2 * Copyright (c) 1989, 1990 William F. Jolitz
3 * Copyright (c) 1990 The Regents of the University of California.
6 * This code is derived from software contributed to Berkeley by
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10 * modification, are permitted provided that the following conditions
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33 * from: @(#)segments.h 7.1 (Berkeley) 5/9/91
37 #ifndef _MACHINE_SEGMENTS_H_
38 #define _MACHINE_SEGMENTS_H_
41 * 386 Segmentation Data Structures and definitions
42 * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
49 #define ISPL(s) ((s)&3) /* what is the priority level of a selector */
51 #define SEL_KPL 1 /* kernel priority level */
53 #define SEL_KPL 0 /* kernel priority level */
55 #define SEL_UPL 3 /* user priority level */
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 LSEL(s,r) (((s)<<3) | SEL_LDT | r) /* a local selector */
60 #define GSEL(s,r) (((s)<<3) | r) /* a global selector */
63 * Memory and System segment descriptors
65 struct segment_descriptor {
66 unsigned sd_lolimit:16 ; /* segment extent (lsb) */
67 unsigned sd_lobase:24 __packed; /* segment base address (lsb) */
68 unsigned sd_type:5 ; /* segment type */
69 unsigned sd_dpl:2 ; /* segment descriptor priority level */
70 unsigned sd_p:1 ; /* segment descriptor present */
71 unsigned sd_hilimit:4 ; /* segment extent (msb) */
72 unsigned sd_xx:2 ; /* unused */
73 unsigned sd_def32:1 ; /* default 32 vs 16 bit size */
74 unsigned sd_gran:1 ; /* limit granularity (byte/page units)*/
75 unsigned sd_hibase:8 ; /* segment base address (msb) */
79 * Gate descriptors (e.g. indirect descriptors)
81 struct gate_descriptor {
82 unsigned gd_looffset:16 ; /* gate offset (lsb) */
83 unsigned gd_selector:16 ; /* gate segment selector */
84 unsigned gd_stkcpy:5 ; /* number of stack wds to cpy */
85 unsigned gd_xx:3 ; /* unused */
86 unsigned gd_type:5 ; /* segment type */
87 unsigned gd_dpl:2 ; /* segment descriptor priority level */
88 unsigned gd_p:1 ; /* segment descriptor present */
89 unsigned gd_hioffset:16 ; /* gate offset (msb) */
96 struct segment_descriptor sd;
97 struct gate_descriptor gd;
100 /* system segments and gate types */
101 #define SDT_SYSNULL 0 /* system null */
102 #define SDT_SYS286TSS 1 /* system 286 TSS available */
103 #define SDT_SYSLDT 2 /* system local descriptor table */
104 #define SDT_SYS286BSY 3 /* system 286 TSS busy */
105 #define SDT_SYS286CGT 4 /* system 286 call gate */
106 #define SDT_SYSTASKGT 5 /* system task gate */
107 #define SDT_SYS286IGT 6 /* system 286 interrupt gate */
108 #define SDT_SYS286TGT 7 /* system 286 trap gate */
109 #define SDT_SYSNULL2 8 /* system null again */
110 #define SDT_SYS386TSS 9 /* system 386 TSS available */
111 #define SDT_SYSNULL3 10 /* system null again */
112 #define SDT_SYS386BSY 11 /* system 386 TSS busy */
113 #define SDT_SYS386CGT 12 /* system 386 call gate */
114 #define SDT_SYSNULL4 13 /* system null again */
115 #define SDT_SYS386IGT 14 /* system 386 interrupt gate */
116 #define SDT_SYS386TGT 15 /* system 386 trap gate */
118 /* memory segment types */
119 #define SDT_MEMRO 16 /* memory read only */
120 #define SDT_MEMROA 17 /* memory read only accessed */
121 #define SDT_MEMRW 18 /* memory read write */
122 #define SDT_MEMRWA 19 /* memory read write accessed */
123 #define SDT_MEMROD 20 /* memory read only expand dwn limit */
124 #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */
125 #define SDT_MEMRWD 22 /* memory read write expand dwn limit */
126 #define SDT_MEMRWDA 23 /* memory read write expand dwn limit accessed */
127 #define SDT_MEME 24 /* memory execute only */
128 #define SDT_MEMEA 25 /* memory execute only accessed */
129 #define SDT_MEMER 26 /* memory execute read */
130 #define SDT_MEMERA 27 /* memory execute read accessed */
131 #define SDT_MEMEC 28 /* memory execute only conforming */
132 #define SDT_MEMEAC 29 /* memory execute only accessed conforming */
133 #define SDT_MEMERC 30 /* memory execute read conforming */
134 #define SDT_MEMERAC 31 /* memory execute read accessed conforming */
137 * Software definitions are in this convenient format,
138 * which are translated into inconvenient segment descriptors
139 * when needed to be used by the 386 hardware
142 struct soft_segment_descriptor {
143 unsigned ssd_base ; /* segment base address */
144 unsigned ssd_limit ; /* segment extent */
145 unsigned ssd_type:5 ; /* segment type */
146 unsigned ssd_dpl:2 ; /* segment descriptor priority level */
147 unsigned ssd_p:1 ; /* segment descriptor present */
148 unsigned ssd_xx:4 ; /* unused */
149 unsigned ssd_xx1:2 ; /* unused */
150 unsigned ssd_def32:1 ; /* default 32 vs 16 bit size */
151 unsigned ssd_gran:1 ; /* limit granularity (byte/page units)*/
155 * region descriptors, used to load gdt/idt tables before segments yet exist.
157 struct region_descriptor {
158 unsigned rd_limit:16; /* segment extent */
159 unsigned rd_base:32 __packed; /* base address */
163 * Segment Protection Exception code bits
166 #define SEGEX_EXT 0x01 /* recursive or externally induced */
167 #define SEGEX_IDT 0x02 /* interrupt descriptor table */
168 #define SEGEX_TI 0x04 /* local descriptor table */
169 /* other bits are affected descriptor index */
170 #define SEGEX_IDX(s) (((s)>>3)&0x1fff)
176 #define NIDT 256 /* 32 reserved, 0x80 syscall, most are h/w */
177 #define NRSVIDT 32 /* reserved entries for cpu exceptions */
180 * Entries in the Interrupt Descriptor Table (IDT)
182 #define IDT_DE 0 /* #DE: Divide Error */
183 #define IDT_DB 1 /* #DB: Debug */
184 #define IDT_NMI 2 /* Nonmaskable External Interrupt */
185 #define IDT_BP 3 /* #BP: Breakpoint */
186 #define IDT_OF 4 /* #OF: Overflow */
187 #define IDT_BR 5 /* #BR: Bound Range Exceeded */
188 #define IDT_UD 6 /* #UD: Undefined/Invalid Opcode */
189 #define IDT_NM 7 /* #NM: No Math Coprocessor */
190 #define IDT_DF 8 /* #DF: Double Fault */
191 #define IDT_FPUGP 9 /* Coprocessor Segment Overrun */
192 #define IDT_TS 10 /* #TS: Invalid TSS */
193 #define IDT_NP 11 /* #NP: Segment Not Present */
194 #define IDT_SS 12 /* #SS: Stack Segment Fault */
195 #define IDT_GP 13 /* #GP: General Protection Fault */
196 #define IDT_PF 14 /* #PF: Page Fault */
197 #define IDT_MF 16 /* #MF: FPU Floating-Point Error */
198 #define IDT_AC 17 /* #AC: Alignment Check */
199 #define IDT_MC 18 /* #MC: Machine Check */
200 #define IDT_XF 19 /* #XF: SIMD Floating-Point Exception */
201 #define IDT_IO_INTS NRSVIDT /* Base of IDT entries for I/O interrupts. */
202 #define IDT_SYSCALL 0x80 /* System Call Interrupt Vector */
205 * Entries in the Global Descriptor Table (GDT)
206 * Note that each 4 entries share a single 32 byte L1 cache line.
207 * Some of the fast syscall instructions require a specific order here.
209 #define GNULL_SEL 0 /* Null Descriptor */
210 #define GPRIV_SEL 1 /* SMP Per-Processor Private Data */
211 #define GUFS_SEL 2 /* User %fs Descriptor (order critical: 1) */
212 #define GUGS_SEL 3 /* User %gs Descriptor (order critical: 2) */
213 #define GCODE_SEL 4 /* Kernel Code Descriptor (order critical: 1) */
214 #define GDATA_SEL 5 /* Kernel Data Descriptor (order critical: 2) */
215 #define GUCODE_SEL 6 /* User Code Descriptor (order critical: 3) */
216 #define GUDATA_SEL 7 /* User Data Descriptor (order critical: 4) */
217 #define GBIOSLOWMEM_SEL 8 /* BIOS low memory access (must be entry 8) */
218 #define GPROC0_SEL 9 /* Task state process slot zero and up */
219 #define GLDT_SEL 10 /* Default User LDT */
220 #define GUSERLDT_SEL 11 /* User LDT */
221 #define GPANIC_SEL 12 /* Task state to consider panic from */
222 #define GBIOSCODE32_SEL 13 /* BIOS interface (32bit Code) */
223 #define GBIOSCODE16_SEL 14 /* BIOS interface (16bit Code) */
224 #define GBIOSDATA_SEL 15 /* BIOS interface (Data) */
225 #define GBIOSUTIL_SEL 16 /* BIOS interface (Utility) */
226 #define GBIOSARGS_SEL 17 /* BIOS interface (Arguments) */
227 #define GNDIS_SEL 18 /* For the NDIS layer */
236 * Entries in the Local Descriptor Table (LDT)
238 #define LSYS5CALLS_SEL 0 /* forced by intel BCS */
239 #define LSYS5SIGR_SEL 1
240 #define L43BSDCALLS_SEL 2 /* notyet */
242 #define LSOL26CALLS_SEL 4 /* Solaris >= 2.6 system call gate */
244 /* separate stack, es,fs,gs sels ? */
245 /* #define LPOSIXCALLS_SEL 5*/ /* notyet */
246 #define LBSDICALLS_SEL 16 /* BSDI system call gate */
247 #define NLDT (LBSDICALLS_SEL + 1)
250 extern int _default_ldt;
252 extern union descriptor *gdt;
253 extern union descriptor *ldt;
255 extern union descriptor gdt[];
256 extern union descriptor ldt[NLDT];
258 extern struct soft_segment_descriptor gdt_segs[];
259 extern struct gate_descriptor *idt;
260 extern struct region_descriptor r_gdt, r_idt;
262 void lgdt(struct region_descriptor *rdp);
263 void sdtossd(struct segment_descriptor *sdp,
264 struct soft_segment_descriptor *ssdp);
265 void ssdtosd(struct soft_segment_descriptor *ssdp,
266 struct segment_descriptor *sdp);
269 #endif /* !_MACHINE_SEGMENTS_H_ */