On 21/12/2017 15:29, Laurent Vivier wrote: > The first call of set_cc_op() in a new translation sequence > is done with old_op set to CC_OP_DYNAMIC (-1). > > This will do an out of bound access to the array cc_op_live[]. > > We fix that by adding an entry in cc_op_live[] for CC_OP_DYNAMIC, > and in this case we can also discard QREG_CC_OP. > > Reported-by: Thomas Huth <[email protected]> > Signed-off-by: Laurent Vivier <[email protected]> > --- > target/m68k/cpu.h | 2 +- > target/m68k/translate.c | 6 ++++++ > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/target/m68k/cpu.h b/target/m68k/cpu.h > index afae5f68ac..5d03764eab 100644 > --- a/target/m68k/cpu.h > +++ b/target/m68k/cpu.h > @@ -182,7 +182,7 @@ void cpu_m68k_set_fpcr(CPUM68KState *env, uint32_t val); > */ > typedef enum { > /* Translator only -- use env->cc_op. */ > - CC_OP_DYNAMIC = -1, > + CC_OP_DYNAMIC, > > /* Each flag bit computed into cc_[xcnvz]. */ > CC_OP_FLAGS, > diff --git a/target/m68k/translate.c b/target/m68k/translate.c > index b60909222c..61ac1a8e83 100644 > --- a/target/m68k/translate.c > +++ b/target/m68k/translate.c > @@ -207,6 +207,7 @@ typedef void (*disas_proc)(CPUM68KState *env, > DisasContext *s, uint16_t insn); > #endif > > static const uint8_t cc_op_live[CC_OP_NB] = { > + [CC_OP_DYNAMIC] = CCF_C | CCF_V | CCF_Z | CCF_N | CCF_X, > [CC_OP_FLAGS] = CCF_C | CCF_V | CCF_Z | CCF_N | CCF_X, > [CC_OP_ADDB ... CC_OP_ADDL] = CCF_X | CCF_N | CCF_V, > [CC_OP_SUBB ... CC_OP_SUBL] = CCF_X | CCF_N | CCF_V, > @@ -237,6 +238,11 @@ static void set_cc_op(DisasContext *s, CCOp op) > if (dead & CCF_V) { > tcg_gen_discard_i32(QREG_CC_V); > } > + > + /* Discard any computed CC_OP value */ > + if (old_op == CC_OP_DYNAMIC) { > + tcg_gen_discard_i32(QREG_CC_OP); > + } > } > > /* Update the CPU env CC_OP state. */ >
Reviewed-by: Paolo Bonzini <[email protected]>
