arch/x86/include/asm/desc.h

   1 #ifndef _ASM_X86_DESC_H
   2 #define _ASM_X86_DESC_H
   3
   4 #include <asm/desc_defs.h>
   5 #include <asm/ldt.h>
   6 #include <asm/mmu.h>
   7
   8 #include <linux/smp.h>
   9
  10 static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *info)
  11 {
  12         desc->limit0            = info->limit & 0x0ffff;
  13
  14         desc->base0             = (info->base_addr & 0x0000ffff);
  15         desc->base1             = (info->base_addr & 0x00ff0000) >> 16;
  16
  17         desc->type              = (info->read_exec_only ^ 1) << 1;
  18         desc->type             |= info->contents << 2;
  19
  20         desc->s                 = 1;
  21         desc->dpl               = 0x3;
  22         desc->p                 = info->seg_not_present ^ 1;
  23         desc->limit             = (info->limit & 0xf0000) >> 16;
  24         desc->avl               = info->useable;
  25         desc->d                 = info->seg_32bit;
  26         desc->g                 = info->limit_in_pages;
  27
  28         desc->base2             = (info->base_addr & 0xff000000) >> 24;
  29         /*
  30          * Don't allow setting of the lm bit. It is useless anyway
  31          * because 64bit system calls require __USER_CS:
  32          */
  33         desc->l                 = 0;
  34 }
  35
  36 extern struct desc_ptr idt_descr;
  37 extern gate_desc idt_table[];
  38
  39 struct gdt_page {
  40         struct desc_struct gdt[GDT_ENTRIES];
  41 } __attribute__((aligned(PAGE_SIZE)));
  42
  43 DECLARE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page);
  44
  45 static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
  46 {
  47         return per_cpu(gdt_page, cpu).gdt;
  48 }
  49
  50 #ifdef CONFIG_X86_64
  51
  52 static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
  53                              unsigned dpl, unsigned ist, unsigned seg)
  54 {
  55         gate->offset_low        = PTR_LOW(func);
  56         gate->segment           = __KERNEL_CS;
  57         gate->ist               = ist;
  58         gate->p                 = 1;
  59         gate->dpl               = dpl;
  60         gate->zero0             = 0;
  61         gate->zero1             = 0;
  62         gate->type              = type;
  63         gate->offset_middle     = PTR_MIDDLE(func);
  64         gate->offset_high       = PTR_HIGH(func);
  65 }
  66
  67 #else
  68 static inline void pack_gate(gate_desc *gate, unsigned char type,
  69                              unsigned long base, unsigned dpl, unsigned flags,
  70                              unsigned short seg)
  71 {
  72         gate->a = (seg << 16) | (base & 0xffff);
  73         gate->b = (base & 0xffff0000) | (((0x80 | type | (dpl << 5)) & 0xff) << 8);
  74 }
  75
  76 #endif
  77
  78 static inline int desc_empty(const void *ptr)
  79 {
  80         const u32 *desc = ptr;
  81
  82         return !(desc[0] | desc[1]);
  83 }
  84
  85 #ifdef CONFIG_PARAVIRT
  86 #include <asm/paravirt.h>
  87 #else
  88 #define load_TR_desc()                          native_load_tr_desc()
  89 #define load_gdt(dtr)                           native_load_gdt(dtr)
  90 #define load_idt(dtr)                           native_load_idt(dtr)
  91 #define load_tr(tr)                             asm volatile("ltr %0"::"m" (tr))
  92 #define load_ldt(ldt)                           asm volatile("lldt %0"::"m" (ldt))
  93
  94 #define store_gdt(dtr)                          native_store_gdt(dtr)
  95 #define store_idt(dtr)                          native_store_idt(dtr)
  96 #define store_tr(tr)                            (tr = native_store_tr())
  97
  98 #define load_TLS(t, cpu)                        native_load_tls(t, cpu)
  99 #define set_ldt                                 native_set_ldt
 100
 101 #define write_ldt_entry(dt, entry, desc)        native_write_ldt_entry(dt, entry, desc)
 102 #define write_gdt_entry(dt, entry, desc, type)  native_write_gdt_entry(dt, entry, desc, type)
 103 #define write_idt_entry(dt, entry, g)           native_write_idt_entry(dt, entry, g)
 104
 105 static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 106 {
 107 }
 108
 109 static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries)
 110 {
 111 }
 112 #endif  /* CONFIG_PARAVIRT */
 113
 114 #define store_ldt(ldt) asm("sldt %0" : "=m"(ldt))
 115
 116 static inline void native_write_idt_entry(gate_desc *idt, int entry, const gate_desc *gate)
 117 {
 118         memcpy(&idt[entry], gate, sizeof(*gate));
 119 }
 120
 121 static inline void native_write_ldt_entry(struct desc_struct *ldt, int entry, const void *desc)
 122 {
 123         memcpy(&ldt[entry], desc, 8);
 124 }
 125
 126 static inline void
 127 native_write_gdt_entry(struct desc_struct *gdt, int entry, const void *desc, int type)
 128 {
 129         unsigned int size;
 130
 131         switch (type) {
 132         case DESC_TSS:  size = sizeof(tss_desc);        break;
 133         case DESC_LDT:  size = sizeof(ldt_desc);        break;
 134         default:        size = sizeof(*gdt);            break;
 135         }
 136
 137         memcpy(&gdt[entry], desc, size);
 138 }
 139
 140 static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
 141                                    unsigned long limit, unsigned char type,
 142                                    unsigned char flags)
 143 {
 144         desc->a = ((base & 0xffff) << 16) | (limit & 0xffff);
 145         desc->b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
 146                 (limit & 0x000f0000) | ((type & 0xff) << 8) |
 147                 ((flags & 0xf) << 20);
 148         desc->p = 1;
 149 }
 150
 151
 152 static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned type, unsigned size)
 153 {
 154 #ifdef CONFIG_X86_64
 155         struct ldttss_desc64 *desc = d;
 156
 157         memset(desc, 0, sizeof(*desc));
 158
 159         desc->limit0            = size & 0xFFFF;
 160         desc->base0             = PTR_LOW(addr);
 161         desc->base1             = PTR_MIDDLE(addr) & 0xFF;
 162         desc->type              = type;
 163         desc->p                 = 1;
 164         desc->limit1            = (size >> 16) & 0xF;
 165         desc->base2             = (PTR_MIDDLE(addr) >> 8) & 0xFF;
 166         desc->base3             = PTR_HIGH(addr);
 167 #else
 168         pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);
 169 #endif
 170 }
 171
 172 static inline void __set_tss_desc(unsigned cpu, unsigned int entry, void *addr)
 173 {
 174         struct desc_struct *d = get_cpu_gdt_table(cpu);
 175         tss_desc tss;
 176
 177         /*
 178          * sizeof(unsigned long) coming from an extra "long" at the end
 179          * of the iobitmap. See tss_struct definition in processor.h
 180          *
 181          * -1? seg base+limit should be pointing to the address of the
 182          * last valid byte
 183          */
 184         set_tssldt_descriptor(&tss, (unsigned long)addr, DESC_TSS,
 185                               IO_BITMAP_OFFSET + IO_BITMAP_BYTES +
 186                               sizeof(unsigned long) - 1);
 187         write_gdt_entry(d, entry, &tss, DESC_TSS);
 188 }
 189
 190 #define set_tss_desc(cpu, addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 191
 192 static inline void native_set_ldt(const void *addr, unsigned int entries)
 193 {
 194         if (likely(entries == 0))
 195                 asm volatile("lldt %w0"::"q" (0));
 196         else {
 197                 unsigned cpu = smp_processor_id();
 198                 ldt_desc ldt;
 199
 200                 set_tssldt_descriptor(&ldt, (unsigned long)addr, DESC_LDT,
 201                                       entries * LDT_ENTRY_SIZE - 1);
 202                 write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT,
 203                                 &ldt, DESC_LDT);
 204                 asm volatile("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
 205         }
 206 }
 207
 208 static inline void native_load_tr_desc(void)
 209 {
 210         asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
 211 }
 212
 213 static inline void native_load_gdt(const struct desc_ptr *dtr)
 214 {
 215         asm volatile("lgdt %0"::"m" (*dtr));
 216 }
 217
 218 static inline void native_load_idt(const struct desc_ptr *dtr)
 219 {
 220         asm volatile("lidt %0"::"m" (*dtr));
 221 }
 222
 223 static inline void native_store_gdt(struct desc_ptr *dtr)
 224 {
 225         asm volatile("sgdt %0":"=m" (*dtr));
 226 }
 227
 228 static inline void native_store_idt(struct desc_ptr *dtr)
 229 {
 230         asm volatile("sidt %0":"=m" (*dtr));
 231 }
 232
 233 static inline unsigned long native_store_tr(void)
 234 {
 235         unsigned long tr;
 236
 237         asm volatile("str %0":"=r" (tr));
 238
 239         return tr;
 240 }
 241
 242 static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
 243 {
 244         struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 245         unsigned int i;
 246
 247         for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
 248                 gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
 249 }
 250
 251 #define _LDT_empty(info)                                \
 252         ((info)->base_addr              == 0    &&      \
 253          (info)->limit                  == 0    &&      \
 254          (info)->contents               == 0    &&      \
 255          (info)->read_exec_only         == 1    &&      \
 256          (info)->seg_32bit              == 0    &&      \
 257          (info)->limit_in_pages         == 0    &&      \
 258          (info)->seg_not_present        == 1    &&      \
 259          (info)->useable                == 0)
 260
 261 #ifdef CONFIG_X86_64
 262 #define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0))
 263 #else
 264 #define LDT_empty(info) (_LDT_empty(info))
 265 #endif
 266
 267 static inline void clear_LDT(void)
 268 {
 269         set_ldt(NULL, 0);
 270 }
 271
 272 /*
 273  * load one particular LDT into the current CPU
 274  */
 275 static inline void load_LDT_nolock(mm_context_t *pc)
 276 {
 277         set_ldt(pc->ldt, pc->size);
 278 }
 279
 280 static inline void load_LDT(mm_context_t *pc)
 281 {
 282         preempt_disable();
 283         load_LDT_nolock(pc);
 284         preempt_enable();
 285 }
 286
 287 static inline unsigned long get_desc_base(const struct desc_struct *desc)
 288 {
 289         return (unsigned)(desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24));
 290 }
 291
 292 static inline void set_desc_base(struct desc_struct *desc, unsigned long base)
 293 {
 294         desc->base0 = base & 0xffff;
 295         desc->base1 = (base >> 16) & 0xff;
 296         desc->base2 = (base >> 24) & 0xff;
 297 }
 298
 299 static inline unsigned long get_desc_limit(const struct desc_struct *desc)
 300 {
 301         return desc->limit0 | (desc->limit << 16);
 302 }
 303
 304 static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
 305 {
 306         desc->limit0 = limit & 0xffff;
 307         desc->limit = (limit >> 16) & 0xf;
 308 }
 309
 310 static inline void _set_gate(int gate, unsigned type, void *addr,
 311                              unsigned dpl, unsigned ist, unsigned seg)
 312 {
 313         gate_desc s;
 314
 315         pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 316         /*
 317          * does not need to be atomic because it is only done once at
 318          * setup time
 319          */
 320         write_idt_entry(idt_table, gate, &s);
 321 }
 322
 323 /*
 324  * This needs to use 'idt_table' rather than 'idt', and
 325  * thus use the _nonmapped_ version of the IDT, as the
 326  * Pentium F0 0F bugfix can have resulted in the mapped
 327  * IDT being write-protected.
 328  */
 329 static inline void set_intr_gate(unsigned int n, void *addr)
 330 {
 331         BUG_ON((unsigned)n > 0xFF);
 332         _set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
 333 }
 334
 335 extern int first_system_vector;
 336 /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
 337 extern unsigned long used_vectors[];
 338
 339 static inline void alloc_system_vector(int vector)
 340 {
 341         if (!test_bit(vector, used_vectors)) {
 342                 set_bit(vector, used_vectors);
 343                 if (first_system_vector > vector)
 344                         first_system_vector = vector;
 345         } else {
 346                 BUG();
 347         }
 348 }
 349
 350 static inline void alloc_intr_gate(unsigned int n, void *addr)
 351 {
 352         alloc_system_vector(n);
 353         set_intr_gate(n, addr);
 354 }
 355
 356 /*
 357  * This routine sets up an interrupt gate at directory privilege level 3.
 358  */
 359 static inline void set_system_intr_gate(unsigned int n, void *addr)
 360 {
 361         BUG_ON((unsigned)n > 0xFF);
 362         _set_gate(n, GATE_INTERRUPT, addr, 0x3, 0, __KERNEL_CS);
 363 }
 364
 365 static inline void set_system_trap_gate(unsigned int n, void *addr)
 366 {
 367         BUG_ON((unsigned)n > 0xFF);
 368         _set_gate(n, GATE_TRAP, addr, 0x3, 0, __KERNEL_CS);
 369 }
 370
 371 static inline void set_trap_gate(unsigned int n, void *addr)
 372 {
 373         BUG_ON((unsigned)n > 0xFF);
 374         _set_gate(n, GATE_TRAP, addr, 0, 0, __KERNEL_CS);
 375 }
 376
 377 static inline void set_task_gate(unsigned int n, unsigned int gdt_entry)
 378 {
 379         BUG_ON((unsigned)n > 0xFF);
 380         _set_gate(n, GATE_TASK, (void *)0, 0, 0, (gdt_entry<<3));
 381 }
 382
 383 static inline void set_intr_gate_ist(int n, void *addr, unsigned ist)
 384 {
 385         BUG_ON((unsigned)n > 0xFF);
 386         _set_gate(n, GATE_INTERRUPT, addr, 0, ist, __KERNEL_CS);
 387 }
 388
 389 static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist)
 390 {
 391         BUG_ON((unsigned)n > 0xFF);
 392         _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
 393 }
 394
 395 #endif /* _ASM_X86_DESC_H */