Re: [PATCH v3 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning

From: Andrey Konovalov <andreyknvl@google.com>
To: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Kate Stewart <kstewart@linuxfoundation.org>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will.deacon@arm.com>,
	Paul Lawrence <paullawrence@google.com>,
	Linux Memory Management List <linux-mm@kvack.org>,
	Alexander Potapenko <glider@google.com>,
	Chintan Pandya <cpandya@codeaurora.org>,
	Christoph Lameter <cl@linux.com>, Ingo Molnar <mingo@kernel.org>,
	Jacob Bramley <Jacob.Bramley@arm.com>,
	Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
	Mark Brand <markbrand@google.com>,
	kasan-dev <kasan-dev@googlegroups.com>,
	linux-sparse@vger.kernel.org,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Linux ARM <linux-arm-kernel@lists.infradead.org>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Dave Martin <dave.martin@arm.com>,
	Evgeniy Stepanov <eugenis@google.com>,
	Vishwath Mohan <vishwath@google.com>,
	Arnd Bergmann <arnd@arndb.de>,
	Linux Kbuild mailing list <linux-kbuild@vger.kernel.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Dmitry Vyukov <dvyukov@google.com>,
	Kostya Serebryany <kcc@google.com>, Jann Horn <jannh@google.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Nick Desaulniers <ndesaulniers@google.com>,
	LKML <linux-kernel@vger.kernel.org>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	Lee Smith <Lee.Smith@arm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v3 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning
Date: Fri, 11 Jan 2019 14:48:52 +0100	[thread overview]
Message-ID: <CAAeHK+wYo95G3pSoxDWwUs2wf-tBoupwf+0XjO68WXjLzsNWaw@mail.gmail.com> (raw)
In-Reply-To: <fc93e5a4-fa54-98a1-ea5f-4708568d7857@arm.com>

On Wed, Jan 9, 2019 at 11:10 AM Vincenzo Frascino
<vincenzo.frascino@arm.com> wrote:
>
> On 03/01/2019 18:45, Andrey Konovalov wrote:
> > Instead of changing cache->align to be aligned to KASAN_SHADOW_SCALE_SIZE
> > in kasan_cache_create() we can reuse the ARCH_SLAB_MINALIGN macro.
> >
> > Suggested-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> > Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> > ---
> >  arch/arm64/include/asm/cache.h | 6 ++++++
> >  mm/kasan/common.c              | 2 --
> >  2 files changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/cache.h b/arch/arm64/include/asm/cache.h
> > index 13dd42c3ad4e..eb43e09c1980 100644
> > --- a/arch/arm64/include/asm/cache.h
> > +++ b/arch/arm64/include/asm/cache.h
> > @@ -58,6 +58,12 @@
> >   */
> >  #define ARCH_DMA_MINALIGN    (128)
> >
> > +#ifdef CONFIG_KASAN_SW_TAGS
> > +#define ARCH_SLAB_MINALIGN   (1ULL << KASAN_SHADOW_SCALE_SHIFT)
> > +#else
> > +#define ARCH_SLAB_MINALIGN   __alignof__(unsigned long long)
> > +#endif
> > +
>
> Could you please remove the "#else" case here, because it is redundant (it is
> defined in linux/slab.h as ifndef) and could be misleading in future?

Sure, sent a patch. Thanks!

>
> >  #ifndef __ASSEMBLY__
> >
> >  #include <linux/bitops.h>
> > diff --git a/mm/kasan/common.c b/mm/kasan/common.c
> > index 03d5d1374ca7..44390392d4c9 100644
> > --- a/mm/kasan/common.c
> > +++ b/mm/kasan/common.c
> > @@ -298,8 +298,6 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
> >               return;
> >       }
> >
> > -     cache->align = round_up(cache->align, KASAN_SHADOW_SCALE_SIZE);
> > -
> >       *flags |= SLAB_KASAN;
> >  }
> >
> >
>
> --
> Regards,
> Vincenzo
>
> --
> You received this message because you are subscribed to the Google Groups "kasan-dev" group.
> To unsubscribe from this group and stop receiving emails from it, send an email to kasan-dev+unsubscribe@googlegroups.com.
> To post to this group, send email to kasan-dev@googlegroups.com.
> To view this discussion on the web visit https://groups.google.com/d/msgid/kasan-dev/fc93e5a4-fa54-98a1-ea5f-4708568d7857%40arm.com.
> For more options, visit https://groups.google.com/d/optout.

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel