osfmk/i386/mp_desc.h

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
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   6  * This file contains Original Code and/or Modifications of Original Code
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   8  * Version 2.0 (the 'License'). You may not use this file except in
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  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
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  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
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  23  * Please see the License for the specific language governing rights and
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  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * @OSF_COPYRIGHT@
  30  */
  31 /*
  32  * Mach Operating System
  33  * Copyright (c) 1991,1990 Carnegie Mellon University
  34  * All Rights Reserved.
  35  *
  36  * Permission to use, copy, modify and distribute this software and its
  37  * documentation is hereby granted, provided that both the copyright
  38  * notice and this permission notice appear in all copies of the
  39  * software, derivative works or modified versions, and any portions
  40  * thereof, and that both notices appear in supporting documentation.
  41  *
  42  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  43  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  44  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  45  *
  46  * Carnegie Mellon requests users of this software to return to
  47  *
  48  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  49  *  School of Computer Science
  50  *  Carnegie Mellon University
  51  *  Pittsburgh PA 15213-3890
  52  *
  53  * any improvements or extensions that they make and grant Carnegie Mellon
  54  * the rights to redistribute these changes.
  55  */
  56
  57 /*
  58  */
  59
  60 #ifndef _I386_MP_DESC_H_
  61 #define _I386_MP_DESC_H_
  62
  63 #include <mach_kdb.h>
  64 #include <sys/cdefs.h>
  65
  66 __BEGIN_DECLS
  67
  68 /*
  69  * Multiprocessor i386/i486 systems use a separate copy of the
  70  * GDT, IDT, LDT, and kernel TSS per processor.  The first three
  71  * are separate to avoid lock contention: the i386 uses locked
  72  * memory cycles to access the descriptor tables.  The TSS is
  73  * separate since each processor needs its own kernel stack,
  74  * and since using a TSS marks it busy.
  75  */
  76
  77 #include <i386/seg.h>
  78 #include <i386/tss.h>
  79
  80 /*
  81  * The descriptor tables are together in a structure
  82  * allocated one per processor (except for the boot processor).
  83  * Note that dbtss could be conditionalized on MACH_KDB, but
  84  * doing so increases misconfiguration risk.
  85  */
  86 struct mp_desc_table {
  87         struct fake_descriptor  idt[IDTSZ];     /* IDT */
  88         struct fake_descriptor  gdt[GDTSZ];     /* GDT */
  89         struct fake_descriptor  ldt[LDTSZ];     /* LDT */
  90         struct i386_tss         ktss;
  91         struct i386_tss         dbtss;
  92 };
  93
  94 #define current_gdt()   (current_cpu_datap()->cpu_desc_index.cdi_gdt)
  95 #define current_idt()   (current_cpu_datap()->cpu_desc_index.cdi_idt)
  96 #define current_ldt()   (current_cpu_datap()->cpu_desc_index.cdi_ldt)
  97 #define current_ktss()  (current_cpu_datap()->cpu_desc_index.cdi_ktss)
  98 #define current_dbtss() (current_cpu_datap()->cpu_desc_index.cdi_dbtss)
  99
 100 #define gdt_desc_p(sel) \
 101         ((struct real_descriptor *)&current_gdt()[sel_idx(sel)])
 102 #define ldt_desc_p(sel) \
 103         ((struct real_descriptor *)&current_ldt()[sel_idx(sel)])
 104
 105 extern void     mp_desc_init(cpu_data_t *cdp, boolean_t is_boot_cpu);
 106
 107 static inline boolean_t
 108 valid_user_data_selector(uint16_t selector)
 109 {
 110     sel_t       sel = selector_to_sel(selector);
 111
 112     if (selector == 0)
 113         return (TRUE);
 114
 115     if (sel.ti == SEL_LDT)
 116         return (TRUE);
 117     else if (sel.index < GDTSZ) {
 118         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 119             return (TRUE);
 120     }
 121
 122     return (FALSE);
 123 }
 124
 125 static inline boolean_t
 126 valid_user_code_selector(uint16_t selector)
 127 {
 128     sel_t       sel = selector_to_sel(selector);
 129
 130     if (selector == 0)
 131         return (FALSE);
 132
 133     if (sel.ti == SEL_LDT) {
 134         if (sel.rpl == USER_PRIV)
 135             return (TRUE);
 136     }
 137     else if (sel.index < GDTSZ && sel.rpl == USER_PRIV) {
 138         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 139             return (TRUE);
 140     }
 141
 142     return (FALSE);
 143 }
 144
 145 static inline boolean_t
 146 valid_user_stack_selector(uint16_t selector)
 147 {
 148     sel_t       sel = selector_to_sel(selector);
 149
 150     if (selector == 0)
 151         return (FALSE);
 152
 153     if (sel.ti == SEL_LDT) {
 154         if (sel.rpl == USER_PRIV)
 155             return (TRUE);
 156     }
 157     else if (sel.index < GDTSZ && sel.rpl == USER_PRIV) {
 158         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 159             return (TRUE);
 160     }
 161
 162     return (FALSE);
 163 }
 164
 165 extern boolean_t
 166 valid_user_segment_selectors(uint16_t cs,
 167                              uint16_t ss,
 168                              uint16_t ds,
 169                              uint16_t es,
 170                              uint16_t fs,
 171                              uint16_t gs);
 172
 173 __END_DECLS
 174
 175 #endif  /* _I386_MP_DESC_H_ */