/*      $NetBSD: segments.h,v 1.38 2021/04/17 20:12:55 rillig Exp $     */

/*
* 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
*/

/*
* Copyright (c) 1995, 1997
*      Charles M. Hannum.  All rights reserved.
* Copyright (c) 1989, 1990 William F. Jolitz
*
* 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
*/

/*
* Adapted for NetBSD/amd64 by [email protected].
*/

/*
* 386 Segmentation Data Structures and definitions
*      William F. Jolitz ([email protected]) 6/20/1989
*/

#ifndef _AMD64_SEGMENTS_H_
#define _AMD64_SEGMENTS_H_

#ifdef __x86_64__

#ifdef _KERNEL_OPT
#include "opt_xen.h"
#endif

/*
* Selectors
*/

#define ISPL(s)         ((s) & SEL_RPL) /* what is the priority level of a selector */
#ifdef XENPV
#define SEL_KPL         3               /* kernel privilege level */
#define SEL_XPL         0               /* Xen Hypervisor privilege level */
#else
#define SEL_KPL         0               /* kernel privilege level */
#endif
#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 */

#ifdef XENPV
#define IOPL_KPL        1
#else
#define IOPL_KPL        SEL_KPL
#endif

/* Dynamically allocated TSSs and LDTs start (byte offset) */
#define SYSSEL_START    (NGDT_MEM << 3)
#define DYNSEL_START    (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 LDTs.
*
* The rest is 16-byte descriptors for TSS and LDT.
*/

#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)             (ISPL(c) == SEL_UPL)
#ifdef XENPV
/*
* As KPL == UPL, Xen emulate interrupt in kernel context by pushing
* a fake CS with XPL privilege
*/
#define KERNELMODE(c)           (ISPL(c) == SEL_XPL)
#else
#define KERNELMODE(c)           (ISPL(c) == SEL_KPL)
#endif

#ifndef _LOCORE

/*
* Memory and System segment descriptors
*/

/*
* System segment descriptor (16 bytes): used for TSS and LDT.
*/
struct sys_segment_descriptor {
       uint64_t sd_lolimit:16; /* segment extent (lsb) */
       uint64_t sd_lobase:24;  /* segment base address (lsb) */
       uint64_t sd_type:5;     /* segment type */
       uint64_t sd_dpl:2;      /* segment descriptor priority level */
       uint64_t sd_p:1;        /* segment descriptor present */
       uint64_t sd_hilimit:4;  /* segment extent (msb) */
       uint64_t sd_xx1:3;      /* avl, long and def32 (not used) */
       uint64_t sd_gran:1;     /* limit granularity (byte/page) */
       uint64_t sd_hibase:40;  /* segment base address (msb) */
       uint64_t sd_xx2:8;      /* reserved */
       uint64_t sd_zero:5;     /* must be zero */
       uint64_t sd_xx3:19;     /* reserved */
} __packed;

/*
* Memory segment descriptor (8 bytes): used for cs, ds, etc.
*/
struct mem_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_avl:1;      /* available */
       unsigned sd_long:1;     /* long mode */
       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;

/*
* Common part of the above structures. Used to walk descriptor tables.
*/
struct common_segment_descriptor {
       unsigned sdc_lolimit:16;
       unsigned sdc_lobase:24;
       unsigned sdc_type:5;
       unsigned sdc_other:19;
} __packed;

/*
* Gate descriptors (16 bytes).
*/
struct gate_descriptor {
       uint64_t gd_looffset:16;/* gate offset (lsb) */
       uint64_t gd_selector:16;/* gate segment selector */
       uint64_t gd_ist:3;      /* IST select */
       uint64_t gd_xx1:5;      /* reserved */
       uint64_t gd_type:5;     /* segment type */
       uint64_t gd_dpl:2;      /* segment descriptor priority level */
       uint64_t gd_p:1;        /* segment descriptor present */
       uint64_t gd_hioffset:48;/* gate offset (msb) */
       uint64_t gd_xx2:8;      /* reserved */
       uint64_t gd_zero:5;     /* must be zero */
       uint64_t gd_xx3:19;     /* reserved */
} __packed;

/*
* Generic descriptor (8 bytes). Note: it does not include system segment
* descriptors and gate descriptors, since these are 16-byte-long.
*/
union descriptor {
       struct mem_segment_descriptor sd;
       uint32_t raw[2];
       uint64_t raw64;
} __packed;

/*
* Region descriptors, used to load gdt/idt tables before segments yet exist.
*/
struct region_descriptor {
       uint16_t rd_limit;      /* segment extent */
       uint64_t rd_base;       /* base address  */
} __packed;

#ifdef _KERNEL
#ifdef XENPV
typedef struct trap_info idt_descriptor_t;
#else
typedef struct gate_descriptor idt_descriptor_t;
#endif /* XENPV */
extern char *gdtstore;
extern char *ldtstore;

void setgate(struct gate_descriptor *, void *, int, int, int, int);
void unsetgate(struct gate_descriptor *);
void set_idtgate(idt_descriptor_t *, void *, int, int, int, int);
void unset_idtgate(idt_descriptor_t *);
void setregion(struct region_descriptor *, void *, uint16_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);
void update_descriptor(void *, void *);

struct idt_vec;
void idt_vec_reserve(struct idt_vec *, int);
int idt_vec_alloc(struct idt_vec *, int, int);
void idt_vec_set(struct idt_vec *, int, void (*)(void));
void idt_vec_free(struct idt_vec *, int);
void idt_vec_init_cpu_md(struct idt_vec *, cpuid_t);
bool idt_vec_is_pcpu(void);
struct idt_vec * idt_vec_ref(struct idt_vec *);


struct lwp;
void cpu_segregs64_zero(struct lwp *);
void cpu_segregs32_zero(struct lwp *);
void cpu_fsgs_reload(struct lwp *, int, 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 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 */

/*
* 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 NCPUIDT 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 come the predefined LDT (and possibly TSS) descriptors.
* There are NGDT_SYS of them.
*/
#define GNULL_SEL       0       /* Null descriptor */
#define GCODE_SEL       1       /* Kernel code descriptor */
#define GDATA_SEL       2       /* Kernel data descriptor */
#define GUCODE_SEL      3       /* User code descriptor */
#define GUDATA_SEL      4       /* User data descriptor */
#define GAPM32CODE_SEL  5
#define GAPM16CODE_SEL  6
#define GAPMDATA_SEL    7
#define GBIOSCODE_SEL   8
#define GBIOSDATA_SEL   9
#define GPNPBIOSCODE_SEL 10
#define GPNPBIOSDATA_SEL 11
#define GPNPBIOSSCRATCH_SEL 12
#define GPNPBIOSTRAMP_SEL 13
#define GUCODE32_SEL    14
#define GUDATA32_SEL    15
#define GUFS_SEL        16      /* 32-bit Per-thread %fs */
#define GUGS_SEL        17      /* 32-bit Per-thread %gs */
#define NGDT_MEM        18

#define GLDT_SEL        0       /* Default LDT descriptor */
#define NGDT_SYS        1

#define GDT_ADDR_MEM(s,i)       \
   ((struct mem_segment_descriptor *)((s) + ((i) << 3)))
#define GDT_ADDR_SYS(s,i)       \
   ((struct sys_segment_descriptor *)((s) + (((i) << 4) + SYSSEL_START)))

/*
* Byte offsets in the Local Descriptor Table (LDT)
* Strange order because of syscall/sysret insns
*/
#define LUCODE32_SEL    48      /* 32 bit user code descriptor */
#define LUDATA_SEL      56      /* User data descriptor */
#define LUCODE_SEL      64      /* User code descriptor */
#define LUDATA32_SEL    72      /* 32 bit user data descriptor (needed?)*/

#define LDT_SIZE        80

#define LSYSRETBASE_SEL LUCODE32_SEL

/*
* Checks for valid user selectors.
*/
#define VALID_USER_DSEL32(s) \
   (((s) & 0xffff) == GSEL(GUDATA32_SEL, SEL_UPL) || \
    ((s) & 0xffff) == LSEL(LUDATA32_SEL, SEL_UPL))
#define VALID_USER_CSEL32(s) \
   ((s) == GSEL(GUCODE32_SEL, SEL_UPL) || (s) == LSEL(LUCODE32_SEL, SEL_UPL))
#define VALID_USER_FSEL32(s) \
   (((s) & 0xffff) == GSEL(GUFS_SEL, SEL_UPL))
#define VALID_USER_GSEL32(s) \
   (((s) & 0xffff) == GSEL(GUGS_SEL, SEL_UPL))

#define VALID_USER_CSEL(s) \
   ((s) == GSEL(GUCODE_SEL, SEL_UPL) || (s) == LSEL(LUCODE_SEL, SEL_UPL))
#define VALID_USER_DSEL(s) \
   ((s) == GSEL(GUDATA_SEL, SEL_UPL) || (s) == LSEL(LUDATA_SEL, SEL_UPL))

#else   /*      __x86_64__      */

#include <i386/segments.h>

#endif  /*      __x86_64__      */

#endif /* _AMD64_SEGMENTS_H_ */

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