osfmk/i386/mp_desc.h

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
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  25  * Please see the License for the specific language governing rights and
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  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  * @OSF_COPYRIGHT@
  32  */
  33 /*
  34  * Mach Operating System
  35  * Copyright (c) 1991,1990 Carnegie Mellon University
  36  * All Rights Reserved.
  37  *
  38  * Permission to use, copy, modify and distribute this software and its
  39  * documentation is hereby granted, provided that both the copyright
  40  * notice and this permission notice appear in all copies of the
  41  * software, derivative works or modified versions, and any portions
  42  * thereof, and that both notices appear in supporting documentation.
  43  *
  44  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  45  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  46  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  47  *
  48  * Carnegie Mellon requests users of this software to return to
  49  *
  50  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  51  *  School of Computer Science
  52  *  Carnegie Mellon University
  53  *  Pittsburgh PA 15213-3890
  54  *
  55  * any improvements or extensions that they make and grant Carnegie Mellon
  56  * the rights to redistribute these changes.
  57  */
  58
  59 /*
  60  */
  61
  62 #ifndef _I386_MP_DESC_H_
  63 #define _I386_MP_DESC_H_
  64
  65 #include <mach_kdb.h>
  66 #include <sys/cdefs.h>
  67
  68 __BEGIN_DECLS
  69
  70 /*
  71  * Multiprocessor i386/i486 systems use a separate copy of the
  72  * GDT, IDT, LDT, and kernel TSS per processor.  The first three
  73  * are separate to avoid lock contention: the i386 uses locked
  74  * memory cycles to access the descriptor tables.  The TSS is
  75  * separate since each processor needs its own kernel stack,
  76  * and since using a TSS marks it busy.
  77  */
  78
  79 #include <i386/seg.h>
  80 #include <i386/tss.h>
  81
  82 /*
  83  * The descriptor tables are together in a structure
  84  * allocated one per processor (except for the boot processor).
  85  * Note that dbtss could be conditionalized on MACH_KDB, but
  86  * doing so increases misconfiguration risk.
  87  */
  88 struct mp_desc_table {
  89         struct fake_descriptor  idt[IDTSZ];     /* IDT */
  90         struct fake_descriptor  gdt[GDTSZ];     /* GDT */
  91         struct fake_descriptor  ldt[LDTSZ];     /* LDT */
  92         struct i386_tss         ktss;
  93         struct i386_tss         dbtss;
  94 };
  95
  96 #define current_gdt()   (current_cpu_datap()->cpu_desc_index.cdi_gdt)
  97 #define current_idt()   (current_cpu_datap()->cpu_desc_index.cdi_idt)
  98 #define current_ldt()   (current_cpu_datap()->cpu_desc_index.cdi_ldt)
  99 #define current_ktss()  (current_cpu_datap()->cpu_desc_index.cdi_ktss)
 100 #define current_dbtss() (current_cpu_datap()->cpu_desc_index.cdi_dbtss)
 101
 102 #define gdt_desc_p(sel) \
 103         ((struct real_descriptor *)&current_gdt()[sel_idx(sel)])
 104 #define ldt_desc_p(sel) \
 105         ((struct real_descriptor *)&current_ldt()[sel_idx(sel)])
 106
 107 extern void     mp_desc_init(cpu_data_t *cdp, boolean_t is_boot_cpu);
 108
 109 static inline boolean_t
 110 valid_user_data_selector(uint16_t selector)
 111 {
 112     sel_t       sel = selector_to_sel(selector);
 113
 114     if (selector == 0)
 115         return (TRUE);
 116
 117     if (sel.ti == SEL_LDT)
 118         return (TRUE);
 119     else if (sel.index < GDTSZ) {
 120         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 121             return (TRUE);
 122     }
 123
 124     return (FALSE);
 125 }
 126
 127 static inline boolean_t
 128 valid_user_code_selector(uint16_t selector)
 129 {
 130     sel_t       sel = selector_to_sel(selector);
 131
 132     if (selector == 0)
 133         return (FALSE);
 134
 135     if (sel.ti == SEL_LDT) {
 136         if (sel.rpl == USER_PRIV)
 137             return (TRUE);
 138     }
 139     else if (sel.index < GDTSZ && sel.rpl == USER_PRIV) {
 140         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 141             return (TRUE);
 142     }
 143
 144     return (FALSE);
 145 }
 146
 147 static inline boolean_t
 148 valid_user_stack_selector(uint16_t selector)
 149 {
 150     sel_t       sel = selector_to_sel(selector);
 151
 152     if (selector == 0)
 153         return (FALSE);
 154
 155     if (sel.ti == SEL_LDT) {
 156         if (sel.rpl == USER_PRIV)
 157             return (TRUE);
 158     }
 159     else if (sel.index < GDTSZ && sel.rpl == USER_PRIV) {
 160         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 161             return (TRUE);
 162     }
 163
 164     return (FALSE);
 165 }
 166
 167 extern boolean_t
 168 valid_user_segment_selectors(uint16_t cs,
 169                              uint16_t ss,
 170                              uint16_t ds,
 171                              uint16_t es,
 172                              uint16_t fs,
 173                              uint16_t gs);
 174
 175 __END_DECLS
 176
 177 #endif  /* _I386_MP_DESC_H_ */