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      1 /*	$NetBSD: segments.h,v 1.61 2017/08/12 07:35:08 maxv Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990 The Regents of the University of California.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * William Jolitz.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  *
     34  *	@(#)segments.h	7.1 (Berkeley) 5/9/91
     35  */
     36 
     37 /*-
     38  * Copyright (c) 1995, 1997
     39  *	Charles M. Hannum.  All rights reserved.
     40  * Copyright (c) 1989, 1990 William F. Jolitz
     41  *
     42  * This code is derived from software contributed to Berkeley by
     43  * William Jolitz.
     44  *
     45  * Redistribution and use in source and binary forms, with or without
     46  * modification, are permitted provided that the following conditions
     47  * are met:
     48  * 1. Redistributions of source code must retain the above copyright
     49  *    notice, this list of conditions and the following disclaimer.
     50  * 2. Redistributions in binary form must reproduce the above copyright
     51  *    notice, this list of conditions and the following disclaimer in the
     52  *    documentation and/or other materials provided with the distribution.
     53  * 3. All advertising materials mentioning features or use of this software
     54  *    must display the following acknowledgement:
     55  *	This product includes software developed by the University of
     56  *	California, Berkeley and its contributors.
     57  * 4. Neither the name of the University nor the names of its contributors
     58  *    may be used to endorse or promote products derived from this software
     59  *    without specific prior written permission.
     60  *
     61  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     62  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     63  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     64  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     65  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     66  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     67  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     68  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     69  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     70  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     71  * SUCH DAMAGE.
     72  *
     73  *	@(#)segments.h	7.1 (Berkeley) 5/9/91
     74  */
     75 
     76 /*
     77  * 386 Segmentation Data Structures and definitions
     78  *	William F. Jolitz (william (at) ernie.berkeley.edu) 6/20/1989
     79  */
     80 
     81 #ifndef _I386_SEGMENTS_H_
     82 #define _I386_SEGMENTS_H_
     83 #ifdef _KERNEL_OPT
     84 #include "opt_xen.h"
     85 #endif
     86 
     87 /*
     88  * Selectors
     89  */
     90 
     91 #define ISPL(s)		((s) & SEL_RPL)	/* what is the priority level of a selector */
     92 #ifndef XEN
     93 #define SEL_KPL		0		/* kernel privilege level */
     94 #else
     95 #define SEL_XEN		0		/* Xen privilege level */
     96 #define SEL_KPL		1		/* kernel privilege level */
     97 #endif /* XEN */
     98 #define SEL_UPL		3		/* user privilege level */
     99 #define SEL_RPL		3		/* requester's privilege level mask */
    100 #ifdef XEN
    101 #define CHK_UPL		2		/* user privilege level mask */
    102 #else
    103 #define CHK_UPL		SEL_RPL
    104 #endif /* XEN */
    105 #define ISLDT(s)	((s) & SEL_LDT)	/* is it local or global */
    106 #define SEL_LDT		4		/* local descriptor table */
    107 
    108 /* Dynamically allocated TSSs and LDTs start (byte offset) */
    109 #define DYNSEL_START	(NGDT << 3)
    110 
    111 #define IDXSEL(s)	(((s) >> 3) & 0x1fff)		/* index of selector */
    112 #define IDXSELN(s)	(((s) >> 3))			/* index of selector */
    113 #define IDXDYNSEL(s)	((((s) & ~SEL_RPL) - DYNSEL_START) >> 3)
    114 
    115 #define GSEL(s,r)	(((s) << 3) | r)		/* a global selector */
    116 #define GSYSSEL(s,r)	GSEL(s,r)			/* compat with amd64 */
    117 #define GDYNSEL(s,r)	((((s) << 3) + DYNSEL_START) | r | SEL_KPL)
    118 
    119 #define LSEL(s,r)	(((s) << 3) | r | SEL_LDT)	/* a local selector */
    120 
    121 #define USERMODE(c)		(ISPL(c) == SEL_UPL)
    122 #define KERNELMODE(c)		(ISPL(c) == SEL_KPL)
    123 
    124 #ifndef _LOCORE
    125 
    126 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7
    127 #pragma pack(1)
    128 #endif
    129 
    130 /*
    131  * Memory and System segment descriptors (both 8 bytes).
    132  */
    133 struct segment_descriptor {
    134 	unsigned sd_lolimit:16;		/* segment extent (lsb) */
    135 	unsigned sd_lobase:24;		/* segment base address (lsb) */
    136 	unsigned sd_type:5;		/* segment type */
    137 	unsigned sd_dpl:2;		/* segment descriptor priority level */
    138 	unsigned sd_p:1;		/* segment descriptor present */
    139 	unsigned sd_hilimit:4;		/* segment extent (msb) */
    140 	unsigned sd_xx:2;		/* unused */
    141 	unsigned sd_def32:1;		/* default 32 vs 16 bit size */
    142 	unsigned sd_gran:1;		/* limit granularity (byte/page) */
    143 	unsigned sd_hibase:8;		/* segment base address (msb) */
    144 } __packed;
    145 
    146 /*
    147  * Gate descriptors (8 bytes).
    148  */
    149 struct gate_descriptor {
    150 	unsigned gd_looffset:16;	/* gate offset (lsb) */
    151 	unsigned gd_selector:16;	/* gate segment selector */
    152 	unsigned gd_stkcpy:5;		/* number of stack wds to cpy */
    153 	unsigned gd_xx:3;		/* unused */
    154 	unsigned gd_type:5;		/* segment type */
    155 	unsigned gd_dpl:2;		/* segment descriptor priority level */
    156 	unsigned gd_p:1;		/* segment descriptor present */
    157 	unsigned gd_hioffset:16;	/* gate offset (msb) */
    158 } __packed;
    159 
    160 /*
    161  * Xen-specific?
    162  */
    163 struct ldt_descriptor {
    164 	__vaddr_t ld_base;
    165 	uint32_t ld_entries;
    166 } __packed;
    167 
    168 /*
    169  * Generic descriptor (8 bytes).
    170  */
    171 union descriptor {
    172 	struct segment_descriptor sd;
    173 	struct gate_descriptor gd;
    174 	struct ldt_descriptor ld;
    175 	uint32_t raw[2];
    176 	uint64_t raw64;
    177 } __packed;
    178 
    179 /*
    180  * Region descriptors, used to load gdt/idt tables before segments yet exist.
    181  */
    182 struct region_descriptor {
    183 	unsigned rd_limit:16;		/* segment extent */
    184 	unsigned rd_base:32;		/* base address  */
    185 } __packed;
    186 
    187 #if __GNUC__ == 2 && __GNUC_MINOR__ < 7
    188 #pragma pack(4)
    189 #endif
    190 
    191 #ifdef _KERNEL
    192 extern union descriptor *gdtstore, *ldtstore;
    193 extern struct gate_descriptor *idt;
    194 
    195 void setgate(struct gate_descriptor *, void *, int, int, int, int);
    196 void setregion(struct region_descriptor *, void *, size_t);
    197 void setsegment(struct segment_descriptor *, const void *, size_t, int, int,
    198     int, int);
    199 void unsetgate(struct gate_descriptor *);
    200 void cpu_init_idt(void);
    201 void update_descriptor(union descriptor *, union descriptor *);
    202 
    203 #if !defined(XEN)
    204 void idt_vec_reserve(int);
    205 int idt_vec_alloc(int, int);
    206 void idt_vec_set(int, void (*)(void));
    207 void idt_vec_free(int);
    208 #endif
    209 
    210 #endif /* _KERNEL */
    211 
    212 #endif /* !_LOCORE */
    213 
    214 /* system segments and gate types */
    215 #define SDT_SYSNULL	 0	/* system null */
    216 #define SDT_SYS286TSS	 1	/* system 286 TSS available */
    217 #define SDT_SYSLDT	 2	/* system local descriptor table */
    218 #define SDT_SYS286BSY	 3	/* system 286 TSS busy */
    219 #define SDT_SYS286CGT	 4	/* system 286 call gate */
    220 #define SDT_SYSTASKGT	 5	/* system task gate */
    221 #define SDT_SYS286IGT	 6	/* system 286 interrupt gate */
    222 #define SDT_SYS286TGT	 7	/* system 286 trap gate */
    223 #define SDT_SYSNULL2	 8	/* system null again */
    224 #define SDT_SYS386TSS	 9	/* system 386 TSS available */
    225 #define SDT_SYSNULL3	10	/* system null again */
    226 #define SDT_SYS386BSY	11	/* system 386 TSS busy */
    227 #define SDT_SYS386CGT	12	/* system 386 call gate */
    228 #define SDT_SYSNULL4	13	/* system null again */
    229 #define SDT_SYS386IGT	14	/* system 386 interrupt gate */
    230 #define SDT_SYS386TGT	15	/* system 386 trap gate */
    231 
    232 /* memory segment types */
    233 #define SDT_MEMRO	16	/* memory read only */
    234 #define SDT_MEMROA	17	/* memory read only accessed */
    235 #define SDT_MEMRW	18	/* memory read write */
    236 #define SDT_MEMRWA	19	/* memory read write accessed */
    237 #define SDT_MEMROD	20	/* memory read only expand dwn limit */
    238 #define SDT_MEMRODA	21	/* memory read only expand dwn limit accessed */
    239 #define SDT_MEMRWD	22	/* memory read write expand dwn limit */
    240 #define SDT_MEMRWDA	23	/* memory read write expand dwn limit acessed */
    241 #define SDT_MEME	24	/* memory execute only */
    242 #define SDT_MEMEA	25	/* memory execute only accessed */
    243 #define SDT_MEMER	26	/* memory execute read */
    244 #define SDT_MEMERA	27	/* memory execute read accessed */
    245 #define SDT_MEMEC	28	/* memory execute only conforming */
    246 #define SDT_MEMEAC	29	/* memory execute only accessed conforming */
    247 #define SDT_MEMERC	30	/* memory execute read conforming */
    248 #define SDT_MEMERAC	31	/* memory execute read accessed conforming */
    249 
    250 #define SDTYPE(p)	(((const struct segment_descriptor *)(p))->sd_type)
    251 /* is memory segment descriptor pointer ? */
    252 #define ISMEMSDP(s)	(SDTYPE(s) >= SDT_MEMRO && \
    253 			 SDTYPE(s) <= SDT_MEMERAC)
    254 
    255 /* is 286 gate descriptor pointer ? */
    256 #define IS286GDP(s)	(SDTYPE(s) >= SDT_SYS286CGT && \
    257 			 SDTYPE(s) < SDT_SYS286TGT)
    258 
    259 /* is 386 gate descriptor pointer ? */
    260 #define IS386GDP(s)	(SDTYPE(s) >= SDT_SYS386CGT && \
    261 			 SDTYPE(s) < SDT_SYS386TGT)
    262 
    263 /* is gate descriptor pointer ? */
    264 #define ISGDP(s)	(IS286GDP(s) || IS386GDP(s))
    265 
    266 /* is segment descriptor pointer ? */
    267 #define ISSDP(s)	(ISMEMSDP(s) || !ISGDP(s))
    268 
    269 /* is system segment descriptor pointer ? */
    270 #define ISSYSSDP(s)	(!ISMEMSDP(s) && !ISGDP(s))
    271 
    272 /*
    273  * Segment Protection Exception code bits
    274  */
    275 #define SEGEX_EXT	0x01	/* recursive or externally induced */
    276 #define SEGEX_IDT	0x02	/* interrupt descriptor table */
    277 #define SEGEX_TI	0x04	/* local descriptor table */
    278 
    279 /*
    280  * Entries in the Interrupt Descriptor Table (IDT)
    281  */
    282 #define NIDT	256
    283 #define NRSVIDT	32		/* reserved entries for CPU exceptions */
    284 
    285 /*
    286  * Entries in the Global Descriptor Table (GDT).
    287  *
    288  * NB: If you change GBIOSCODE/GBIOSDATA, you *must* rebuild arch/i386/
    289  * bioscall/biostramp.inc, as that relies on GBIOSCODE/GBIOSDATA and a
    290  * normal kernel build does not rebuild it (it's merely included whole-
    291  * sale from i386/bioscall.s)
    292  *
    293  * Also, note that the GEXTBIOSDATA_SEL selector is special, as it maps
    294  * to the value 0x0040 (when created as a KPL global selector).  Some
    295  * BIOSes reference the extended BIOS data area at segment 0040 in a non
    296  * relocatable fashion (even when in protected mode); mapping the zero page
    297  * via the GEXTBIOSDATA_SEL allows these buggy BIOSes to continue to work
    298  * under NetBSD.
    299  *
    300  * The order if the first 5 descriptors is special; the sysenter/sysexit
    301  * instructions depend on them.
    302  */
    303 #define GNULL_SEL	0	/* Null descriptor */
    304 #define GCODE_SEL	1	/* Kernel code descriptor */
    305 #define GDATA_SEL	2	/* Kernel data descriptor */
    306 #define GUCODE_SEL	3	/* User code descriptor */
    307 #define GUDATA_SEL	4	/* User data descriptor */
    308 #define GLDT_SEL	5	/* Default LDT descriptor */
    309 #define GCPU_SEL	6	/* per-CPU segment */
    310 #define GEXTBIOSDATA_SEL 8	/* magic to catch BIOS refs to EBDA */
    311 #define GAPM32CODE_SEL	9	/* 3 APM segments must be consecutive */
    312 #define GAPM16CODE_SEL	10	/* and in the specified order: code32 */
    313 #define GAPMDATA_SEL	11	/* code16 and then data per APM spec */
    314 #define GBIOSCODE_SEL	12
    315 #define GBIOSDATA_SEL	13
    316 #define GPNPBIOSCODE_SEL 14
    317 #define GPNPBIOSDATA_SEL 15
    318 #define GPNPBIOSSCRATCH_SEL 16
    319 #define GPNPBIOSTRAMP_SEL 17
    320 #define GTRAPTSS_SEL	18
    321 #define GIPITSS_SEL	19
    322 #define GUCODEBIG_SEL	20	/* User code with executable stack */
    323 #define GUFS_SEL	21	/* Per-thread %fs */
    324 #define GUGS_SEL	22	/* Per-thread %gs */
    325 #define NGDT		23
    326 
    327 /*
    328  * Entries in the Local Descriptor Table (LDT).
    329  * DO NOT ADD KERNEL DATA/CODE SEGMENTS TO THIS TABLE.
    330  */
    331 #define LSYS5CALLS_SEL	0	/* iBCS system call gate */
    332 #define LSYS5SIGR_SEL	1	/* iBCS sigreturn gate */
    333 #define LUCODE_SEL	2	/* User code descriptor */
    334 #define LUDATA_SEL	3	/* User data descriptor */
    335 #define LSOL26CALLS_SEL	4	/* Solaris 2.6 system call gate */
    336 #define LUCODEBIG_SEL	5	/* User code with executable stack */
    337 #define LBSDICALLS_SEL	16	/* BSDI system call gate */
    338 #define NLDT		17
    339 
    340 #endif /* _I386_SEGMENTS_H_ */
    341