/* $OpenBSD: segments.h,v 1.18 2025/06/27 17:23:49 bluhm Exp $ */ /* $NetBSD: segments.h,v 1.1 2003/04/26 18:39:47 fvdl Exp $ */ /*- * Copyright (c) 1995, 1997 * 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 */ /* * Adapted for NetBSD/amd64 by fvdl@wasabisystems.com. */ /* * 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 SYSSEL_START (NGDT_MEM << 3) #define GDT_SIZE (SYSSEL_START + (NGDT_SYS << 4)) /* * These define the index not from the start of the GDT, but from * the part of the GDT that they're allocated from. * First NGDT_MEM entries are 8-byte descriptors for CS and DS. * Next NGDT_SYS entries are 16-byte descriptors defining TSSs. */ #define IDXSEL(s) (((s) >> 3) & 0x1fff) #define IDXDYNSEL(s) ((((s) & ~SEL_RPL) - DYNSEL_START) >> 4) #define GSEL(s,r) (((s) << 3) | r) #define GSYSSEL(s,r) ((((s) << 4) + SYSSEL_START) | r) #define GDYNSEL(s,r) ((((s) << 4) + DYNSEL_START) | r | SEL_KPL) #define LSEL(s,r) ((s) | r | SEL_LDT) #define USERMODE(c, f) (ISPL(c) == SEL_UPL) #define KERNELMODE(c, f) (ISPL(c) == SEL_KPL) #ifndef _LOCORE /* * Memory and System segment descriptors */ /* * Below is used for TSS and LDT. */ struct sys_segment_descriptor { u_int64_t sd_lolimit:16; /* segment extent (lsb) */ u_int64_t sd_lobase:24; /* segment base address (lsb) */ u_int64_t sd_type:5; /* segment type */ u_int64_t sd_dpl:2; /* segment descriptor priority level */ u_int64_t sd_p:1; /* segment descriptor present */ u_int64_t sd_hilimit:4; /* segment extent (msb) */ u_int64_t sd_xx1:3; /* avl, long and def32 (not used) */ u_int64_t sd_gran:1; /* limit granularity (byte/page) */ u_int64_t sd_hibase:40; /* segment base address (msb) */ u_int64_t sd_xx2:8; /* reserved */ u_int64_t sd_zero:5; /* must be zero */ u_int64_t sd_xx3:19; /* reserved */ } __packed; /* * Below is used for cs, ds, etc. */ struct mem_segment_descriptor { unsigned int sd_lolimit:16; /* segment extent (lsb) */ unsigned int sd_lobase:24; /* segment base address (lsb) */ unsigned int sd_type:5; /* segment type */ unsigned int sd_dpl:2; /* segment descriptor priority level */ unsigned int sd_p:1; /* segment descriptor present */ unsigned int sd_hilimit:4; /* segment extent (msb) */ unsigned int sd_avl:1; /* available */ unsigned int sd_long:1; /* long mode */ unsigned int sd_def32:1; /* default 32 vs 16 bit size */ unsigned int sd_gran:1; /* limit granularity (byte/page) */ unsigned int sd_hibase:8; /* segment base address (msb) */ } __packed; /* * Gate descriptors (e.g. indirect descriptors) */ struct gate_descriptor { u_int64_t gd_looffset:16; /* gate offset (lsb) */ u_int64_t gd_selector:16; /* gate segment selector */ u_int64_t gd_ist:3; /* IST select */ u_int64_t gd_xx1:5; /* reserved */ u_int64_t gd_type:5; /* segment type */ u_int64_t gd_dpl:2; /* segment descriptor priority level */ u_int64_t gd_p:1; /* segment descriptor present */ u_int64_t gd_hioffset:48; /* gate offset (msb) */ u_int64_t gd_xx2:8; /* reserved */ u_int64_t gd_zero:5; /* must be zero */ u_int64_t gd_xx3:19; /* reserved */ } __packed; /* * region descriptors, used to load gdt/idt tables before segments yet exist. */ struct region_descriptor { u_int16_t rd_limit; /* segment extent */ u_int64_t rd_base; /* base address */ } __packed; #ifdef _KERNEL extern struct gate_descriptor *idt; extern struct gate_descriptor early_idt[]; void setgate(struct gate_descriptor *, void *, int, int, int, int); void unsetgate(struct gate_descriptor *); void setregion(struct region_descriptor *, void *, u_int16_t); void set_sys_segment(struct sys_segment_descriptor *, void *, size_t, int, int, int); void set_mem_segment(struct mem_segment_descriptor *, void *, size_t, int, int, int, int, int); int idt_vec_alloc(int, int); int idt_vec_alloc_range(int, int, int); void idt_vec_set(int, void (*)(void)); void idt_vec_free(int); void cpu_init_idt(void); #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) * The code and data descriptors must come first. There * are NGDT_MEM of them. * * Then comes the predefined TSS descriptor. * There are NGDT_SYS of them. * * The particular order of the UDATA and UCODE descriptors is * required by the sysretq instruction. */ #define GNULL_SEL 0 /* Null descriptor */ #define GCODE_SEL 1 /* Kernel code descriptor */ #define GDATA_SEL 2 /* Kernel data descriptor */ #define GUDATA_SEL 3 /* User data descriptor */ #define GUCODE_SEL 4 /* User code descriptor */ #define NGDT_MEM 5 #define GPROC0_SEL 0 /* common TSS */ #define NGDT_SYS 1 #define GDT_SYS_OFFSET (NGDT_MEM << 3) #define GDT_ADDR_MEM(s,i) \ ((struct mem_segment_descriptor *)((char *)(s) + ((i) << 3))) #define GDT_ADDR_SYS(s,i) \ ((struct sys_segment_descriptor *)((char *)(s) + ((i) << 4) + SYSSEL_START)) /* * Checks for valid user selectors. */ #define VALID_USER_CSEL(s) \ ((s) == GSEL(GUCODE_SEL, SEL_UPL)) #define VALID_USER_DSEL(s) \ ((s) == GSEL(GUDATA_SEL, SEL_UPL)) #endif /* _MACHINE_SEGMENTS_H_ */
