Re: [Qemu-devel] [PATCH][SPARC] Fix handling of conditional branches in delay slot of a conditional branch

[Blue Swirl]

On Sat, Aug 6, 2011 at 9:33 PM, Artyom Tarasenko <address@hidden> wrote:
> Since it's a pure bug fix, do you think can it be applied to 0.15 as well?

Maybe. Anthony/Jordan, please consider applying these to stable:
548f66d Fix handling of conditional branches in delay slot of a
conditional branch
6749432 Sparc: fix non-faulting unassigned memory accesses
ccb57e0 SPARC64: fix fnor* and fnand*

> On Sat, Aug 6, 2011 at 10:14 PM, Blue Swirl <address@hidden> wrote:
>> Thanks, applied.
>>
>> On Sat, Aug 6, 2011 at 3:01 PM, Artyom Tarasenko <address@hidden> wrote:
>>> Check whether dc->npc is dynamic before using its value for branch.
>>>
>>> Signed-off-by: Artyom Tarasenko <address@hidden>
>>> ---
>>> Particaluary the patch fixes handling of the constructions like
>>>
>>> 0x13e26c0:  brz,pn   %o0, 0x13e26e4
>>> 0x13e26c4:  brlez,pn   %o1, 0x13e26e4
>>>
>>> present in NetBSD-5.1
>>>
>>>  target-sparc/translate.c |   30 +++++++++++++++++++++---------
>>>  1 files changed, 21 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/target-sparc/translate.c b/target-sparc/translate.c
>>> index 958fbc5..dee67b3 100644
>>> --- a/target-sparc/translate.c
>>> +++ b/target-sparc/translate.c
>>> @@ -1286,7 +1286,6 @@ static inline void gen_cond_reg(TCGv r_dst, int cond, 
>>> TCGv r_src)
>>>  }
>>>  #endif
>>>
>>> -/* XXX: potentially incorrect if dynamic npc */
>>>  static void do_branch(DisasContext *dc, int32_t offset, uint32_t insn, int 
>>> cc,
>>>                       TCGv r_cond)
>>>  {
>>> @@ -1321,13 +1320,17 @@ static void do_branch(DisasContext *dc, int32_t 
>>> offset, uint32_t insn, int cc,
>>>         } else {
>>>             dc->pc = dc->npc;
>>>             dc->jump_pc[0] = target;
>>> -            dc->jump_pc[1] = dc->npc + 4;
>>> -            dc->npc = JUMP_PC;
>>> +            if (unlikely(dc->npc == DYNAMIC_PC)) {
>>> +                dc->jump_pc[1] = DYNAMIC_PC;
>>> +                tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
>>> +            } else {
>>> +                dc->jump_pc[1] = dc->npc + 4;
>>> +                dc->npc = JUMP_PC;
>>> +            }
>>>         }
>>>     }
>>>  }
>>>
>>> -/* XXX: potentially incorrect if dynamic npc */
>>>  static void do_fbranch(DisasContext *dc, int32_t offset, uint32_t insn, 
>>> int cc,
>>>                       TCGv r_cond)
>>>  {
>>> @@ -1362,14 +1365,18 @@ static void do_fbranch(DisasContext *dc, int32_t 
>>> offset, uint32_t insn, int cc,
>>>         } else {
>>>             dc->pc = dc->npc;
>>>             dc->jump_pc[0] = target;
>>> -            dc->jump_pc[1] = dc->npc + 4;
>>> -            dc->npc = JUMP_PC;
>>> +            if (unlikely(dc->npc == DYNAMIC_PC)) {
>>> +                dc->jump_pc[1] = DYNAMIC_PC;
>>> +                tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
>>> +            } else {
>>> +                dc->jump_pc[1] = dc->npc + 4;
>>> +                dc->npc = JUMP_PC;
>>> +            }
>>>         }
>>>     }
>>>  }
>>>
>>>  #ifdef TARGET_SPARC64
>>> -/* XXX: potentially incorrect if dynamic npc */
>>>  static void do_branch_reg(DisasContext *dc, int32_t offset, uint32_t insn,
>>>                           TCGv r_cond, TCGv r_reg)
>>>  {
>>> @@ -1384,8 +1391,13 @@ static void do_branch_reg(DisasContext *dc, int32_t 
>>> offset, uint32_t insn,
>>>     } else {
>>>         dc->pc = dc->npc;
>>>         dc->jump_pc[0] = target;
>>> -        dc->jump_pc[1] = dc->npc + 4;
>>> -        dc->npc = JUMP_PC;
>>> +        if (unlikely(dc->npc == DYNAMIC_PC)) {
>>> +            dc->jump_pc[1] = DYNAMIC_PC;
>>> +            tcg_gen_addi_tl(cpu_pc, cpu_npc, 4);
>>> +        } else {
>>> +            dc->jump_pc[1] = dc->npc + 4;
>>> +            dc->npc = JUMP_PC;
>>> +        }
>>>     }
>>>  }
>>>
>>> --
>>> 1.7.3.4
>>>
>>>
>>
>
>
>
> --
> Regards,
> Artyom Tarasenko
>
> solaris/sparc under qemu blog: http://tyom.blogspot.com/
>