1#ifndef _ASM_SEGMENT_H 2#define _ASM_SEGMENT_H 3 4/* 5 * The layout of the per-CPU GDT under Linux: 6 * 7 * 0 - null 8 * 1 - reserved 9 * 2 - reserved 10 * 3 - reserved 11 * 12 * 4 - unused <==== new cacheline 13 * 5 - unused 14 * 15 * ------- start of TLS (Thread-Local Storage) segments: 16 * 17 * 6 - TLS segment #1 [ glibc's TLS segment ] 18 * 7 - TLS segment #2 [ Wine's %fs Win32 segment ] 19 * 8 - TLS segment #3 20 * 9 - reserved 21 * 10 - reserved 22 * 11 - reserved 23 * 24 * ------- start of kernel segments: 25 * 26 * 12 - kernel code segment <==== new cacheline 27 * 13 - kernel data segment 28 * 14 - default user CS 29 * 15 - default user DS 30 * 16 - TSS 31 * 17 - LDT 32 * 18 - PNPBIOS support (16->32 gate) 33 * 19 - PNPBIOS support 34 * 20 - PNPBIOS support 35 * 21 - PNPBIOS support 36 * 22 - PNPBIOS support 37 * 23 - APM BIOS support 38 * 24 - APM BIOS support 39 * 25 - APM BIOS support 40 * 41 * 26 - ESPFIX small SS 42 * 27 - per-cpu [ offset to per-cpu data area ] 43 * 28 - unused 44 * 29 - unused 45 * 30 - unused 46 * 31 - TSS for double fault handler 47 */ 48#define GDT_ENTRY_TLS_ENTRIES 3 49#define GDT_ENTRY_TLS_MIN 6 50#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1) 51 52#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8) 53 54#define GDT_ENTRY_DEFAULT_USER_CS 14 55#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS * 8 + 3) 56 57#define GDT_ENTRY_DEFAULT_USER_DS 15 58#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS * 8 + 3) 59 60#define GDT_ENTRY_KERNEL_BASE 12 61 62#define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE + 0) 63#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8) 64 65#define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE + 1) 66#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8) 67 68#define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE + 4) 69#define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE + 5) 70 71#define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 6) 72#define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 11) 73 74#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE + 14) 75#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8) 76 77#define GDT_ENTRY_PERCPU (GDT_ENTRY_KERNEL_BASE + 15) 78#ifdef CONFIG_SMP 79#define __KERNEL_PERCPU (GDT_ENTRY_PERCPU * 8) 80#else 81#define __KERNEL_PERCPU 0 82#endif 83 84#define GDT_ENTRY_DOUBLEFAULT_TSS 31 85 86/* 87 * The GDT has 32 entries 88 */ 89#define GDT_ENTRIES 32 90#define GDT_SIZE (GDT_ENTRIES * 8) 91 92/* Simple and small GDT entries for booting only */ 93 94#define GDT_ENTRY_BOOT_CS 2 95#define __BOOT_CS (GDT_ENTRY_BOOT_CS * 8) 96 97#define GDT_ENTRY_BOOT_DS (GDT_ENTRY_BOOT_CS + 1) 98#define __BOOT_DS (GDT_ENTRY_BOOT_DS * 8) 99 100/* The PnP BIOS entries in the GDT */ 101#define GDT_ENTRY_PNPBIOS_CS32 (GDT_ENTRY_PNPBIOS_BASE + 0) 102#define GDT_ENTRY_PNPBIOS_CS16 (GDT_ENTRY_PNPBIOS_BASE + 1) 103#define GDT_ENTRY_PNPBIOS_DS (GDT_ENTRY_PNPBIOS_BASE + 2) 104#define GDT_ENTRY_PNPBIOS_TS1 (GDT_ENTRY_PNPBIOS_BASE + 3) 105#define GDT_ENTRY_PNPBIOS_TS2 (GDT_ENTRY_PNPBIOS_BASE + 4) 106 107/* The PnP BIOS selectors */ 108#define PNP_CS32 (GDT_ENTRY_PNPBIOS_CS32 * 8) /* segment for calling fn */ 109#define PNP_CS16 (GDT_ENTRY_PNPBIOS_CS16 * 8) /* code segment for BIOS */ 110#define PNP_DS (GDT_ENTRY_PNPBIOS_DS * 8) /* data segment for BIOS */ 111#define PNP_TS1 (GDT_ENTRY_PNPBIOS_TS1 * 8) /* transfer data segment */ 112#define PNP_TS2 (GDT_ENTRY_PNPBIOS_TS2 * 8) /* another data segment */ 113 114/* 115 * The interrupt descriptor table has room for 256 idt's, 116 * the global descriptor table is dependent on the number 117 * of tasks we can have.. 118 */ 119#define IDT_ENTRIES 256 120 121/* Bottom two bits of selector give the ring privilege level */ 122#define SEGMENT_RPL_MASK 0x3 123/* Bit 2 is table indicator (LDT/GDT) */ 124#define SEGMENT_TI_MASK 0x4 125 126/* User mode is privilege level 3 */ 127#define USER_RPL 0x3 128/* LDT segment has TI set, GDT has it cleared */ 129#define SEGMENT_LDT 0x4 130#define SEGMENT_GDT 0x0 131 132#ifndef CONFIG_PARAVIRT 133#define get_kernel_rpl() 0 134#endif 135/* 136 * Matching rules for certain types of segments. 137 */ 138 139/* Matches only __KERNEL_CS, ignoring PnP / USER / APM segments */ 140#define SEGMENT_IS_KERNEL_CODE(x) (((x) & 0xfc) == GDT_ENTRY_KERNEL_CS * 8) 141 142/* Matches __KERNEL_CS and __USER_CS (they must be 2 entries apart) */ 143#define SEGMENT_IS_FLAT_CODE(x) (((x) & 0xec) == GDT_ENTRY_KERNEL_CS * 8) 144 145/* Matches PNP_CS32 and PNP_CS16 (they must be consecutive) */ 146#define SEGMENT_IS_PNP_CODE(x) (((x) & 0xf4) == GDT_ENTRY_PNPBIOS_BASE * 8) 147 148#endif 149