LXR linux-bk/include/asm-i386/desc.h

   1#ifndef __ARCH_DESC_H
   2#define __ARCH_DESC_H
   3
   4#include <asm/ldt.h>
   5#include <asm/segment.h>
   6
   7#ifndef __ASSEMBLY__
   8
   9#include <linux/preempt.h>
  10#include <linux/smp.h>
  11
  12#include <asm/mmu.h>
  13
  14extern struct desc_struct cpu_gdt_table[NR_CPUS][GDT_ENTRIES];
  15
  16struct Xgt_desc_struct {
  17        unsigned short size;
  18        unsigned long address __attribute__((packed));
  19        unsigned short pad;
  20} __attribute__ ((packed));
  21
  22extern struct Xgt_desc_struct idt_descr, cpu_gdt_descr[NR_CPUS];
  23
  24#define load_TR_desc() __asm__ __volatile__("ltr %%ax"::"a" (GDT_ENTRY_TSS*8))
  25#define load_LDT_desc() __asm__ __volatile__("lldt %%ax"::"a" (GDT_ENTRY_LDT*8))
  26
  27/*
  28 * This is the ldt that every process will get unless we need
  29 * something other than this.
  30 */
  31extern struct desc_struct default_ldt[];
  32extern void set_intr_gate(unsigned int irq, void * addr);
  33
  34#define _set_tssldt_desc(n,addr,limit,type) \
  35__asm__ __volatile__ ("movw %w3,0(%2)\n\t" \
  36        "movw %%ax,2(%2)\n\t" \
  37        "rorl $16,%%eax\n\t" \
  38        "movb %%al,4(%2)\n\t" \
  39        "movb %4,5(%2)\n\t" \
  40        "movb $0,6(%2)\n\t" \
  41        "movb %%ah,7(%2)\n\t" \
  42        "rorl $16,%%eax" \
  43        : "=m"(*(n)) : "a" (addr), "r"(n), "ir"(limit), "i"(type))
  44
  45static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
  46{
  47        _set_tssldt_desc(&cpu_gdt_table[cpu][entry], (int)addr,
  48                offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
  49}
  50
  51#define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
  52
  53static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
  54{
  55        _set_tssldt_desc(&cpu_gdt_table[cpu][GDT_ENTRY_LDT], (int)addr, ((size << 3)-1), 0x82);
  56}
  57
  58#define LDT_entry_a(info) \
  59        ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
  60
  61#define LDT_entry_b(info) \
  62        (((info)->base_addr & 0xff000000) | \
  63        (((info)->base_addr & 0x00ff0000) >> 16) | \
  64        ((info)->limit & 0xf0000) | \
  65        (((info)->read_exec_only ^ 1) << 9) | \
  66        ((info)->contents << 10) | \
  67        (((info)->seg_not_present ^ 1) << 15) | \
  68        ((info)->seg_32bit << 22) | \
  69        ((info)->limit_in_pages << 23) | \
  70        ((info)->useable << 20) | \
  71        0x7000)
  72
  73#define LDT_empty(info) (\
  74        (info)->base_addr       == 0    && \
  75        (info)->limit           == 0    && \
  76        (info)->contents        == 0    && \
  77        (info)->read_exec_only  == 1    && \
  78        (info)->seg_32bit       == 0    && \
  79        (info)->limit_in_pages  == 0    && \
  80        (info)->seg_not_present == 1    && \
  81        (info)->useable         == 0    )
  82
  83#if TLS_SIZE != 24
  84# error update this code.
  85#endif
  86
  87static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
  88{
  89#define C(i) cpu_gdt_table[cpu][GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
  90        C(0); C(1); C(2);
  91#undef C
  92}
  93
  94static inline void clear_LDT(void)
  95{
  96        int cpu = get_cpu();
  97
  98        set_ldt_desc(cpu, &default_ldt[0], 5);
  99        load_LDT_desc();
 100        put_cpu();
 101}
 102
 103/*
 104 * load one particular LDT into the current CPU
 105 */
 106static inline void load_LDT_nolock(mm_context_t *pc, int cpu)
 107{
 108        void *segments = pc->ldt;
 109        int count = pc->size;
 110
 111        if (likely(!count)) {
 112                segments = &default_ldt[0];
 113                count = 5;
 114        }
 115                
 116        set_ldt_desc(cpu, segments, count);
 117        load_LDT_desc();
 118}
 119
 120static inline void load_LDT(mm_context_t *pc)
 121{
 122        int cpu = get_cpu();
 123        load_LDT_nolock(pc, cpu);
 124        put_cpu();
 125}
 126
 127#endif /* !__ASSEMBLY__ */
 128
 129#endif
 130