LXR linux/arch/x86/math-emu/fpu

   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
  23static 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
  44static 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
  51static inline unsigned long seg_get_limit(struct desc_struct *d)
  52{
  53        return ((unsigned long)d->limit1 << 16) | d->limit0;
  54}
  55
  56static inline unsigned long seg_get_granularity(struct desc_struct *d)
  57{
  58        return d->g ? 4096 : 1;
  59}
  60
  61static inline bool seg_expands_down(struct desc_struct *d)
  62{
  63        return (d->type & SEG_TYPE_EXPAND_MASK) == SEG_TYPE_EXPANDS_DOWN;
  64}
  65
  66static inline bool seg_execute_only(struct desc_struct *d)
  67{
  68        return (d->type & SEG_TYPE_EXECUTE_MASK) == SEG_TYPE_EXECUTE;
  69}
  70
  71static 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
 131