Re: [PATCH 1/2] crypto: ccp - Reduce stack frame size with KASAN

[Gary R Hook]

On 03/28/2017 10:10 AM, Arnd Bergmann wrote:
> On Tue, Mar 28, 2017 at 4:15 PM, Gary R Hook <ghook@xxxxxxx> wrote:
> > On 03/28/2017 04:58 AM, Arnd Bergmann wrote:> The newly added AES GCM
> > implementation uses one of the largest stack frames
>
> > > diff --git a/drivers/crypto/ccp/ccp-dev.h b/drivers/crypto/ccp/ccp-dev.h
> > > index 3a45c2af2fbd..c5ea0796a891 100644
> > > --- a/drivers/crypto/ccp/ccp-dev.h
> > > +++ b/drivers/crypto/ccp/ccp-dev.h
> > > @@ -432,24 +432,24 @@ struct ccp_dma_info {
> > >          unsigned int offset;
> > >          unsigned int length;
> > >          enum dma_data_direction dir;
> > > -};
> > > +} __packed __aligned(4);
> >
> >
> > My gcc 4.8 doesn't understand __aligned(). Shouldn't we use
> > #pragma(4) here?
>
> That is odd, the __aligned() macro gets defined for all compiler versions
> in linux/compiler.h, and the aligned attribute should work for all supported
> compilers (3.2 and higher), while #pragma pack() requires gcc-4.0 or
> higher.
>
> We generally prefer attribute syntax in the kernel over pragmas, even
> when they are functionally the same.

Yes, it's extremely odd, and I understand this preference. Please ignore my
submitted alternate and let me track this down....


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