: #define SDT_MEMRW 18 /* memory read write */
171: #define SDT_MEMRWA 19 /* memory read write accessed */
172: #define SDT_MEMROD 20 /* memory read only expand dwn limit */
173: #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
174: #define SDT_MEMRWD 22 /* memory read write expand dwn limit */
175: #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */
176: #define SDT_MEME 24 /* memory execute only */
177: #define SDT_MEMEA 25 /* memory execute only accessed */
178: #define SDT_MEMER 26 /* memory execute read */
179: #define SDT_MEMERA 27 /* memory execute read accessed */
180: #define SDT_MEMEC 28 /* memory execute only conforming */
181: #define SDT_MEMEAC 29 /* memory execute only accessed conforming */
182: #define SDT_MEMERC 30 /* memory execute read conforming */
183: #define SDT_MEMERAC 31 /* memory execute read accessed conforming */
184:
185: /* is memory segment descriptor pointer ? */
186: #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \
187: (s->d_type) <= SDT_MEMERAC)
188:
189: /* is 286 gate descriptor pointer ? */
190: #define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \
191: (s->d_type) < SDT_SYS286TGT)
192:
193: /* is 386 gate descriptor pointer ? */
194: #define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \
195: (s->d_type) < SDT_SYS386TGT)
196:
197: /* is gate descriptor pointer ? */
198: #define ISGDP(s) (IS286GDP(s) || IS386GDP(s))
199:
200: /* is segment descriptor pointer ? */
201: #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s))
202:
203: /* is system segment descriptor pointer ? */
204: #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s))
205:
206: /*
207: * Segment Protection Exception code bits
208: */
209: #define SEGEX_EXT 0x01 /* recursive or externally induced */
210: #define SEGEX_IDT 0x02 /* interrupt descriptor table */
211: #define SEGEX_TI 0x04 /* local descriptor table */
212:
213: /*
214: * Entries in the Interrupt Descriptor Table (IDT)
215: */
216: #define NIDT 256
217: #define NRSVIDT 32 /* reserved entries for cpu exceptions */
218:
219: /*
220: * Entries in the Global Descriptor Table (GDT)
221: */
222: #define GNULL_SEL 0 /* Null descriptor */
223: #define GCODE_SEL 1 /* Kernel code descriptor */
224: #define GDATA_SEL 2 /* Kernel data descriptor */
225: #define GLDT_SEL 3 /* Default LDT descriptor */
226: #define GUCODE1_SEL 4 /* User code descriptor */
227: #define GUCODE_SEL 5 /* User code descriptor (a stack short) */
228: #define GUDATA_SEL 6 /* User data descriptor */
229: #define GAPM32CODE_SEL 7 /* 32 bit APM code descriptor */
230: #define GAPM16CODE_SEL 8 /* 16 bit APM code descriptor */
231: #define GAPMDATA_SEL 9 /* APM data descriptor */
232: #define GICODE_SEL 10 /* Interrupt code descriptor (same as Kernel code) */
233: #define GCPU_SEL 11 /* per-CPU segment */
234: #define NGDT 12
235:
236: /*
237: * Entries in the Local Descriptor Table (LDT)
238: */
239: #define LSYS5CALLS_SEL 0 /* iBCS system call gate */
240: #define LSYS5SIGR_SEL 1 /* iBCS sigreturn gate */
241: #define LUCODE1_SEL 2 /* User code descriptor */
242: #define LUCODE_SEL 3 /* User code descriptor (a stack short) */
243: #define LUDATA_SEL 4 /* User data descriptor */
244: #define LBSDICALLS_SEL 16 /* BSDI system call gate */
245: #define NLDT 17
246:
247: #endif /* _I386_SEGMENTS_H_ */
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