Qing Zhao via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
>>> +Return-Oriented Programming (ROP) or preventing information leak
>>
>> leakage
>>
>> (FWIW, I'm not sure “mitigating ROP” is really correct usage, but I don't
>> have any better suggestions.)
>
> Do you mean whether “mitigating ROP’ is one of the major purpose of this new
> feature?
No, I meant just the English usage. E.g., I think you mitigate the
damage caused by earthquakes rather than mitigate earthquakes themselves.
But I could be wrong. It's not a word I use very often ;-)
>>> +In order to satisfy users with different security needs and control the
>>> +run-time overhead at the same time, GCC provides a flexible way to choose
>>> +the subset of the call-used registers to be zeroed.
>>
>> Maybe s/GCC/the @var{choice} parameter/.
> Okay.
>>
>>> +
>>> +The three basic values of @var{choice} are:
>>
>> After which, I think this should be part of the previous paragraph.
>
> Don’t understand here, could you explain a little bit more?
I meant:
In order to satisfy users with different security needs and control the
run-time overhead at the same time, @var{choice} provides a flexible way
to choose the subset of the call-used registers to be zeroed. The three
basic values of @var{choice} are:
>>> + /* If gpr_only is true, only zero call-used registers that are
>>> + general-purpose registers; if used_only is true, only zero
>>> + call-used registers that are used in the current function;
>>> + if arg_only is true, only zero call-used registers that pass
>>> + parameters defined by the flatform's calling conversion. */
>>> +
>>> + gpr_only = crtl->zero_call_used_regs & ONLY_GPR;
>>> + used_only = crtl->zero_call_used_regs & ONLY_USED;
>>> + arg_only = crtl->zero_call_used_regs & ONLY_ARG;
>>
>> Guess it would be nice to be consistent about which side the “only”
>> goes on. FWIW, I don't mind which way: GPR_ONLY etc. would be
>> OK with me if you prefer that.
> The current names are okay for me.
OK. But I think one of them should change to match the other.
E.g. either the local variable should be “only_gpr” or the
flag should be “GPR_ONLY”.
Thanks,
Richard
