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 #include <linux/percpu.h>
  10
  11 static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *info)
  12 {
  13         desc->limit0            = info->limit & 0x0ffff;
  14
  15         desc->base0             = (info->base_addr & 0x0000ffff);
  16         desc->base1             = (info->base_addr & 0x00ff0000) >> 16;
  17
  18         desc->type              = (info->read_exec_only ^ 1) << 1;
  19         desc->type             |= info->contents << 2;
  20
  21         desc->s                 = 1;
  22         desc->dpl               = 0x3;
  23         desc->p                 = info->seg_not_present ^ 1;
  24         desc->limit             = (info->limit & 0xf0000) >> 16;
  25         desc->avl               = info->useable;
  26         desc->d                 = info->seg_32bit;
  27         desc->g                 = info->limit_in_pages;
  28
  29         desc->base2             = (info->base_addr & 0xff000000) >> 24;
  30         /*
  31          * Don't allow setting of the lm bit. It would confuse
  32          * user_64bit_mode and would get overridden by sysret anyway.
  33          */
  34         desc->l                 = 0;
  35 }
  36
  37 extern struct desc_ptr idt_descr;
  38 extern gate_desc idt_table[];
  39 extern struct desc_ptr debug_idt_descr;
  40 extern gate_desc debug_idt_table[];
  41
  42 struct gdt_page {
  43         struct desc_struct gdt[GDT_ENTRIES];
  44 } __attribute__((aligned(PAGE_SIZE)));
  45
  46 DECLARE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page);
  47
  48 static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
  49 {
  50         return per_cpu(gdt_page, cpu).gdt;
  51 }
  52
  53 #ifdef CONFIG_X86_64
  54
  55 static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
  56                              unsigned dpl, unsigned ist, unsigned seg)
  57 {
  58         gate->offset_low        = PTR_LOW(func);
  59         gate->segment           = __KERNEL_CS;
  60         gate->ist               = ist;
  61         gate->p                 = 1;
  62         gate->dpl               = dpl;
  63         gate->zero0             = 0;
  64         gate->zero1             = 0;
  65         gate->type              = type;
  66         gate->offset_middle     = PTR_MIDDLE(func);
  67         gate->offset_high       = PTR_HIGH(func);
  68 }
  69
  70 #else
  71 static inline void pack_gate(gate_desc *gate, unsigned char type,
  72                              unsigned long base, unsigned dpl, unsigned flags,
  73                              unsigned short seg)
  74 {
  75         gate->a = (seg << 16) | (base & 0xffff);
  76         gate->b = (base & 0xffff0000) | (((0x80 | type | (dpl << 5)) & 0xff) << 8);
  77 }
  78
  79 #endif
  80
  81 static inline int desc_empty(const void *ptr)
  82 {
  83         const u32 *desc = ptr;
  84
  85         return !(desc[0] | desc[1]);
  86 }
  87
  88 #ifdef CONFIG_PARAVIRT
  89 #include <asm/paravirt.h>
  90 #else
  91 #define load_TR_desc()                          native_load_tr_desc()
  92 #define load_gdt(dtr)                           native_load_gdt(dtr)
  93 #define load_idt(dtr)                           native_load_idt(dtr)
  94 #define load_tr(tr)                             asm volatile("ltr %0"::"m" (tr))
  95 #define load_ldt(ldt)                           asm volatile("lldt %0"::"m" (ldt))
  96
  97 #define store_gdt(dtr)                          native_store_gdt(dtr)
  98 #define store_idt(dtr)                          native_store_idt(dtr)
  99 #define store_tr(tr)                            (tr = native_store_tr())
 100
 101 #define load_TLS(t, cpu)                        native_load_tls(t, cpu)
 102 #define set_ldt                                 native_set_ldt
 103
 104 #define write_ldt_entry(dt, entry, desc)        native_write_ldt_entry(dt, entry, desc)
 105 #define write_gdt_entry(dt, entry, desc, type)  native_write_gdt_entry(dt, entry, desc, type)
 106 #define write_idt_entry(dt, entry, g)           native_write_idt_entry(dt, entry, g)
 107
 108 static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 109 {
 110 }
 111
 112 static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries)
 113 {
 114 }
 115 #endif  /* CONFIG_PARAVIRT */
 116
 117 #define store_ldt(ldt) asm("sldt %0" : "=m"(ldt))
 118
 119 static inline void native_write_idt_entry(gate_desc *idt, int entry, const gate_desc *gate)
 120 {
 121         memcpy(&idt[entry], gate, sizeof(*gate));
 122 }
 123
 124 static inline void native_write_ldt_entry(struct desc_struct *ldt, int entry, const void *desc)
 125 {
 126         memcpy(&ldt[entry], desc, 8);
 127 }
 128
 129 static inline void
 130 native_write_gdt_entry(struct desc_struct *gdt, int entry, const void *desc, int type)
 131 {
 132         unsigned int size;
 133
 134         switch (type) {
 135         case DESC_TSS:  size = sizeof(tss_desc);        break;
 136         case DESC_LDT:  size = sizeof(ldt_desc);        break;
 137         default:        size = sizeof(*gdt);            break;
 138         }
 139
 140         memcpy(&gdt[entry], desc, size);
 141 }
 142
 143 static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
 144                                    unsigned long limit, unsigned char type,
 145                                    unsigned char flags)
 146 {
 147         desc->a = ((base & 0xffff) << 16) | (limit & 0xffff);
 148         desc->b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
 149                 (limit & 0x000f0000) | ((type & 0xff) << 8) |
 150                 ((flags & 0xf) << 20);
 151         desc->p = 1;
 152 }
 153
 154
 155 static inline void set_tssldt_descriptor(void *d, unsigned long addr, unsigned type, unsigned size)
 156 {
 157 #ifdef CONFIG_X86_64
 158         struct ldttss_desc64 *desc = d;
 159
 160         memset(desc, 0, sizeof(*desc));
 161
 162         desc->limit0            = size & 0xFFFF;
 163         desc->base0             = PTR_LOW(addr);
 164         desc->base1             = PTR_MIDDLE(addr) & 0xFF;
 165         desc->type              = type;
 166         desc->p                 = 1;
 167         desc->limit1            = (size >> 16) & 0xF;
 168         desc->base2             = (PTR_MIDDLE(addr) >> 8) & 0xFF;
 169         desc->base3             = PTR_HIGH(addr);
 170 #else
 171         pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);
 172 #endif
 173 }
 174
 175 static inline void __set_tss_desc(unsigned cpu, unsigned int entry, void *addr)
 176 {
 177         struct desc_struct *d = get_cpu_gdt_table(cpu);
 178         tss_desc tss;
 179
 180         /*
 181          * sizeof(unsigned long) coming from an extra "long" at the end
 182          * of the iobitmap. See tss_struct definition in processor.h
 183          *
 184          * -1? seg base+limit should be pointing to the address of the
 185          * last valid byte
 186          */
 187         set_tssldt_descriptor(&tss, (unsigned long)addr, DESC_TSS,
 188                               IO_BITMAP_OFFSET + IO_BITMAP_BYTES +
 189                               sizeof(unsigned long) - 1);
 190         write_gdt_entry(d, entry, &tss, DESC_TSS);
 191 }
 192
 193 #define set_tss_desc(cpu, addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 194
 195 static inline void native_set_ldt(const void *addr, unsigned int entries)
 196 {
 197         if (likely(entries == 0))
 198                 asm volatile("lldt %w0"::"q" (0));
 199         else {
 200                 unsigned cpu = smp_processor_id();
 201                 ldt_desc ldt;
 202
 203                 set_tssldt_descriptor(&ldt, (unsigned long)addr, DESC_LDT,
 204                                       entries * LDT_ENTRY_SIZE - 1);
 205                 write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT,
 206                                 &ldt, DESC_LDT);
 207                 asm volatile("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
 208         }
 209 }
 210
 211 static inline void native_load_tr_desc(void)
 212 {
 213         asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
 214 }
 215
 216 static inline void native_load_gdt(const struct desc_ptr *dtr)
 217 {
 218         asm volatile("lgdt %0"::"m" (*dtr));
 219 }
 220
 221 static inline void native_load_idt(const struct desc_ptr *dtr)
 222 {
 223         asm volatile("lidt %0"::"m" (*dtr));
 224 }
 225
 226 static inline void native_store_gdt(struct desc_ptr *dtr)
 227 {
 228         asm volatile("sgdt %0":"=m" (*dtr));
 229 }
 230
 231 static inline void native_store_idt(struct desc_ptr *dtr)
 232 {
 233         asm volatile("sidt %0":"=m" (*dtr));
 234 }
 235
 236 static inline unsigned long native_store_tr(void)
 237 {
 238         unsigned long tr;
 239
 240         asm volatile("str %0":"=r" (tr));
 241
 242         return tr;
 243 }
 244
 245 static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
 246 {
 247         struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 248         unsigned int i;
 249
 250         for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
 251                 gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
 252 }
 253
 254 /* This intentionally ignores lm, since 32-bit apps don't have that field. */
 255 #define LDT_empty(info)                                 \
 256         ((info)->base_addr              == 0    &&      \
 257          (info)->limit                  == 0    &&      \
 258          (info)->contents               == 0    &&      \
 259          (info)->read_exec_only         == 1    &&      \
 260          (info)->seg_32bit              == 0    &&      \
 261          (info)->limit_in_pages         == 0    &&      \
 262          (info)->seg_not_present        == 1    &&      \
 263          (info)->useable                == 0)
 264
 265 /* Lots of programs expect an all-zero user_desc to mean "no segment at all". */
 266 static inline bool LDT_zero(const struct user_desc *info)
 267 {
 268         return (info->base_addr         == 0 &&
 269                 info->limit             == 0 &&
 270                 info->contents          == 0 &&
 271                 info->read_exec_only    == 0 &&
 272                 info->seg_32bit         == 0 &&
 273                 info->limit_in_pages    == 0 &&
 274                 info->seg_not_present   == 0 &&
 275                 info->useable           == 0);
 276 }
 277
 278 static inline void clear_LDT(void)
 279 {
 280         set_ldt(NULL, 0);
 281 }
 282
 283 static inline unsigned long get_desc_base(const struct desc_struct *desc)
 284 {
 285         return (unsigned)(desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24));
 286 }
 287
 288 static inline void set_desc_base(struct desc_struct *desc, unsigned long base)
 289 {
 290         desc->base0 = base & 0xffff;
 291         desc->base1 = (base >> 16) & 0xff;
 292         desc->base2 = (base >> 24) & 0xff;
 293 }
 294
 295 static inline unsigned long get_desc_limit(const struct desc_struct *desc)
 296 {
 297         return desc->limit0 | (desc->limit << 16);
 298 }
 299
 300 static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
 301 {
 302         desc->limit0 = limit & 0xffff;
 303         desc->limit = (limit >> 16) & 0xf;
 304 }
 305
 306 #ifdef CONFIG_X86_64
 307 static inline void set_nmi_gate(int gate, void *addr)
 308 {
 309         gate_desc s;
 310
 311         pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS);
 312         write_idt_entry(debug_idt_table, gate, &s);
 313 }
 314 #endif
 315
 316 #ifdef CONFIG_TRACING
 317 extern struct desc_ptr trace_idt_descr;
 318 extern gate_desc trace_idt_table[];
 319 static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 320 {
 321         write_idt_entry(trace_idt_table, entry, gate);
 322 }
 323
 324 static inline void _trace_set_gate(int gate, unsigned type, void *addr,
 325                                    unsigned dpl, unsigned ist, unsigned seg)
 326 {
 327         gate_desc s;
 328
 329         pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 330         /*
 331          * does not need to be atomic because it is only done once at
 332          * setup time
 333          */
 334         write_trace_idt_entry(gate, &s);
 335 }
 336 #else
 337 static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 338 {
 339 }
 340
 341 #define _trace_set_gate(gate, type, addr, dpl, ist, seg)
 342 #endif
 343
 344 static inline void _set_gate(int gate, unsigned type, void *addr,
 345                              unsigned dpl, unsigned ist, unsigned seg)
 346 {
 347         gate_desc s;
 348
 349         pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 350         /*
 351          * does not need to be atomic because it is only done once at
 352          * setup time
 353          */
 354         write_idt_entry(idt_table, gate, &s);
 355         write_trace_idt_entry(gate, &s);
 356 }
 357
 358 /*
 359  * This needs to use 'idt_table' rather than 'idt', and
 360  * thus use the _nonmapped_ version of the IDT, as the
 361  * Pentium F0 0F bugfix can have resulted in the mapped
 362  * IDT being write-protected.
 363  */
 364 #define set_intr_gate_notrace(n, addr)                                  \
 365         do {                                                            \
 366                 BUG_ON((unsigned)n > 0xFF);                             \
 367                 _set_gate(n, GATE_INTERRUPT, (void *)addr, 0, 0,        \
 368                           __KERNEL_CS);                                 \
 369         } while (0)
 370
 371 #define set_intr_gate(n, addr)                                          \
 372         do {                                                            \
 373                 set_intr_gate_notrace(n, addr);                         \
 374                 _trace_set_gate(n, GATE_INTERRUPT, (void *)trace_##addr,\
 375                                 0, 0, __KERNEL_CS);                     \
 376         } while (0)
 377
 378 extern int first_system_vector;
 379 /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
 380 extern unsigned long used_vectors[];
 381
 382 static inline void alloc_system_vector(int vector)
 383 {
 384         if (!test_bit(vector, used_vectors)) {
 385                 set_bit(vector, used_vectors);
 386                 if (first_system_vector > vector)
 387                         first_system_vector = vector;
 388         } else {
 389                 BUG();
 390         }
 391 }
 392
 393 #define alloc_intr_gate(n, addr)                                \
 394         do {                                                    \
 395                 alloc_system_vector(n);                         \
 396                 set_intr_gate(n, addr);                         \
 397         } while (0)
 398
 399 /*
 400  * This routine sets up an interrupt gate at directory privilege level 3.
 401  */
 402 static inline void set_system_intr_gate(unsigned int n, void *addr)
 403 {
 404         BUG_ON((unsigned)n > 0xFF);
 405         _set_gate(n, GATE_INTERRUPT, addr, 0x3, 0, __KERNEL_CS);
 406 }
 407
 408 static inline void set_system_trap_gate(unsigned int n, void *addr)
 409 {
 410         BUG_ON((unsigned)n > 0xFF);
 411         _set_gate(n, GATE_TRAP, addr, 0x3, 0, __KERNEL_CS);
 412 }
 413
 414 static inline void set_trap_gate(unsigned int n, void *addr)
 415 {
 416         BUG_ON((unsigned)n > 0xFF);
 417         _set_gate(n, GATE_TRAP, addr, 0, 0, __KERNEL_CS);
 418 }
 419
 420 static inline void set_task_gate(unsigned int n, unsigned int gdt_entry)
 421 {
 422         BUG_ON((unsigned)n > 0xFF);
 423         _set_gate(n, GATE_TASK, (void *)0, 0, 0, (gdt_entry<<3));
 424 }
 425
 426 static inline void set_intr_gate_ist(int n, void *addr, unsigned ist)
 427 {
 428         BUG_ON((unsigned)n > 0xFF);
 429         _set_gate(n, GATE_INTERRUPT, addr, 0, ist, __KERNEL_CS);
 430 }
 431
 432 static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist)
 433 {
 434         BUG_ON((unsigned)n > 0xFF);
 435         _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
 436 }
 437
 438 #ifdef CONFIG_X86_64
 439 DECLARE_PER_CPU(u32, debug_idt_ctr);
 440 static inline bool is_debug_idt_enabled(void)
 441 {
 442         if (this_cpu_read(debug_idt_ctr))
 443                 return true;
 444
 445         return false;
 446 }
 447
 448 static inline void load_debug_idt(void)
 449 {
 450         load_idt((const struct desc_ptr *)&debug_idt_descr);
 451 }
 452 #else
 453 static inline bool is_debug_idt_enabled(void)
 454 {
 455         return false;
 456 }
 457
 458 static inline void load_debug_idt(void)
 459 {
 460 }
 461 #endif
 462
 463 #ifdef CONFIG_TRACING
 464 extern atomic_t trace_idt_ctr;
 465 static inline bool is_trace_idt_enabled(void)
 466 {
 467         if (atomic_read(&trace_idt_ctr))
 468                 return true;
 469
 470         return false;
 471 }
 472
 473 static inline void load_trace_idt(void)
 474 {
 475         load_idt((const struct desc_ptr *)&trace_idt_descr);
 476 }
 477 #else
 478 static inline bool is_trace_idt_enabled(void)
 479 {
 480         return false;
 481 }
 482
 483 static inline void load_trace_idt(void)
 484 {
 485 }
 486 #endif
 487
 488 /*
 489  * The load_current_idt() must be called with interrupts disabled
 490  * to avoid races. That way the IDT will always be set back to the expected
 491  * descriptor. It's also called when a CPU is being initialized, and
 492  * that doesn't need to disable interrupts, as nothing should be
 493  * bothering the CPU then.
 494  */
 495 static inline void load_current_idt(void)
 496 {
 497         if (is_debug_idt_enabled())
 498                 load_debug_idt();
 499         else if (is_trace_idt_enabled())
 500                 load_trace_idt();
 501         else
 502                 load_idt((const struct desc_ptr *)&idt_descr);
 503 }
 504 #endif /* _ASM_X86_DESC_H */