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 <linux/smp.h>
  12
  13 #include <asm/segment.h>
  14 #include <asm/mmu.h>
  15
  16 // 8 byte segment descriptor
  17 struct desc_struct {
  18         u16 limit0;
  19         u16 base0;
  20         unsigned base1 : 8, type : 4, s : 1, dpl : 2, p : 1;
  21         unsigned limit : 4, avl : 1, l : 1, d : 1, g : 1, base2 : 8;
  22 } __attribute__((packed));
  23
  24 struct n_desc_struct {
  25         unsigned int a,b;
  26 };
  27
  28 extern struct desc_struct cpu_gdt_table[NR_CPUS][GDT_ENTRIES];
  29
  30 enum {
  31         GATE_INTERRUPT = 0xE,
  32         GATE_TRAP = 0xF,
  33         GATE_CALL = 0xC,
  34 };
  35
  36 // 16byte gate
  37 struct gate_struct {
  38         u16 offset_low;
  39         u16 segment;
  40         unsigned ist : 3, zero0 : 5, type : 5, dpl : 2, p : 1;
  41         u16 offset_middle;
  42         u32 offset_high;
  43         u32 zero1;
  44 } __attribute__((packed));
  45
  46 #define PTR_LOW(x) ((unsigned long)(x) & 0xFFFF)
  47 #define PTR_MIDDLE(x) (((unsigned long)(x) >> 16) & 0xFFFF)
  48 #define PTR_HIGH(x) ((unsigned long)(x) >> 32)
  49
  50 enum {
  51         DESC_TSS = 0x9,
  52         DESC_LDT = 0x2,
  53 };
  54
  55 // LDT or TSS descriptor in the GDT. 16 bytes.
  56 struct ldttss_desc {
  57         u16 limit0;
  58         u16 base0;
  59         unsigned base1 : 8, type : 5, dpl : 2, p : 1;
  60         unsigned limit1 : 4, zero0 : 3, g : 1, base2 : 8;
  61         u32 base3;
  62         u32 zero1;
  63 } __attribute__((packed));
  64
  65 struct desc_ptr {
  66         unsigned short size;
  67         unsigned long address;
  68 } __attribute__((packed)) ;
  69
  70 #define load_TR_desc() asm volatile("ltr %w0"::"r" (GDT_ENTRY_TSS*8))
  71 #define load_LDT_desc() asm volatile("lldt %w0"::"r" (GDT_ENTRY_LDT*8))
  72 #define clear_LDT()  asm volatile("lldt %w0"::"r" (0))
  73
  74 /*
  75  * This is the ldt that every process will get unless we need
  76  * something other than this.
  77  */
  78 extern struct desc_struct default_ldt[];
  79 extern struct gate_struct idt_table[];
  80 extern struct desc_ptr cpu_gdt_descr[];
  81
  82 static inline void _set_gate(void *adr, unsigned type, unsigned long func, unsigned dpl, unsigned ist)
  83 {
  84         struct gate_struct s;
  85         s.offset_low = PTR_LOW(func);
  86         s.segment = __KERNEL_CS;
  87         s.ist = ist;
  88         s.p = 1;
  89         s.dpl = dpl;
  90         s.zero0 = 0;
  91         s.zero1 = 0;
  92         s.type = type;
  93         s.offset_middle = PTR_MIDDLE(func);
  94         s.offset_high = PTR_HIGH(func);
  95         /* does not need to be atomic because it is only done once at setup time */
  96         memcpy(adr, &s, 16);
  97 }
  98
  99 static inline void set_intr_gate(int nr, void *func)
 100 {
 101         BUG_ON((unsigned)nr > 0xFF);
 102         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, 0);
 103 }
 104
 105 static inline void set_intr_gate_ist(int nr, void *func, unsigned ist)
 106 {
 107         BUG_ON((unsigned)nr > 0xFF);
 108         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 0, ist);
 109 }
 110
 111 static inline void set_system_gate(int nr, void *func)
 112 {
 113         BUG_ON((unsigned)nr > 0xFF);
 114         _set_gate(&idt_table[nr], GATE_INTERRUPT, (unsigned long) func, 3, 0);
 115 }
 116
 117 static inline void set_tssldt_descriptor(void *ptr, unsigned long tss, unsigned type,
 118                                          unsigned size)
 119 {
 120         struct ldttss_desc d;
 121         memset(&d,0,sizeof(d));
 122         d.limit0 = size & 0xFFFF;
 123         d.base0 = PTR_LOW(tss);
 124         d.base1 = PTR_MIDDLE(tss) & 0xFF;
 125         d.type = type;
 126         d.p = 1;
 127         d.limit1 = (size >> 16) & 0xF;
 128         d.base2 = (PTR_MIDDLE(tss) >> 8) & 0xFF;
 129         d.base3 = PTR_HIGH(tss);
 130         memcpy(ptr, &d, 16);
 131 }
 132
 133 static inline void set_tss_desc(unsigned cpu, void *addr)
 134 {
 135         /*
 136          * sizeof(unsigned long) coming from an extra "long" at the end
 137          * of the iobitmap. See tss_struct definition in processor.h
 138          *
 139          * -1? seg base+limit should be pointing to the address of the
 140          * last valid byte
 141          */
 142         set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_TSS],
 143                 (unsigned long)addr, DESC_TSS,
 144                 IO_BITMAP_OFFSET + IO_BITMAP_BYTES + sizeof(unsigned long) - 1);
 145 }
 146
 147 static inline void set_ldt_desc(unsigned cpu, void *addr, int size)
 148 {
 149         set_tssldt_descriptor(&cpu_gdt_table[cpu][GDT_ENTRY_LDT], (unsigned long)addr,
 150                               DESC_LDT, size * 8 - 1);
 151 }
 152
 153 static inline void set_seg_base(unsigned cpu, int entry, void *base)
 154 {
 155         struct desc_struct *d = &cpu_gdt_table[cpu][entry];
 156         u32 addr = (u32)(u64)base;
 157         BUG_ON((u64)base >> 32);
 158         d->base0 = addr & 0xffff;
 159         d->base1 = (addr >> 16) & 0xff;
 160         d->base2 = (addr >> 24) & 0xff;
 161 }
 162
 163 #define LDT_entry_a(info) \
 164         ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
 165 /* Don't allow setting of the lm bit. It is useless anyways because
 166    64bit system calls require __USER_CS. */
 167 #define LDT_entry_b(info) \
 168         (((info)->base_addr & 0xff000000) | \
 169         (((info)->base_addr & 0x00ff0000) >> 16) | \
 170         ((info)->limit & 0xf0000) | \
 171         (((info)->read_exec_only ^ 1) << 9) | \
 172         ((info)->contents << 10) | \
 173         (((info)->seg_not_present ^ 1) << 15) | \
 174         ((info)->seg_32bit << 22) | \
 175         ((info)->limit_in_pages << 23) | \
 176         ((info)->useable << 20) | \
 177         /* ((info)->lm << 21) | */ \
 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         (info)->lm              == 0)
 190
 191 #if TLS_SIZE != 24
 192 # error update this code.
 193 #endif
 194
 195 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
 196 {
 197         u64 *gdt = (u64 *)(cpu_gdt_table[cpu] + GDT_ENTRY_TLS_MIN);
 198         gdt[0] = t->tls_array[0];
 199         gdt[1] = t->tls_array[1];
 200         gdt[2] = t->tls_array[2];
 201 }
 202
 203 /*
 204  * load one particular LDT into the current CPU
 205  */
 206 static inline void load_LDT_nolock (mm_context_t *pc, int cpu)
 207 {
 208         int count = pc->size;
 209
 210         if (likely(!count)) {
 211                 clear_LDT();
 212                 return;
 213         }
 214
 215         set_ldt_desc(cpu, pc->ldt, count);
 216         load_LDT_desc();
 217 }
 218
 219 static inline void load_LDT(mm_context_t *pc)
 220 {
 221         int cpu = get_cpu();
 222         load_LDT_nolock(pc, cpu);
 223         put_cpu();
 224 }
 225
 226 extern struct desc_ptr idt_descr;
 227
 228 #endif /* !__ASSEMBLY__ */
 229
 230 #endif