Re: [PATCH] powerpc/kprobes: Pass ppc_inst as a pointer to emulate_step() on ppc32

["Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>]

Christophe Leroy wrote:
> 
> 
> Le 20/05/2021 à 12:54, Naveen N. Rao a écrit :
>> Christophe Leroy wrote:
>>>
>>>
>>> Le 20/05/2021 à 09:29, Naveen N. Rao a écrit :
>>>> diff --git a/arch/powerpc/kernel/optprobes.c 
>>>> b/arch/powerpc/kernel/optprobes.c
>>>> index cdf87086fa33a0..2bc53fa48a1b33 100644
>>>> --- a/arch/powerpc/kernel/optprobes.c
>>>> +++ b/arch/powerpc/kernel/optprobes.c
>>>> @@ -281,8 +281,12 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op, struct kprobe 
>>>> *p)
>>>>       /*
>>>>        * 3. load instruction to be emulated into relevant register, and
>>>>        */
>>>> -    temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
>>>> -    patch_imm_load_insns(ppc_inst_as_ulong(temp), 4, buff + TMPL_INSN_IDX);
>>>> +    if (IS_ENABLED(CONFIG_PPC64)) {
>>>> +        temp = ppc_inst_read((struct ppc_inst *)p->ainsn.insn);
>>>> +        patch_imm_load_insns(ppc_inst_as_ulong(temp), 4, buff + TMPL_INSN_IDX);
>>>> +    } else {
>>>> +        patch_imm_load_insns((unsigned long)p->ainsn.insn, 4, buff + TMPL_INSN_IDX);
>>>> +    }
>>>
>>> It means commit https://github.com/linuxppc/linux/commit/693557ebf407a85ea400a0b501bb97687d8f4856 
>>> was not necessary and may be reverted.
>> 
>> Indeed, I will send a revert for it.
>> 
> 
> I'm not completely sure it is worth reverting, on an other hand it is pointless anyway to have 
> something to convert to a u64 something that cannot be more than 32 bits on a PPC32, so now that we 
> have ppc_inst_as_ulong() it is as good I think.

Sure. If necessary, the revert can go in separately as part of your 
other cleanup series.

- Naveen