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linux-brain/arch/x86/math-emu/load_store.c
Linus Torvalds 96d4f267e4 Remove 'type' argument from access_ok() function 
Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.

It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access.  But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.

A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model.  And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.

This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.

There were a couple of notable cases:

 - csky still had the old "verify_area()" name as an alias.

 - the iter_iov code had magical hardcoded knowledge of the actual
   values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
   really used it)

 - microblaze used the type argument for a debug printout

but other than those oddities this should be a total no-op patch.

I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something.  Any missed conversion should be trivially fixable, though.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-01-03 18:57:57 -08:00

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// SPDX-License-Identifier: GPL-2.0
/*---------------------------------------------------------------------------+
| load_store.c |
| |
| This file contains most of the code to interpret the FPU instructions |
| which load and store from user memory. |
| |
| Copyright (C) 1992,1993,1994,1997 |
| 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 <linux/uaccess.h>
#include "fpu_system.h"
#include "exception.h"
#include "fpu_emu.h"
#include "status_w.h"
#include "control_w.h"
#define _NONE_ 0 /* st0_ptr etc not needed */
#define _REG0_ 1 /* Will be storing st(0) */
#define _PUSH_ 3 /* Need to check for space to push onto stack */
#define _null_ 4 /* Function illegal or not implemented */
#define pop_0() { FPU_settag0(TAG_Empty); top++; }
/* index is a 5-bit value: (3-bit FPU_modrm.reg field | opcode[2,1]) */
static u_char const type_table[32] = {
_PUSH_, _PUSH_, _PUSH_, _PUSH_, /* /0: d9:fld f32, db:fild m32, dd:fld f64, df:fild m16 */
_null_, _REG0_, _REG0_, _REG0_, /* /1: d9:undef, db,dd,df:fisttp m32/64/16 */
_REG0_, _REG0_, _REG0_, _REG0_, /* /2: d9:fst f32, db:fist m32, dd:fst f64, df:fist m16 */
_REG0_, _REG0_, _REG0_, _REG0_, /* /3: d9:fstp f32, db:fistp m32, dd:fstp f64, df:fistp m16 */
_NONE_, _null_, _NONE_, _PUSH_,
_NONE_, _PUSH_, _null_, _PUSH_,
_NONE_, _null_, _NONE_, _REG0_,
_NONE_, _REG0_, _NONE_, _REG0_
};
u_char const data_sizes_16[32] = {
4, 4, 8, 2,
0, 4, 8, 2, /* /1: d9:undef, db,dd,df:fisttp */
4, 4, 8, 2,
4, 4, 8, 2,
14, 0, 94, 10, 2, 10, 0, 8,
14, 0, 94, 10, 2, 10, 2, 8
};
static u_char const data_sizes_32[32] = {
4, 4, 8, 2,
0, 4, 8, 2, /* /1: d9:undef, db,dd,df:fisttp */
4, 4, 8, 2,
4, 4, 8, 2,
28, 0, 108, 10, 2, 10, 0, 8,
28, 0, 108, 10, 2, 10, 2, 8
};
int FPU_load_store(u_char type, fpu_addr_modes addr_modes,
void __user * data_address)
{
FPU_REG loaded_data;
FPU_REG *st0_ptr;
u_char st0_tag = TAG_Empty; /* This is just to stop a gcc warning. */
u_char loaded_tag;
int sv_cw;
st0_ptr = NULL; /* Initialized just to stop compiler warnings. */
if (addr_modes.default_mode & PROTECTED) {
if (addr_modes.default_mode == SEG32) {
if (access_limit < data_sizes_32[type])
math_abort(FPU_info, SIGSEGV);
} else if (addr_modes.default_mode == PM16) {
if (access_limit < data_sizes_16[type])
math_abort(FPU_info, SIGSEGV);
}
#ifdef PARANOID
else
EXCEPTION(EX_INTERNAL | 0x140);
#endif /* PARANOID */
}
switch (type_table[type]) {
case _NONE_:
break;
case _REG0_:
st0_ptr = &st(0); /* Some of these instructions pop after
storing */
st0_tag = FPU_gettag0();
break;
case _PUSH_:
{
if (FPU_gettagi(-1) != TAG_Empty) {
FPU_stack_overflow();
return 0;
}
top--;
st0_ptr = &st(0);
}
break;
case _null_:
FPU_illegal();
return 0;
#ifdef PARANOID
default:
EXCEPTION(EX_INTERNAL | 0x141);
return 0;
#endif /* PARANOID */
}
switch (type) {
/* type is a 5-bit value: (3-bit FPU_modrm.reg field | opcode[2,1]) */
case 000: /* fld m32real (d9 /0) */
clear_C1();
loaded_tag =
FPU_load_single((float __user *)data_address, &loaded_data);
if ((loaded_tag == TAG_Special)
&& isNaN(&loaded_data)
&& (real_1op_NaN(&loaded_data) < 0)) {
top++;
break;
}
FPU_copy_to_reg0(&loaded_data, loaded_tag);
break;
case 001: /* fild m32int (db /0) */
clear_C1();
loaded_tag =
FPU_load_int32((long __user *)data_address, &loaded_data);
FPU_copy_to_reg0(&loaded_data, loaded_tag);
break;
case 002: /* fld m64real (dd /0) */
clear_C1();
loaded_tag =
FPU_load_double((double __user *)data_address,
&loaded_data);
if ((loaded_tag == TAG_Special)
&& isNaN(&loaded_data)
&& (real_1op_NaN(&loaded_data) < 0)) {
top++;
break;
}
FPU_copy_to_reg0(&loaded_data, loaded_tag);
break;
case 003: /* fild m16int (df /0) */
clear_C1();
loaded_tag =
FPU_load_int16((short __user *)data_address, &loaded_data);
FPU_copy_to_reg0(&loaded_data, loaded_tag);
break;
/* case 004: undefined (d9 /1) */
/* fisttp are enabled if CPUID(1).ECX(0) "sse3" is set */
case 005: /* fisttp m32int (db /1) */
clear_C1();
sv_cw = control_word;
control_word |= RC_CHOP;
if (FPU_store_int32
(st0_ptr, st0_tag, (long __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
control_word = sv_cw;
break;
case 006: /* fisttp m64int (dd /1) */
clear_C1();
sv_cw = control_word;
control_word |= RC_CHOP;
if (FPU_store_int64
(st0_ptr, st0_tag, (long long __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
control_word = sv_cw;
break;
case 007: /* fisttp m16int (df /1) */
clear_C1();
sv_cw = control_word;
control_word |= RC_CHOP;
if (FPU_store_int16
(st0_ptr, st0_tag, (short __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
control_word = sv_cw;
break;
case 010: /* fst m32real */
clear_C1();
FPU_store_single(st0_ptr, st0_tag,
(float __user *)data_address);
break;
case 011: /* fist m32int */
clear_C1();
FPU_store_int32(st0_ptr, st0_tag, (long __user *)data_address);
break;
case 012: /* fst m64real */
clear_C1();
FPU_store_double(st0_ptr, st0_tag,
(double __user *)data_address);
break;
case 013: /* fist m16int */
clear_C1();
FPU_store_int16(st0_ptr, st0_tag, (short __user *)data_address);
break;
case 014: /* fstp m32real */
clear_C1();
if (FPU_store_single
(st0_ptr, st0_tag, (float __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
break;
case 015: /* fistp m32int */
clear_C1();
if (FPU_store_int32
(st0_ptr, st0_tag, (long __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
break;
case 016: /* fstp m64real */
clear_C1();
if (FPU_store_double
(st0_ptr, st0_tag, (double __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
break;
case 017: /* fistp m16int */
clear_C1();
if (FPU_store_int16
(st0_ptr, st0_tag, (short __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
break;
case 020: /* fldenv m14/28byte */
fldenv(addr_modes, (u_char __user *) data_address);
/* Ensure that the values just loaded are not changed by
fix-up operations. */
return 1;
case 022: /* frstor m94/108byte */
frstor(addr_modes, (u_char __user *) data_address);
/* Ensure that the values just loaded are not changed by
fix-up operations. */
return 1;
case 023: /* fbld m80dec */
clear_C1();
loaded_tag = FPU_load_bcd((u_char __user *) data_address);
FPU_settag0(loaded_tag);
break;
case 024: /* fldcw */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(data_address, 2);
FPU_get_user(control_word,
(unsigned short __user *)data_address);
RE_ENTRANT_CHECK_ON;
if (partial_status & ~control_word & CW_Exceptions)
partial_status |= (SW_Summary | SW_Backward);
else
partial_status &= ~(SW_Summary | SW_Backward);
#ifdef PECULIAR_486
control_word |= 0x40; /* An 80486 appears to always set this bit */
#endif /* PECULIAR_486 */
return 1;
case 025: /* fld m80real */
clear_C1();
loaded_tag =
FPU_load_extended((long double __user *)data_address, 0);
FPU_settag0(loaded_tag);
break;
case 027: /* fild m64int */
clear_C1();
loaded_tag = FPU_load_int64((long long __user *)data_address);
if (loaded_tag == TAG_Error)
return 0;
FPU_settag0(loaded_tag);
break;
case 030: /* fstenv m14/28byte */
fstenv(addr_modes, (u_char __user *) data_address);
return 1;
case 032: /* fsave */
fsave(addr_modes, (u_char __user *) data_address);
return 1;
case 033: /* fbstp m80dec */
clear_C1();
if (FPU_store_bcd
(st0_ptr, st0_tag, (u_char __user *) data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
break;
case 034: /* fstcw m16int */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(data_address, 2);
FPU_put_user(control_word,
(unsigned short __user *)data_address);
RE_ENTRANT_CHECK_ON;
return 1;
case 035: /* fstp m80real */
clear_C1();
if (FPU_store_extended
(st0_ptr, st0_tag, (long double __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
break;
case 036: /* fstsw m2byte */
RE_ENTRANT_CHECK_OFF;
FPU_access_ok(data_address, 2);
FPU_put_user(status_word(),
(unsigned short __user *)data_address);
RE_ENTRANT_CHECK_ON;
return 1;
case 037: /* fistp m64int */
clear_C1();
if (FPU_store_int64
(st0_ptr, st0_tag, (long long __user *)data_address))
pop_0(); /* pop only if the number was actually stored
(see the 80486 manual p16-28) */
break;
}
return 0;
}
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