2017-04-28 18:57:53

by Vineet Gupta

Subject: 4.2+ stable inclusion request: ARCv2: save r30 on kernel entry as gcc uses it for code-gen

Hi,

Can we please backport upstream ecd43afdbe72017aefe48080631eb625e177ef4d ("ARCv2:
save r30 on kernel entry as gcc uses it for code-gen") to 4.2 to 4.9 kernels.

While the issue cites gcc, it is general deficiency of kernel as userspace
programs can modify r30 register in hand/inline assembly and those will not be
preserved without this change.

Thx,
-Vineet

2017-04-30 14:12:57

by Greg KH

Subject: Re: 4.2+ stable inclusion request: ARCv2: save r30 on kernel entry as gcc uses it for code-gen

On Fri, Apr 28, 2017 at 11:57:36AM -0700, Vineet Gupta wrote:
> Hi,
>
> Can we please backport upstream ecd43afdbe72017aefe48080631eb625e177ef4d ("ARCv2:
> save r30 on kernel entry as gcc uses it for code-gen") to 4.2 to 4.9 kernels.
>
> While the issue cites gcc, it is general deficiency of kernel as userspace
> programs can modify r30 register in hand/inline assembly and those will not be
> preserved without this change.

Queued up for 4.9 and 4.4 stable trees, thanks.

greg k-h