arch/x86/math-emu/fpu_system.h

   1 /*---------------------------------------------------------------------------+
   2  |  fpu_system.h                                                             |
   3  |                                                                           |
   4  | Copyright (C) 1992,1994,1997                                              |
   5  |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   6  |                       Australia.  E-mail   billm@suburbia.net             |
   7  |                                                                           |
   8  +---------------------------------------------------------------------------*/
   9
  10 #ifndef _FPU_SYSTEM_H
  11 #define _FPU_SYSTEM_H
  12
  13 /* system dependent definitions */
  14
  15 #include <linux/sched.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mm.h>
  18
  19 #include <asm/desc.h>
  20 #include <asm/mmu_context.h>
  21
  22 static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)
  23 {
  24         static struct desc_struct zero_desc;
  25         struct desc_struct ret = zero_desc;
  26
  27 #ifdef CONFIG_MODIFY_LDT_SYSCALL
  28         seg >>= 3;
  29         mutex_lock(&current->mm->context.lock);
  30         if (current->mm->context.ldt && seg < current->mm->context.ldt->nr_entries)
  31                 ret = current->mm->context.ldt->entries[seg];
  32         mutex_unlock(&current->mm->context.lock);
  33 #endif
  34         return ret;
  35 }
  36
  37 #define SEG_TYPE_WRITABLE       (1U << 1)
  38 #define SEG_TYPE_EXPANDS_DOWN   (1U << 2)
  39 #define SEG_TYPE_EXECUTE        (1U << 3)
  40 #define SEG_TYPE_EXPAND_MASK    (SEG_TYPE_EXPANDS_DOWN | SEG_TYPE_EXECUTE)
  41 #define SEG_TYPE_EXECUTE_MASK   (SEG_TYPE_WRITABLE | SEG_TYPE_EXECUTE)
  42
  43 static inline unsigned long seg_get_base(struct desc_struct *d)
  44 {
  45         unsigned long base = (unsigned long)d->base2 << 24;
  46
  47         return base | ((unsigned long)d->base1 << 16) | d->base0;
  48 }
  49
  50 static inline unsigned long seg_get_limit(struct desc_struct *d)
  51 {
  52         return ((unsigned long)d->limit1 << 16) | d->limit0;
  53 }
  54
  55 static inline unsigned long seg_get_granularity(struct desc_struct *d)
  56 {
  57         return d->g ? 4096 : 1;
  58 }
  59
  60 static inline bool seg_expands_down(struct desc_struct *d)
  61 {
  62         return (d->type & SEG_TYPE_EXPAND_MASK) == SEG_TYPE_EXPANDS_DOWN;
  63 }
  64
  65 static inline bool seg_execute_only(struct desc_struct *d)
  66 {
  67         return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_EXECUTE;
  68 }
  69
  70 static inline bool seg_writable(struct desc_struct *d)
  71 {
  72         return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_WRITABLE;
  73 }
  74
  75 #define I387                    (&current->thread.fpu.state)
  76 #define FPU_info                (I387->soft.info)
  77
  78 #define FPU_CS                  (*(unsigned short *) &(FPU_info->regs->cs))
  79 #define FPU_SS                  (*(unsigned short *) &(FPU_info->regs->ss))
  80 #define FPU_DS                  (*(unsigned short *) &(FPU_info->regs->ds))
  81 #define FPU_EAX                 (FPU_info->regs->ax)
  82 #define FPU_EFLAGS              (FPU_info->regs->flags)
  83 #define FPU_EIP                 (FPU_info->regs->ip)
  84 #define FPU_ORIG_EIP            (FPU_info->___orig_eip)
  85
  86 #define FPU_lookahead           (I387->soft.lookahead)
  87
  88 /* nz if ip_offset and cs_selector are not to be set for the current
  89    instruction. */
  90 #define no_ip_update            (*(u_char *)&(I387->soft.no_update))
  91 #define FPU_rm                  (*(u_char *)&(I387->soft.rm))
  92
  93 /* Number of bytes of data which can be legally accessed by the current
  94    instruction. This only needs to hold a number <= 108, so a byte will do. */
  95 #define access_limit            (*(u_char *)&(I387->soft.alimit))
  96
  97 #define partial_status          (I387->soft.swd)
  98 #define control_word            (I387->soft.cwd)
  99 #define fpu_tag_word            (I387->soft.twd)
 100 #define registers               (I387->soft.st_space)
 101 #define top                     (I387->soft.ftop)
 102
 103 #define instruction_address     (*(struct address *)&I387->soft.fip)
 104 #define operand_address         (*(struct address *)&I387->soft.foo)
 105
 106 #define FPU_access_ok(x,y,z)    if ( !access_ok(x,y,z) ) \
 107                                 math_abort(FPU_info,SIGSEGV)
 108 #define FPU_abort               math_abort(FPU_info, SIGSEGV)
 109
 110 #undef FPU_IGNORE_CODE_SEGV
 111 #ifdef FPU_IGNORE_CODE_SEGV
 112 /* access_ok() is very expensive, and causes the emulator to run
 113    about 20% slower if applied to the code. Anyway, errors due to bad
 114    code addresses should be much rarer than errors due to bad data
 115    addresses. */
 116 #define FPU_code_access_ok(z)
 117 #else
 118 /* A simpler test than access_ok() can probably be done for
 119    FPU_code_access_ok() because the only possible error is to step
 120    past the upper boundary of a legal code area. */
 121 #define FPU_code_access_ok(z) FPU_access_ok(VERIFY_READ,(void __user *)FPU_EIP,z)
 122 #endif
 123
 124 #define FPU_get_user(x,y)       get_user((x),(y))
 125 #define FPU_put_user(x,y)       put_user((x),(y))
 126
 127 #endif