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