osfmk/i386/mp_desc.h

   1 /*
   2  * Copyright (c) 2000-2005 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * @OSF_COPYRIGHT@
  24  */
  25 /*
  26  * Mach Operating System
  27  * Copyright (c) 1991,1990 Carnegie Mellon University
  28  * All Rights Reserved.
  29  *
  30  * Permission to use, copy, modify and distribute this software and its
  31  * documentation is hereby granted, provided that both the copyright
  32  * notice and this permission notice appear in all copies of the
  33  * software, derivative works or modified versions, and any portions
  34  * thereof, and that both notices appear in supporting documentation.
  35  *
  36  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  37  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  38  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  39  *
  40  * Carnegie Mellon requests users of this software to return to
  41  *
  42  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  43  *  School of Computer Science
  44  *  Carnegie Mellon University
  45  *  Pittsburgh PA 15213-3890
  46  *
  47  * any improvements or extensions that they make and grant Carnegie Mellon
  48  * the rights to redistribute these changes.
  49  */
  50
  51 /*
  52  */
  53
  54 #ifndef _I386_MP_DESC_H_
  55 #define _I386_MP_DESC_H_
  56
  57 #include <mach_kdb.h>
  58 #include <sys/cdefs.h>
  59
  60 __BEGIN_DECLS
  61
  62 /*
  63  * Multiprocessor i386/i486 systems use a separate copy of the
  64  * GDT, IDT, LDT, and kernel TSS per processor.  The first three
  65  * are separate to avoid lock contention: the i386 uses locked
  66  * memory cycles to access the descriptor tables.  The TSS is
  67  * separate since each processor needs its own kernel stack,
  68  * and since using a TSS marks it busy.
  69  */
  70
  71 #include <i386/seg.h>
  72 #include <i386/tss.h>
  73
  74 /*
  75  * The descriptor tables are together in a structure
  76  * allocated one per processor (except for the boot processor).
  77  * Note that dbtss could be conditionalized on MACH_KDB, but
  78  * doing so increases misconfiguration risk.
  79  */
  80 struct mp_desc_table {
  81         struct fake_descriptor  idt[IDTSZ];     /* IDT */
  82         struct fake_descriptor  gdt[GDTSZ];     /* GDT */
  83         struct fake_descriptor  ldt[LDTSZ];     /* LDT */
  84         struct i386_tss         ktss;
  85         struct i386_tss         dbtss;
  86 };
  87
  88 #define current_gdt()   (current_cpu_datap()->cpu_desc_index.cdi_gdt)
  89 #define current_idt()   (current_cpu_datap()->cpu_desc_index.cdi_idt)
  90 #define current_ldt()   (current_cpu_datap()->cpu_desc_index.cdi_ldt)
  91 #define current_ktss()  (current_cpu_datap()->cpu_desc_index.cdi_ktss)
  92 #define current_dbtss() (current_cpu_datap()->cpu_desc_index.cdi_dbtss)
  93
  94 #define gdt_desc_p(sel) \
  95         ((struct real_descriptor *)&current_gdt()[sel_idx(sel)])
  96 #define ldt_desc_p(sel) \
  97         ((struct real_descriptor *)&current_ldt()[sel_idx(sel)])
  98
  99 extern void     mp_desc_init(cpu_data_t *cdp, boolean_t is_boot_cpu);
 100
 101 static inline boolean_t
 102 valid_user_data_selector(uint16_t selector)
 103 {
 104     sel_t       sel = selector_to_sel(selector);
 105
 106     if (selector == 0)
 107         return (TRUE);
 108
 109     if (sel.ti == SEL_LDT)
 110         return (TRUE);
 111     else if (sel.index < GDTSZ) {
 112         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 113             return (TRUE);
 114     }
 115
 116     return (FALSE);
 117 }
 118
 119 static inline boolean_t
 120 valid_user_code_selector(uint16_t selector)
 121 {
 122     sel_t       sel = selector_to_sel(selector);
 123
 124     if (selector == 0)
 125         return (FALSE);
 126
 127     if (sel.ti == SEL_LDT) {
 128         if (sel.rpl == USER_PRIV)
 129             return (TRUE);
 130     }
 131     else if (sel.index < GDTSZ && sel.rpl == USER_PRIV) {
 132         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 133             return (TRUE);
 134     }
 135
 136     return (FALSE);
 137 }
 138
 139 static inline boolean_t
 140 valid_user_stack_selector(uint16_t selector)
 141 {
 142     sel_t       sel = selector_to_sel(selector);
 143
 144     if (selector == 0)
 145         return (FALSE);
 146
 147     if (sel.ti == SEL_LDT) {
 148         if (sel.rpl == USER_PRIV)
 149             return (TRUE);
 150     }
 151     else if (sel.index < GDTSZ && sel.rpl == USER_PRIV) {
 152         if ((gdt_desc_p(selector)->access & ACC_PL_U) == ACC_PL_U)
 153             return (TRUE);
 154     }
 155
 156     return (FALSE);
 157 }
 158
 159 extern boolean_t
 160 valid_user_segment_selectors(uint16_t cs,
 161                              uint16_t ss,
 162                              uint16_t ds,
 163                              uint16_t es,
 164                              uint16_t fs,
 165                              uint16_t gs);
 166
 167 __END_DECLS
 168
 169 #endif  /* _I386_MP_DESC_H_ */