include/asm-x86/desc_64.h

   1 /* Written 2000 by Andi Kleen */
   2 #ifndef __ARCH_DESC_H
   3 #define __ARCH_DESC_H
   4
   5 #include <linux/threads.h>
   6 #include <asm/ldt.h>
   7
   8 #ifndef __ASSEMBLY__
   9
  10 #include <linux/string.h>
  11 #include <linux/smp.h>
  12 #include <asm/desc_defs.h>
  13
  14 #include <asm/segment.h>
  15 #include <asm/mmu.h>
  16
  17 extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
  18
  19 #define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))
  20 #define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
  21 #define clear_LDT()  asm volatile("lldt %w0"::"r" (0))
  22
  23 static inline unsigned long __store_tr(void)
  24 {
  25        unsigned long tr;
  26
  27        asm volatile ("str %w0":"=r" (tr));
  28        return tr;
  29 }
  30
  31 #define store_tr(tr) (tr) = __store_tr()
  32
  33 /*
  34  * This is the ldt that every process will get unless we need
  35  * something other than this.
  36  */
  37 extern struct desc_struct default_ldt[];
  38 extern struct gate_struct idt_table[];
  39 extern struct desc_ptr cpu_gdt_descr[];
  40
  41 /* the cpu gdt accessor */
  42 #define cpu_gdt(_cpu) ((struct desc_struct *)cpu_gdt_descr[_cpu].address)
  43
  44 static inline void load_gdt(const struct desc_ptr *ptr)
  45 {
  46         asm volatile("lgdt %w0"::"m" (*ptr));
  47 }
  48
  49 static inline void store_gdt(struct desc_ptr *ptr)
  50 {
  51        asm("sgdt %w0":"=m" (*ptr));
  52 }
  53
  54 static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)
  55 {
  56         struct gate_struct s;
  57         s.offset_low = PTR_LOW(func);
  58         s.segment = __KERNEL_CS;
  59         s.ist = ist;
  60         s.p = 1;
  61         s.dpl = dpl;
  62         s.zero0 = 0;
  63         s.zero1 = 0;
  64         s.type = type;
  65         s.offset_middle = PTR_MIDDLE(func);
  66         s.offset_high = PTR_HIGH(func);
  67         /* does not need to be atomic because it is only done once at setup time */
  68         memcpy(adr, &s, 16);
  69 }
  70
  71 static inline void set_intr_gate(int nr, void *func)
  72 {
  73         BUG_ON((unsigned)nr > 0xFF);
  74         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
  75 }
  76
  77 static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
  78 {
  79         BUG_ON((unsigned)nr > 0xFF);
  80         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
  81 }
  82
  83 static inline void set_system_gate(int nr, void *func)
  84 {
  85         BUG_ON((unsigned)nr > 0xFF);
  86         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
  87 }
  88
  89 static inline void set_system_gate_ist(int nr, void *func, unsigned ist)
  90 {
  91         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, ist);
  92 }
  93
  94 static inline void load_idt(const struct desc_ptr *ptr)
  95 {
  96         asm volatile("lidt %w0"::"m" (*ptr));
  97 }
  98
  99 static inline void store_idt(struct desc_ptr *dtr)
 100 {
 101        asm("sidt %w0":"=m" (*dtr));
 102 }
 103
 104 static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type,
 105                                          unsigned size)
 106 {
 107         struct ldttss_desc d;
 108         memset(&d,0,sizeof(d));
 109         d.limit0 = size & 0xFFFF;
 110         d.base0 = PTR_LOW(tss);
 111         d.base1 = PTR_MIDDLE(tss) & 0xFF;
 112         d.type = type;
 113         d.p = 1;
 114         d.limit1 = (size >> 16) & 0xF;
 115         d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
 116         d.base3 = PTR_HIGH(tss);
 117         memcpy(ptr, &d, 16);
 118 }
 119
 120 static inline void set_tss_desc(unsigned cpu, void *addr)
 121 {
 122         /*
 123          * sizeof(unsigned long) coming from an extra "long" at the end
 124          * of the iobitmap. See tss_struct definition in processor.h
 125          *
 126          * -1? seg base+limit should be pointing to the address of the
 127          * last valid byte
 128          */
 129         set_tssldt_descriptor(&cpu_gdt(cpu)[GDT_ENTRY_TSS],
 130                 (unsigned long)addr, DESC_TSS,
 131                 IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1);
 132 }
 133
 134 static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
 135 {
 136         set_tssldt_descriptor(&cpu_gdt(cpu)[GDT_ENTRY_LDT], (unsigned long)addr,
 137                               DESC_LDT, size * 8 - 1);
 138 }
 139
 140 #define LDT_entry_a(info) \
 141         ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
 142 /* Don't allow setting of the lm bit. It is useless anyways because
 143    64bit system calls require __USER_CS. */
 144 #define LDT_entry_b(info) \
 145         (((info)->base_addr & 0xff000000) | \
 146         (((info)->base_addr & 0x00ff0000) >> 16) | \
 147         ((info)->limit & 0xf0000) | \
 148         (((info)->read_exec_only ^ 1) << 9) | \
 149         ((info)->contents << 10) | \
 150         (((info)->seg_not_present ^ 1) << 15) | \
 151         ((info)->seg_32bit << 22) | \
 152         ((info)->limit_in_pages << 23) | \
 153         ((info)->useable << 20) | \
 154         /* ((info)->lm << 21) | */ \
 155         0x7000)
 156
 157 #define LDT_empty(info) (\
 158         (info)->base_addr       == 0    && \
 159         (info)->limit           == 0    && \
 160         (info)->contents        == 0    && \
 161         (info)->read_exec_only  == 1    && \
 162         (info)->seg_32bit       == 0    && \
 163         (info)->limit_in_pages  == 0    && \
 164         (info)->seg_not_present == 1    && \
 165         (info)->useable         == 0    && \
 166         (info)->lm              == 0)
 167
 168 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
 169 {
 170         unsigned int i;
 171         u64 *gdt = (u64 *)(cpu_gdt(cpu) + GDT_ENTRY_TLS_MIN);
 172
 173         for (i = 0; i < GDT_ENTRY_TLS_ENTRIES; i++)
 174                 gdt[i] = t->tls_array[i];
 175 }
 176
 177 /*
 178  * load one particular LDT into the current CPU
 179  */
 180 static inline void load_LDT_nolock (mm_context_t *pc, int cpu)
 181 {
 182         int count = pc->size;
 183
 184         if (likely(!count)) {
 185                 clear_LDT();
 186                 return;
 187         }
 188
 189         set_ldt_desc(cpu, pc->ldt, count);
 190         load_LDT_desc();
 191 }
 192
 193 static inline void load_LDT(mm_context_t *pc)
 194 {
 195         int cpu = get_cpu();
 196         load_LDT_nolock(pc, cpu);
 197         put_cpu();
 198 }
 199
 200 extern struct desc_ptr idt_descr;
 201
 202 #endif /* !__ASSEMBLY__ */
 203
 204 #endif