/* $OpenBSD: segments.h,v 1.28 2020/09/24 11:36:50 deraadt Exp $ */ /* $NetBSD: segments.h,v 1.23 1996/02/01 22:31:03 mycroft Exp $ */ /*- * Copyright (c) 1995 Charles M. Hannum. All rights reserved. * Copyright (c) 1989, 1990 William F. Jolitz * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * This code is derived from software contributed to Berkeley by * William Jolitz. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)segments.h 7.1 (Berkeley) 5/9/91 */ /* * 386 Segmentation Data Structures and definitions * William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989 */ #ifndef _MACHINE_SEGMENTS_H_ #define _MACHINE_SEGMENTS_H_ /* * Selectors */ #define ISPL(s) ((s) & SEL_RPL) /* what is the priority level of a selector */ #define SEL_KPL 0 /* kernel privilege level */ #define SEL_UPL 3 /* user privilege level */ #define SEL_RPL 3 /* requester's privilege level mask */ #define ISLDT(s) ((s) & SEL_LDT) /* is it local or global */ #define SEL_LDT 4 /* local descriptor table */ #define IDXSEL(s) (((s) >> 3) & 0x1fff) /* index of selector */ #define GSEL(s,r) (((s) << 3) | r) /* a global selector */ #define LSEL(s,r) (((s) << 3) | r | SEL_LDT) /* a local selector */ #define USERMODE(c, f) (ISPL(c) == SEL_UPL) #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL) #ifndef _LOCORE /* * Memory and System segment descriptors */ struct segment_descriptor { unsigned sd_lolimit:16; /* segment extent (lsb) */ unsigned sd_lobase:24; /* segment base address (lsb) */ unsigned sd_type:5; /* segment type */ unsigned sd_dpl:2; /* segment descriptor priority level */ unsigned sd_p:1; /* segment descriptor present */ unsigned sd_hilimit:4; /* segment extent (msb) */ unsigned sd_xx:2; /* unused */ unsigned sd_def32:1; /* default 32 vs 16 bit size */ unsigned sd_gran:1; /* limit granularity (byte/page) */ unsigned sd_hibase:8; /* segment base address (msb) */ } __packed; /* * Gate descriptors (e.g. indirect descriptors) */ struct gate_descriptor { unsigned gd_looffset:16; /* gate offset (lsb) */ unsigned gd_selector:16; /* gate segment selector */ unsigned gd_stkcpy:5; /* number of stack wds to cpy */ unsigned gd_xx:3; /* unused */ unsigned gd_type:5; /* segment type */ unsigned gd_dpl:2; /* segment descriptor priority level */ unsigned gd_p:1; /* segment descriptor present */ unsigned gd_hioffset:16; /* gate offset (msb) */ } __packed; /* * Generic descriptor */ union descriptor { struct segment_descriptor sd; struct gate_descriptor gd; } __packed; /* * region descriptors, used to load gdt/idt tables before segments yet exist. */ struct region_descriptor { unsigned rd_limit:16; /* segment extent */ unsigned rd_base:32; /* base address */ } __packed; #ifdef _KERNEL extern union descriptor *gdt; extern struct gate_descriptor idt_region[]; extern struct gate_descriptor *idt; #define SEGDESC_LIMIT(sd) (ptoa(((sd).sd_hilimit << 16) | (sd).sd_lolimit)) void setgate(struct gate_descriptor *, void *, int, int, int, int); void setregion(struct region_descriptor *, void *, size_t); void setsegment(struct segment_descriptor *, void *, size_t, int, int, int, int); void initcodesegment(struct segment_descriptor *); void unsetgate(struct gate_descriptor *); void cpu_init_idt(void); int idt_vec_alloc(int, int); void idt_vec_set(int, void (*)(void)); void idt_vec_free(int); #endif /* _KERNEL */ #endif /* !_LOCORE */ /* system segments and gate types */ #define SDT_SYSNULL 0 /* system null */ #define SDT_SYS286TSS 1 /* system 286 TSS available */ #define SDT_SYSLDT 2 /* system local descriptor table */ #define SDT_SYS286BSY 3 /* system 286 TSS busy */ #define SDT_SYS286CGT 4 /* system 286 call gate */ #define SDT_SYSTASKGT 5 /* system task gate */ #define SDT_SYS286IGT 6 /* system 286 interrupt gate */ #define SDT_SYS286TGT 7 /* system 286 trap gate */ #define SDT_SYSNULL2 8 /* system null again */ #define SDT_SYS386TSS 9 /* system 386 TSS available */ #define SDT_SYSNULL3 10 /* system null again */ #define SDT_SYS386BSY 11 /* system 386 TSS busy */ #define SDT_SYS386CGT 12 /* system 386 call gate */ #define SDT_SYSNULL4 13 /* system null again */ #define SDT_SYS386IGT 14 /* system 386 interrupt gate */ #define SDT_SYS386TGT 15 /* system 386 trap gate */ /* memory segment types */ #define SDT_MEMRO 16 /* memory read only */ #define SDT_MEMROA 17 /* memory read only accessed */ #define SDT_MEMRW 18 /* memory read write */ #define SDT_MEMRWA 19 /* memory read write accessed */ #define SDT_MEMROD 20 /* memory read only expand dwn limit */ #define SDT_MEMRODA 21 /* memory read only expand dwn limit accessed */ #define SDT_MEMRWD 22 /* memory read write expand dwn limit */ #define SDT_MEMRWDA 23 /* memory read write expand dwn limit acessed */ #define SDT_MEME 24 /* memory execute only */ #define SDT_MEMEA 25 /* memory execute only accessed */ #define SDT_MEMER 26 /* memory execute read */ #define SDT_MEMERA 27 /* memory execute read accessed */ #define SDT_MEMEC 28 /* memory execute only conforming */ #define SDT_MEMEAC 29 /* memory execute only accessed conforming */ #define SDT_MEMERC 30 /* memory execute read conforming */ #define SDT_MEMERAC 31 /* memory execute read accessed conforming */ /* is memory segment descriptor pointer ? */ #define ISMEMSDP(s) ((s->d_type) >= SDT_MEMRO && \ (s->d_type) <= SDT_MEMERAC) /* is 286 gate descriptor pointer ? */ #define IS286GDP(s) ((s->d_type) >= SDT_SYS286CGT && \ (s->d_type) < SDT_SYS286TGT) /* is 386 gate descriptor pointer ? */ #define IS386GDP(s) ((s->d_type) >= SDT_SYS386CGT && \ (s->d_type) < SDT_SYS386TGT) /* is gate descriptor pointer ? */ #define ISGDP(s) (IS286GDP(s) || IS386GDP(s)) /* is segment descriptor pointer ? */ #define ISSDP(s) (ISMEMSDP(s) || !ISGDP(s)) /* is system segment descriptor pointer ? */ #define ISSYSSDP(s) (!ISMEMSDP(s) && !ISGDP(s)) /* * Segment Protection Exception code bits */ #define SEGEX_EXT 0x01 /* recursive or externally induced */ #define SEGEX_IDT 0x02 /* interrupt descriptor table */ #define SEGEX_TI 0x04 /* local descriptor table */ /* * Entries in the Interrupt Descriptor Table (IDT) */ #define NIDT 256 #define NRSVIDT 32 /* reserved entries for cpu exceptions */ /* * Entries in the Global Descriptor Table (GDT) */ #define GNULL_SEL 0 /* Null descriptor */ #define GCODE_SEL 1 /* Kernel code descriptor */ #define GDATA_SEL 2 /* Kernel data descriptor */ #define GLDT_SEL 3 /* Default LDT descriptor (UNUSED) */ #define GCPU_SEL 4 /* per-CPU segment */ #define GUCODE_SEL 5 /* User code descriptor (a stack short) */ #define GUDATA_SEL 6 /* User data descriptor */ #define GAPM32CODE_SEL 7 /* 32 bit APM code descriptor */ #define GAPM16CODE_SEL 8 /* 16 bit APM code descriptor */ #define GAPMDATA_SEL 9 /* APM data descriptor */ #define GICODE_SEL 10 /* Interrupt code descriptor (same as Kernel code) */ #define GUFS_SEL 11 /* User per-thread (%fs) descriptor */ #define GUGS_SEL 12 /* User per-thread (%gs) descriptor */ #define GTSS_SEL 13 /* common TSS */ #define GNMITSS_SEL 14 /* NMI TSS */ #define GBIOS32_SEL 15 /* spare slot for 32 bit BIOS calls */ #define NGDT 16 #define GDT_SIZE (NGDT << 3) #endif /* _MACHINE_SEGMENTS_H_ */
