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001 /* Copyright (C) 2004 The SOS Team 002 003 This program is free software; you can redistribute it and/or 004 modify it under the terms of the GNU General Public License 005 as published by the Free Software Foundation; either version 2 006 of the License, or (at your option) any later version. 007 008 This program is distributed in the hope that it will be useful, 009 but WITHOUT ANY WARRANTY; without even the implied warranty of 010 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 011 GNU General Public License for more details. 012 013 You should have received a copy of the GNU General Public License 014 along with this program; if not, write to the Free Software 015 Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, 016 USA. 017 */ 018 #ifndef _SOS_HWSEGS_H_ 019 #define _SOS_HWSEGS_H_ 020 021 /** 022 * @file segments.h 023 * 024 * Global and local (GDT/LDT) segment descriptor definition and 025 * structure. These segments map virtual addresses (ie 026 * data/instruction addresses, relative to these segment descriptors) 027 * to linear addresses (ie addresses in the paged-memory space). 028 * 029 * @see Intel x86 doc, vol 3 chapter 3. 030 */ 031 032 033 /* 034 * Global segment selectors (GDT) for SOS/x86. 035 * 036 * @see gdt.h 037 */ 038 #define SOS_SEG_NULL 0 /* NULL segment, unused by the procesor */ 039 #define SOS_SEG_KCODE 1 /* Kernel code segment */ 040 #define SOS_SEG_KDATA 2 /* Kernel data segment */ 041 #define SOS_SEG_UCODE 3 /* User code segment */ 042 #define SOS_SEG_UDATA 4 /* User data segment */ 043 #define SOS_SEG_KERNEL_TSS 5 /* Kernel TSS for CPL3 -> CPL0 privilege change */ 044 045 046 #ifndef ASM_SOURCE 047 /** 048 * Helper macro that builds a segment register's value 049 */ 050 #define SOS_BUILD_SEGMENT_REG_VALUE(desc_privilege,in_ldt,seg_index) \ 051 ( (((desc_privilege) & 0x3) << 0) \ 052 | (((in_ldt)?1:0) << 2) \ 053 | ((seg_index) << 3) ) 054 #else 055 /* 056 * Assembler-compliant version. 057 * 058 * Caution: In assembler code, "in_ldt" MUST be either 1 or 0, nothing 059 * else. 060 */ 061 #define SOS_BUILD_SEGMENT_REG_VALUE(desc_privilege,in_ldt,seg_index) \ 062 ( (((desc_privilege) & 0x3) << 0) \ 063 | ((in_ldt & 1) << 2) \ 064 | ((seg_index) << 3) ) 065 #endif 066 067 068 /* 069 * Local segment selectors (LDT) for SOS/x86 070 */ 071 /* None */ 072 073 #endif /* _SOS_HWSEGS_H_ */
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