root/arch/x86/math-emu/fpu_system.h

INCLUDED FROM

DEFINITIONS

1. FPU_get_ldt_descriptor
2. seg_get_base
3. seg_get_limit
4. seg_get_granularity
5. seg_expands_down
6. seg_execute_only
7. seg_writable

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*---------------------------------------------------------------------------+
   3  |  fpu_system.h                                                             |
   4  |                                                                           |
   5  | Copyright (C) 1992,1994,1997                                              |
   6  |                       W. Metzenthen, 22 Parker St, Ormond, Vic 3163,      |
   7  |                       Australia.  E-mail   billm@suburbia.net             |
   8  |                                                                           |
   9  +---------------------------------------------------------------------------*/
  10 
  11 #ifndef _FPU_SYSTEM_H
  12 #define _FPU_SYSTEM_H
  13 
  14 /* system dependent definitions */
  15 
  16 #include <linux/sched.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mm.h>
  19 
  20 #include <asm/desc.h>
  21 #include <asm/mmu_context.h>
  22 
  23 static inline struct desc_struct FPU_get_ldt_descriptor(unsigned seg)
  24 {
  25         static struct desc_struct zero_desc;
  26         struct desc_struct ret = zero_desc;
  27 
  28 #ifdef CONFIG_MODIFY_LDT_SYSCALL
  29         seg >>= 3;
  30         mutex_lock(&current->mm->context.lock);
  31         if (current->mm->context.ldt && seg < current->mm->context.ldt->nr_entries)
  32                 ret = current->mm->context.ldt->entries[seg];
  33         mutex_unlock(&current->mm->context.lock);
  34 #endif
  35         return ret;
  36 }
  37 
  38 #define SEG_TYPE_WRITABLE       (1U << 1)
  39 #define SEG_TYPE_EXPANDS_DOWN   (1U << 2)
  40 #define SEG_TYPE_EXECUTE        (1U << 3)
  41 #define SEG_TYPE_EXPAND_MASK    (SEG_TYPE_EXPANDS_DOWN | SEG_TYPE_EXECUTE)
  42 #define SEG_TYPE_EXECUTE_MASK   (SEG_TYPE_WRITABLE | SEG_TYPE_EXECUTE)
  43 
  44 static inline unsigned long seg_get_base(struct desc_struct *d)
  45 {
  46         unsigned long base = (unsigned long)d->base2 << 24;
  47 
  48         return base | ((unsigned long)d->base1 << 16) | d->base0;
  49 }
  50 
  51 static inline unsigned long seg_get_limit(struct desc_struct *d)
  52 {
  53         return ((unsigned long)d->limit1 << 16) | d->limit0;
  54 }
  55 
  56 static inline unsigned long seg_get_granularity(struct desc_struct *d)
  57 {
  58         return d->g ? 4096 : 1;
  59 }
  60 
  61 static inline bool seg_expands_down(struct desc_struct *d)
  62 {
  63         return (d->type & SEG_TYPE_EXPAND_MASK) == SEG_TYPE_EXPANDS_DOWN;
  64 }
  65 
  66 static inline bool seg_execute_only(struct desc_struct *d)
  67 {
  68         return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_EXECUTE;
  69 }
  70 
  71 static inline bool seg_writable(struct desc_struct *d)
  72 {
  73         return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_WRITABLE;
  74 }
  75 
  76 #define I387                    (&current->thread.fpu.state)
  77 #define FPU_info                (I387->soft.info)
  78 
  79 #define FPU_CS                  (*(unsigned short *) &(FPU_info->regs->cs))
  80 #define FPU_SS                  (*(unsigned short *) &(FPU_info->regs->ss))
  81 #define FPU_DS                  (*(unsigned short *) &(FPU_info->regs->ds))
  82 #define FPU_EAX                 (FPU_info->regs->ax)
  83 #define FPU_EFLAGS              (FPU_info->regs->flags)
  84 #define FPU_EIP                 (FPU_info->regs->ip)
  85 #define FPU_ORIG_EIP            (FPU_info->___orig_eip)
  86 
  87 #define FPU_lookahead           (I387->soft.lookahead)
  88 
  89 /* nz if ip_offset and cs_selector are not to be set for the current
  90    instruction. */
  91 #define no_ip_update            (*(u_char *)&(I387->soft.no_update))
  92 #define FPU_rm                  (*(u_char *)&(I387->soft.rm))
  93 
  94 /* Number of bytes of data which can be legally accessed by the current
  95    instruction. This only needs to hold a number <= 108, so a byte will do. */
  96 #define access_limit            (*(u_char *)&(I387->soft.alimit))
  97 
  98 #define partial_status          (I387->soft.swd)
  99 #define control_word            (I387->soft.cwd)
 100 #define fpu_tag_word            (I387->soft.twd)
 101 #define registers               (I387->soft.st_space)
 102 #define top                     (I387->soft.ftop)
 103 
 104 #define instruction_address     (*(struct address *)&I387->soft.fip)
 105 #define operand_address         (*(struct address *)&I387->soft.foo)
 106 
 107 #define FPU_access_ok(y,z)      if ( !access_ok(y,z) ) \
 108                                 math_abort(FPU_info,SIGSEGV)
 109 #define FPU_abort               math_abort(FPU_info, SIGSEGV)
 110 #define FPU_copy_from_user(to, from, n) \
 111                 do { if (copy_from_user(to, from, n)) FPU_abort; } while (0)
 112 
 113 #undef FPU_IGNORE_CODE_SEGV
 114 #ifdef FPU_IGNORE_CODE_SEGV
 115 /* access_ok() is very expensive, and causes the emulator to run
 116    about 20% slower if applied to the code. Anyway, errors due to bad
 117    code addresses should be much rarer than errors due to bad data
 118    addresses. */
 119 #define FPU_code_access_ok(z)
 120 #else
 121 /* A simpler test than access_ok() can probably be done for
 122    FPU_code_access_ok() because the only possible error is to step
 123    past the upper boundary of a legal code area. */
 124 #define FPU_code_access_ok(z) FPU_access_ok((void __user *)FPU_EIP,z)
 125 #endif
 126 
 127 #define FPU_get_user(x,y) do { if (get_user((x),(y))) FPU_abort; } while (0)
 128 #define FPU_put_user(x,y) do { if (put_user((x),(y))) FPU_abort; } while (0)
 129 
 130 #endif