From b8e4a910e576961009a87d07f6b7eff67c5c2e34 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Fri, 18 Sep 2015 16:53:29 +0200 Subject: [PATCH] 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 Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner 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 --- arch/x86/math-emu/fpu_entry.c | 27 ++++--- arch/x86/math-emu/fpu_proto.h | 4 + arch/x86/math-emu/reg_compare.c | 128 ++++++++++++++++++++++++++++++++ 3 files changed, 147 insertions(+), 12 deletions(-) diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c index 65afd46643f0..4ecf68342d7b 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 @@ 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 diff --git a/arch/x86/math-emu/fpu_proto.h b/arch/x86/math-emu/fpu_proto.h index 9779df436b7d..1f8d130663ad 100644 --- a/arch/x86/math-emu/fpu_proto.h +++ b/arch/x86/math-emu/fpu_proto.h @@ -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 */ diff --git a/arch/x86/math-emu/reg_compare.c b/arch/x86/math-emu/reg_compare.c index ecce55fc2e2e..b77360fdbf4a 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(); +} -- 2.20.1