/* Written 2000 by Andi Kleen */ 

#ifndef __ARCH_DESC_H

#define __ARCH_DESC_H

#include <linux/threads.h>

#include <asm/ldt.h>

#ifndef __ASSEMBLY__

#include <linux/string.h>

#include <linux/smp.h>

#include <asm/segment.h>

#include <asm/mmu.h>

// 8 byte segment descriptor

struct desc_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)); 

struct n_desc_struct { 

	unsigned int a,b;

}; 	

extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];

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)) ;

#define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))

#define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))

#define clear_LDT()  asm volatile("lldt %w0"::"r" (0))

/*

 * This is the ldt that every process will get unless we need

 * something other than this.

 */

extern struct desc_struct default_ldt[];

extern struct gate_struct idt_table[]; 

extern struct desc_ptr cpu_gdt_descr[];

/* the cpu gdt accessor */

#define cpu_gdt(_cpu) ((struct desc_struct *)cpu_gdt_descr[_cpu].address)

static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)  

{

	struct gate_struct s; 	

	s.offset_low = PTR_LOW(func); 

	s.segment = __KERNEL_CS;

	s.ist = ist; 

	s.p = 1;

	s.dpl = dpl; 

	s.zero0 = 0;

	s.zero1 = 0; 

	s.type = type; 

	s.offset_middle = PTR_MIDDLE(func); 

	s.offset_high = PTR_HIGH(func); 

	/* does not need to be atomic because it is only done once at setup time */ 

	memcpy(adr, &s, 16); 

} 

static inline void set_intr_gate(int nr, void *func) 

{ 

	BUG_ON((unsigned)nr > 0xFF);

	_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0); 

} 

static inline void set_intr_gate_ist(int nr, void *func, unsigned ist) 

{ 

	BUG_ON((unsigned)nr > 0xFF);

	_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist); 

} 

static inline void set_system_gate(int nr, void *func) 

{ 

	BUG_ON((unsigned)nr > 0xFF);

	_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0); 

} 

static inline void set_system_gate_ist(int nr, void *func, unsigned ist)

{

	_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, ist);

}

static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type, 

					 unsigned size) 

{ 

	struct ldttss_desc d;

	memset(&d,0,sizeof(d)); 

	d.limit0 = size & 0xFFFF;

	d.base0 = PTR_LOW(tss); 

	d.base1 = PTR_MIDDLE(tss) & 0xFF; 

	d.type = type;

	d.p = 1; 

	d.limit1 = (size >> 16) & 0xF;

	d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF; 

	d.base3 = PTR_HIGH(tss); 

	memcpy(ptr, &d, 16); 

}

static inline void set_tss_desc(unsigned cpu, void *addr)

{ 

	/*

	 * sizeof(unsigned long) coming from an extra "long" at the end

	 * of the iobitmap. See tss_struct definition in processor.h

	 *

	 * -1? seg base+limit should be pointing to the address of the

	 * last valid byte

	 */

	set_tssldt_descriptor(&cpu_gdt(cpu)[GDT_ENTRY_TSS],

		(unsigned long)addr, DESC_TSS,

		IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1);

} 

static inline void set_ldt_desc(unsigned cpu, void *addr, int size)

{ 

	set_tssldt_descriptor(&cpu_gdt(cpu)[GDT_ENTRY_LDT], (unsigned long)addr,

			      DESC_LDT, size * 8 - 1);

}

static inline void set_seg_base(unsigned cpu, int entry, void *base)

{ 

	struct desc_struct *d = &cpu_gdt(cpu)[entry];

	u32 addr = (u32)(u64)base;

	BUG_ON((u64)base >> 32); 

	d->base0 = addr & 0xffff;

	d->base1 = (addr >> 16) & 0xff;

	d->base2 = (addr >> 24) & 0xff;

} 

#define LDT_entry_a(info) \

	((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))

/* Don't allow setting of the lm bit. It is useless anyways because 

   64bit system calls require __USER_CS. */ 

#define LDT_entry_b(info) \

	(((info)->base_addr & 0xff000000) | \

	(((info)->base_addr & 0x00ff0000) >> 16) | \

	((info)->limit & 0xf0000) | \

	(((info)->read_exec_only ^ 1) << 9) | \

	((info)->contents << 10) | \

	(((info)->seg_not_present ^ 1) << 15) | \

	((info)->seg_32bit << 22) | \

	((info)->limit_in_pages << 23) | \

	((info)->useable << 20) | \

	/* ((info)->lm << 21) | */ \

	0x7000)

#define LDT_empty(info) (\

	(info)->base_addr	== 0	&& \

	(info)->limit		== 0	&& \

	(info)->contents	== 0	&& \

	(info)->read_exec_only	== 1	&& \

	(info)->seg_32bit	== 0	&& \

	(info)->limit_in_pages	== 0	&& \

	(info)->seg_not_present	== 1	&& \

	(info)->useable		== 0	&& \

	(info)->lm		== 0)

#if TLS_SIZE != 24

# error update this code.

#endif

static inline void load_TLS(struct thread_struct *t, unsigned int cpu)

{

	u64 *gdt = (u64 *)(cpu_gdt(cpu) + GDT_ENTRY_TLS_MIN);

	gdt[0] = t->tls_array[0];

	gdt[1] = t->tls_array[1];

	gdt[2] = t->tls_array[2];

} 

/*

 * load one particular LDT into the current CPU

 */

static inline void load_LDT_nolock (mm_context_t *pc, int cpu)

{

	int count = pc->size;

	if (likely(!count)) {

		clear_LDT();

		return;

	}

	set_ldt_desc(cpu, pc->ldt, count);

	load_LDT_desc();

}

static inline void load_LDT(mm_context_t *pc)

{

	int cpu = get_cpu();

	load_LDT_nolock(pc, cpu);

	put_cpu();

}

extern struct desc_ptr idt_descr;

#endif /* !__ASSEMBLY__ */

#endif