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Commit b8e4a910 authored by Denys Vlasenko's avatar Denys Vlasenko Committed by Ingo Molnar
Browse files

x86/fpu/math-emu: Add support for F[U]COMI[P] insns 



Run-tested by booting with "no387 nofxsr" and running test
program:

  [RUN]   Testing f[u]comi[p] instructions

  [OK]    f[u]comi[p]

Signed-off-by: default avatarDenys Vlasenko <dvlasenk@redhat.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
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>
Cc: linux-kernel@vger.kernel.org
Link: http://lkml.kernel.org/r/1442588010-20055-2-git-send-email-dvlasenk@redhat.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 4aef363e

arch/x86/math-emu/fpu_entry.c

+15 −12
Original line number Diff line number Diff line
@@ -40,6 +40,8 @@ 


#define __BAD__ FPU_illegal	/* Illegal on an 80486, causes SIGILL */



/* 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 them provided by Linus Torvalds. */
@@ -57,10 +59,10 @@ static FUNC const st_instr_table[64] = { 
/* 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,	__BAD__,

/* e8..f */	fsub_i,		fucomp,		fsubp_,		__BAD__,

/* f0..7 */	fdiv__,		FPU_triga,	__BAD__,	__BAD__,

/* f0..7 */	fdivri,		__BAD__,	fdivrp,		__BAD__,

/* 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__,

};
@@ -77,14 +79,15 @@ 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_, _null_, _null_, _REGIi, _REGi_, _REGIp, _REGi_,

/* c8..f */	_REGI_, _REGIn, _null_, _null_, _REGIi, _REGI_, _REGIp, _REGI_,

/* d0..7 */	_REGIc, _NONE_, _null_, _null_, _REGIc, _REG0_, _REGIc, _REG0_,

/* d8..f */	_REGIc, _REG0_, _null_, _null_, _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

arch/x86/math-emu/fpu_proto.h

+4 −0
Original line number Diff line number Diff line
@@ -108,6 +108,10 @@ 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 */

arch/x86/math-emu/reg_compare.c

+128 −0
Original line number Diff line number Diff line
@@ -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();

}