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/* 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 <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[NR_CPUS][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[];
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)
{
_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)
{
_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
}
static inline void set_system_gate(int nr, void *func)
{
_set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
}
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)
{
set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_TSS], (unsigned long)addr,
DESC_TSS,
sizeof(struct tss_struct) - 1);
}
static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
{
set_tssldt_descriptor(&cpu_gdt_table[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_table[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_table[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
*/
extern 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
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