linux/arch/x86/include/asm/desc.h
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   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#include <linux/smp.h>
   8
   9static inline void fill_ldt(struct desc_struct *desc,
  10                            const struct user_desc *info)
  11{
  12        desc->limit0 = info->limit & 0x0ffff;
  13        desc->base0 = info->base_addr & 0x0000ffff;
  14
  15        desc->base1 = (info->base_addr & 0x00ff0000) >> 16;
  16        desc->type = (info->read_exec_only ^ 1) << 1;
  17        desc->type |= info->contents << 2;
  18        desc->s = 1;
  19        desc->dpl = 0x3;
  20        desc->p = info->seg_not_present ^ 1;
  21        desc->limit = (info->limit & 0xf0000) >> 16;
  22        desc->avl = info->useable;
  23        desc->d = info->seg_32bit;
  24        desc->g = info->limit_in_pages;
  25        desc->base2 = (info->base_addr & 0xff000000) >> 24;
  26        /*
  27         * Don't allow setting of the lm bit. It is useless anyway
  28         * because 64bit system calls require __USER_CS:
  29         */
  30        desc->l = 0;
  31}
  32
  33extern struct desc_ptr idt_descr;
  34extern gate_desc idt_table[];
  35
  36struct gdt_page {
  37        struct desc_struct gdt[GDT_ENTRIES];
  38} __attribute__((aligned(PAGE_SIZE)));
  39DECLARE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page);
  40
  41static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
  42{
  43        return per_cpu(gdt_page, cpu).gdt;
  44}
  45
  46#ifdef CONFIG_X86_64
  47
  48static inline void pack_gate(gate_desc *gate, unsigned type, unsigned long func,
  49                             unsigned dpl, unsigned ist, unsigned seg)
  50{
  51        gate->offset_low = PTR_LOW(func);
  52        gate->segment = __KERNEL_CS;
  53        gate->ist = ist;
  54        gate->p = 1;
  55        gate->dpl = dpl;
  56        gate->zero0 = 0;
  57        gate->zero1 = 0;
  58        gate->type = type;
  59        gate->offset_middle = PTR_MIDDLE(func);
  60        gate->offset_high = PTR_HIGH(func);
  61}
  62
  63#else
  64static inline void pack_gate(gate_desc *gate, unsigned char type,
  65                             unsigned long base, unsigned dpl, unsigned flags,
  66                             unsigned short seg)
  67{
  68        gate->a = (seg << 16) | (base & 0xffff);
  69        gate->b = (base & 0xffff0000) |
  70                  (((0x80 | type | (dpl << 5)) & 0xff) << 8);
  71}
  72
  73#endif
  74
  75static inline int desc_empty(const void *ptr)
  76{
  77        const u32 *desc = ptr;
  78        return !(desc[0] | desc[1]);
  79}
  80
  81#ifdef CONFIG_PARAVIRT
  82#include <asm/paravirt.h>
  83#else
  84#define load_TR_desc() native_load_tr_desc()
  85#define load_gdt(dtr) native_load_gdt(dtr)
  86#define load_idt(dtr) native_load_idt(dtr)
  87#define load_tr(tr) asm volatile("ltr %0"::"m" (tr))
  88#define load_ldt(ldt) asm volatile("lldt %0"::"m" (ldt))
  89
  90#define store_gdt(dtr) native_store_gdt(dtr)
  91#define store_idt(dtr) native_store_idt(dtr)
  92#define store_tr(tr) (tr = native_store_tr())
  93
  94#define load_TLS(t, cpu) native_load_tls(t, cpu)
  95#define set_ldt native_set_ldt
  96
  97#define write_ldt_entry(dt, entry, desc)        \
  98        native_write_ldt_entry(dt, entry, desc)
  99#define write_gdt_entry(dt, entry, desc, type)          \
 100        native_write_gdt_entry(dt, entry, desc, type)
 101#define write_idt_entry(dt, entry, g)           \
 102        native_write_idt_entry(dt, entry, g)
 103
 104static inline void paravirt_alloc_ldt(struct desc_struct *ldt, unsigned entries)
 105{
 106}
 107
 108static inline void paravirt_free_ldt(struct desc_struct *ldt, unsigned entries)
 109{
 110}
 111#endif  /* CONFIG_PARAVIRT */
 112
 113#define store_ldt(ldt) asm("sldt %0" : "=m"(ldt))
 114
 115static 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
 121static 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
 127static 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
 145static 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
 157static 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
 176static 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
 196static 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
 212static inline void native_load_tr_desc(void)
 213{
 214        asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
 215}
 216
 217static inline void native_load_gdt(const struct desc_ptr *dtr)
 218{
 219        asm volatile("lgdt %0"::"m" (*dtr));
 220}
 221
 222static inline void native_load_idt(const struct desc_ptr *dtr)
 223{
 224        asm volatile("lidt %0"::"m" (*dtr));
 225}
 226
 227static inline void native_store_gdt(struct desc_ptr *dtr)
 228{
 229        asm volatile("sgdt %0":"=m" (*dtr));
 230}
 231
 232static inline void native_store_idt(struct desc_ptr *dtr)
 233{
 234        asm volatile("sidt %0":"=m" (*dtr));
 235}
 236
 237static inline unsigned long native_store_tr(void)
 238{
 239        unsigned long tr;
 240        asm volatile("str %0":"=r" (tr));
 241        return tr;
 242}
 243
 244static 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
 269static inline void clear_LDT(void)
 270{
 271        set_ldt(NULL, 0);
 272}
 273
 274/*
 275 * load one particular LDT into the current CPU
 276 */
 277static inline void load_LDT_nolock(mm_context_t *pc)
 278{
 279        set_ldt(pc->ldt, pc->size);
 280}
 281
 282static inline void load_LDT(mm_context_t *pc)
 283{
 284        preempt_disable();
 285        load_LDT_nolock(pc);
 286        preempt_enable();
 287}
 288
 289static inline unsigned long get_desc_base(const struct desc_struct *desc)
 290{
 291        return (unsigned)(desc->base0 | ((desc->base1) << 16) | ((desc->base2) << 24));
 292}
 293
 294static inline void set_desc_base(struct desc_struct *desc, unsigned long base)
 295{
 296        desc->base0 = base & 0xffff;
 297        desc->base1 = (base >> 16) & 0xff;
 298        desc->base2 = (base >> 24) & 0xff;
 299}
 300
 301static inline unsigned long get_desc_limit(const struct desc_struct *desc)
 302{
 303        return desc->limit0 | (desc->limit << 16);
 304}
 305
 306static inline void set_desc_limit(struct desc_struct *desc, unsigned long limit)
 307{
 308        desc->limit0 = limit & 0xffff;
 309        desc->limit = (limit >> 16) & 0xf;
 310}
 311
 312static inline void _set_gate(int gate, unsigned type, void *addr,
 313                             unsigned dpl, unsigned ist, unsigned seg)
 314{
 315        gate_desc s;
 316        pack_gate(&s, type, (unsigned long)addr, dpl, ist, seg);
 317        /*
 318         * does not need to be atomic because it is only done once at
 319         * setup time
 320         */
 321        write_idt_entry(idt_table, gate, &s);
 322}
 323
 324/*
 325 * This needs to use 'idt_table' rather than 'idt', and
 326 * thus use the _nonmapped_ version of the IDT, as the
 327 * Pentium F0 0F bugfix can have resulted in the mapped
 328 * IDT being write-protected.
 329 */
 330static inline void set_intr_gate(unsigned int n, void *addr)
 331{
 332        BUG_ON((unsigned)n > 0xFF);
 333        _set_gate(n, GATE_INTERRUPT, addr, 0, 0, __KERNEL_CS);
 334}
 335
 336extern int first_system_vector;
 337/* used_vectors is BITMAP for irq is not managed by percpu vector_irq */
 338extern unsigned long used_vectors[];
 339
 340static inline void alloc_system_vector(int vector)
 341{
 342        if (!test_bit(vector, used_vectors)) {
 343                set_bit(vector, used_vectors);
 344                if (first_system_vector > vector)
 345                        first_system_vector = vector;
 346        } else
 347                BUG();
 348}
 349
 350static 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 */
 359static 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
 365static 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
 371static 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
 377static 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
 383static 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
 389static 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 */
 396