On 18 September 2012 20:52, malc <av1...@comtv.ru> wrote: > > Looks like PPC/PPC64 is also hit by shift issues, on top of that xtensa > exposed another bug in power's tcg - gototb's target was expected to be > always filled via tb_set_jmp_target (even though it's clearly not what > tcg/README prescribes, sorry about that). > > Thanks to Max Filippov for pointing to xtensa test suite that helped to > narrow the search to gototb. > > Testing of the following with other targets on ppc flavours is welcome.. > > P.S. Xtensa does mighty weird things with shifts i must say... > > diff --git a/tcg/ppc/tcg-target.c b/tcg/ppc/tcg-target.c > index 26c4b33..08f62fa 100644 > --- a/tcg/ppc/tcg-target.c > +++ b/tcg/ppc/tcg-target.c > @@ -409,6 +409,7 @@ static int tcg_target_const_match(tcg_target_long val, > > #define TW XO31(4) > #define TRAP (TW | TO (31)) > +#define NOP 0x60000000 > > #define RT(r) ((r)<<21) > #define RS(r) ((r)<<21) > @@ -1306,10 +1307,10 @@ void ppc_tb_set_jmp_target (unsigned long jmp_addr, > unsigned long addr) > *ptr = 0x48000000 | (disp & 0x03fffffc); /* b disp */ > patch_size = 4; > } else { > - ptr[0] = 0x60000000; /* nop */ > - ptr[1] = 0x60000000; > - ptr[2] = 0x60000000; > - ptr[3] = 0x60000000; > + ptr[0] = NOP; > + ptr[1] = NOP; > + ptr[2] = NOP; > + ptr[3] = NOP; > patch_size = 16; > } > } > @@ -1330,7 +1331,10 @@ static void tcg_out_op(TCGContext *s, TCGOpcode opc, > const TCGArg *args, > /* direct jump method */ > > s->tb_jmp_offset[args[0]] = s->code_ptr - s->code_buf; > - s->code_ptr += 16; > + tcg_out32 (s, NOP); > + tcg_out32 (s, NOP); > + tcg_out32 (s, NOP); > + tcg_out32 (s, NOP);
Not too familiar with the PPC backend, but doesn't this mean that in the retranslation case we will overwrite a correct jump destination with these NOP words and then rewrite it again with the correct destination? That can cause problems with cache incoherency; compare the fix applied in commit c69806ab8276 for ARM. thanks -- PMM