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 /*
 284  * load one particular LDT into the current CPU
 285  */
 286 static inline void load_LDT_nolock(mm_context_t *pc)
 287 {
 288         set_ldt(pc->ldt, pc->size);
 289 }
 290
 291 static inline void load_LDT(mm_context_t *pc)
 292 {
 293         preempt_disable();
 294         load_LDT_nolock(pc);
 295         preempt_enable();
 296 }
 297
 298 static inline unsigned long get_desc_base(const struct desc_struct *desc)
 299 {
 300         return (unsigned)(desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24));
 301 }
 302
 303 static inline void set_desc_base(struct desc_struct *desc, unsigned long base)
 304 {
 305         desc->base0 = base & 0xffff;
 306         desc->base1 = (base >> 16) & 0xff;
 307         desc->base2 = (base >> 24) & 0xff;
 308 }
 309
 310 static inline unsigned long get_desc_limit(const struct desc_struct *desc)
 311 {
 312         return desc->limit0 | (desc->limit << 16);
 313 }
 314
 315 static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
 316 {
 317         desc->limit0 = limit & 0xffff;
 318         desc->limit = (limit >> 16) & 0xf;
 319 }
 320
 321 #ifdef CONFIG_X86_64
 322 static inline void set_nmi_gate(int gate, void *addr)
 323 {
 324         gate_desc s;
 325
 326         pack_gate(&s, GATE_INTERRUPT, (unsigned long)addr, 0, 0, __KERNEL_CS);
 327         write_idt_entry(debug_idt_table, gate, &s);
 328 }
 329 #endif
 330
 331 #ifdef CONFIG_TRACING
 332 extern struct desc_ptr trace_idt_descr;
 333 extern gate_desc trace_idt_table[];
 334 static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 335 {
 336         write_idt_entry(trace_idt_table, entry, gate);
 337 }
 338
 339 static inline void _trace_set_gate(int gate, unsigned type, void *addr,
 340                                    unsigned dpl, unsigned ist, unsigned seg)
 341 {
 342         gate_desc s;
 343
 344         pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 345         /*
 346          * does not need to be atomic because it is only done once at
 347          * setup time
 348          */
 349         write_trace_idt_entry(gate, &s);
 350 }
 351 #else
 352 static inline void write_trace_idt_entry(int entry, const gate_desc *gate)
 353 {
 354 }
 355
 356 #define _trace_set_gate(gate, type, addr, dpl, ist, seg)
 357 #endif
 358
 359 static inline void _set_gate(int gate, unsigned type, void *addr,
 360                              unsigned dpl, unsigned ist, unsigned seg)
 361 {
 362         gate_desc s;
 363
 364         pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 365         /*
 366          * does not need to be atomic because it is only done once at
 367          * setup time
 368          */
 369         write_idt_entry(idt_table, gate, &s);
 370         write_trace_idt_entry(gate, &s);
 371 }
 372
 373 /*
 374  * This needs to use 'idt_table' rather than 'idt', and
 375  * thus use the _nonmapped_ version of the IDT, as the
 376  * Pentium F0 0F bugfix can have resulted in the mapped
 377  * IDT being write-protected.
 378  */
 379 #define set_intr_gate_notrace(n, addr)                                  \
 380         do {                                                            \
 381                 BUG_ON((unsigned)n > 0xFF);                             \
 382                 _set_gate(n, GATE_INTERRUPT, (void *)addr, 0, 0,        \
 383                           __KERNEL_CS);                                 \
 384         } while (0)
 385
 386 #define set_intr_gate(n, addr)                                          \
 387         do {                                                            \
 388                 set_intr_gate_notrace(n, addr);                         \
 389                 _trace_set_gate(n, GATE_INTERRUPT, (void *)trace_##addr,\
 390                                 0, 0, __KERNEL_CS);                     \
 391         } while (0)
 392
 393 extern int first_system_vector;
 394 /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
 395 extern unsigned long used_vectors[];
 396
 397 static inline void alloc_system_vector(int vector)
 398 {
 399         if (!test_bit(vector, used_vectors)) {
 400                 set_bit(vector, used_vectors);
 401                 if (first_system_vector > vector)
 402                         first_system_vector = vector;
 403         } else {
 404                 BUG();
 405         }
 406 }
 407
 408 #define alloc_intr_gate(n, addr)                                \
 409         do {                                                    \
 410                 alloc_system_vector(n);                         \
 411                 set_intr_gate(n, addr);                         \
 412         } while (0)
 413
 414 /*
 415  * This routine sets up an interrupt gate at directory privilege level 3.
 416  */
 417 static inline void set_system_intr_gate(unsigned int n, void *addr)
 418 {
 419         BUG_ON((unsigned)n > 0xFF);
 420         _set_gate(n, GATE_INTERRUPT, addr, 0x3, 0, __KERNEL_CS);
 421 }
 422
 423 static inline void set_system_trap_gate(unsigned int n, void *addr)
 424 {
 425         BUG_ON((unsigned)n > 0xFF);
 426         _set_gate(n, GATE_TRAP, addr, 0x3, 0, __KERNEL_CS);
 427 }
 428
 429 static inline void set_trap_gate(unsigned int n, void *addr)
 430 {
 431         BUG_ON((unsigned)n > 0xFF);
 432         _set_gate(n, GATE_TRAP, addr, 0, 0, __KERNEL_CS);
 433 }
 434
 435 static inline void set_task_gate(unsigned int n, unsigned int gdt_entry)
 436 {
 437         BUG_ON((unsigned)n > 0xFF);
 438         _set_gate(n, GATE_TASK, (void *)0, 0, 0, (gdt_entry<<3));
 439 }
 440
 441 static inline void set_intr_gate_ist(int n, void *addr, unsigned ist)
 442 {
 443         BUG_ON((unsigned)n > 0xFF);
 444         _set_gate(n, GATE_INTERRUPT, addr, 0, ist, __KERNEL_CS);
 445 }
 446
 447 static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist)
 448 {
 449         BUG_ON((unsigned)n > 0xFF);
 450         _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
 451 }
 452
 453 #ifdef CONFIG_X86_64
 454 DECLARE_PER_CPU(u32, debug_idt_ctr);
 455 static inline bool is_debug_idt_enabled(void)
 456 {
 457         if (this_cpu_read(debug_idt_ctr))
 458                 return true;
 459
 460         return false;
 461 }
 462
 463 static inline void load_debug_idt(void)
 464 {
 465         load_idt((const struct desc_ptr *)&debug_idt_descr);
 466 }
 467 #else
 468 static inline bool is_debug_idt_enabled(void)
 469 {
 470         return false;
 471 }
 472
 473 static inline void load_debug_idt(void)
 474 {
 475 }
 476 #endif
 477
 478 #ifdef CONFIG_TRACING
 479 extern atomic_t trace_idt_ctr;
 480 static inline bool is_trace_idt_enabled(void)
 481 {
 482         if (atomic_read(&trace_idt_ctr))
 483                 return true;
 484
 485         return false;
 486 }
 487
 488 static inline void load_trace_idt(void)
 489 {
 490         load_idt((const struct desc_ptr *)&trace_idt_descr);
 491 }
 492 #else
 493 static inline bool is_trace_idt_enabled(void)
 494 {
 495         return false;
 496 }
 497
 498 static inline void load_trace_idt(void)
 499 {
 500 }
 501 #endif
 502
 503 /*
 504  * The load_current_idt() must be called with interrupts disabled
 505  * to avoid races. That way the IDT will always be set back to the expected
 506  * descriptor. It's also called when a CPU is being initialized, and
 507  * that doesn't need to disable interrupts, as nothing should be
 508  * bothering the CPU then.
 509  */
 510 static inline void load_current_idt(void)
 511 {
 512         if (is_debug_idt_enabled())
 513                 load_debug_idt();
 514         else if (is_trace_idt_enabled())
 515                 load_trace_idt();
 516         else
 517                 load_idt((const struct desc_ptr *)&idt_descr);
 518 }
 519 #endif /* _ASM_X86_DESC_H */