FreeBSD/Linux Kernel Cross Reference
sys/amd64/include/segments.h

     /*-
      * 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.
     * 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.
     *
     *      from: @(#)segments.h    7.1 (Berkeley) 5/9/91
     * $FreeBSD: releng/9.0/sys/amd64/include/segments.h 227946 2011-11-24 18:44:14Z rstone $
     */
    
    #ifndef _MACHINE_SEGMENTS_H_
    #define _MACHINE_SEGMENTS_H_
    
    /*
     * AMD64 Segmentation Data Structures and definitions
     */
    
    /*
     * Selectors
     */
    
    #define SEL_RPL_MASK    3       /* requester priv level */
    #define ISPL(s) ((s)&3)         /* what is the priority level of a selector */
    #define SEL_KPL 0               /* kernel priority level */
    #define SEL_UPL 3               /* user priority level */
    #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 LSEL(s,r)       (((s)<<3) | SEL_LDT | r)        /* a local selector */
    #define GSEL(s,r)       (((s)<<3) | r)                  /* a global selector */
    
    /*
     * User segment descriptors (%cs, %ds etc for compatability apps. 64 bit wide)
     * For long-mode apps, %cs only has the conforming bit in sd_type, the sd_dpl,
     * sd_p, sd_l and sd_def32 which must be zero).  %ds only has sd_p.
     */
    struct  user_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_xx:1;              /* unused */
            u_int64_t sd_long:1;            /* long mode (cs only) */
            u_int64_t sd_def32:1;           /* default 32 vs 16 bit size */
            u_int64_t sd_gran:1;            /* limit granularity (byte/page units)*/
            u_int64_t sd_hibase:8;          /* segment base address  (msb) */
    } __packed;
    
    #define USD_GETBASE(sd)         (((sd)->sd_lobase) | (sd)->sd_hibase << 24) 
    #define USD_SETBASE(sd, b)      (sd)->sd_lobase = (b);  \
                                    (sd)->sd_hibase = ((b) >> 24);
    #define USD_GETLIMIT(sd)        (((sd)->sd_lolimit) | (sd)->sd_hilimit << 16)
    #define USD_SETLIMIT(sd, l)     (sd)->sd_lolimit = (l); \
                                    (sd)->sd_hilimit = ((l) >> 16);
    
    /*
     * System segment descriptors (128 bit wide)
     */
    struct  system_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_xx0:3;             /* unused */
            u_int64_t sd_gran:1;            /* limit granularity (byte/page units)*/
            u_int64_t sd_hibase:40 __packed;/* segment base address  (msb) */
            u_int64_t sd_xx1:8;
            u_int64_t sd_mbz:5;             /* MUST be zero */
            u_int64_t sd_xx2:19;
   } __packed;
   
   /*
    * Gate descriptors (e.g. indirect descriptors, trap, interrupt etc. 128 bit)
    * Only interrupt and trap gates have gd_ist.
    */
   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 table index */
           u_int64_t gd_xx:5;              /* unused */
           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 __packed;      /* gate offset (msb) */
           u_int64_t sd_xx1:32;
   } __packed;
   
   /*
    * Generic descriptor
    */
   union   descriptor      {
           struct  user_segment_descriptor sd;
           struct  gate_descriptor gd;
   };
   
           /* system segments and gate types */
   #define SDT_SYSNULL      0      /* system null */
   #define SDT_SYS286TSS    1      /* system 286 TSS available */
   #define SDT_SYSLDT       2      /* system 64 bit 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_SYSTSS       9      /* system available 64 bit TSS */
   #define SDT_SYSNULL3    10      /* system null again */
   #define SDT_SYSBSY      11      /* system busy 64 bit TSS */
   #define SDT_SYSCGT      12      /* system 64 bit call gate */
   #define SDT_SYSNULL4    13      /* system null again */
   #define SDT_SYSIGT      14      /* system 64 bit interrupt gate */
   #define SDT_SYSTGT      15      /* system 64 bit 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 accessed */
   #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 */
   
   /*
    * Software definitions are in this convenient format,
    * which are translated into inconvenient segment descriptors
    * when needed to be used by the 386 hardware
    */
   
   struct  soft_segment_descriptor {
           unsigned long ssd_base;         /* segment base address  */
           unsigned long ssd_limit;        /* segment extent */
           unsigned long ssd_type:5;       /* segment type */
           unsigned long ssd_dpl:2;        /* segment descriptor priority level */
           unsigned long ssd_p:1;          /* segment descriptor present */
           unsigned long ssd_long:1;       /* long mode (for %cs) */
           unsigned long ssd_def32:1;      /* default 32 vs 16 bit size */
           unsigned long ssd_gran:1;       /* limit granularity (byte/page units)*/
   } __packed;
   
   /*
    * region descriptors, used to load gdt/idt tables before segments yet exist.
    */
   struct region_descriptor {
           unsigned long rd_limit:16;              /* segment extent */
           unsigned long rd_base:64 __packed;      /* base address  */
   } __packed;
   
   /*
    * Size of IDT table
    */
   #define NIDT    256             /* 32 reserved, 16 h/w, 0 s/w, linux's 0x80 */
   #define NRSVIDT 32              /* reserved entries for cpu exceptions */
   
   /*
    * Entries in the Interrupt Descriptor Table (IDT)
    */
   #define IDT_DE          0       /* #DE: Divide Error */
   #define IDT_DB          1       /* #DB: Debug */
   #define IDT_NMI         2       /* Nonmaskable External Interrupt */
   #define IDT_BP          3       /* #BP: Breakpoint */
   #define IDT_OF          4       /* #OF: Overflow */
   #define IDT_BR          5       /* #BR: Bound Range Exceeded */
   #define IDT_UD          6       /* #UD: Undefined/Invalid Opcode */
   #define IDT_NM          7       /* #NM: No Math Coprocessor */
   #define IDT_DF          8       /* #DF: Double Fault */
   #define IDT_FPUGP       9       /* Coprocessor Segment Overrun */
   #define IDT_TS          10      /* #TS: Invalid TSS */
   #define IDT_NP          11      /* #NP: Segment Not Present */
   #define IDT_SS          12      /* #SS: Stack Segment Fault */
   #define IDT_GP          13      /* #GP: General Protection Fault */
   #define IDT_PF          14      /* #PF: Page Fault */
   #define IDT_MF          16      /* #MF: FPU Floating-Point Error */
   #define IDT_AC          17      /* #AC: Alignment Check */
   #define IDT_MC          18      /* #MC: Machine Check */
   #define IDT_XF          19      /* #XF: SIMD Floating-Point Exception */
   #define IDT_IO_INTS     NRSVIDT /* Base of IDT entries for I/O interrupts. */
   #define IDT_SYSCALL     0x80    /* System Call Interrupt Vector */
   #define IDT_DTRACE_RET  0x20    /* DTrace pid provider Interrupt Vector */
   
   /*
    * Entries in the Global Descriptor Table (GDT)
    */
   #define GNULL_SEL       0       /* Null Descriptor */
   #define GNULL2_SEL      1       /* Null Descriptor */
   #define GUFS32_SEL      2       /* User 32 bit %fs Descriptor */
   #define GUGS32_SEL      3       /* User 32 bit %gs Descriptor */
   #define GCODE_SEL       4       /* Kernel Code Descriptor */
   #define GDATA_SEL       5       /* Kernel Data Descriptor */
   #define GUCODE32_SEL    6       /* User 32 bit code Descriptor */
   #define GUDATA_SEL      7       /* User 32/64 bit Data Descriptor */
   #define GUCODE_SEL      8       /* User 64 bit Code Descriptor */
   #define GPROC0_SEL      9       /* TSS for entering kernel etc */
   /* slot 10 is second half of GPROC0_SEL */
   #define GUSERLDT_SEL    11      /* LDT */
   /* slot 11 is second half of GUSERLDT_SEL */
   #define NGDT            13
   
   #ifdef _KERNEL
   extern struct user_segment_descriptor gdt[];
   extern struct soft_segment_descriptor gdt_segs[];
   extern struct gate_descriptor *idt;
   extern struct region_descriptor r_gdt, r_idt;
   
   void    lgdt(struct region_descriptor *rdp);
   void    sdtossd(struct user_segment_descriptor *sdp,
               struct soft_segment_descriptor *ssdp);
   void    ssdtosd(struct soft_segment_descriptor *ssdp,
               struct user_segment_descriptor *sdp);
   void    ssdtosyssd(struct soft_segment_descriptor *ssdp,
               struct system_segment_descriptor *sdp);
   void    update_gdt_gsbase(struct thread *td, uint32_t base);
   void    update_gdt_fsbase(struct thread *td, uint32_t base);
   
   #endif /* _KERNEL */
   
   #endif /* !_MACHINE_SEGMENTS_H_ */

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