1 /* Written 2000 by Andi Kleen */ 2 #ifndef _ASM_X86_DESC_DEFS_H 3 #define _ASM_X86_DESC_DEFS_H 4 5 /* 6 * Segment descriptor structure definitions, usable from both x86_64 and i386 7 * archs. 8 */ 9 10 #ifndef __ASSEMBLY__ 11 12 #include <linux/types.h> 13 14 /* 15 * FIXME: Accessing the desc_struct through its fields is more elegant, 16 * and should be the one valid thing to do. However, a lot of open code 17 * still touches the a and b accessors, and doing this allow us to do it 18 * incrementally. We keep the signature as a struct, rather than an union, 19 * so we can get rid of it transparently in the future -- glommer 20 */ 21 /* 8 byte segment descriptor */ 22 struct desc_struct { 23 union { 24 struct { 25 unsigned int a; 26 unsigned int b; 27 }; 28 struct { 29 u16 limit0; 30 u16 base0; 31 unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1; 32 unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8; 33 }; 34 }; 35 } __attribute__((packed)); 36 37 #define GDT_ENTRY_INIT(flags, base, limit) { { { \ 38 .a = ((limit) & 0xffff) | (((base) & 0xffff) << 16), \ 39 .b = (((base) & 0xff0000) >> 16) | (((flags) & 0xf0ff) << 8) | \ 40 ((limit) & 0xf0000) | ((base) & 0xff000000), \ 41 } } } 42 43 enum { 44 GATE_INTERRUPT = 0xE, 45 GATE_TRAP = 0xF, 46 GATE_CALL = 0xC, 47 GATE_TASK = 0x5, 48 }; 49 50 /* 16byte gate */ 51 struct gate_struct64 { 52 u16 offset_low; 53 u16 segment; 54 unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1; 55 u16 offset_middle; 56 u32 offset_high; 57 u32 zero1; 58 } __attribute__((packed)); 59 60 #define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF) 61 #define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF) 62 #define PTR_HIGH(x) ((unsigned long long)(x) >> 32) 63 64 enum { 65 DESC_TSS = 0x9, 66 DESC_LDT = 0x2, 67 DESCTYPE_S = 0x10, /* !system */ 68 }; 69 70 /* LDT or TSS descriptor in the GDT. 16 bytes. */ 71 struct ldttss_desc64 { 72 u16 limit0; 73 u16 base0; 74 unsigned base1 : 8, type : 5, dpl : 2, p : 1; 75 unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8; 76 u32 base3; 77 u32 zero1; 78 } __attribute__((packed)); 79 80 #ifdef CONFIG_X86_64 81 typedef struct gate_struct64 gate_desc; 82 typedef struct ldttss_desc64 ldt_desc; 83 typedef struct ldttss_desc64 tss_desc; 84 #define gate_offset(g) ((g).offset_low | ((unsigned long)(g).offset_middle << 16) | ((unsigned long)(g).offset_high << 32)) 85 #define gate_segment(g) ((g).segment) 86 #else 87 typedef struct desc_struct gate_desc; 88 typedef struct desc_struct ldt_desc; 89 typedef struct desc_struct tss_desc; 90 #define gate_offset(g) (((g).b & 0xffff0000) | ((g).a & 0x0000ffff)) 91 #define gate_segment(g) ((g).a >> 16) 92 #endif 93 94 struct desc_ptr { 95 unsigned short size; 96 unsigned long address; 97 } __attribute__((packed)) ; 98 99 #endif /* !__ASSEMBLY__ */ 100 101 #endif /* _ASM_X86_DESC_DEFS_H */ 102