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: Acessing 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 acessors, 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 enum { 38 GATE_INTERRUPT = 0xE, 39 GATE_TRAP = 0xF, 40 GATE_CALL = 0xC, 41 GATE_TASK = 0x5, 42 }; 43 44 /* 16byte gate */ 45 struct gate_struct64 { 46 u16 offset_low; 47 u16 segment; 48 unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1; 49 u16 offset_middle; 50 u32 offset_high; 51 u32 zero1; 52 } __attribute__((packed)); 53 54 #define PTR_LOW(x) ((unsigned long long)(x) & 0xFFFF) 55 #define PTR_MIDDLE(x) (((unsigned long long)(x) >> 16) & 0xFFFF) 56 #define PTR_HIGH(x) ((unsigned long long)(x) >> 32) 57 58 enum { 59 DESC_TSS = 0x9, 60 DESC_LDT = 0x2, 61 DESCTYPE_S = 0x10, /* !system */ 62 }; 63 64 /* LDT or TSS descriptor in the GDT. 16 bytes. */ 65 struct ldttss_desc64 { 66 u16 limit0; 67 u16 base0; 68 unsigned base1 : 8, type : 5, dpl : 2, p : 1; 69 unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8; 70 u32 base3; 71 u32 zero1; 72 } __attribute__((packed)); 73 74 #ifdef CONFIG_X86_64 75 typedef struct gate_struct64 gate_desc; 76 typedef struct ldttss_desc64 ldt_desc; 77 typedef struct ldttss_desc64 tss_desc; 78 #define gate_offset(g) ((g).offset_low | ((unsigned long)(g).offset_middle << 16) | ((unsigned long)(g).offset_high << 32)) 79 #define gate_segment(g) ((g).segment) 80 #else 81 typedef struct desc_struct gate_desc; 82 typedef struct desc_struct ldt_desc; 83 typedef struct desc_struct tss_desc; 84 #define gate_offset(g) (((g).b & 0xffff0000) | ((g).a & 0x0000ffff)) 85 #define gate_segment(g) ((g).a >> 16) 86 #endif 87 88 struct desc_ptr { 89 unsigned short size; 90 unsigned long address; 91 } __attribute__((packed)) ; 92 93 #endif /* !__ASSEMBLY__ */ 94 95 #endif /* _ASM_X86_DESC_DEFS_H */ 96