include/asm-x86_64/desc.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 <asm/segment.h>
  12 #include <asm/mmu.h>
  13
  14 // 8 byte segment descriptor
  15 struct desc_struct {
  16         u16 limit0;
  17         u16 base0;
  18         unsigned base1 : 8, type : 4, s : 1, dpl : 2, p : 1;
  19         unsigned limit : 4, avl : 1, l : 1, d : 1, g : 1, base2 : 8;
  20 } __attribute__((packed));
  21
  22 struct n_desc_struct {
  23         unsigned int a,b;
  24 };
  25
  26 extern struct desc_struct cpu_gdt_table[NR_CPUS][GDT_ENTRIES];
  27
  28 enum {
  29         GATE_INTERRUPT = 0xE,
  30         GATE_TRAP = 0xF,
  31         GATE_CALL = 0xC,
  32 };
  33
  34 // 16byte gate
  35 struct gate_struct {
  36         u16 offset_low;
  37         u16 segment;
  38         unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
  39         u16 offset_middle;
  40         u32 offset_high;
  41         u32 zero1;
  42 } __attribute__((packed));
  43
  44 #define PTR_LOW(x) ((unsigned long)(x) & 0xFFFF)
  45 #define PTR_MIDDLE(x) (((unsigned long)(x) >> 16) & 0xFFFF)
  46 #define PTR_HIGH(x) ((unsigned long)(x) >> 32)
  47
  48 enum {
  49         DESC_TSS = 0x9,
  50         DESC_LDT = 0x2,
  51 };
  52
  53 // LDT or TSS descriptor in the GDT. 16 bytes.
  54 struct ldttss_desc {
  55         u16 limit0;
  56         u16 base0;
  57         unsigned base1 : 8, type : 5, dpl : 2, p : 1;
  58         unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
  59         u32 base3;
  60         u32 zero1;
  61 } __attribute__((packed));
  62
  63 struct desc_ptr {
  64         unsigned short size;
  65         unsigned long address;
  66 } __attribute__((packed)) ;
  67
  68 #define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))
  69 #define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
  70 #define clear_LDT()  asm volatile("lldt %w0"::"r" (0))
  71
  72 /*
  73  * This is the ldt that every process will get unless we need
  74  * something other than this.
  75  */
  76 extern struct desc_struct default_ldt[];
  77 extern struct gate_struct idt_table[];
  78 extern struct desc_ptr cpu_gdt_descr[];
  79
  80 static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)
  81 {
  82         struct gate_struct s;
  83         s.offset_low = PTR_LOW(func);
  84         s.segment = __KERNEL_CS;
  85         s.ist = ist;
  86         s.p = 1;
  87         s.dpl = dpl;
  88         s.zero0 = 0;
  89         s.zero1 = 0;
  90         s.type = type;
  91         s.offset_middle = PTR_MIDDLE(func);
  92         s.offset_high = PTR_HIGH(func);
  93         /* does not need to be atomic because it is only done once at setup time */
  94         memcpy(adr, &s, 16);
  95 }
  96
  97 static inline void set_intr_gate(int nr, void *func)
  98 {
  99         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
 100 }
 101
 102 static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
 103 {
 104         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
 105 }
 106
 107 static inline void set_system_gate(int nr, void *func)
 108 {
 109         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
 110 }
 111
 112 static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type,
 113                                          unsigned size)
 114 {
 115         struct ldttss_desc d;
 116         memset(&d,0,sizeof(d));
 117         d.limit0 = size & 0xFFFF;
 118         d.base0 = PTR_LOW(tss);
 119         d.base1 = PTR_MIDDLE(tss) & 0xFF;
 120         d.type = type;
 121         d.p = 1;
 122         d.limit1 = (size >> 16) & 0xF;
 123         d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
 124         d.base3 = PTR_HIGH(tss);
 125         memcpy(ptr, &d, 16);
 126 }
 127
 128 static inline void set_tss_desc(unsigned cpu, void *addr)
 129 {
 130         set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_TSS], (unsigned long)addr,
 131                               DESC_TSS,
 132                               sizeof(struct tss_struct) - 1);
 133 }
 134
 135 static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
 136 {
 137         set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_LDT], (unsigned long)addr,
 138                               DESC_LDT, size * 8 - 1);
 139 }
 140
 141 static inline void set_seg_base(unsigned cpu, int entry, void *base)
 142 {
 143         struct desc_struct *d = &cpu_gdt_table[cpu][entry];
 144         u32 addr = (u32)(u64)base;
 145         BUG_ON((u64)base >> 32);
 146         d->base0 = addr & 0xffff;
 147         d->base1 = (addr >> 16) & 0xff;
 148         d->base2 = (addr >> 24) & 0xff;
 149 }
 150
 151 #define LDT_entry_a(info) \
 152         ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
 153 /* Don't allow setting of the lm bit. It is useless anyways because
 154    64bit system calls require __USER_CS. */
 155 #define LDT_entry_b(info) \
 156         (((info)->base_addr & 0xff000000) | \
 157         (((info)->base_addr & 0x00ff0000) >> 16) | \
 158         ((info)->limit & 0xf0000) | \
 159         (((info)->read_exec_only ^ 1) << 9) | \
 160         ((info)->contents << 10) | \
 161         (((info)->seg_not_present ^ 1) << 15) | \
 162         ((info)->seg_32bit << 22) | \
 163         ((info)->limit_in_pages << 23) | \
 164         ((info)->useable << 20) | \
 165         /* ((info)->lm << 21) | */ \
 166         0x7000)
 167
 168 #define LDT_empty(info) (\
 169         (info)->base_addr       == 0    && \
 170         (info)->limit           == 0    && \
 171         (info)->contents        == 0    && \
 172         (info)->read_exec_only  == 1    && \
 173         (info)->seg_32bit       == 0    && \
 174         (info)->limit_in_pages  == 0    && \
 175         (info)->seg_not_present == 1    && \
 176         (info)->useable         == 0    && \
 177         (info)->lm              == 0)
 178
 179 #if TLS_SIZE != 24
 180 # error update this code.
 181 #endif
 182
 183 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
 184 {
 185         u64 *gdt = (u64 *)(cpu_gdt_table[cpu] + GDT_ENTRY_TLS_MIN);
 186         gdt[0] = t->tls_array[0];
 187         gdt[1] = t->tls_array[1];
 188         gdt[2] = t->tls_array[2];
 189 }
 190
 191 /*
 192  * load one particular LDT into the current CPU
 193  */
 194 extern inline void load_LDT_nolock (mm_context_t *pc, int cpu)
 195 {
 196         int count = pc->size;
 197
 198         if (likely(!count)) {
 199                 clear_LDT();
 200                 return;
 201         }
 202
 203         set_ldt_desc(cpu, pc->ldt, count);
 204         load_LDT_desc();
 205 }
 206
 207 static inline void load_LDT(mm_context_t *pc)
 208 {
 209         int cpu = get_cpu();
 210         load_LDT_nolock(pc, cpu);
 211         put_cpu();
 212 }
 213
 214 extern struct desc_ptr idt_descr;
 215
 216 #endif /* !__ASSEMBLY__ */
 217
 218 #endif