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 #define CPU_16BIT_STACK_SIZE 1024
   8
   9 #ifndef __ASSEMBLY__
  10
  11 #include <linux/preempt.h>
  12 #include <linux/smp.h>
  13 #include <linux/percpu.h>
  14
  15 #include <asm/mmu.h>
  16
  17 extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
  18
  19 DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
  20
  21 struct Xgt_desc_struct {
  22         unsigned short size;
  23         unsigned long address __attribute__((packed));
  24         unsigned short pad;
  25 } __attribute__ ((packed));
  26
  27 extern struct Xgt_desc_struct idt_descr;
  28 DECLARE_PER_CPU(struct Xgt_desc_struct, cpu_gdt_descr);
  29
  30
  31 static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
  32 {
  33         return (struct desc_struct *)per_cpu(cpu_gdt_descr, cpu).address;
  34 }
  35
  36 /*
  37  * This is the ldt that every process will get unless we need
  38  * something other than this.
  39  */
  40 extern struct desc_struct default_ldt[];
  41 extern struct desc_struct idt_table[];
  42 extern void set_intr_gate(unsigned int irq, void * addr);
  43
  44 static inline void pack_descriptor(__u32 *a, __u32 *b,
  45         unsigned long base, unsigned long limit, unsigned char type, unsigned char flags)
  46 {
  47         *a = ((base & 0xffff) << 16) | (limit & 0xffff);
  48         *b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
  49                 (limit & 0x000f0000) | ((type & 0xff) << 8) | ((flags & 0xf) << 20);
  50 }
  51
  52 static inline void pack_gate(__u32 *a, __u32 *b,
  53         unsigned long base, unsigned short seg, unsigned char type, unsigned char flags)
  54 {
  55         *a = (seg << 16) | (base & 0xffff);
  56         *b = (base & 0xffff0000) | ((type & 0xff) << 8) | (flags & 0xff);
  57 }
  58
  59 #define DESCTYPE_LDT    0x82    /* present, system, DPL-0, LDT */
  60 #define DESCTYPE_TSS    0x89    /* present, system, DPL-0, 32-bit TSS */
  61 #define DESCTYPE_TASK   0x85    /* present, system, DPL-0, task gate */
  62 #define DESCTYPE_INT    0x8e    /* present, system, DPL-0, interrupt gate */
  63 #define DESCTYPE_TRAP   0x8f    /* present, system, DPL-0, trap gate */
  64 #define DESCTYPE_DPL3   0x60    /* DPL-3 */
  65 #define DESCTYPE_S      0x10    /* !system */
  66
  67 #define load_TR_desc() __asm__ __volatile__("ltr %w0"::"q" (GDT_ENTRY_TSS*8))
  68 #define load_LDT_desc() __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8))
  69
  70 #define load_gdt(dtr) __asm__ __volatile("lgdt %0"::"m" (*dtr))
  71 #define load_idt(dtr) __asm__ __volatile("lidt %0"::"m" (*dtr))
  72 #define load_tr(tr) __asm__ __volatile("ltr %0"::"m" (tr))
  73 #define load_ldt(ldt) __asm__ __volatile("lldt %0"::"m" (ldt))
  74
  75 #define store_gdt(dtr) __asm__ ("sgdt %0":"=m" (*dtr))
  76 #define store_idt(dtr) __asm__ ("sidt %0":"=m" (*dtr))
  77 #define store_tr(tr) __asm__ ("str %0":"=m" (tr))
  78 #define store_ldt(ldt) __asm__ ("sldt %0":"=m" (ldt))
  79
  80 #if TLS_SIZE != 24
  81 # error update this code.
  82 #endif
  83
  84 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
  85 {
  86 #define C(i) get_cpu_gdt_table(cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
  87         C(0); C(1); C(2);
  88 #undef C
  89 }
  90
  91 static inline void write_dt_entry(void *dt, int entry, __u32 entry_a, __u32 entry_b)
  92 {
  93         __u32 *lp = (__u32 *)((char *)dt + entry*8);
  94         *lp = entry_a;
  95         *(lp+1) = entry_b;
  96 }
  97
  98 #define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
  99 #define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
 100 #define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
 101
 102 static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
 103 {
 104         __u32 a, b;
 105         pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
 106         write_idt_entry(idt_table, gate, a, b);
 107 }
 108
 109 static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
 110 {
 111         __u32 a, b;
 112         pack_descriptor(&a, &b, (unsigned long)addr,
 113                         offsetof(struct tss_struct, __cacheline_filler) - 1,
 114                         DESCTYPE_TSS, 0);
 115         write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
 116 }
 117
 118 static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int entries)
 119 {
 120         __u32 a, b;
 121         pack_descriptor(&a, &b, (unsigned long)addr,
 122                         entries * sizeof(struct desc_struct) - 1,
 123                         DESCTYPE_LDT, 0);
 124         write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, a, b);
 125 }
 126
 127 #define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 128
 129 #define LDT_entry_a(info) \
 130         ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
 131
 132 #define LDT_entry_b(info) \
 133         (((info)->base_addr & 0xff000000) | \
 134         (((info)->base_addr & 0x00ff0000) >> 16) | \
 135         ((info)->limit & 0xf0000) | \
 136         (((info)->read_exec_only ^ 1) << 9) | \
 137         ((info)->contents << 10) | \
 138         (((info)->seg_not_present ^ 1) << 15) | \
 139         ((info)->seg_32bit << 22) | \
 140         ((info)->limit_in_pages << 23) | \
 141         ((info)->useable << 20) | \
 142         0x7000)
 143
 144 #define LDT_empty(info) (\
 145         (info)->base_addr       == 0    && \
 146         (info)->limit           == 0    && \
 147         (info)->contents        == 0    && \
 148         (info)->read_exec_only  == 1    && \
 149         (info)->seg_32bit       == 0    && \
 150         (info)->limit_in_pages  == 0    && \
 151         (info)->seg_not_present == 1    && \
 152         (info)->useable         == 0    )
 153
 154 static inline void clear_LDT(void)
 155 {
 156         int cpu = get_cpu();
 157
 158         set_ldt_desc(cpu, &default_ldt[0], 5);
 159         load_LDT_desc();
 160         put_cpu();
 161 }
 162
 163 /*
 164  * load one particular LDT into the current CPU
 165  */
 166 static inline void load_LDT_nolock(mm_context_t *pc, int cpu)
 167 {
 168         void *segments = pc->ldt;
 169         int count = pc->size;
 170
 171         if (likely(!count)) {
 172                 segments = &default_ldt[0];
 173                 count = 5;
 174         }
 175
 176         set_ldt_desc(cpu, segments, count);
 177         load_LDT_desc();
 178 }
 179
 180 static inline void load_LDT(mm_context_t *pc)
 181 {
 182         int cpu = get_cpu();
 183         load_LDT_nolock(pc, cpu);
 184         put_cpu();
 185 }
 186
 187 static inline unsigned long get_desc_base(unsigned long *desc)
 188 {
 189         unsigned long base;
 190         base = ((desc[0] >> 16)  & 0x0000ffff) |
 191                 ((desc[1] << 16) & 0x00ff0000) |
 192                 (desc[1] & 0xff000000);
 193         return base;
 194 }
 195
 196 #endif /* !__ASSEMBLY__ */
 197
 198 #endif