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06c03cac94
Patch from Lennert Buytenhek The routine that nwfpe uses for converting floats/doubles to extended precision fails to zero two bytes of kernel stack. This is not immediately obvious, as the floatx80 structure has 16 bits of implicit padding (by design.) These two bytes are copied to userspace when an stfe is emulated, causing a possible info leak. Make the padding explicit and zero it out in the relevant places. Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
91 lines
2.9 KiB
C
91 lines
2.9 KiB
C
/*
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NetWinder Floating Point Emulator
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(c) Rebel.COM, 1998,1999
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Direct questions, comments to Scott Bambrough <scottb@netwinder.org>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/config.h>
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#include "fpa11.h"
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#include "softfloat.h"
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#include "fpopcode.h"
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#include "fpsr.h"
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#include "fpmodule.h"
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#include "fpmodule.inl"
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#ifdef CONFIG_FPE_NWFPE_XP
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const floatx80 floatx80Constant[] = {
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{ .high = 0x0000, .low = 0x0000000000000000ULL},/* extended 0.0 */
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{ .high = 0x3fff, .low = 0x8000000000000000ULL},/* extended 1.0 */
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{ .high = 0x4000, .low = 0x8000000000000000ULL},/* extended 2.0 */
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{ .high = 0x4000, .low = 0xc000000000000000ULL},/* extended 3.0 */
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{ .high = 0x4001, .low = 0x8000000000000000ULL},/* extended 4.0 */
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{ .high = 0x4001, .low = 0xa000000000000000ULL},/* extended 5.0 */
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{ .high = 0x3ffe, .low = 0x8000000000000000ULL},/* extended 0.5 */
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{ .high = 0x4002, .low = 0xa000000000000000ULL},/* extended 10.0 */
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};
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#endif
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const float64 float64Constant[] = {
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0x0000000000000000ULL, /* double 0.0 */
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0x3ff0000000000000ULL, /* double 1.0 */
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0x4000000000000000ULL, /* double 2.0 */
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0x4008000000000000ULL, /* double 3.0 */
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0x4010000000000000ULL, /* double 4.0 */
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0x4014000000000000ULL, /* double 5.0 */
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0x3fe0000000000000ULL, /* double 0.5 */
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0x4024000000000000ULL /* double 10.0 */
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};
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const float32 float32Constant[] = {
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0x00000000, /* single 0.0 */
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0x3f800000, /* single 1.0 */
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0x40000000, /* single 2.0 */
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0x40400000, /* single 3.0 */
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0x40800000, /* single 4.0 */
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0x40a00000, /* single 5.0 */
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0x3f000000, /* single 0.5 */
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0x41200000 /* single 10.0 */
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};
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/* condition code lookup table
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index into the table is test code: EQ, NE, ... LT, GT, AL, NV
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bit position in short is condition code: NZCV */
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static const unsigned short aCC[16] = {
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0xF0F0, // EQ == Z set
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0x0F0F, // NE
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0xCCCC, // CS == C set
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0x3333, // CC
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0xFF00, // MI == N set
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0x00FF, // PL
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0xAAAA, // VS == V set
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0x5555, // VC
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0x0C0C, // HI == C set && Z clear
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0xF3F3, // LS == C clear || Z set
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0xAA55, // GE == (N==V)
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0x55AA, // LT == (N!=V)
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0x0A05, // GT == (!Z && (N==V))
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0xF5FA, // LE == (Z || (N!=V))
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0xFFFF, // AL always
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0 // NV
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};
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unsigned int checkCondition(const unsigned int opcode, const unsigned int ccodes)
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{
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return (aCC[opcode >> 28] >> (ccodes >> 28)) & 1;
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}
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