[PATCH 1/3] x86/math-emu: Remove !NO_UNDOC_CODE

[PATCH 1/3] x86/math-emu: Remove !NO_UNDOC_CODE

[Denys Vlasenko]

We always want to support all FPU opcodes, including undocumented ones.
That define was fully justified ~20 years ago but not today.
Let's not complicate code with it.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
 arch/x86/math-emu/fpu_entry.c | 36 ------------------------------------
 1 file changed, 36 deletions(-)

diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 3d8f2e4..929b1d5 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -40,8 +40,6 @@
 
 #define __BAD__ FPU_illegal	/* Illegal on an 80486, causes SIGILL */
 
-#ifndef NO_UNDOC_CODE		/* Un-documented FPU op-codes supported by default. */
-
 /* WARNING: These codes are not documented by Intel in their 80486 manual
    and may not work on FPU clones or later Intel FPUs. */
 
@@ -68,21 +66,6 @@ static FUNC const st_instr_table[64] = {
 	fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
 };
 
-#else /* Support only documented FPU op-codes */
-
-static FUNC const st_instr_table[64] = {
-	fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, __BAD__,
-	fmul__, fxch_i, __BAD__, __BAD__, fmul_i, __BAD__, fmulp_, __BAD__,
-	fcom_st, fp_nop, __BAD__, __BAD__, __BAD__, fst_i_, __BAD__, __BAD__,
-	fcompst, __BAD__, __BAD__, __BAD__, __BAD__, fstp_i, fcompp, __BAD__,
-	fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,
-	fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,
-	fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,
-	fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
-};
-
-#endif /* NO_UNDOC_CODE */
-
 #define _NONE_ 0		/* Take no special action */
 #define _REG0_ 1		/* Need to check for not empty st(0) */
 #define _REGI_ 2		/* Need to check for not empty st(0) and st(rm) */
@@ -94,10 +77,6 @@ static FUNC const st_instr_table[64] = {
 #define _REGIc 0		/* Compare st(0) and st(rm) */
 #define _REGIn 0		/* Uses st(0) and st(rm), but handle checks later */
 
-#ifndef NO_UNDOC_CODE
-
-/* Un-documented FPU op-codes supported by default. (see above) */
-
 static u_char const type_table[64] = {
 	_REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,
 	_REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,
@@ -109,21 +88,6 @@ static u_char const type_table[64] = {
 	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
 };
 
-#else /* Support only documented FPU op-codes */
-
-static u_char const type_table[64] = {
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_,
-	_REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
-	_REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_,
-	_REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_,
-	_REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
-	_REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
-};
-
-#endif /* NO_UNDOC_CODE */
-
 #ifdef RE_ENTRANT_CHECKING
 u_char emulating = 0;
 #endif /* RE_ENTRANT_CHECKING */
-- 
1.8.1.4

[PATCH 2/3] x86/math-emu: Add support for FCMOVcc and F[U]COMI[P] insns

[Denys Vlasenko]

Only compile-tested.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
CC: linux-kernel@vger.kernel.org
---
 arch/x86/math-emu/fpu_aux.c     |  70 ++++++++++++++++++++++
 arch/x86/math-emu/fpu_entry.c   |  49 +++++++++------
 arch/x86/math-emu/fpu_proto.h   |  12 ++++
 arch/x86/math-emu/reg_compare.c | 128 ++++++++++++++++++++++++++++++++++++++++
 4 files changed, 241 insertions(+), 18 deletions(-)

diff --git a/arch/x86/math-emu/fpu_aux.c b/arch/x86/math-emu/fpu_aux.c
index dd76a05..024f6e9 100644
--- a/arch/x86/math-emu/fpu_aux.c
+++ b/arch/x86/math-emu/fpu_aux.c
@@ -169,6 +169,76 @@ void fxch_i(void)
 	fpu_tag_word = tag_word;
 }
 
+static void fcmovCC(void)
+{
+	/* fcmovCC st(i) */
+	int i = FPU_rm;
+	FPU_REG *st0_ptr = &st(0);
+	FPU_REG *sti_ptr = &st(i);
+	long tag_word = fpu_tag_word;
+	int regnr = top & 7;
+	int regnri = (top + i) & 7;
+	u_char sti_tag = (tag_word >> (regnri * 2)) & 3;
+
+	if (sti_tag == TAG_Empty) {
+		FPU_stack_underflow();
+		clear_C1();
+		return;
+	}
+	reg_copy(sti_ptr, st0_ptr);
+	tag_word &= ~(3 << (regnr * 2));
+	tag_word |= (sti_tag << (regnr * 2));
+	fpu_tag_word = tag_word;
+}
+
+void fcmovb(void)
+{
+	if (FPU_EFLAGS & X86_EFLAGS_CF)
+		fcmovCC();
+}
+
+void fcmove(void)
+{
+	if (FPU_EFLAGS & X86_EFLAGS_ZF)
+		fcmovCC();
+}
+
+void fcmovbe(void)
+{
+	if (FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF))
+		fcmovCC();
+}
+
+void fcmovu(void)
+{
+	if (FPU_EFLAGS & X86_EFLAGS_PF)
+		fcmovCC();
+}
+
+void fcmovnb(void)
+{
+	if (!(FPU_EFLAGS & X86_EFLAGS_CF))
+		fcmovCC();
+}
+
+void fcmovne(void)
+{
+	if (!(FPU_EFLAGS & X86_EFLAGS_ZF))
+		fcmovCC();
+}
+
+void fcmovnbe(void)
+{
+	if (!(FPU_EFLAGS & (X86_EFLAGS_CF|X86_EFLAGS_ZF)))
+		fcmovCC();
+}
+
+void fcmovnu(void)
+{
+	if (!(FPU_EFLAGS & X86_EFLAGS_PF))
+		fcmovCC();
+}
+
 void ffree_(void)
 {
 	/* ffree st(i) */
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 929b1d5..77c6505 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -40,10 +40,10 @@
 
 #define __BAD__ FPU_illegal	/* Illegal on an 80486, causes SIGILL */
 
-/* WARNING: These codes are not documented by Intel in their 80486 manual
+/* 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-doc codes provided by Linus Torvalds. */
+/* 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) */
@@ -55,15 +55,27 @@
 #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 */
+
 static FUNC const st_instr_table[64] = {
-	fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, _df_c0_,
-	fmul__, fxch_i, __BAD__, __BAD__, fmul_i, _dd_c8_, fmulp_, _df_c8_,
-	fcom_st, fp_nop, __BAD__, __BAD__, _dc_d0_, fst_i_, _de_d0_, _df_d0_,
-	fcompst, _d9_d8_, __BAD__, __BAD__, _dc_d8_, fstp_i, fcompp, _df_d8_,
-	fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,
-	fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,
-	fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,
-	fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
+/* Opcode:	d8		d9		da		db */
+/*		dc		dd		de		df */
+/* c0..7 */	fadd__,		fld_i_,		fcmovb,		fcmovnb,
+/* c0..7 */	fadd_i,		ffree_,		faddp_,		_df_c0_,
+/* c8..f */	fmul__,		fxch_i,		fcmove,		fcmovne,
+/* c8..f */	fmul_i,		_dd_c8_,	fmulp_,		_df_c8_,
+/* 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_,
+/* e0..7 */	fsub__,		FPU_etc,	__BAD__,	finit_,
+/* e0..7 */	fsubri,		fucom_,		fsubrp,		fstsw_,
+/* e8..f */	fsubr_,		fconst,		fucompp,	fucomi_,
+/* e8..f */	fsub_i,		fucomp,		fsubp_,		fucomip,
+/* f0..7 */	fdiv__,		FPU_triga,	__BAD__,	fcomi_,
+/* f0..7 */	fdivri,		__BAD__,	fdivrp,		fcomip,
+/* f8..f */	fdivr_,		FPU_trigb,	__BAD__,	__BAD__,
+/* f8..f */	fdiv_i,		__BAD__,	fdivp_,		__BAD__,
 };
 
 #define _NONE_ 0		/* Take no special action */
@@ -78,14 +90,15 @@ static FUNC const st_instr_table[64] = {
 #define _REGIn 0		/* Uses st(0) and st(rm), but handle checks later */
 
 static u_char const type_table[64] = {
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,
-	_REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,
-	_REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
-	_REGIc, _REG0_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,
-	_REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
-	_REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
+/* Opcode:	d8	d9	da	db	dc	dd	de	df */
+/* c0..7 */	_REGI_, _NONE_, _REGIn, _REGIn, _REGIi, _REGi_, _REGIp, _REGi_,
+/* c8..f */	_REGI_, _REGIn, _REGIn, _REGIn, _REGIi, _REGI_, _REGIp, _REGI_,
+/* d0..7 */	_REGIc, _NONE_, _REGIn, _REGIn, _REGIc, _REG0_, _REGIc, _REG0_,
+/* d8..f */	_REGIc, _REG0_, _REGIn, _REGIn, _REGIc, _REG0_, _REGIc, _REG0_,
+/* e0..7 */	_REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
+/* e8..f */	_REGI_, _NONE_, _REGIc, _REGIc, _REGIi, _REGIc, _REGIp, _REGIc,
+/* f0..7 */	_REGI_, _NONE_, _null_, _REGIc, _REGIi, _null_, _REGIp, _REGIc,
+/* f8..f */	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
 };
 
 #ifdef RE_ENTRANT_CHECKING
diff --git a/arch/x86/math-emu/fpu_proto.h b/arch/x86/math-emu/fpu_proto.h
index 9779df4..caff438 100644
--- a/arch/x86/math-emu/fpu_proto.h
+++ b/arch/x86/math-emu/fpu_proto.h
@@ -46,6 +46,14 @@ extern void fstsw_(void);
 extern void fp_nop(void);
 extern void fld_i_(void);
 extern void fxch_i(void);
+extern void fcmovb(void);
+extern void fcmove(void);
+extern void fcmovbe(void);
+extern void fcmovu(void);
+extern void fcmovnb(void);
+extern void fcmovne(void);
+extern void fcmovnbe(void);
+extern void fcmovnu(void);
 extern void ffree_(void);
 extern void ffreep(void);
 extern void fst_i_(void);
@@ -108,6 +116,10 @@ extern void fcompp(void);
 extern void fucom_(void);
 extern void fucomp(void);
 extern void fucompp(void);
+extern void fcomi_(void);
+extern void fcomip(void);
+extern void fucomi_(void);
+extern void fucomip(void);
 /* reg_constant.c */
 extern void fconst(void);
 /* reg_ld_str.c */
diff --git a/arch/x86/math-emu/reg_compare.c b/arch/x86/math-emu/reg_compare.c
index ecce55f..b77360f 100644
--- a/arch/x86/math-emu/reg_compare.c
+++ b/arch/x86/math-emu/reg_compare.c
@@ -249,6 +249,54 @@ static int compare_st_st(int nr)
 	return 0;
 }
 
+static int compare_i_st_st(int nr)
+{
+	int f, c;
+	FPU_REG *st_ptr;
+
+	if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
+		FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+		/* Stack fault */
+		EXCEPTION(EX_StackUnder);
+		return !(control_word & CW_Invalid);
+	}
+
+	partial_status &= ~SW_C0;
+	st_ptr = &st(nr);
+	c = compare(st_ptr, FPU_gettagi(nr));
+	if (c & COMP_NaN) {
+		FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+		EXCEPTION(EX_Invalid);
+		return !(control_word & CW_Invalid);
+	}
+
+	switch (c & 7) {
+	case COMP_A_lt_B:
+		f = X86_EFLAGS_CF;
+		break;
+	case COMP_A_eq_B:
+		f = X86_EFLAGS_ZF;
+		break;
+	case COMP_A_gt_B:
+		f = 0;
+		break;
+	case COMP_No_Comp:
+		f = X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF;
+		break;
+#ifdef PARANOID
+	default:
+		EXCEPTION(EX_INTERNAL | 0x122);
+		f = 0;
+		break;
+#endif /* PARANOID */
+	}
+	FPU_EFLAGS = (FPU_EFLAGS & ~(X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF)) | f;
+	if (c & COMP_Denormal) {
+		return denormal_operand() < 0;
+	}
+	return 0;
+}
+
 static int compare_u_st_st(int nr)
 {
 	int f = 0, c;
@@ -299,6 +347,58 @@ static int compare_u_st_st(int nr)
 	return 0;
 }
 
+static int compare_ui_st_st(int nr)
+{
+	int f = 0, c;
+	FPU_REG *st_ptr;
+
+	if (!NOT_EMPTY(0) || !NOT_EMPTY(nr)) {
+		FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+		/* Stack fault */
+		EXCEPTION(EX_StackUnder);
+		return !(control_word & CW_Invalid);
+	}
+
+	partial_status &= ~SW_C0;
+	st_ptr = &st(nr);
+	c = compare(st_ptr, FPU_gettagi(nr));
+	if (c & COMP_NaN) {
+		FPU_EFLAGS |= (X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF);
+		if (c & COMP_SNaN) {	/* This is the only difference between
+					   un-ordered and ordinary comparisons */
+			EXCEPTION(EX_Invalid);
+			return !(control_word & CW_Invalid);
+		}
+		return 0;
+	}
+
+	switch (c & 7) {
+	case COMP_A_lt_B:
+		f = X86_EFLAGS_CF;
+		break;
+	case COMP_A_eq_B:
+		f = X86_EFLAGS_ZF;
+		break;
+	case COMP_A_gt_B:
+		f = 0;
+		break;
+	case COMP_No_Comp:
+		f = X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF;
+		break;
+#ifdef PARANOID
+	default:
+		EXCEPTION(EX_INTERNAL | 0x123);
+		f = 0;
+		break;
+#endif /* PARANOID */
+	}
+	FPU_EFLAGS = (FPU_EFLAGS & ~(X86_EFLAGS_ZF | X86_EFLAGS_PF | X86_EFLAGS_CF)) | f;
+	if (c & COMP_Denormal) {
+		return denormal_operand() < 0;
+	}
+	return 0;
+}
+
 /*---------------------------------------------------------------------------*/
 
 void fcom_st(void)
@@ -348,3 +448,31 @@ void fucompp(void)
 	} else
 		FPU_illegal();
 }
+
+/* P6+ compare-to-EFLAGS ops */
+
+void fcomi_(void)
+{
+	/* fcomi st(i) */
+	compare_i_st_st(FPU_rm);
+}
+
+void fcomip(void)
+{
+	/* fcomip st(i) */
+	if (!compare_i_st_st(FPU_rm))
+		FPU_pop();
+}
+
+void fucomi_(void)
+{
+	/* fucomi st(i) */
+	compare_ui_st_st(FPU_rm);
+}
+
+void fucomip(void)
+{
+	/* fucomip st(i) */
+	if (!compare_ui_st_st(FPU_rm))
+		FPU_pop();
+}
-- 
1.8.1.4

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

[Denys Vlasenko]

No code changes.
Only compile-tested.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
CC: Ingo Molnar <mingo@kernel.org>
CC: Borislav Petkov <bp@alien8.de>
CC: "H. Peter Anvin" <hpa@zytor.com>
CC: Andy Lutomirski <luto@amacapital.net>
CC: Kees Cook <keescook@chromium.org>
CC: x86@kernel.org
CC: linux-kernel@vger.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

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

[Ingo Molnar]

* Denys Vlasenko <dvlasenk@redhat.com> wrote:

> No code changes.
> Only compile-tested.

So this series really needs to be tested for real before I can apply any of them.

Thanks,

	Ingo

[tip:x86/fpu] x86/fpu/math-emu: Remove !NO_UNDOC_CODE

[tip-bot for Denys Vlasenko]

Commit-ID:  73477bbb09e7022063d1737c7322ad2e08968c23
Gitweb:     http://git.kernel.org/tip/73477bbb09e7022063d1737c7322ad2e08968c23
Author:     Denys Vlasenko <dvlasenk@redhat.com>
AuthorDate: Thu, 27 Aug 2015 20:15:28 +0200
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 15 Sep 2015 08:01:46 +0200

x86/fpu/math-emu: Remove !NO_UNDOC_CODE

We always want to support all FPU opcodes, including
undocumented ones. That define was fully justified ~20 years ago
but not today. Let's not complicate the code with it.

Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1440699330-1305-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/math-emu/fpu_entry.c | 36 ------------------------------------
 1 file changed, 36 deletions(-)

diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 3d8f2e4..929b1d5 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -40,8 +40,6 @@
 
 #define __BAD__ FPU_illegal	/* Illegal on an 80486, causes SIGILL */
 
-#ifndef NO_UNDOC_CODE		/* Un-documented FPU op-codes supported by default. */
-
 /* WARNING: These codes are not documented by Intel in their 80486 manual
    and may not work on FPU clones or later Intel FPUs. */
 
@@ -68,21 +66,6 @@ static FUNC const st_instr_table[64] = {
 	fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
 };
 
-#else /* Support only documented FPU op-codes */
-
-static FUNC const st_instr_table[64] = {
-	fadd__, fld_i_, __BAD__, __BAD__, fadd_i, ffree_, faddp_, __BAD__,
-	fmul__, fxch_i, __BAD__, __BAD__, fmul_i, __BAD__, fmulp_, __BAD__,
-	fcom_st, fp_nop, __BAD__, __BAD__, __BAD__, fst_i_, __BAD__, __BAD__,
-	fcompst, __BAD__, __BAD__, __BAD__, __BAD__, fstp_i, fcompp, __BAD__,
-	fsub__, FPU_etc, __BAD__, finit_, fsubri, fucom_, fsubrp, fstsw_,
-	fsubr_, fconst, fucompp, __BAD__, fsub_i, fucomp, fsubp_, __BAD__,
-	fdiv__, FPU_triga, __BAD__, __BAD__, fdivri, __BAD__, fdivrp, __BAD__,
-	fdivr_, FPU_trigb, __BAD__, __BAD__, fdiv_i, __BAD__, fdivp_, __BAD__,
-};
-
-#endif /* NO_UNDOC_CODE */
-
 #define _NONE_ 0		/* Take no special action */
 #define _REG0_ 1		/* Need to check for not empty st(0) */
 #define _REGI_ 2		/* Need to check for not empty st(0) and st(rm) */
@@ -94,10 +77,6 @@ static FUNC const st_instr_table[64] = {
 #define _REGIc 0		/* Compare st(0) and st(rm) */
 #define _REGIn 0		/* Uses st(0) and st(rm), but handle checks later */
 
-#ifndef NO_UNDOC_CODE
-
-/* Un-documented FPU op-codes supported by default. (see above) */
-
 static u_char const type_table[64] = {
 	_REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,
 	_REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,
@@ -109,21 +88,6 @@ static u_char const type_table[64] = {
 	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
 };
 
-#else /* Support only documented FPU op-codes */
-
-static u_char const type_table[64] = {
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _REGi_, _REGIp, _null_,
-	_REGI_, _REGIn, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
-	_REGIc, _NONE_, _null_, _null_, _null_, _REG0_, _null_, _null_,
-	_REGIc, _null_, _null_, _null_, _null_, _REG0_, _REGIc, _null_,
-	_REGI_, _NONE_, _null_, _NONE_, _REGIi, _REGIc, _REGIp, _NONE_,
-	_REGI_, _NONE_, _REGIc, _null_, _REGIi, _REGIc, _REGIp, _null_,
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_,
-	_REGI_, _NONE_, _null_, _null_, _REGIi, _null_, _REGIp, _null_
-};
-
-#endif /* NO_UNDOC_CODE */
-
 #ifdef RE_ENTRANT_CHECKING
 u_char emulating = 0;
 #endif /* RE_ENTRANT_CHECKING */