linux-kernel - [PATCH 3/3] x86/math-emu: Remove define layer for undocumented opcodes

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Date:	Thu, 27 Aug 2015 20:15:30 +0200
From:	Denys Vlasenko <dvlasenk@...hat.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	Denys Vlasenko <dvlasenk@...hat.com>,
	Borislav Petkov <bp@...en8.de>,
	"H. Peter Anvin" <hpa@...or.com>,
	Andy Lutomirski <luto@...capital.net>,
	Kees Cook <keescook@...omium.org>, x86@...nel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] x86/math-emu: Remove define layer for undocumented opcodes

No code changes.
Only compile-tested.

Signed-off-by: Denys Vlasenko <dvlasenk@...hat.com>
CC: Ingo Molnar <mingo@...nel.org>
CC: Borislav Petkov <bp@...en8.de>
CC: "H. Peter Anvin" <hpa@...or.com>
CC: Andy Lutomirski <luto@...capital.net>
CC: Kees Cook <keescook@...omium.org>
CC: x86@...nel.org
CC: linux-kernel@...r.kernel.org
---
 arch/x86/math-emu/fpu_entry.c | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)

diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 77c6505..0e86006 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -40,34 +40,23 @@
 
 #define __BAD__ FPU_illegal	/* Illegal on an 80486, causes SIGILL */
 
-/* WARNING: These codes are not all documented by Intel in their 80486 manual
-   and may not work on FPU clones or later Intel FPUs. */
-
-/* Changes to support the un-documented instructions provided by Linus Torvalds. */
-
-#define _d9_d8_ fstp_i		/* unofficial code (19) */
-#define _dc_d0_ fcom_st		/* unofficial code (14) */
-#define _dc_d8_ fcompst		/* unofficial code (1c) */
-#define _dd_c8_ fxch_i		/* unofficial code (0d) */
-#define _de_d0_ fcompst		/* unofficial code (16) */
-#define _df_c0_ ffreep		/* unofficial code (07) ffree + pop */
-#define _df_c8_ fxch_i		/* unofficial code (0f) */
-#define _df_d0_ fstp_i		/* unofficial code (17) */
-#define _df_d8_ fstp_i		/* unofficial code (1f) */
-
 /* fcmovCC and f(u)comi(p) are enabled if CPUID(1).EDX(15) "cmov" is set */
 
+/* WARNING: "u" entries are not documented by Intel in their 80486 manual
+   and may not work on FPU clones or later Intel FPUs.
+   Changes to support the un-documented instructions provided by Linus Torvalds. */
+
 static FUNC const st_instr_table[64] = {
 /* Opcode:	d8		d9		da		db */
 /*		dc		dd		de		df */
 /* c0..7 */	fadd__,		fld_i_,		fcmovb,		fcmovnb,
-/* c0..7 */	fadd_i,		ffree_,		faddp_,		_df_c0_,
+/* c0..7 */	fadd_i,		ffree_,		faddp_,		ffreep,/*u*/
 /* c8..f */	fmul__,		fxch_i,		fcmove,		fcmovne,
-/* c8..f */	fmul_i,		_dd_c8_,	fmulp_,		_df_c8_,
+/* c8..f */	fmul_i,		fxch_i,/*u*/	fmulp_,		fxch_i,/*u*/
 /* d0..7 */	fcom_st,	fp_nop,		fcmovbe,	fcmovnbe,
-/* d0..7 */	_dc_d0_,	fst_i_,		_de_d0_,	_df_d0_,
-/* d8..f */	fcompst,	_d9_d8_,	fcmovu,		fcmovnu,
-/* d8..f */	_dc_d8_,	fstp_i,		fcompp,		_df_d8_,
+/* d0..7 */	fcom_st,/*u*/	fst_i_,		fcompst,/*u*/	fstp_i,/*u*/
+/* d8..f */	fcompst,	fstp_i,/*u*/	fcmovu,		fcmovnu,
+/* d8..f */	fcompst,/*u*/	fstp_i,		fcompp,		fstp_i,/*u*/
 /* e0..7 */	fsub__,		FPU_etc,	__BAD__,	finit_,
 /* e0..7 */	fsubri,		fucom_,		fsubrp,		fstsw_,
 /* e8..f */	fsubr_,		fconst,		fucompp,	fucomi_,
-- 
1.8.1.4

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