PING[STAGE 1][PATCH][x86][1/3]: Add -mzero-caller-saved-regs=[skip|used-gpr|all-gpr|used|all]

[Qing Zhao]

Hi, Kees,


> On May 4, 2020, at 1:21 PM, Kees Cook <keescook@chromium.org> wrote:
> 
> On Mon, May 04, 2020 at 11:51:49AM -0500, Qing Zhao wrote:
>> Hi,
>> 
>> This is a PING for this patch for gcc11 stage 1. 
>> 
>> https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544058.html <https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544058.html>
>> 
>> Please take a look on it.
> 
> Hi!
> 
> I think the best course of action here would be the rebase these patches
> and resend them against the current GCC code base as inline patches
> (not attachments as you sent earlier),

Actually, the patches sent on April 17, 2020 were the rebased patches against the current GCC code. 

In addition to this patch, there are two more patches that fix the new regressions exposed by this patch on the current GCC code base. (Those two patches have been
sent for review with this one at the same time as):
https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544056.html <https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544056.html>
https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544057.html <https://gcc.gnu.org/pipermail/gcc-patches/2020-April/544057.html>


thanks.

Qing
> following the details here:
> https://gcc.gnu.org/contribute.html
> 
>>> https://outflux.net/slides/2019/lpc/gcc-and-clang.pdf <https://outflux.net/slides/2019/lpc/gcc-and-clang.pdf>
>>> Tested on  x86-64 with bootstrapping GCC trunk, regression tests exposed several new regressions, these new regressions are
>>> fixed by 2 following patches I will send in next two emails.
> 
> I look forward to seeing these! I'd really like to have the feature
> available as another defense in depth for the Linux kernel.
> 
> -Kees
> 
> -- 
> Kees Cook