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: 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>
diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c
index 65afd46..4ecf683 100644
--- a/arch/x86/math-emu/fpu_entry.c
+++ b/arch/x86/math-emu/fpu_entry.c
@@ -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 @@
/* 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 @@
#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
diff --git a/arch/x86/math-emu/fpu_proto.h b/arch/x86/math-emu/fpu_proto.h
index 9779df4..1f8d130 100644
--- a/arch/x86/math-emu/fpu_proto.h
+++ b/arch/x86/math-emu/fpu_proto.h
@@ -108,6 +108,10 @@
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 @@
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 @@
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 @@
} 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();
+}