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#ifndef __ARCH_DESC_H
#define __ARCH_DESC_H
struct desc_struct {
unsigned long a,b;
};
extern struct desc_struct gdt_table[];
extern struct desc_struct *idt, *gdt;
struct Xgt_desc_struct {
unsigned short size;
unsigned long address __attribute__((packed));
};
#define idt_descr (*(struct Xgt_desc_struct *)((char *)&idt - 2))
#define gdt_descr (*(struct Xgt_desc_struct *)((char *)&gdt - 2))
/*
* Entry into gdt where to find first TSS. GDT layout:
* 0 - null
* 1 - not used
* 2 - kernel code segment
* 3 - kernel data segment
* 4 - user code segment
* 5 - user data segment
* 6 - not used
* 7 - not used
* 8 - APM BIOS support
* 9 - APM BIOS support
* 10 - APM BIOS support
* 11 - APM BIOS support
* 12 - TSS #0
* 13 - LDT #0
* 14 - TSS #1
* 15 - LDT #1
*/
#define FIRST_TSS_ENTRY 12
#define FIRST_LDT_ENTRY (FIRST_TSS_ENTRY+1)
#define _TSS(n) ((((unsigned long) n)<<4)+(FIRST_TSS_ENTRY<<3))
#define _LDT(n) ((((unsigned long) n)<<4)+(FIRST_LDT_ENTRY<<3))
#define load_TR(n) __asm__ __volatile__("ltr %%ax": /* no output */ :"a" (_TSS(n)))
#define load_ldt(n) __asm__ __volatile__("lldt %%ax": /* no output */ :"a" (_LDT(n)))
#define store_TR(n) \
__asm__("str %%ax\n\t" \
"subl %2,%%eax\n\t" \
"shrl $4,%%eax" \
:"=a" (n) \
:"0" (0),"i" (FIRST_TSS_ENTRY<<3))
extern void set_intr_gate(unsigned int irq, void * addr);
extern void set_ldt_desc(unsigned int n, void *addr, unsigned int size);
extern void set_tss_desc(unsigned int n, void *addr);
/*
* This is the ldt that every process will get unless we need
* something other than this.
*/
extern struct desc_struct default_ldt;
#endif
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