segments.h

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/*-
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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
 */
#ifndef __MACHDEP_SEGMENTS_H__
#define __MACHDEP_SEGMENTS_H__
/*
 * 386 Segmentation Data Structures and definitions
 *      William F. Jolitz (william@ernie.berkeley.edu) 6/20/1989
 */

/* modified for LSE/OS by Vianney Rancurel */

/*
 * Selectors
 */

#define ISRING(s)       ((s) & SEL_RPL) /* what is the ring of a selector */
#define RING0           0               /* kernel privilege level */    
#define RING1           1               /* Ring 1                 */
#define RING2           2               /* Ring 2                 */
#define RING3           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 */

#if defined(_KERNEL) && !defined(_LKM)
#include "opt_vm86.h"
#endif

#ifdef VM86
#define USERMODE(c, f)          (ISPL(c) == SEL_UPL || ((f) & PSL_VM) != 0)
#define KERNELMODE(c, f)        (ISPL(c) == SEL_KPL && ((f) & PSL_VM) == 0)
#else
#define USERMODE(c, f)          (ISPL(c) == SEL_UPL)
#define KERNELMODE(c, f)        (ISPL(c) == SEL_KPL)
#endif

#ifndef __LOCORE__

#if __GNUC__ == 2 && __GNUC_MINOR__ < 7
#pragma pack(1)
#endif

/*
 * 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) */
} __attribute__((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) */
} __attribute__((packed));

/*
 * Generic descriptor
 */
union descriptor {
        struct segment_descriptor sd;
        struct gate_descriptor gd;
} __attribute__((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  */
} __attribute__((packed));

#if __GNUC__ == 2 && __GNUC_MINOR__ < 7
#pragma pack(4)
#endif

#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

/*
 * Entries in the Global Descriptor Table (GDT)
 */
#define GNULL_IDXSEL    0       /* Null descriptor */
#define GCODE_IDXSEL    1       /* Kernel code descriptor */
#define GDATA_IDXSEL    2       /* Kernel data descriptor */
#define GLDT_IDXSEL     3       /* Default LDT descriptor */
#define G1CODE_IDXSEL   4       /* pl1 code descriptor */
#define G1DATA_IDXSEL   5       /* pl1 data descriptor */
#define G2CODE_IDXSEL   6       /* pl2 code descriptor */
#define G2DATA_IDXSEL   7       /* pl2 data descriptor */
#define GUCODE_IDXSEL   8       /* User code descriptor */
#define GUDATA_IDXSEL   9       /* User data descriptor */

/*
 * task selectors
 */
#define GBSTRAP_TSS_IDXSEL      15      /* bootstrap tss        */
#define GKERN0_TSS_IDXSEL       16      /* kernel tss           */
#define GKERN1_TSS_IDXSEL       17      /* kernel tss           */
#define GKERN2_TSS_IDXSEL       18      /* kernel tss           */
#define GKERN3_TSS_IDXSEL       19      /* kernel tss           */
#define GKERN4_TSS_IDXSEL       20      /* kernel tss           */
#define GKERN5_TSS_IDXSEL       21      /* kernel tss           */
#define GKERN6_TSS_IDXSEL       22      /* kernel tss           */
#define GKERN7_TSS_IDXSEL       23      /* kernel tss           */
#define GCORE0_TSS_IDXSEL       24      /* core server tss      */
#define GCORE1_TSS_IDXSEL       25      /* core server tss      */
#define GCORE2_TSS_IDXSEL       26      /* core server tss      */
#define GCORE3_TSS_IDXSEL       27      /* core server tss      */
#define GCORE4_TSS_IDXSEL       28      /* core server tss      */
#define GCORE5_TSS_IDXSEL       29      /* core server tss      */
#define GCORE6_TSS_IDXSEL       30      /* core server tss      */
#define GCORE7_TSS_IDXSEL       31      /* core server tss      */
#define GTRAP0_TSS_IDXSEL       32      /* trap server tss      */
#define GTRAP1_TSS_IDXSEL       33      /* trap server tss      */
#define GTRAP2_TSS_IDXSEL       34      /* trap server tss      */
#define GTRAP3_TSS_IDXSEL       35      /* trap server tss      */
#define GTRAP4_TSS_IDXSEL       36      /* trap server tss      */
#define GTRAP5_TSS_IDXSEL       37      /* trap server tss      */
#define GTRAP6_TSS_IDXSEL       38      /* trap server tss      */
#define GTRAP7_TSS_IDXSEL       39      /* trap server tss      */
#define GPGFLT0_TSS_IDXSEL      40      /* page fault server tss        */
#define GPGFLT1_TSS_IDXSEL      41      /* page fault server tss        */
#define GPGFLT2_TSS_IDXSEL      42      /* page fault server tss        */
#define GPGFLT3_TSS_IDXSEL      43      /* page fault server tss        */
#define GPGFLT4_TSS_IDXSEL      44      /* page fault server tss        */
#define GPGFLT5_TSS_IDXSEL      45      /* page fault server tss        */
#define GPGFLT6_TSS_IDXSEL      46      /* page fault server tss        */
#define GPGFLT7_TSS_IDXSEL      47      /* page fault server tss        */
#define GDBLFLT0_TSS_IDXSEL     48      /* dblflt server tss            */
#define GDBLFLT1_TSS_IDXSEL     49      /* dblflt server tss            */
#define GDBLFLT2_TSS_IDXSEL     50      /* dblflt server tss            */
#define GDBLFLT3_TSS_IDXSEL     51      /* dblflt server tss            */
#define GDBLFLT4_TSS_IDXSEL     52      /* dblflt server tss            */
#define GDBLFLT5_TSS_IDXSEL     53      /* dblflt server tss            */
#define GDBLFLT6_TSS_IDXSEL     54      /* dblflt server tss            */
#define GDBLFLT7_TSS_IDXSEL     55      /* dblflt server tss            */
#define GSTRAY0_TSS_IDXSEL      56      /* stray interrupt tss          */
#define GSTRAY1_TSS_IDXSEL      57      /* stray interrupt tss          */
#define GSTRAY2_TSS_IDXSEL      58      /* stray interrupt tss          */
#define GSTRAY3_TSS_IDXSEL      59      /* stray interrupt tss          */
#define GSTRAY4_TSS_IDXSEL      60      /* stray interrupt tss          */
#define GSTRAY5_TSS_IDXSEL      61      /* stray interrupt tss          */
#define GSTRAY6_TSS_IDXSEL      62      /* stray interrupt tss          */
#define GSTRAY7_TSS_IDXSEL      63      /* stray interrupt tss          */
#define GBREAKPOINT0_TSS_IDXSEL 64      /* breakpoint tss               */
#define GBREAKPOINT1_TSS_IDXSEL 65      /* breakpoint tss               */
#define GBREAKPOINT2_TSS_IDXSEL 66      /* breakpoint tss               */
#define GBREAKPOINT3_TSS_IDXSEL 67      /* breakpoint tss               */
#define GBREAKPOINT4_TSS_IDXSEL 68      /* breakpoint tss               */
#define GBREAKPOINT5_TSS_IDXSEL 69      /* breakpoint tss               */
#define GBREAKPOINT6_TSS_IDXSEL 70      /* breakpoint tss               */
#define GBREAKPOINT7_TSS_IDXSEL 71      /* breakpoint tss               */
#define GIDLE0_TSS_IDXSEL       72      /* idle proc tss                */
#define GIDLE1_TSS_IDXSEL       73      /* idle proc tss                */
#define GIDLE2_TSS_IDXSEL       74      /* idle proc tss                */
#define GIDLE3_TSS_IDXSEL       75      /* idle proc tss                */
#define GIDLE4_TSS_IDXSEL       76      /* idle proc tss                */
#define GIDLE5_TSS_IDXSEL       77      /* idle proc tss                */
#define GIDLE6_TSS_IDXSEL       78      /* idle proc tss                */
#define GIDLE7_TSS_IDXSEL       79      /* idle proc tss                */
#define GSOFTSW0_TSS_IDXSEL     80      /* soft csw tss                 */
#define GSOFTSW1_TSS_IDXSEL     81      /* soft csw tss                 */
#define GSOFTSW2_TSS_IDXSEL     82      /* soft csw tss                 */
#define GSOFTSW3_TSS_IDXSEL     83      /* soft csw tss                 */
#define GSOFTSW4_TSS_IDXSEL     84      /* soft csw tss                 */
#define GSOFTSW5_TSS_IDXSEL     85      /* soft csw tss                 */
#define GSOFTSW6_TSS_IDXSEL     86      /* soft csw tss                 */
#define GSOFTSW7_TSS_IDXSEL     87      /* soft csw tss                 */
#define GFIRST_IDXSEL           88      /* start of user entries of the gdt */

#endif

---