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linux/arch/x86/math-emu/reg_ld_str.c
Arnd Bergmann e6b44ce192 x86/math-emu: Check __copy_from_user() result 
The new __must_check annotation on __copy_from_user() successfully
identified some code that has lacked the check since at least
linux-2.1.73:

  arch/x86/math-emu/reg_ld_str.c:88:2: error: ignoring return value of \
  function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
          __copy_from_user(sti_ptr, s, 10);
          ^~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~
  arch/x86/math-emu/reg_ld_str.c:1129:2: error: ignoring return value of \
  function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
          __copy_from_user(register_base + offset, s, other);
          ^~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  arch/x86/math-emu/reg_ld_str.c:1131:3: error: ignoring return value of \
  function declared with 'warn_unused_result' attribute [-Werror,-Wunused-result]
                  __copy_from_user(register_base, s + other, offset);
                ^~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In addition, the get_user()/put_user() helpers do not enforce a return
value check, but actually still require one. These have been missing for
even longer.

Change the internal wrappers around get_user()/put_user() to force
a signal and add a corresponding wrapper around __copy_from_user()
to check all such cases.

 [ bp: Break long lines. ]

Fixes: 257e458057e5 ("Import 2.1.73")
Fixes: 9dd819a151 ("uaccess: add missing __must_check attributes")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Bill Metzenthen <billm@melbpc.org.au>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20191001142344.1274185-1-arnd@arndb.de
2019-10-03 10:51:08 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*---------------------------------------------------------------------------+
| reg_ld_str.c |
| |
| All of the functions which transfer data between user memory and FPU_REGs.|
| |
| Copyright (C) 1992,1993,1994,1996,1997 |
| W. Metzenthen, 22 Parker St, Ormond, Vic 3163, Australia |
| E-mail billm@suburbia.net |
| |
| |
+---------------------------------------------------------------------------*/
/*---------------------------------------------------------------------------+
| Note: |
| The file contains code which accesses user memory. |
| Emulator static data may change when user memory is accessed, due to |
| other processes using the emulator while swapping is in progress. |
+---------------------------------------------------------------------------*/
#include "fpu_emu.h"
#include <linux/uaccess.h>
#include "fpu_system.h"
#include "exception.h"
#include "reg_constant.h"
#include "control_w.h"
#include "status_w.h"
#define DOUBLE_Emax 1023 /* largest valid exponent */
#define DOUBLE_Ebias 1023
#define DOUBLE_Emin (-1022) /* smallest valid exponent */
#define SINGLE_Emax 127 /* largest valid exponent */
#define SINGLE_Ebias 127
#define SINGLE_Emin (-126) /* smallest valid exponent */
static u_char normalize_no_excep(FPU_REG *r, int exp, int sign)
{
u_char tag;
setexponent16(r, exp);
tag = FPU_normalize_nuo(r);
stdexp(r);
if (sign)
setnegative(r);
return tag;
}
int FPU_tagof(FPU_REG *ptr)
{
int exp;
exp = exponent16(ptr) & 0x7fff;
if (exp == 0) {
if (!(ptr->sigh | ptr->sigl)) {
return TAG_Zero;
}
/* The number is a de-normal or pseudodenormal. */
return TAG_Special;
}
if (exp == 0x7fff) {
/* Is an Infinity, a NaN, or an unsupported data type. */
return TAG_Special;
}
if (!(ptr->sigh & 0x80000000)) {
/* Unsupported data type. */
/* Valid numbers have the ms bit set to 1. */
/* Unnormal. */
return TAG_Special;
}
return TAG_Valid;
}
/* Get a long double from user memory */
int FPU_load_extended(long double __user *s, int stnr)
{
FPU_REG *sti_ptr = &st(stnr);
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(s, 10);
FPU_copy_from_user(sti_ptr, s, 10);
RE_ENTRANT_CHECK_ON;
return FPU_tagof(sti_ptr);
}
/* Get a double from user memory */
int FPU_load_double(double __user *dfloat, FPU_REG *loaded_data)
{
int exp, tag, negative;
unsigned m64, l64;
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(dfloat, 8);
FPU_get_user(m64, 1 + (unsigned long __user *)dfloat);
FPU_get_user(l64, (unsigned long __user *)dfloat);
RE_ENTRANT_CHECK_ON;
negative = (m64 & 0x80000000) ? SIGN_Negative : SIGN_Positive;
exp = ((m64 & 0x7ff00000) >> 20) - DOUBLE_Ebias + EXTENDED_Ebias;
m64 &= 0xfffff;
if (exp > DOUBLE_Emax + EXTENDED_Ebias) {
/* Infinity or NaN */
if ((m64 == 0) && (l64 == 0)) {
/* +- infinity */
loaded_data->sigh = 0x80000000;
loaded_data->sigl = 0x00000000;
exp = EXP_Infinity + EXTENDED_Ebias;
tag = TAG_Special;
} else {
/* Must be a signaling or quiet NaN */
exp = EXP_NaN + EXTENDED_Ebias;
loaded_data->sigh = (m64 << 11) | 0x80000000;
loaded_data->sigh |= l64 >> 21;
loaded_data->sigl = l64 << 11;
tag = TAG_Special; /* The calling function must look for NaNs */
}
} else if (exp < DOUBLE_Emin + EXTENDED_Ebias) {
/* Zero or de-normal */
if ((m64 == 0) && (l64 == 0)) {
/* Zero */
reg_copy(&CONST_Z, loaded_data);
exp = 0;
tag = TAG_Zero;
} else {
/* De-normal */
loaded_data->sigh = m64 << 11;
loaded_data->sigh |= l64 >> 21;
loaded_data->sigl = l64 << 11;
return normalize_no_excep(loaded_data, DOUBLE_Emin,
negative)
| (denormal_operand() < 0 ? FPU_Exception : 0);
}
} else {
loaded_data->sigh = (m64 << 11) | 0x80000000;
loaded_data->sigh |= l64 >> 21;
loaded_data->sigl = l64 << 11;
tag = TAG_Valid;
}
setexponent16(loaded_data, exp | negative);
return tag;
}
/* Get a float from user memory */
int FPU_load_single(float __user *single, FPU_REG *loaded_data)
{
unsigned m32;
int exp, tag, negative;
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(single, 4);
FPU_get_user(m32, (unsigned long __user *)single);
RE_ENTRANT_CHECK_ON;
negative = (m32 & 0x80000000) ? SIGN_Negative : SIGN_Positive;
if (!(m32 & 0x7fffffff)) {
/* Zero */
reg_copy(&CONST_Z, loaded_data);
addexponent(loaded_data, negative);
return TAG_Zero;
}
exp = ((m32 & 0x7f800000) >> 23) - SINGLE_Ebias + EXTENDED_Ebias;
m32 = (m32 & 0x7fffff) << 8;
if (exp < SINGLE_Emin + EXTENDED_Ebias) {
/* De-normals */
loaded_data->sigh = m32;
loaded_data->sigl = 0;
return normalize_no_excep(loaded_data, SINGLE_Emin, negative)
| (denormal_operand() < 0 ? FPU_Exception : 0);
} else if (exp > SINGLE_Emax + EXTENDED_Ebias) {
/* Infinity or NaN */
if (m32 == 0) {
/* +- infinity */
loaded_data->sigh = 0x80000000;
loaded_data->sigl = 0x00000000;
exp = EXP_Infinity + EXTENDED_Ebias;
tag = TAG_Special;
} else {
/* Must be a signaling or quiet NaN */
exp = EXP_NaN + EXTENDED_Ebias;
loaded_data->sigh = m32 | 0x80000000;
loaded_data->sigl = 0;
tag = TAG_Special; /* The calling function must look for NaNs */
}
} else {
loaded_data->sigh = m32 | 0x80000000;
loaded_data->sigl = 0;
tag = TAG_Valid;
}
setexponent16(loaded_data, exp | negative); /* Set the sign. */
return tag;
}
/* Get a long long from user memory */
int FPU_load_int64(long long __user *_s)
{
long long s;
int sign;
FPU_REG *st0_ptr = &st(0);
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(_s, 8);
if (copy_from_user(&s, _s, 8))
FPU_abort;
RE_ENTRANT_CHECK_ON;
if (s == 0) {
reg_copy(&CONST_Z, st0_ptr);
return TAG_Zero;
}
if (s > 0)
sign = SIGN_Positive;
else {
s = -s;
sign = SIGN_Negative;
}
significand(st0_ptr) = s;
return normalize_no_excep(st0_ptr, 63, sign);
}
/* Get a long from user memory */
int FPU_load_int32(long __user *_s, FPU_REG *loaded_data)
{
long s;
int negative;
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(_s, 4);
FPU_get_user(s, _s);
RE_ENTRANT_CHECK_ON;
if (s == 0) {
reg_copy(&CONST_Z, loaded_data);
return TAG_Zero;
}
if (s > 0)
negative = SIGN_Positive;
else {
s = -s;
negative = SIGN_Negative;
}
loaded_data->sigh = s;
loaded_data->sigl = 0;
return normalize_no_excep(loaded_data, 31, negative);
}
/* Get a short from user memory */
int FPU_load_int16(short __user *_s, FPU_REG *loaded_data)
{
int s, negative;
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(_s, 2);
/* Cast as short to get the sign extended. */
FPU_get_user(s, _s);
RE_ENTRANT_CHECK_ON;
if (s == 0) {
reg_copy(&CONST_Z, loaded_data);
return TAG_Zero;
}
if (s > 0)
negative = SIGN_Positive;
else {
s = -s;
negative = SIGN_Negative;
}
loaded_data->sigh = s << 16;
loaded_data->sigl = 0;
return normalize_no_excep(loaded_data, 15, negative);
}
/* Get a packed bcd array from user memory */
int FPU_load_bcd(u_char __user *s)
{
FPU_REG *st0_ptr = &st(0);
int pos;
u_char bcd;
long long l = 0;
int sign;
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(s, 10);
RE_ENTRANT_CHECK_ON;
for (pos = 8; pos >= 0; pos--) {
l *= 10;
RE_ENTRANT_CHECK_OFF;
FPU_get_user(bcd, s + pos);
RE_ENTRANT_CHECK_ON;
l += bcd >> 4;
l *= 10;
l += bcd & 0x0f;
}
RE_ENTRANT_CHECK_OFF;
FPU_get_user(sign, s + 9);
sign = sign & 0x80 ? SIGN_Negative : SIGN_Positive;
RE_ENTRANT_CHECK_ON;
if (l == 0) {
reg_copy(&CONST_Z, st0_ptr);
addexponent(st0_ptr, sign); /* Set the sign. */
return TAG_Zero;
} else {
significand(st0_ptr) = l;
return normalize_no_excep(st0_ptr, 63, sign);
}
}
/*===========================================================================*/
/* Put a long double into user memory */
int FPU_store_extended(FPU_REG *st0_ptr, u_char st0_tag,
long double __user * d)
{
/*
The only exception raised by an attempt to store to an
extended format is the Invalid Stack exception, i.e.
attempting to store from an empty register.
*/
if (st0_tag != TAG_Empty) {
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 10);
FPU_put_user(st0_ptr->sigl, (unsigned long __user *)d);
FPU_put_user(st0_ptr->sigh,
(unsigned long __user *)((u_char __user *) d + 4));
FPU_put_user(exponent16(st0_ptr),
(unsigned short __user *)((u_char __user *) d +
8));
RE_ENTRANT_CHECK_ON;
return 1;
}
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & CW_Invalid) {
/* The masked response */
/* Put out the QNaN indefinite */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 10);
FPU_put_user(0, (unsigned long __user *)d);
FPU_put_user(0xc0000000, 1 + (unsigned long __user *)d);
FPU_put_user(0xffff, 4 + (short __user *)d);
RE_ENTRANT_CHECK_ON;
return 1;
} else
return 0;
}
/* Put a double into user memory */
int FPU_store_double(FPU_REG *st0_ptr, u_char st0_tag, double __user *dfloat)
{
unsigned long l[2];
unsigned long increment = 0; /* avoid gcc warnings */
int precision_loss;
int exp;
FPU_REG tmp;
l[0] = 0;
l[1] = 0;
if (st0_tag == TAG_Valid) {
reg_copy(st0_ptr, &tmp);
exp = exponent(&tmp);
if (exp < DOUBLE_Emin) { /* It may be a denormal */
addexponent(&tmp, -DOUBLE_Emin + 52); /* largest exp to be 51 */
denormal_arg:
if ((precision_loss = FPU_round_to_int(&tmp, st0_tag))) {
#ifdef PECULIAR_486
/* Did it round to a non-denormal ? */
/* This behaviour might be regarded as peculiar, it appears
that the 80486 rounds to the dest precision, then
converts to decide underflow. */
if (!
((tmp.sigh == 0x00100000) && (tmp.sigl == 0)
&& (st0_ptr->sigl & 0x000007ff)))
#endif /* PECULIAR_486 */
{
EXCEPTION(EX_Underflow);
/* This is a special case: see sec 16.2.5.1 of
the 80486 book */
if (!(control_word & CW_Underflow))
return 0;
}
EXCEPTION(precision_loss);
if (!(control_word & CW_Precision))
return 0;
}
l[0] = tmp.sigl;
l[1] = tmp.sigh;
} else {
if (tmp.sigl & 0x000007ff) {
precision_loss = 1;
switch (control_word & CW_RC) {
case RC_RND:
/* Rounding can get a little messy.. */
increment = ((tmp.sigl & 0x7ff) > 0x400) | /* nearest */
((tmp.sigl & 0xc00) == 0xc00); /* odd -> even */
break;
case RC_DOWN: /* towards -infinity */
increment =
signpositive(&tmp) ? 0 : tmp.
sigl & 0x7ff;
break;
case RC_UP: /* towards +infinity */
increment =
signpositive(&tmp) ? tmp.
sigl & 0x7ff : 0;
break;
case RC_CHOP:
increment = 0;
break;
}
/* Truncate the mantissa */
tmp.sigl &= 0xfffff800;
if (increment) {
if (tmp.sigl >= 0xfffff800) {
/* the sigl part overflows */
if (tmp.sigh == 0xffffffff) {
/* The sigh part overflows */
tmp.sigh = 0x80000000;
exp++;
if (exp >= EXP_OVER)
goto overflow;
} else {
tmp.sigh++;
}
tmp.sigl = 0x00000000;
} else {
/* We only need to increment sigl */
tmp.sigl += 0x00000800;
}
}
} else
precision_loss = 0;
l[0] = (tmp.sigl >> 11) | (tmp.sigh << 21);
l[1] = ((tmp.sigh >> 11) & 0xfffff);
if (exp > DOUBLE_Emax) {
overflow:
EXCEPTION(EX_Overflow);
if (!(control_word & CW_Overflow))
return 0;
set_precision_flag_up();
if (!(control_word & CW_Precision))
return 0;
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
/* Overflow to infinity */
l[1] = 0x7ff00000; /* Set to + INF */
} else {
if (precision_loss) {
if (increment)
set_precision_flag_up();
else
set_precision_flag_down();
}
/* Add the exponent */
l[1] |= (((exp + DOUBLE_Ebias) & 0x7ff) << 20);
}
}
} else if (st0_tag == TAG_Zero) {
/* Number is zero */
} else if (st0_tag == TAG_Special) {
st0_tag = FPU_Special(st0_ptr);
if (st0_tag == TW_Denormal) {
/* A denormal will always underflow. */
#ifndef PECULIAR_486
/* An 80486 is supposed to be able to generate
a denormal exception here, but... */
/* Underflow has priority. */
if (control_word & CW_Underflow)
denormal_operand();
#endif /* PECULIAR_486 */
reg_copy(st0_ptr, &tmp);
goto denormal_arg;
} else if (st0_tag == TW_Infinity) {
l[1] = 0x7ff00000;
} else if (st0_tag == TW_NaN) {
/* Is it really a NaN ? */
if ((exponent(st0_ptr) == EXP_OVER)
&& (st0_ptr->sigh & 0x80000000)) {
/* See if we can get a valid NaN from the FPU_REG */
l[0] =
(st0_ptr->sigl >> 11) | (st0_ptr->
sigh << 21);
l[1] = ((st0_ptr->sigh >> 11) & 0xfffff);
if (!(st0_ptr->sigh & 0x40000000)) {
/* It is a signalling NaN */
EXCEPTION(EX_Invalid);
if (!(control_word & CW_Invalid))
return 0;
l[1] |= (0x40000000 >> 11);
}
l[1] |= 0x7ff00000;
} else {
/* It is an unsupported data type */
EXCEPTION(EX_Invalid);
if (!(control_word & CW_Invalid))
return 0;
l[1] = 0xfff80000;
}
}
} else if (st0_tag == TAG_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & CW_Invalid) {
/* The masked response */
/* Put out the QNaN indefinite */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(dfloat, 8);
FPU_put_user(0, (unsigned long __user *)dfloat);
FPU_put_user(0xfff80000,
1 + (unsigned long __user *)dfloat);
RE_ENTRANT_CHECK_ON;
return 1;
} else
return 0;
}
if (getsign(st0_ptr))
l[1] |= 0x80000000;
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(dfloat, 8);
FPU_put_user(l[0], (unsigned long __user *)dfloat);
FPU_put_user(l[1], 1 + (unsigned long __user *)dfloat);
RE_ENTRANT_CHECK_ON;
return 1;
}
/* Put a float into user memory */
int FPU_store_single(FPU_REG *st0_ptr, u_char st0_tag, float __user *single)
{
long templ = 0;
unsigned long increment = 0; /* avoid gcc warnings */
int precision_loss;
int exp;
FPU_REG tmp;
if (st0_tag == TAG_Valid) {
reg_copy(st0_ptr, &tmp);
exp = exponent(&tmp);
if (exp < SINGLE_Emin) {
addexponent(&tmp, -SINGLE_Emin + 23); /* largest exp to be 22 */
denormal_arg:
if ((precision_loss = FPU_round_to_int(&tmp, st0_tag))) {
#ifdef PECULIAR_486
/* Did it round to a non-denormal ? */
/* This behaviour might be regarded as peculiar, it appears
that the 80486 rounds to the dest precision, then
converts to decide underflow. */
if (!((tmp.sigl == 0x00800000) &&
((st0_ptr->sigh & 0x000000ff)
|| st0_ptr->sigl)))
#endif /* PECULIAR_486 */
{
EXCEPTION(EX_Underflow);
/* This is a special case: see sec 16.2.5.1 of
the 80486 book */
if (!(control_word & CW_Underflow))
return 0;
}
EXCEPTION(precision_loss);
if (!(control_word & CW_Precision))
return 0;
}
templ = tmp.sigl;
} else {
if (tmp.sigl | (tmp.sigh & 0x000000ff)) {
unsigned long sigh = tmp.sigh;
unsigned long sigl = tmp.sigl;
precision_loss = 1;
switch (control_word & CW_RC) {
case RC_RND:
increment = ((sigh & 0xff) > 0x80) /* more than half */
||(((sigh & 0xff) == 0x80) && sigl) /* more than half */
||((sigh & 0x180) == 0x180); /* round to even */
break;
case RC_DOWN: /* towards -infinity */
increment = signpositive(&tmp)
? 0 : (sigl | (sigh & 0xff));
break;
case RC_UP: /* towards +infinity */
increment = signpositive(&tmp)
? (sigl | (sigh & 0xff)) : 0;
break;
case RC_CHOP:
increment = 0;
break;
}
/* Truncate part of the mantissa */
tmp.sigl = 0;
if (increment) {
if (sigh >= 0xffffff00) {
/* The sigh part overflows */
tmp.sigh = 0x80000000;
exp++;
if (exp >= EXP_OVER)
goto overflow;
} else {
tmp.sigh &= 0xffffff00;
tmp.sigh += 0x100;
}
} else {
tmp.sigh &= 0xffffff00; /* Finish the truncation */
}
} else
precision_loss = 0;
templ = (tmp.sigh >> 8) & 0x007fffff;
if (exp > SINGLE_Emax) {
overflow:
EXCEPTION(EX_Overflow);
if (!(control_word & CW_Overflow))
return 0;
set_precision_flag_up();
if (!(control_word & CW_Precision))
return 0;
/* This is a special case: see sec 16.2.5.1 of the 80486 book. */
/* Masked response is overflow to infinity. */
templ = 0x7f800000;
} else {
if (precision_loss) {
if (increment)
set_precision_flag_up();
else
set_precision_flag_down();
}
/* Add the exponent */
templ |= ((exp + SINGLE_Ebias) & 0xff) << 23;
}
}
} else if (st0_tag == TAG_Zero) {
templ = 0;
} else if (st0_tag == TAG_Special) {
st0_tag = FPU_Special(st0_ptr);
if (st0_tag == TW_Denormal) {
reg_copy(st0_ptr, &tmp);
/* A denormal will always underflow. */
#ifndef PECULIAR_486
/* An 80486 is supposed to be able to generate
a denormal exception here, but... */
/* Underflow has priority. */
if (control_word & CW_Underflow)
denormal_operand();
#endif /* PECULIAR_486 */
goto denormal_arg;
} else if (st0_tag == TW_Infinity) {
templ = 0x7f800000;
} else if (st0_tag == TW_NaN) {
/* Is it really a NaN ? */
if ((exponent(st0_ptr) == EXP_OVER)
&& (st0_ptr->sigh & 0x80000000)) {
/* See if we can get a valid NaN from the FPU_REG */
templ = st0_ptr->sigh >> 8;
if (!(st0_ptr->sigh & 0x40000000)) {
/* It is a signalling NaN */
EXCEPTION(EX_Invalid);
if (!(control_word & CW_Invalid))
return 0;
templ |= (0x40000000 >> 8);
}
templ |= 0x7f800000;
} else {
/* It is an unsupported data type */
EXCEPTION(EX_Invalid);
if (!(control_word & CW_Invalid))
return 0;
templ = 0xffc00000;
}
}
#ifdef PARANOID
else {
EXCEPTION(EX_INTERNAL | 0x164);
return 0;
}
#endif
} else if (st0_tag == TAG_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
if (control_word & EX_Invalid) {
/* The masked response */
/* Put out the QNaN indefinite */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(single, 4);
FPU_put_user(0xffc00000,
(unsigned long __user *)single);
RE_ENTRANT_CHECK_ON;
return 1;
} else
return 0;
}
#ifdef PARANOID
else {
EXCEPTION(EX_INTERNAL | 0x163);
return 0;
}
#endif
if (getsign(st0_ptr))
templ |= 0x80000000;
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(single, 4);
FPU_put_user(templ, (unsigned long __user *)single);
RE_ENTRANT_CHECK_ON;
return 1;
}
/* Put a long long into user memory */
int FPU_store_int64(FPU_REG *st0_ptr, u_char st0_tag, long long __user *d)
{
FPU_REG t;
long long tll;
int precision_loss;
if (st0_tag == TAG_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
goto invalid_operand;
} else if (st0_tag == TAG_Special) {
st0_tag = FPU_Special(st0_ptr);
if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
EXCEPTION(EX_Invalid);
goto invalid_operand;
}
}
reg_copy(st0_ptr, &t);
precision_loss = FPU_round_to_int(&t, st0_tag);
((long *)&tll)[0] = t.sigl;
((long *)&tll)[1] = t.sigh;
if ((precision_loss == 1) ||
((t.sigh & 0x80000000) &&
!((t.sigh == 0x80000000) && (t.sigl == 0) && signnegative(&t)))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
invalid_operand:
if (control_word & EX_Invalid) {
/* Produce something like QNaN "indefinite" */
tll = 0x8000000000000000LL;
} else
return 0;
} else {
if (precision_loss)
set_precision_flag(precision_loss);
if (signnegative(&t))
tll = -tll;
}
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 8);
if (copy_to_user(d, &tll, 8))
FPU_abort;
RE_ENTRANT_CHECK_ON;
return 1;
}
/* Put a long into user memory */
int FPU_store_int32(FPU_REG *st0_ptr, u_char st0_tag, long __user *d)
{
FPU_REG t;
int precision_loss;
if (st0_tag == TAG_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
goto invalid_operand;
} else if (st0_tag == TAG_Special) {
st0_tag = FPU_Special(st0_ptr);
if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
EXCEPTION(EX_Invalid);
goto invalid_operand;
}
}
reg_copy(st0_ptr, &t);
precision_loss = FPU_round_to_int(&t, st0_tag);
if (t.sigh ||
((t.sigl & 0x80000000) &&
!((t.sigl == 0x80000000) && signnegative(&t)))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
invalid_operand:
if (control_word & EX_Invalid) {
/* Produce something like QNaN "indefinite" */
t.sigl = 0x80000000;
} else
return 0;
} else {
if (precision_loss)
set_precision_flag(precision_loss);
if (signnegative(&t))
t.sigl = -(long)t.sigl;
}
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 4);
FPU_put_user(t.sigl, (unsigned long __user *)d);
RE_ENTRANT_CHECK_ON;
return 1;
}
/* Put a short into user memory */
int FPU_store_int16(FPU_REG *st0_ptr, u_char st0_tag, short __user *d)
{
FPU_REG t;
int precision_loss;
if (st0_tag == TAG_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
goto invalid_operand;
} else if (st0_tag == TAG_Special) {
st0_tag = FPU_Special(st0_ptr);
if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
EXCEPTION(EX_Invalid);
goto invalid_operand;
}
}
reg_copy(st0_ptr, &t);
precision_loss = FPU_round_to_int(&t, st0_tag);
if (t.sigh ||
((t.sigl & 0xffff8000) &&
!((t.sigl == 0x8000) && signnegative(&t)))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
invalid_operand:
if (control_word & EX_Invalid) {
/* Produce something like QNaN "indefinite" */
t.sigl = 0x8000;
} else
return 0;
} else {
if (precision_loss)
set_precision_flag(precision_loss);
if (signnegative(&t))
t.sigl = -t.sigl;
}
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 2);
FPU_put_user((short)t.sigl, d);
RE_ENTRANT_CHECK_ON;
return 1;
}
/* Put a packed bcd array into user memory */
int FPU_store_bcd(FPU_REG *st0_ptr, u_char st0_tag, u_char __user *d)
{
FPU_REG t;
unsigned long long ll;
u_char b;
int i, precision_loss;
u_char sign = (getsign(st0_ptr) == SIGN_NEG) ? 0x80 : 0;
if (st0_tag == TAG_Empty) {
/* Empty register (stack underflow) */
EXCEPTION(EX_StackUnder);
goto invalid_operand;
} else if (st0_tag == TAG_Special) {
st0_tag = FPU_Special(st0_ptr);
if ((st0_tag == TW_Infinity) || (st0_tag == TW_NaN)) {
EXCEPTION(EX_Invalid);
goto invalid_operand;
}
}
reg_copy(st0_ptr, &t);
precision_loss = FPU_round_to_int(&t, st0_tag);
ll = significand(&t);
/* Check for overflow, by comparing with 999999999999999999 decimal. */
if ((t.sigh > 0x0de0b6b3) ||
((t.sigh == 0x0de0b6b3) && (t.sigl > 0xa763ffff))) {
EXCEPTION(EX_Invalid);
/* This is a special case: see sec 16.2.5.1 of the 80486 book */
invalid_operand:
if (control_word & CW_Invalid) {
/* Produce the QNaN "indefinite" */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 10);
for (i = 0; i < 7; i++)
FPU_put_user(0, d + i); /* These bytes "undefined" */
FPU_put_user(0xc0, d + 7); /* This byte "undefined" */
FPU_put_user(0xff, d + 8);
FPU_put_user(0xff, d + 9);
RE_ENTRANT_CHECK_ON;
return 1;
} else
return 0;
} else if (precision_loss) {
/* Precision loss doesn't stop the data transfer */
set_precision_flag(precision_loss);
}
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 10);
RE_ENTRANT_CHECK_ON;
for (i = 0; i < 9; i++) {
b = FPU_div_small(&ll, 10);
b |= (FPU_div_small(&ll, 10)) << 4;
RE_ENTRANT_CHECK_OFF;
FPU_put_user(b, d + i);
RE_ENTRANT_CHECK_ON;
}
RE_ENTRANT_CHECK_OFF;
FPU_put_user(sign, d + 9);
RE_ENTRANT_CHECK_ON;
return 1;
}
/*===========================================================================*/
/* r gets mangled such that sig is int, sign:
it is NOT normalized */
/* The return value (in eax) is zero if the result is exact,
if bits are changed due to rounding, truncation, etc, then
a non-zero value is returned */
/* Overflow is signalled by a non-zero return value (in eax).
In the case of overflow, the returned significand always has the
largest possible value */
int FPU_round_to_int(FPU_REG *r, u_char tag)
{
u_char very_big;
unsigned eax;
if (tag == TAG_Zero) {
/* Make sure that zero is returned */
significand(r) = 0;
return 0; /* o.k. */
}
if (exponent(r) > 63) {
r->sigl = r->sigh = ~0; /* The largest representable number */
return 1; /* overflow */
}
eax = FPU_shrxs(&r->sigl, 63 - exponent(r));
very_big = !(~(r->sigh) | ~(r->sigl)); /* test for 0xfff...fff */
#define half_or_more (eax & 0x80000000)
#define frac_part (eax)
#define more_than_half ((eax & 0x80000001) == 0x80000001)
switch (control_word & CW_RC) {
case RC_RND:
if (more_than_half /* nearest */
|| (half_or_more && (r->sigl & 1))) { /* odd -> even */
if (very_big)
return 1; /* overflow */
significand(r)++;
return PRECISION_LOST_UP;
}
break;
case RC_DOWN:
if (frac_part && getsign(r)) {
if (very_big)
return 1; /* overflow */
significand(r)++;
return PRECISION_LOST_UP;
}
break;
case RC_UP:
if (frac_part && !getsign(r)) {
if (very_big)
return 1; /* overflow */
significand(r)++;
return PRECISION_LOST_UP;
}
break;
case RC_CHOP:
break;
}
return eax ? PRECISION_LOST_DOWN : 0;
}
/*===========================================================================*/
u_char __user *fldenv(fpu_addr_modes addr_modes, u_char __user *s)
{
unsigned short tag_word = 0;
u_char tag;
int i;
if ((addr_modes.default_mode == VM86) ||
((addr_modes.default_mode == PM16)
^ (addr_modes.override.operand_size == OP_SIZE_PREFIX))) {
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(s, 0x0e);
FPU_get_user(control_word, (unsigned short __user *)s);
FPU_get_user(partial_status, (unsigned short __user *)(s + 2));
FPU_get_user(tag_word, (unsigned short __user *)(s + 4));
FPU_get_user(instruction_address.offset,
(unsigned short __user *)(s + 6));
FPU_get_user(instruction_address.selector,
(unsigned short __user *)(s + 8));
FPU_get_user(operand_address.offset,
(unsigned short __user *)(s + 0x0a));
FPU_get_user(operand_address.selector,
(unsigned short __user *)(s + 0x0c));
RE_ENTRANT_CHECK_ON;
s += 0x0e;
if (addr_modes.default_mode == VM86) {
instruction_address.offset
+= (instruction_address.selector & 0xf000) << 4;
operand_address.offset +=
(operand_address.selector & 0xf000) << 4;
}
} else {
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(s, 0x1c);
FPU_get_user(control_word, (unsigned short __user *)s);
FPU_get_user(partial_status, (unsigned short __user *)(s + 4));
FPU_get_user(tag_word, (unsigned short __user *)(s + 8));
FPU_get_user(instruction_address.offset,
(unsigned long __user *)(s + 0x0c));
FPU_get_user(instruction_address.selector,
(unsigned short __user *)(s + 0x10));
FPU_get_user(instruction_address.opcode,
(unsigned short __user *)(s + 0x12));
FPU_get_user(operand_address.offset,
(unsigned long __user *)(s + 0x14));
FPU_get_user(operand_address.selector,
(unsigned long __user *)(s + 0x18));
RE_ENTRANT_CHECK_ON;
s += 0x1c;
}
#ifdef PECULIAR_486
control_word &= ~0xe080;
#endif /* PECULIAR_486 */
top = (partial_status >> SW_Top_Shift) & 7;
if (partial_status & ~control_word & CW_Exceptions)
partial_status |= (SW_Summary | SW_Backward);
else
partial_status &= ~(SW_Summary | SW_Backward);
for (i = 0; i < 8; i++) {
tag = tag_word & 3;
tag_word >>= 2;
if (tag == TAG_Empty)
/* New tag is empty. Accept it */
FPU_settag(i, TAG_Empty);
else if (FPU_gettag(i) == TAG_Empty) {
/* Old tag is empty and new tag is not empty. New tag is determined
by old reg contents */
if (exponent(&fpu_register(i)) == -EXTENDED_Ebias) {
if (!
(fpu_register(i).sigl | fpu_register(i).
sigh))
FPU_settag(i, TAG_Zero);
else
FPU_settag(i, TAG_Special);
} else if (exponent(&fpu_register(i)) ==
0x7fff - EXTENDED_Ebias) {
FPU_settag(i, TAG_Special);
} else if (fpu_register(i).sigh & 0x80000000)
FPU_settag(i, TAG_Valid);
else
FPU_settag(i, TAG_Special); /* An Un-normal */
}
/* Else old tag is not empty and new tag is not empty. Old tag
remains correct */
}
return s;
}
void frstor(fpu_addr_modes addr_modes, u_char __user *data_address)
{
int i, regnr;
u_char __user *s = fldenv(addr_modes, data_address);
int offset = (top & 7) * 10, other = 80 - offset;
/* Copy all registers in stack order. */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(s, 80);
FPU_copy_from_user(register_base + offset, s, other);
if (offset)
FPU_copy_from_user(register_base, s + other, offset);
RE_ENTRANT_CHECK_ON;
for (i = 0; i < 8; i++) {
regnr = (i + top) & 7;
if (FPU_gettag(regnr) != TAG_Empty)
/* The loaded data over-rides all other cases. */
FPU_settag(regnr, FPU_tagof(&st(i)));
}
}
u_char __user *fstenv(fpu_addr_modes addr_modes, u_char __user *d)
{
if ((addr_modes.default_mode == VM86) ||
((addr_modes.default_mode == PM16)
^ (addr_modes.override.operand_size == OP_SIZE_PREFIX))) {
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 14);
#ifdef PECULIAR_486
FPU_put_user(control_word & ~0xe080, (unsigned long __user *)d);
#else
FPU_put_user(control_word, (unsigned short __user *)d);
#endif /* PECULIAR_486 */
FPU_put_user(status_word(), (unsigned short __user *)(d + 2));
FPU_put_user(fpu_tag_word, (unsigned short __user *)(d + 4));
FPU_put_user(instruction_address.offset,
(unsigned short __user *)(d + 6));
FPU_put_user(operand_address.offset,
(unsigned short __user *)(d + 0x0a));
if (addr_modes.default_mode == VM86) {
FPU_put_user((instruction_address.
offset & 0xf0000) >> 4,
(unsigned short __user *)(d + 8));
FPU_put_user((operand_address.offset & 0xf0000) >> 4,
(unsigned short __user *)(d + 0x0c));
} else {
FPU_put_user(instruction_address.selector,
(unsigned short __user *)(d + 8));
FPU_put_user(operand_address.selector,
(unsigned short __user *)(d + 0x0c));
}
RE_ENTRANT_CHECK_ON;
d += 0x0e;
} else {
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 7 * 4);
#ifdef PECULIAR_486
control_word &= ~0xe080;
/* An 80486 sets nearly all of the reserved bits to 1. */
control_word |= 0xffff0040;
partial_status = status_word() | 0xffff0000;
fpu_tag_word |= 0xffff0000;
I387->soft.fcs &= ~0xf8000000;
I387->soft.fos |= 0xffff0000;
#endif /* PECULIAR_486 */
if (__copy_to_user(d, &control_word, 7 * 4))
FPU_abort;
RE_ENTRANT_CHECK_ON;
d += 0x1c;
}
control_word |= CW_Exceptions;
partial_status &= ~(SW_Summary | SW_Backward);
return d;
}
void fsave(fpu_addr_modes addr_modes, u_char __user *data_address)
{
u_char __user *d;
int offset = (top & 7) * 10, other = 80 - offset;
d = fstenv(addr_modes, data_address);
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(d, 80);
/* Copy all registers in stack order. */
if (__copy_to_user(d, register_base + offset, other))
FPU_abort;
if (offset)
if (__copy_to_user(d + other, register_base, offset))
FPU_abort;
RE_ENTRANT_CHECK_ON;
finit();
}
/*===========================================================================*/
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