include/asm-i386/desc.h

   1 #ifndef __ARCH_DESC_H
   2 #define __ARCH_DESC_H
   3
   4 #include <asm/ldt.h>
   5 #include <asm/segment.h>
   6
   7 #ifndef __ASSEMBLY__
   8
   9 #include <linux/preempt.h>
  10 #include <linux/smp.h>
  11 #include <linux/percpu.h>
  12
  13 #include <asm/mmu.h>
  14
  15 struct Xgt_desc_struct {
  16         unsigned short size;
  17         unsigned long address __attribute__((packed));
  18         unsigned short pad;
  19 } __attribute__ ((packed));
  20
  21 struct gdt_page
  22 {
  23         struct desc_struct gdt[GDT_ENTRIES];
  24 } __attribute__((aligned(PAGE_SIZE)));
  25 DECLARE_PER_CPU(struct gdt_page, gdt_page);
  26
  27 static inline struct desc_struct *get_cpu_gdt_table(unsigned int cpu)
  28 {
  29         return per_cpu(gdt_page, cpu).gdt;
  30 }
  31
  32 extern struct Xgt_desc_struct idt_descr;
  33 extern struct desc_struct idt_table[];
  34 extern void set_intr_gate(unsigned int irq, void * addr);
  35
  36 static inline void pack_descriptor(__u32 *a, __u32 *b,
  37         unsigned long base, unsigned long limit, unsigned char type, unsigned char flags)
  38 {
  39         *a = ((base & 0xffff) << 16) | (limit & 0xffff);
  40         *b = (base & 0xff000000) | ((base & 0xff0000) >> 16) |
  41                 (limit & 0x000f0000) | ((type & 0xff) << 8) | ((flags & 0xf) << 20);
  42 }
  43
  44 static inline void pack_gate(__u32 *a, __u32 *b,
  45         unsigned long base, unsigned short seg, unsigned char type, unsigned char flags)
  46 {
  47         *a = (seg << 16) | (base & 0xffff);
  48         *b = (base & 0xffff0000) | ((type & 0xff) << 8) | (flags & 0xff);
  49 }
  50
  51 #define DESCTYPE_LDT    0x82    /* present, system, DPL-0, LDT */
  52 #define DESCTYPE_TSS    0x89    /* present, system, DPL-0, 32-bit TSS */
  53 #define DESCTYPE_TASK   0x85    /* present, system, DPL-0, task gate */
  54 #define DESCTYPE_INT    0x8e    /* present, system, DPL-0, interrupt gate */
  55 #define DESCTYPE_TRAP   0x8f    /* present, system, DPL-0, trap gate */
  56 #define DESCTYPE_DPL3   0x60    /* DPL-3 */
  57 #define DESCTYPE_S      0x10    /* !system */
  58
  59 #ifdef CONFIG_PARAVIRT
  60 #include <asm/paravirt.h>
  61 #else
  62 #define load_TR_desc() native_load_tr_desc()
  63 #define load_gdt(dtr) native_load_gdt(dtr)
  64 #define load_idt(dtr) native_load_idt(dtr)
  65 #define load_tr(tr) __asm__ __volatile("ltr %0"::"m" (tr))
  66 #define load_ldt(ldt) __asm__ __volatile("lldt %0"::"m" (ldt))
  67
  68 #define store_gdt(dtr) native_store_gdt(dtr)
  69 #define store_idt(dtr) native_store_idt(dtr)
  70 #define store_tr(tr) (tr = native_store_tr())
  71 #define store_ldt(ldt) __asm__ ("sldt %0":"=m" (ldt))
  72
  73 #define load_TLS(t, cpu) native_load_tls(t, cpu)
  74 #define set_ldt native_set_ldt
  75
  76 #define write_ldt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
  77 #define write_gdt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
  78 #define write_idt_entry(dt, entry, a, b) write_dt_entry(dt, entry, a, b)
  79 #endif
  80
  81 static inline void write_dt_entry(struct desc_struct *dt,
  82                                   int entry, u32 entry_low, u32 entry_high)
  83 {
  84         dt[entry].a = entry_low;
  85         dt[entry].b = entry_high;
  86 }
  87
  88 static inline void native_set_ldt(const void *addr, unsigned int entries)
  89 {
  90         if (likely(entries == 0))
  91                 __asm__ __volatile__("lldt %w0"::"q" (0));
  92         else {
  93                 unsigned cpu = smp_processor_id();
  94                 __u32 a, b;
  95
  96                 pack_descriptor(&a, &b, (unsigned long)addr,
  97                                 entries * sizeof(struct desc_struct) - 1,
  98                                 DESCTYPE_LDT, 0);
  99                 write_gdt_entry(get_cpu_gdt_table(cpu), GDT_ENTRY_LDT, a, b);
 100                 __asm__ __volatile__("lldt %w0"::"q" (GDT_ENTRY_LDT*8));
 101         }
 102 }
 103
 104
 105 static inline void native_load_tr_desc(void)
 106 {
 107         asm volatile("ltr %w0"::"q" (GDT_ENTRY_TSS*8));
 108 }
 109
 110 static inline void native_load_gdt(const struct Xgt_desc_struct *dtr)
 111 {
 112         asm volatile("lgdt %0"::"m" (*dtr));
 113 }
 114
 115 static inline void native_load_idt(const struct Xgt_desc_struct *dtr)
 116 {
 117         asm volatile("lidt %0"::"m" (*dtr));
 118 }
 119
 120 static inline void native_store_gdt(struct Xgt_desc_struct *dtr)
 121 {
 122         asm ("sgdt %0":"=m" (*dtr));
 123 }
 124
 125 static inline void native_store_idt(struct Xgt_desc_struct *dtr)
 126 {
 127         asm ("sidt %0":"=m" (*dtr));
 128 }
 129
 130 static inline unsigned long native_store_tr(void)
 131 {
 132         unsigned long tr;
 133         asm ("str %0":"=r" (tr));
 134         return tr;
 135 }
 136
 137 static inline void native_load_tls(struct thread_struct *t, unsigned int cpu)
 138 {
 139         unsigned int i;
 140         struct desc_struct *gdt = get_cpu_gdt_table(cpu);
 141
 142         for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
 143                 gdt[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i];
 144 }
 145
 146 static inline void _set_gate(int gate, unsigned int type, void *addr, unsigned short seg)
 147 {
 148         __u32 a, b;
 149         pack_gate(&a, &b, (unsigned long)addr, seg, type, 0);
 150         write_idt_entry(idt_table, gate, a, b);
 151 }
 152
 153 static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, const void *addr)
 154 {
 155         __u32 a, b;
 156         pack_descriptor(&a, &b, (unsigned long)addr,
 157                         offsetof(struct tss_struct, __cacheline_filler) - 1,
 158                         DESCTYPE_TSS, 0);
 159         write_gdt_entry(get_cpu_gdt_table(cpu), entry, a, b);
 160 }
 161
 162
 163 #define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
 164
 165 #define LDT_entry_a(info) \
 166         ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
 167
 168 #define LDT_entry_b(info) \
 169         (((info)->base_addr & 0xff000000) | \
 170         (((info)->base_addr & 0x00ff0000) >> 16) | \
 171         ((info)->limit & 0xf0000) | \
 172         (((info)->read_exec_only ^ 1) << 9) | \
 173         ((info)->contents << 10) | \
 174         (((info)->seg_not_present ^ 1) << 15) | \
 175         ((info)->seg_32bit << 22) | \
 176         ((info)->limit_in_pages << 23) | \
 177         ((info)->useable << 20) | \
 178         0x7000)
 179
 180 #define LDT_empty(info) (\
 181         (info)->base_addr       == 0    && \
 182         (info)->limit           == 0    && \
 183         (info)->contents        == 0    && \
 184         (info)->read_exec_only  == 1    && \
 185         (info)->seg_32bit       == 0    && \
 186         (info)->limit_in_pages  == 0    && \
 187         (info)->seg_not_present == 1    && \
 188         (info)->useable         == 0    )
 189
 190 static inline void clear_LDT(void)
 191 {
 192         set_ldt(NULL, 0);
 193 }
 194
 195 /*
 196  * load one particular LDT into the current CPU
 197  */
 198 static inline void load_LDT_nolock(mm_context_t *pc)
 199 {
 200         set_ldt(pc->ldt, pc->size);
 201 }
 202
 203 static inline void load_LDT(mm_context_t *pc)
 204 {
 205         preempt_disable();
 206         load_LDT_nolock(pc);
 207         preempt_enable();
 208 }
 209
 210 static inline unsigned long get_desc_base(unsigned long *desc)
 211 {
 212         unsigned long base;
 213         base = ((desc[0] >> 16)  & 0x0000ffff) |
 214                 ((desc[1] << 16) & 0x00ff0000) |
 215                 (desc[1] & 0xff000000);
 216         return base;
 217 }
 218
 219 #else /* __ASSEMBLY__ */
 220
 221 /*
 222  * GET_DESC_BASE reads the descriptor base of the specified segment.
 223  *
 224  * Args:
 225  *    idx - descriptor index
 226  *    gdt - GDT pointer
 227  *    base - 32bit register to which the base will be written
 228  *    lo_w - lo word of the "base" register
 229  *    lo_b - lo byte of the "base" register
 230  *    hi_b - hi byte of the low word of the "base" register
 231  *
 232  * Example:
 233  *    GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah)
 234  *    Will read the base address of GDT_ENTRY_ESPFIX_SS and put it into %eax.
 235  */
 236 #define GET_DESC_BASE(idx, gdt, base, lo_w, lo_b, hi_b) \
 237         movb idx*8+4(gdt), lo_b; \
 238         movb idx*8+7(gdt), hi_b; \
 239         shll $16, base; \
 240         movw idx*8+2(gdt), lo_w;
 241
 242 #endif /* !__ASSEMBLY__ */
 243
 244 #endif