target/i386: Generate #UD when applying LOCK to a register destination

Fixes a TCG crash due to attempting the atomic operation without
having set up the address first.  This does not attempt to fix
all of the other missing checks for LOCK.

Fixes: a7cee522f3
Fixes: https://bugs.launchpad.net/qemu/+bug/1803160
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20181113193510.24862-1-richard.henderson@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Richard Henderson 2018-11-13 20:35:10 +01:00 committed by Paolo Bonzini
parent f1e35acf78
commit e84fcd7f66

View File

@ -1268,10 +1268,30 @@ static void gen_helper_fp_arith_STN_ST0(int op, int opreg)
}
}
static void gen_exception(DisasContext *s, int trapno, target_ulong cur_eip)
{
gen_update_cc_op(s);
gen_jmp_im(s, cur_eip);
gen_helper_raise_exception(cpu_env, tcg_const_i32(trapno));
s->base.is_jmp = DISAS_NORETURN;
}
/* Generate #UD for the current instruction. The assumption here is that
the instruction is known, but it isn't allowed in the current cpu mode. */
static void gen_illegal_opcode(DisasContext *s)
{
gen_exception(s, EXCP06_ILLOP, s->pc_start - s->cs_base);
}
/* if d == OR_TMP0, it means memory operand (address in A0) */
static void gen_op(DisasContext *s1, int op, TCGMemOp ot, int d)
{
if (d != OR_TMP0) {
if (s1->prefix & PREFIX_LOCK) {
/* Lock prefix when destination is not memory. */
gen_illegal_opcode(s1);
return;
}
gen_op_mov_v_reg(s1, ot, s1->T0, d);
} else if (!(s1->prefix & PREFIX_LOCK)) {
gen_op_ld_v(s1, ot, s1->T0, s1->A0);
@ -2469,21 +2489,6 @@ static void gen_leave(DisasContext *s)
gen_op_mov_reg_v(s, a_ot, R_ESP, s->T1);
}
static void gen_exception(DisasContext *s, int trapno, target_ulong cur_eip)
{
gen_update_cc_op(s);
gen_jmp_im(s, cur_eip);
gen_helper_raise_exception(cpu_env, tcg_const_i32(trapno));
s->base.is_jmp = DISAS_NORETURN;
}
/* Generate #UD for the current instruction. The assumption here is that
the instruction is known, but it isn't allowed in the current cpu mode. */
static void gen_illegal_opcode(DisasContext *s)
{
gen_exception(s, EXCP06_ILLOP, s->pc_start - s->cs_base);
}
/* Similarly, except that the assumption here is that we don't decode
the instruction at all -- either a missing opcode, an unimplemented
feature, or just a bogus instruction stream. */