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

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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: Denys 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Denys Vlasenko 2015-09-18 16:53:29 +02:00 committed by Ingo Molnar
parent 4aef363e48
commit b8e4a910e5
3 changed files with 147 additions and 12 deletions
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27
arch/x86/math-emu/fpu_entry.c
View file

@ -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

4
arch/x86/math-emu/fpu_proto.h
View file

@ -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 */

128
arch/x86/math-emu/reg_compare.c
View file

@ -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();
}