diff --git a/target/i386/cpu.h b/target/i386/cpu.h index ecdd4518c6..7f0786e8b9 100644 --- a/target/i386/cpu.h +++ b/target/i386/cpu.h @@ -1285,6 +1285,7 @@ typedef enum { CC_OP_NB, } CCOp; +QEMU_BUILD_BUG_ON(CC_OP_NB >= 128); typedef struct SegmentCache { uint32_t selector; diff --git a/target/i386/tcg/decode-new.c.inc b/target/i386/tcg/decode-new.c.inc index f30889dbc0..717d730772 100644 --- a/target/i386/tcg/decode-new.c.inc +++ b/target/i386/tcg/decode-new.c.inc @@ -1662,6 +1662,7 @@ static void disas_insn_new(DisasContext *s, CPUState *cpu, int b) bool first = true; X86DecodedInsn decode; X86DecodeFunc decode_func = decode_root; + uint8_t cc_live; s->has_modrm = false; @@ -1815,6 +1816,7 @@ static void disas_insn_new(DisasContext *s, CPUState *cpu, int b) } memset(&decode, 0, sizeof(decode)); + decode.cc_op = -1; decode.b = b; if (!decode_insn(s, env, decode_func, &decode)) { goto illegal_op; @@ -1953,6 +1955,38 @@ static void disas_insn_new(DisasContext *s, CPUState *cpu, int b) decode.e.gen(s, env, &decode); gen_writeback(s, &decode, 0, s->T0); } + + /* + * Write back flags after last memory access. Some newer ALU instructions, as + * well as SSE instructions, write flags in the gen_* function, but that can + * cause incorrect tracking of CC_OP for instructions that write to both memory + * and flags. + */ + if (decode.cc_op != -1) { + if (decode.cc_dst) { + tcg_gen_mov_tl(cpu_cc_dst, decode.cc_dst); + } + if (decode.cc_src) { + tcg_gen_mov_tl(cpu_cc_src, decode.cc_src); + } + if (decode.cc_src2) { + tcg_gen_mov_tl(cpu_cc_src2, decode.cc_src2); + } + if (decode.cc_op == CC_OP_DYNAMIC) { + tcg_gen_mov_i32(cpu_cc_op, decode.cc_op_dynamic); + } + set_cc_op(s, decode.cc_op); + cc_live = cc_op_live[decode.cc_op]; + } else { + cc_live = 0; + } + if (decode.cc_op != CC_OP_DYNAMIC) { + assert(!decode.cc_op_dynamic); + assert(!!decode.cc_dst == !!(cc_live & USES_CC_DST)); + assert(!!decode.cc_src == !!(cc_live & USES_CC_SRC)); + assert(!!decode.cc_src2 == !!(cc_live & USES_CC_SRC2)); + } + return; gp_fault: gen_exception_gpf(s); diff --git a/target/i386/tcg/decode-new.h b/target/i386/tcg/decode-new.h index 70b6717227..25220fc436 100644 --- a/target/i386/tcg/decode-new.h +++ b/target/i386/tcg/decode-new.h @@ -283,6 +283,10 @@ struct X86DecodedInsn { target_ulong immediate; AddressParts mem; + TCGv cc_dst, cc_src, cc_src2; + TCGv_i32 cc_op_dynamic; + int8_t cc_op; + uint8_t b; }; diff --git a/target/i386/tcg/emit.c.inc b/target/i386/tcg/emit.c.inc index 4c2006fdd0..fd120e7b9b 100644 --- a/target/i386/tcg/emit.c.inc +++ b/target/i386/tcg/emit.c.inc @@ -339,6 +339,19 @@ static inline int vector_len(DisasContext *s, X86DecodedInsn *decode) return s->vex_l ? 32 : 16; } +static void prepare_update1_cc(X86DecodedInsn *decode, DisasContext *s, CCOp op) +{ + decode->cc_dst = s->T0; + decode->cc_op = op; +} + +static void prepare_update2_cc(X86DecodedInsn *decode, DisasContext *s, CCOp op) +{ + decode->cc_src = s->T1; + decode->cc_dst = s->T0; + decode->cc_op = op; +} + static void gen_store_sse(DisasContext *s, X86DecodedInsn *decode, int src_ofs) { MemOp ot = decode->op[0].ot; @@ -1027,6 +1040,7 @@ static void gen_##uname(DisasContext *s, CPUX86State *env, X86DecodedInsn *decod VSIB_AVX(VPGATHERD, vpgatherd) VSIB_AVX(VPGATHERQ, vpgatherq) +/* ADCX/ADOX do not have memory operands and can use set_cc_op. */ static void gen_ADCOX(DisasContext *s, CPUX86State *env, MemOp ot, int cc_op) { int opposite_cc_op; @@ -1089,8 +1103,7 @@ static void gen_ANDN(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) MemOp ot = decode->op[0].ot; tcg_gen_andc_tl(s->T0, s->T1, s->T0); - gen_op_update1_cc(s); - set_cc_op(s, CC_OP_LOGICB + ot); + prepare_update1_cc(decode, s, CC_OP_LOGICB + ot); } static void gen_BEXTR(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) @@ -1118,10 +1131,10 @@ static void gen_BEXTR(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) tcg_gen_movcond_tl(TCG_COND_LEU, s->T1, s->A0, bound, s->T1, zero); tcg_gen_andc_tl(s->T0, s->T0, s->T1); - gen_op_update1_cc(s); - set_cc_op(s, CC_OP_LOGICB + ot); + prepare_update1_cc(decode, s, CC_OP_LOGICB + ot); } +/* BLSI do not have memory operands and can use set_cc_op. */ static void gen_BLSI(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) { MemOp ot = decode->op[0].ot; @@ -1133,6 +1146,7 @@ static void gen_BLSI(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) set_cc_op(s, CC_OP_BMILGB + ot); } +/* BLSMSK do not have memory operands and can use set_cc_op. */ static void gen_BLSMSK(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) { MemOp ot = decode->op[0].ot; @@ -1144,6 +1158,7 @@ static void gen_BLSMSK(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode set_cc_op(s, CC_OP_BMILGB + ot); } +/* BLSR do not have memory operands and can use set_cc_op. */ static void gen_BLSR(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) { MemOp ot = decode->op[0].ot; @@ -1164,18 +1179,15 @@ static void gen_BZHI(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) tcg_gen_ext8u_tl(s->T1, s->T1); + tcg_gen_shl_tl(s->A0, mone, s->T1); + tcg_gen_movcond_tl(TCG_COND_LEU, s->A0, s->T1, bound, s->A0, zero); + tcg_gen_andc_tl(s->T0, s->T0, s->A0); /* * Note that since we're using BMILG (in order to get O * cleared) we need to store the inverse into C. */ - tcg_gen_setcond_tl(TCG_COND_LEU, cpu_cc_src, s->T1, bound); - - tcg_gen_shl_tl(s->A0, mone, s->T1); - tcg_gen_movcond_tl(TCG_COND_LEU, s->A0, s->T1, bound, s->A0, zero); - tcg_gen_andc_tl(s->T0, s->T0, s->A0); - - gen_op_update1_cc(s); - set_cc_op(s, CC_OP_BMILGB + ot); + tcg_gen_setcond_tl(TCG_COND_LEU, s->T1, s->T1, bound); + prepare_update2_cc(decode, s, CC_OP_BMILGB + ot); } static void gen_CRC32(DisasContext *s, CPUX86State *env, X86DecodedInsn *decode) diff --git a/tests/tcg/i386/Makefile.target b/tests/tcg/i386/Makefile.target index 3dec7c6c42..9906f9e116 100644 --- a/tests/tcg/i386/Makefile.target +++ b/tests/tcg/i386/Makefile.target @@ -13,7 +13,7 @@ config-cc.mak: Makefile I386_SRCS=$(notdir $(wildcard $(I386_SRC)/*.c)) ALL_X86_TESTS=$(I386_SRCS:.c=) -SKIP_I386_TESTS=test-i386-ssse3 test-avx test-3dnow test-mmx +SKIP_I386_TESTS=test-i386-ssse3 test-avx test-3dnow test-mmx test-flags X86_64_TESTS:=$(filter test-i386-adcox test-i386-bmi2 $(SKIP_I386_TESTS), $(ALL_X86_TESTS)) test-i386-sse-exceptions: CFLAGS += -msse4.1 -mfpmath=sse diff --git a/tests/tcg/i386/test-flags.c b/tests/tcg/i386/test-flags.c new file mode 100644 index 0000000000..c379e29627 --- /dev/null +++ b/tests/tcg/i386/test-flags.c @@ -0,0 +1,37 @@ +#define _GNU_SOURCE +#include +#include +#include +#include + +volatile unsigned long flags; +volatile unsigned long flags_after; +int *addr; + +void sigsegv(int sig, siginfo_t *info, ucontext_t *uc) +{ + flags = uc->uc_mcontext.gregs[REG_EFL]; + mprotect(addr, 4096, PROT_READ|PROT_WRITE); +} + +int main() +{ + struct sigaction sa = { .sa_handler = (void *)sigsegv, .sa_flags = SA_SIGINFO }; + sigaction(SIGSEGV, &sa, NULL); + + /* fault in the page then protect it */ + addr = mmap (NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANON, -1, 0); + *addr = 0x1234; + mprotect(addr, 4096, PROT_READ); + + asm("# set flags to all ones \n" + "mov $-1, %%eax \n" + "movq addr, %%rdi \n" + "sahf \n" + "sub %%eax, (%%rdi) \n" + "pushf \n" + "pop flags_after(%%rip) \n" : : : "eax", "edi", "memory"); + + /* OF can have any value before the SUB instruction. */ + assert((flags & 0xff) == 0xd7 && (flags_after & 0x8ff) == 0x17); +}