arch/x86/include/asm/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_PAGE_ALIGNED(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
  95 #define load_TLS(t, cpu) native_load_tls(t, cpu)
  96 #define set_ldt native_set_ldt
  97
  98 #define write_ldt_entry(dt, entry, desc)        \
  99         native_write_ldt_entry(dt, entry, desc)
 100 #define write_gdt_entry(dt, entry, desc, type)          \
 101         native_write_gdt_entry(dt, entry, desc, type)
 102 #define write_idt_entry(dt, entry, g)           \
 103         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,
 117                                           const gate_desc *gate)
 118 {
 119         memcpy(&idt[entry], gate, sizeof(*gate));
 120 }
 121
 122 static inline void native_write_ldt_entry(struct desc_struct *ldt, int entry,
 123                                           const void *desc)
 124 {
 125         memcpy(&ldt[entry], desc, 8);
 126 }
 127
 128 static inline void native_write_gdt_entry(struct desc_struct *gdt, int entry,
 129                                           const void *desc, int type)
 130 {
 131         unsigned int size;
 132         switch (type) {
 133         case DESC_TSS:
 134                 size = sizeof(tss_desc);
 135                 break;
 136         case DESC_LDT:
 137                 size = sizeof(ldt_desc);
 138                 break;
 139         default:
 140                 size = sizeof(struct desc_struct);
 141                 break;
 142         }
 143         memcpy(&gdt[entry], desc, size);
 144 }
 145
 146 static inline void pack_descriptor(struct desc_struct *desc, unsigned long base,
 147                                    unsigned long limit, unsigned char type,
 148                                    unsigned char flags)
 149 {
 150         desc->a = ((base & 0xffff) << 16) | (limit & 0xffff);
 151         desc->b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
 152                 (limit & 0x000f0000) | ((type & 0xff) << 8) |
 153                 ((flags & 0xf) << 20);
 154         desc->p = 1;
 155 }
 156
 157
 158 static inline void set_tssldt_descriptor(void *d, unsigned long addr,
 159                                          unsigned type, unsigned size)
 160 {
 161 #ifdef CONFIG_X86_64
 162         struct ldttss_desc64 *desc = d;
 163         memset(desc, 0, sizeof(*desc));
 164         desc->limit0 = size & 0xFFFF;
 165         desc->base0 = PTR_LOW(addr);
 166         desc->base1 = PTR_MIDDLE(addr) & 0xFF;
 167         desc->type = type;
 168         desc->p = 1;
 169         desc->limit1 = (size >> 16) & 0xF;
 170         desc->base2 = (PTR_MIDDLE(addr) >> 8) & 0xFF;
 171         desc->base3 = PTR_HIGH(addr);
 172 #else
 173         pack_descriptor((struct desc_struct *)d, addr, size, 0x80 | type, 0);
 174 #endif
 175 }
 176
 177 static inline void __set_tss_desc(unsigned cpu, unsigned int entry, void *addr)
 178 {
 179         struct desc_struct *d = get_cpu_gdt_table(cpu);
 180         tss_desc tss;
 181
 182         /*
 183          * sizeof(unsigned long) coming from an extra "long" at the end
 184          * of the iobitmap. See tss_struct definition in processor.h
 185          *
 186          * -1? seg base+limit should be pointing to the address of the
 187          * last valid byte
 188          */
 189         set_tssldt_descriptor(&tss, (unsigned long)addr, DESC_TSS,
 190                               IO_BITMAP_OFFSET + IO_BITMAP_BYTES +
 191                               sizeof(unsigned long) - 1);
 192         write_gdt_entry(d, entry, &tss, DESC_TSS);
 193 }
 194
 195 #define set_tss_desc(cpu, addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 196
 197 static inline void native_set_ldt(const void *addr, unsigned int entries)
 198 {
 199         if (likely(entries == 0))
 200                 asm volatile("lldt %w0"::"q" (0));
 201         else {
 202                 unsigned cpu = smp_processor_id();
 203                 ldt_desc ldt;
 204
 205                 set_tssldt_descriptor(&ldt, (unsigned long)addr, DESC_LDT,
 206                                       entries * LDT_ENTRY_SIZE - 1);
 207                 write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT,
 208                                 &ldt, DESC_LDT);
 209                 asm volatile("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
 210         }
 211 }
 212
 213 static inline void native_load_tr_desc(void)
 214 {
 215         asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
 216 }
 217
 218 static inline void native_load_gdt(const struct desc_ptr *dtr)
 219 {
 220         asm volatile("lgdt %0"::"m" (*dtr));
 221 }
 222
 223 static inline void native_load_idt(const struct desc_ptr *dtr)
 224 {
 225         asm volatile("lidt %0"::"m" (*dtr));
 226 }
 227
 228 static inline void native_store_gdt(struct desc_ptr *dtr)
 229 {
 230         asm volatile("sgdt %0":"=m" (*dtr));
 231 }
 232
 233 static inline void native_store_idt(struct desc_ptr *dtr)
 234 {
 235         asm volatile("sidt %0":"=m" (*dtr));
 236 }
 237
 238 static inline unsigned long native_store_tr(void)
 239 {
 240         unsigned long tr;
 241         asm volatile("str %0":"=r" (tr));
 242         return tr;
 243 }
 244
 245 static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
 246 {
 247         unsigned int i;
 248         struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 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 #define _LDT_empty(info)                                \
 255         ((info)->base_addr              == 0    &&      \
 256          (info)->limit                  == 0    &&      \
 257          (info)->contents               == 0    &&      \
 258          (info)->read_exec_only         == 1    &&      \
 259          (info)->seg_32bit              == 0    &&      \
 260          (info)->limit_in_pages         == 0    &&      \
 261          (info)->seg_not_present        == 1    &&      \
 262          (info)->useable                == 0)
 263
 264 #ifdef CONFIG_X86_64
 265 #define LDT_empty(info) (_LDT_empty(info) && ((info)->lm == 0))
 266 #else
 267 #define LDT_empty(info) (_LDT_empty(info))
 268 #endif
 269
 270 static inline void clear_LDT(void)
 271 {
 272         set_ldt(NULL, 0);
 273 }
 274
 275 /*
 276  * load one particular LDT into the current CPU
 277  */
 278 static inline void load_LDT_nolock(mm_context_t *pc)
 279 {
 280         set_ldt(pc->ldt, pc->size);
 281 }
 282
 283 static inline void load_LDT(mm_context_t *pc)
 284 {
 285         preempt_disable();
 286         load_LDT_nolock(pc);
 287         preempt_enable();
 288 }
 289
 290 static inline unsigned long get_desc_base(const struct desc_struct *desc)
 291 {
 292         return desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24);
 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_gate(int gate, unsigned type, void *addr,
 301                              unsigned dpl, unsigned ist, unsigned seg)
 302 {
 303         gate_desc s;
 304         pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 305         /*
 306          * does not need to be atomic because it is only done once at
 307          * setup time
 308          */
 309         write_idt_entry(idt_table, gate, &s);
 310 }
 311
 312 /*
 313  * This needs to use 'idt_table' rather than 'idt', and
 314  * thus use the _nonmapped_ version of the IDT, as the
 315  * Pentium F0 0F bugfix can have resulted in the mapped
 316  * IDT being write-protected.
 317  */
 318 static inline void set_intr_gate(unsigned int n, void *addr)
 319 {
 320         BUG_ON((unsigned)n > 0xFF);
 321         _set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
 322 }
 323
 324 extern int first_system_vector;
 325 /* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
 326 extern unsigned long used_vectors[];
 327
 328 static inline void alloc_system_vector(int vector)
 329 {
 330         if (!test_bit(vector, used_vectors)) {
 331                 set_bit(vector, used_vectors);
 332                 if (first_system_vector > vector)
 333                         first_system_vector = vector;
 334         } else
 335                 BUG();
 336 }
 337
 338 static inline void alloc_intr_gate(unsigned int n, void *addr)
 339 {
 340         alloc_system_vector(n);
 341         set_intr_gate(n, addr);
 342 }
 343
 344 /*
 345  * This routine sets up an interrupt gate at directory privilege level 3.
 346  */
 347 static inline void set_system_intr_gate(unsigned int n, void *addr)
 348 {
 349         BUG_ON((unsigned)n > 0xFF);
 350         _set_gate(n, GATE_INTERRUPT, addr, 0x3, 0, __KERNEL_CS);
 351 }
 352
 353 static inline void set_system_trap_gate(unsigned int n, void *addr)
 354 {
 355         BUG_ON((unsigned)n > 0xFF);
 356         _set_gate(n, GATE_TRAP, addr, 0x3, 0, __KERNEL_CS);
 357 }
 358
 359 static inline void set_trap_gate(unsigned int n, void *addr)
 360 {
 361         BUG_ON((unsigned)n > 0xFF);
 362         _set_gate(n, GATE_TRAP, addr, 0, 0, __KERNEL_CS);
 363 }
 364
 365 static inline void set_task_gate(unsigned int n, unsigned int gdt_entry)
 366 {
 367         BUG_ON((unsigned)n > 0xFF);
 368         _set_gate(n, GATE_TASK, (void *)0, 0, 0, (gdt_entry<<3));
 369 }
 370
 371 static inline void set_intr_gate_ist(int n, void *addr, unsigned ist)
 372 {
 373         BUG_ON((unsigned)n > 0xFF);
 374         _set_gate(n, GATE_INTERRUPT, addr, 0, ist, __KERNEL_CS);
 375 }
 376
 377 static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist)
 378 {
 379         BUG_ON((unsigned)n > 0xFF);
 380         _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS);
 381 }
 382
 383 #else
 384 /*
 385  * GET_DESC_BASE reads the descriptor base of the specified segment.
 386  *
 387  * Args:
 388  *    idx - descriptor index
 389  *    gdt - GDT pointer
 390  *    base - 32bit register to which the base will be written
 391  *    lo_w - lo word of the "base" register
 392  *    lo_b - lo byte of the "base" register
 393  *    hi_b - hi byte of the low word of the "base" register
 394  *
 395  * Example:
 396  *    GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah)
 397  *    Will read the base address of GDT_ENTRY_ESPFIX_SS and put it into %eax.
 398  */
 399 #define GET_DESC_BASE(idx, gdt, base, lo_w, lo_b, hi_b) \
 400         movb idx * 8 + 4(gdt), lo_b;                    \
 401         movb idx * 8 + 7(gdt), hi_b;                    \
 402         shll $16, base;                                 \
 403         movw idx * 8 + 2(gdt), lo_w;
 404
 405
 406 #endif /* __ASSEMBLY__ */
 407
 408 #endif /* _ASM_X86_DESC_H */