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 #define CPU_16BIT_STACK_SIZE 1024
   8
   9 #ifndef __ASSEMBLY__
  10
  11 #include <linux/preempt.h>
  12 #include <linux/smp.h>
  13 #include <linux/percpu.h>
  14
  15 #include <asm/mmu.h>
  16
  17 extern struct desc_struct cpu_gdt_table[GDT_ENTRIES];
  18 DECLARE_PER_CPU(struct desc_struct, cpu_gdt_table[GDT_ENTRIES]);
  19
  20 DECLARE_PER_CPU(unsigned char, cpu_16bit_stack[CPU_16BIT_STACK_SIZE]);
  21
  22 struct Xgt_desc_struct {
  23         unsigned short size;
  24         unsigned long address __attribute__((packed));
  25         unsigned short pad;
  26 } __attribute__ ((packed));
  27
  28 extern struct Xgt_desc_struct idt_descr, cpu_gdt_descr[NR_CPUS];
  29
  30 #define load_TR_desc() __asm__ __volatile__("ltr %%ax"::"a" (GDT_ENTRY_TSS*8))
  31 #define load_LDT_desc() __asm__ __volatile__("lldt %%ax"::"a" (GDT_ENTRY_LDT*8))
  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 void set_intr_gate(unsigned int irq, void * addr);
  39
  40 #define _set_tssldt_desc(n,addr,limit,type) \
  41 __asm__ __volatile__ ("movw %w3,0(%2)\n\t" \
  42         "movw %%ax,2(%2)\n\t" \
  43         "rorl $16,%%eax\n\t" \
  44         "movb %%al,4(%2)\n\t" \
  45         "movb %4,5(%2)\n\t" \
  46         "movb $0,6(%2)\n\t" \
  47         "movb %%ah,7(%2)\n\t" \
  48         "rorl $16,%%eax" \
  49         : "=m"(*(n)) : "a" (addr), "r"(n), "ir"(limit), "i"(type))
  50
  51 static inline void __set_tss_desc(unsigned int cpu, unsigned int entry, void *addr)
  52 {
  53         _set_tssldt_desc(&per_cpu(cpu_gdt_table, cpu)[entry], (int)addr,
  54                 offsetof(struct tss_struct, __cacheline_filler) - 1, 0x89);
  55 }
  56
  57 #define set_tss_desc(cpu,addr) __set_tss_desc(cpu, GDT_ENTRY_TSS, addr)
  58
  59 static inline void set_ldt_desc(unsigned int cpu, void *addr, unsigned int size)
  60 {
  61         _set_tssldt_desc(&per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_LDT], (int)addr, ((size << 3)-1), 0x82);
  62 }
  63
  64 #define LDT_entry_a(info) \
  65         ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff))
  66
  67 #define LDT_entry_b(info) \
  68         (((info)->base_addr & 0xff000000) | \
  69         (((info)->base_addr & 0x00ff0000) >> 16) | \
  70         ((info)->limit & 0xf0000) | \
  71         (((info)->read_exec_only ^ 1) << 9) | \
  72         ((info)->contents << 10) | \
  73         (((info)->seg_not_present ^ 1) << 15) | \
  74         ((info)->seg_32bit << 22) | \
  75         ((info)->limit_in_pages << 23) | \
  76         ((info)->useable << 20) | \
  77         0x7000)
  78
  79 #define LDT_empty(info) (\
  80         (info)->base_addr       == 0    && \
  81         (info)->limit           == 0    && \
  82         (info)->contents        == 0    && \
  83         (info)->read_exec_only  == 1    && \
  84         (info)->seg_32bit       == 0    && \
  85         (info)->limit_in_pages  == 0    && \
  86         (info)->seg_not_present == 1    && \
  87         (info)->useable         == 0    )
  88
  89 #if TLS_SIZE != 24
  90 # error update this code.
  91 #endif
  92
  93 static inline void load_TLS(struct thread_struct *t, unsigned int cpu)
  94 {
  95 #define C(i) per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TLS_MIN + i] = t->tls_array[i]
  96         C(0); C(1); C(2);
  97 #undef C
  98 }
  99
 100 static inline void clear_LDT(void)
 101 {
 102         int cpu = get_cpu();
 103
 104         set_ldt_desc(cpu, &default_ldt[0], 5);
 105         load_LDT_desc();
 106         put_cpu();
 107 }
 108
 109 /*
 110  * load one particular LDT into the current CPU
 111  */
 112 static inline void load_LDT_nolock(mm_context_t *pc, int cpu)
 113 {
 114         void *segments = pc->ldt;
 115         int count = pc->size;
 116
 117         if (likely(!count)) {
 118                 segments = &default_ldt[0];
 119                 count = 5;
 120         }
 121
 122         set_ldt_desc(cpu, segments, count);
 123         load_LDT_desc();
 124 }
 125
 126 static inline void load_LDT(mm_context_t *pc)
 127 {
 128         int cpu = get_cpu();
 129         load_LDT_nolock(pc, cpu);
 130         put_cpu();
 131 }
 132
 133 static inline unsigned long get_desc_base(unsigned long *desc)
 134 {
 135         unsigned long base;
 136         base = ((desc[0] >> 16)  & 0x0000ffff) |
 137                 ((desc[1] << 16) & 0x00ff0000) |
 138                 (desc[1] & 0xff000000);
 139         return base;
 140 }
 141
 142 #endif /* !__ASSEMBLY__ */
 143
 144 #endif