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/* Written 2000 by Andi Kleen */
#ifndef __ARCH_DESC_DEFS_H
#define __ARCH_DESC_DEFS_H
/*
* Segment descriptor structure definitions, usable from both x86_64 and i386
* archs.
*/
#ifndef __ASSEMBLY__
#include <linux/types.h>
/*
* FIXME: Acessing the desc_struct through its fields is more elegant,
* and should be the one valid thing to do. However, a lot of open code
* still touches the a and b acessors, and doing this allow us to do it
* incrementally. We keep the signature as a struct, rather than an union,
* so we can get rid of it transparently in the future -- glommer
*/
// 8 byte segment descriptor
struct desc_struct {
union {
struct { unsigned int a, b; };
struct {
u16 limit0;
u16 base0;
unsigned base1: 8, type: 4, s: 1, dpl: 2, p: 1;
unsigned limit: 4, avl: 1, l: 1, d: 1, g: 1, base2: 8;
};
};
} __attribute__((packed));
enum {
GATE_INTERRUPT = 0xE,
GATE_TRAP = 0xF,
GATE_CALL = 0xC,
};
// 16byte gate
struct gate_struct {
u16 offset_low;
u16 segment;
unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
u16 offset_middle;
u32 offset_high;
u32 zero1;
} __attribute__((packed));
#define PTR_LOW(x) ((unsigned long)(x) & 0xFFFF)
#define PTR_MIDDLE(x) (((unsigned long)(x) >> 16) & 0xFFFF)
#define PTR_HIGH(x) ((unsigned long)(x) >> 32)
enum {
DESC_TSS = 0x9,
DESC_LDT = 0x2,
};
// LDT or TSS descriptor in the GDT. 16 bytes.
struct ldttss_desc {
u16 limit0;
u16 base0;
unsigned base1 : 8, type : 5, dpl : 2, p : 1;
unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
u32 base3;
u32 zero1;
} __attribute__((packed));
struct desc_ptr {
unsigned short size;
unsigned long address;
} __attribute__((packed)) ;
#endif /* !__ASSEMBLY__ */
#endif
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