include/asm-x86/desc.h

   1 #ifndef ASM_X86__DESC_H
   2 #define ASM_X86__DESC_H
   3
   4 #ifndef __ASSEMBLY__
   5 #include <asm/desc_defs.h>
   6 #include <asm/ldt.h>
   7 #include <asm/mmu.h>
   8 #include <linux/smp.h>
   9
  10 static inline void fill_ldt(struct desc_struct *desc,
  11                             const struct user_desc *info)
  12 {
  13         desc->limit0 = info->limit & 0x0ffff;
  14         desc->base0 = info->base_addr & 0x0000ffff;
  15
  16         desc->base1 = (info->base_addr & 0x00ff0000) >> 16;
  17         desc->type = (info->read_exec_only ^ 1) << 1;
  18         desc->type |= info->contents << 2;
  19         desc->s = 1;
  20         desc->dpl = 0x3;
  21         desc->p = info->seg_not_present ^ 1;
  22         desc->limit = (info->limit & 0xf0000) >> 16;
  23         desc->avl = info->useable;
  24         desc->d = info->seg_32bit;
  25         desc->g = info->limit_in_pages;
  26         desc->base2 = (info->base_addr & 0xff000000) >> 24;
  27         /*
  28          * Don't allow setting of the lm bit. It is useless anyway
  29          * because 64bit system calls require __USER_CS:
  30          */
  31         desc->l = 0;
  32 }
  33
  34 extern struct desc_ptr idt_descr;
  35 extern gate_desc idt_table[];
  36
  37 struct gdt_page {
  38         struct desc_struct gdt[GDT_ENTRIES];
  39 } __attribute__((aligned(PAGE_SIZE)));
  40 DECLARE_PER_CPU(struct gdt_page, gdt_page);
  41
  42 static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
  43 {
  44         return per_cpu(gdt_page, cpu).gdt;
  45 }
  46
  47 #ifdef CONFIG_X86_64
  48
  49 static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
  50                              unsigned dpl, unsigned ist, unsigned seg)
  51 {
  52         gate->offset_low = PTR_LOW(func);
  53         gate->segment = __KERNEL_CS;
  54         gate->ist = ist;
  55         gate->p = 1;
  56         gate->dpl = dpl;
  57         gate->zero0 = 0;
  58         gate->zero1 = 0;
  59         gate->type = type;
  60         gate->offset_middle = PTR_MIDDLE(func);
  61         gate->offset_high = PTR_HIGH(func);
  62 }
  63
  64 #else
  65 static inline void pack_gate(gate_desc *gate, unsigned char type,
  66                              unsigned long base, unsigned dpl, unsigned flags,
  67                              unsigned short seg)
  68 {
  69         gate->a = (seg << 16) | (base & 0xffff);
  70         gate->b = (base & 0xffff0000) |
  71                   (((0x80 | type | (dpl << 5)) & 0xff) << 8);
  72 }
  73
  74 #endif
  75
  76 static inline int desc_empty(const void *ptr)
  77 {
  78         const u32 *desc = ptr;
  79         return !(desc[0] | desc[1]);
  80 }
  81
  82 #ifdef CONFIG_PARAVIRT
  83 #include <asm/paravirt.h>
  84 #else
  85 #define load_TR_desc() native_load_tr_desc()
  86 #define load_gdt(dtr) native_load_gdt(dtr)
  87 #define load_idt(dtr) native_load_idt(dtr)
  88 #define load_tr(tr) asm volatile("ltr %0"::"m" (tr))
  89 #define load_ldt(ldt) asm volatile("lldt %0"::"m" (ldt))
  90
  91 #define store_gdt(dtr) native_store_gdt(dtr)
  92 #define store_idt(dtr) native_store_idt(dtr)
  93 #define store_tr(tr) (tr = native_store_tr())
  94 #define store_ldt(ldt) asm("sldt %0":"=m" (ldt))
  95
  96 #define load_TLS(t, cpu) native_load_tls(t, cpu)
  97 #define set_ldt native_set_ldt
  98
  99 #define write_ldt_entry(dt, entry, desc)        \
 100         native_write_ldt_entry(dt, entry, desc)
 101 #define write_gdt_entry(dt, entry, desc, type)          \
 102         native_write_gdt_entry(dt, entry, desc, type)
 103 #define write_idt_entry(dt, entry, g)           \
 104         native_write_idt_entry(dt, entry, g)
 105
 106 static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 107 {
 108 }
 109
 110 static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries)
 111 {
 112 }
 113 #endif  /* CONFIG_PARAVIRT */
 114
 115 static inline void native_write_idt_entry(gate_desc *idt, int entry,
 116                                           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,
 122                                           const void *desc)
 123 {
 124         memcpy(&ldt[entry], desc, 8);
 125 }
 126
 127 static inline void native_write_gdt_entry(struct desc_struct *gdt, int entry,
 128                                           const void *desc, int type)
 129 {
 130         unsigned int size;
 131         switch (type) {
 132         case DESC_TSS:
 133                 size = sizeof(tss_desc);
 134                 break;
 135         case DESC_LDT:
 136                 size = sizeof(ldt_desc);
 137                 break;
 138         default:
 139                 size = sizeof(struct desc_struct);
 140                 break;
 141         }
 142         memcpy(&gdt[entry], desc, size);
 143 }
 144
 145 static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
 146                                    unsigned long limit, unsigned char type,
 147                                    unsigned char flags)
 148 {
 149         desc->a = ((base & 0xffff) << 16) | (limit & 0xffff);
 150         desc->b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
 151                 (limit & 0x000f0000) | ((type & 0xff) << 8) |
 152                 ((flags & 0xf) << 20);
 153         desc->p = 1;
 154 }
 155
 156
 157 static inline void set_tssldt_descriptor(void *d, unsigned long addr,
 158                                          unsigned type, unsigned size)
 159 {
 160 #ifdef CONFIG_X86_64
 161         struct ldttss_desc64 *desc = d;
 162         memset(desc, 0, sizeof(*desc));
 163         desc->limit0 = size & 0xFFFF;
 164         desc->base0 = PTR_LOW(addr);
 165         desc->base1 = PTR_MIDDLE(addr) & 0xFF;
 166         desc->type = type;
 167         desc->p = 1;
 168         desc->limit1 = (size >> 16) & 0xF;
 169         desc->base2 = (PTR_MIDDLE(addr) >> 8) & 0xFF;
 170         desc->base3 = PTR_HIGH(addr);
 171 #else
 172         pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);
 173 #endif
 174 }
 175
 176 static inline void __set_tss_desc(unsigned cpu, unsigned int entry, void *addr)
 177 {
 178         struct desc_struct *d = get_cpu_gdt_table(cpu);
 179         tss_desc tss;
 180
 181         /*
 182          * sizeof(unsigned long) coming from an extra "long" at the end
 183          * of the iobitmap. See tss_struct definition in processor.h
 184          *
 185          * -1? seg base+limit should be pointing to the address of the
 186          * last valid byte
 187          */
 188         set_tssldt_descriptor(&tss, (unsigned long)addr, DESC_TSS,
 189                               IO_BITMAP_OFFSET + IO_BITMAP_BYTES +
 190                               sizeof(unsigned long) - 1);
 191         write_gdt_entry(d, entry, &tss, DESC_TSS);
 192 }
 193
 194 #define set_tss_desc(cpu, addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 195
 196 static inline void native_set_ldt(const void *addr, unsigned int entries)
 197 {
 198         if (likely(entries == 0))
 199                 asm volatile("lldt %w0"::"q" (0));
 200         else {
 201                 unsigned cpu = smp_processor_id();
 202                 ldt_desc ldt;
 203
 204                 set_tssldt_descriptor(&ldt, (unsigned long)addr, DESC_LDT,
 205                                       entries * LDT_ENTRY_SIZE - 1);
 206                 write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT,
 207                                 &ldt, DESC_LDT);
 208                 asm volatile("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
 209         }
 210 }
 211
 212 static inline void native_load_tr_desc(void)
 213 {
 214         asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
 215 }
 216
 217 static inline void native_load_gdt(const struct desc_ptr *dtr)
 218 {
 219         asm volatile("lgdt %0"::"m" (*dtr));
 220 }
 221
 222 static inline void native_load_idt(const struct desc_ptr *dtr)
 223 {
 224         asm volatile("lidt %0"::"m" (*dtr));
 225 }
 226
 227 static inline void native_store_gdt(struct desc_ptr *dtr)
 228 {
 229         asm volatile("sgdt %0":"=m" (*dtr));
 230 }
 231
 232 static inline void native_store_idt(struct desc_ptr *dtr)
 233 {
 234         asm volatile("sidt %0":"=m" (*dtr));
 235 }
 236
 237 static inline unsigned long native_store_tr(void)
 238 {
 239         unsigned long tr;
 240         asm volatile("str %0":"=r" (tr));
 241         return tr;
 242 }
 243
 244 static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
 245 {
 246         unsigned int i;
 247         struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 248
 249         for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
 250                 gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
 251 }
 252
 253 #define _LDT_empty(info)                                \
 254         ((info)->base_addr              == 0    &&      \
 255          (info)->limit                  == 0    &&      \
 256          (info)->contents               == 0    &&      \
 257          (info)->read_exec_only         == 1    &&      \
 258          (info)->seg_32bit              == 0    &&      \
 259          (info)->limit_in_pages         == 0    &&      \
 260          (info)->seg_not_present        == 1    &&      \
 261          (info)->useable                == 0)
 262
 263 #ifdef CONFIG_X86_64
 264 #define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0))
 265 #else
 266 #define LDT_empty(info) (_LDT_empty(info))
 267 #endif
 268
 269 static inline void clear_LDT(void)
 270 {
 271         set_ldt(NULL, 0);
 272 }
 273
 274 /*
 275  * load one particular LDT into the current CPU
 276  */
 277 static inline void load_LDT_nolock(mm_context_t *pc)
 278 {
 279         set_ldt(pc->ldt, pc->size);
 280 }
 281
 282 static inline void load_LDT(mm_context_t *pc)
 283 {
 284         preempt_disable();
 285         load_LDT_nolock(pc);
 286         preempt_enable();
 287 }
 288
 289 static inline unsigned long get_desc_base(const struct desc_struct *desc)
 290 {
 291         return desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24);
 292 }
 293
 294 static inline unsigned long get_desc_limit(const struct desc_struct *desc)
 295 {
 296         return desc->limit0 | (desc->limit << 16);
 297 }
 298
 299 static inline void _set_gate(int gate, unsigned type, void *addr,
 300                              unsigned dpl, unsigned ist, unsigned seg)
 301 {
 302         gate_desc s;
 303         pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 304         /*
 305          * does not need to be atomic because it is only done once at
 306          * setup time
 307          */
 308         write_idt_entry(idt_table, gate, &s);
 309 }
 310
 311 /*
 312  * This needs to use 'idt_table' rather than 'idt', and
 313  * thus use the _nonmapped_ version of the IDT, as the
 314  * Pentium F0 0F bugfix can have resulted in the mapped
 315  * IDT being write-protected.
 316  */
 317 static inline void set_intr_gate(unsigned int n, void *addr)
 318 {
 319         BUG_ON((unsigned)n > 0xFF);
 320         _set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
 321 }
 322
 323 #define SYS_VECTOR_FREE         0
 324 #define SYS_VECTOR_ALLOCED      1
 325
 326 extern int first_system_vector;
 327 extern char system_vectors[];
 328
 329 static inline void alloc_system_vector(int vector)
 330 {
 331         if (system_vectors[vector] == SYS_VECTOR_FREE) {
 332                 system_vectors[vector] = SYS_VECTOR_ALLOCED;
 333                 if (first_system_vector > vector)
 334                         first_system_vector = vector;
 335         } else
 336                 BUG();
 337 }
 338
 339 static inline void alloc_intr_gate(unsigned int n, void *addr)
 340 {
 341         alloc_system_vector(n);
 342         set_intr_gate(n, addr);
 343 }
 344
 345 /*
 346  * This routine sets up an interrupt gate at directory privilege level 3.
 347  */
 348 static inline void set_system_intr_gate(unsigned int n, void *addr)
 349 {
 350         BUG_ON((unsigned)n > 0xFF);
 351         _set_gate(n, GATE_INTERRUPT, addr, 0x3, 0, __KERNEL_CS);
 352 }
 353
 354 static inline void set_system_trap_gate(unsigned int n, void *addr)
 355 {
 356         BUG_ON((unsigned)n > 0xFF);
 357         _set_gate(n, GATE_TRAP, addr, 0x3, 0, __KERNEL_CS);
 358 }
 359
 360 static inline void set_trap_gate(unsigned int n, void *addr)
 361 {
 362         BUG_ON((unsigned)n > 0xFF);
 363         _set_gate(n, GATE_TRAP, addr, 0, 0, __KERNEL_CS);
 364 }
 365
 366 static inline void set_task_gate(unsigned int n, unsigned int gdt_entry)
 367 {
 368         BUG_ON((unsigned)n > 0xFF);
 369         _set_gate(n, GATE_TASK, (void *)0, 0, 0, (gdt_entry<<3));
 370 }
 371
 372 static inline void set_intr_gate_ist(int n, void *addr, unsigned ist)
 373 {
 374         BUG_ON((unsigned)n > 0xFF);
 375         _set_gate(n, GATE_INTERRUPT, addr, 0, ist, __KERNEL_CS);
 376 }
 377
 378 static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist)
 379 {
 380         BUG_ON((unsigned)n > 0xFF);
 381         _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
 382 }
 383
 384 #else
 385 /*
 386  * GET_DESC_BASE reads the descriptor base of the specified segment.
 387  *
 388  * Args:
 389  *    idx - descriptor index
 390  *    gdt - GDT pointer
 391  *    base - 32bit register to which the base will be written
 392  *    lo_w - lo word of the "base" register
 393  *    lo_b - lo byte of the "base" register
 394  *    hi_b - hi byte of the low word of the "base" register
 395  *
 396  * Example:
 397  *    GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah)
 398  *    Will read the base address of GDT_ENTRY_ESPFIX_SS and put it into %eax.
 399  */
 400 #define GET_DESC_BASE(idx, gdt, base, lo_w, lo_b, hi_b) \
 401         movb idx * 8 + 4(gdt), lo_b;                    \
 402         movb idx * 8 + 7(gdt), hi_b;                    \
 403         shll $16, base;                                 \
 404         movw idx * 8 + 2(gdt), lo_w;
 405
 406
 407 #endif /* __ASSEMBLY__ */
 408
 409 #endif /* ASM_X86__DESC_H */