* Re: [PATCH v2 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning
2019-01-02 20:14 ` [PATCH v2 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning Andrew Morton
@ 2019-01-03 15:52 ` Will Deacon
2019-01-03 18:46 ` Andrey Konovalov
1 sibling, 0 replies; 3+ messages in thread
From: Will Deacon @ 2019-01-03 15:52 UTC (permalink / raw)
To: Andrew Morton
Cc: Andrey Konovalov, Andrey Ryabinin, Alexander Potapenko,
Dmitry Vyukov, Catalin Marinas, Christoph Lameter, Mark Rutland,
Nick Desaulniers, Marc Zyngier, Dave Martin, Ard Biesheuvel,
Eric W . Biederman, Ingo Molnar, Paul Lawrence,
Geert Uytterhoeven, Arnd Bergmann, Kirill A . Shutemov,
Greg Kroah-Hartman, Kate Stewart <kst>
On Wed, Jan 02, 2019 at 12:14:36PM -0800, Andrew Morton wrote:
> On Wed, 2 Jan 2019 18:36:06 +0100 Andrey Konovalov <andreyknvl@google.com> 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.
> >
> > ...
> >
> > --- a/arch/arm64/include/asm/kasan.h
> > +++ b/arch/arm64/include/asm/kasan.h
> > @@ -36,6 +36,10 @@
> > #define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \
> > (64 - KASAN_SHADOW_SCALE_SHIFT)))
> >
> > +#ifdef CONFIG_KASAN_SW_TAGS
> > +#define ARCH_SLAB_MINALIGN (1ULL << KASAN_SHADOW_SCALE_SHIFT)
> > +#endif
> > +
> > void kasan_init(void);
> > void kasan_copy_shadow(pgd_t *pgdir);
> > asmlinkage void kasan_early_init(void);
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index 11b45f7ae405..d87f913ab4e8 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -16,6 +16,7 @@
> > #include <linux/overflow.h>
> > #include <linux/types.h>
> > #include <linux/workqueue.h>
> > +#include <linux/kasan.h>
> >
>
> This still seems unadvisable. Like other architectures, arm defines
> ARCH_SLAB_MINALIGN in arch/arm/include/asm/cache.h.
> arch/arm/include/asm64/cache.h doesn't define ARCH_SLAB_MINALIGN
> afaict.
>
> If arch/arm/include/asm64/cache.h later gets a definition of
> ARCH_SLAB_MINALIGN then we again face the risk that different .c files
> will see different values of ARCH_SLAB_MINALIGN depending on which
> headers they include.
>
> So what to say about this? The architecture's ARCH_SLAB_MINALIGN
> should be defined in the architecture's cache.h, end of story. Not in
> slab.h, not in kasan.h.
Agreed. Also, as far as I can tell, this patch isn't actually a fix (unlike
the other two in this series) so it should be harmless to drop it for now.
Will
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning
2019-01-02 20:14 ` [PATCH v2 1/3] kasan, arm64: use ARCH_SLAB_MINALIGN instead of manual aligning Andrew Morton
2019-01-03 15:52 ` Will Deacon
@ 2019-01-03 18:46 ` Andrey Konovalov
1 sibling, 0 replies; 3+ messages in thread
From: Andrey Konovalov @ 2019-01-03 18:46 UTC (permalink / raw)
To: Andrew Morton
Cc: Andrey Ryabinin, Alexander Potapenko, Dmitry Vyukov,
Catalin Marinas, Will Deacon, Christoph Lameter, Mark Rutland,
Nick Desaulniers, Marc Zyngier, Dave Martin, Ard Biesheuvel,
Eric W . Biederman, Ingo Molnar, Paul Lawrence,
Geert Uytterhoeven, Arnd Bergmann, Kirill A . Shutemov,
Greg Kroah-Hartman, Kate Stewart
On Wed, Jan 2, 2019 at 9:14 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Wed, 2 Jan 2019 18:36:06 +0100 Andrey Konovalov <andreyknvl@google.com> 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.
> >
> > ...
> >
> > --- a/arch/arm64/include/asm/kasan.h
> > +++ b/arch/arm64/include/asm/kasan.h
> > @@ -36,6 +36,10 @@
> > #define KASAN_SHADOW_OFFSET (KASAN_SHADOW_END - (1ULL << \
> > (64 - KASAN_SHADOW_SCALE_SHIFT)))
> >
> > +#ifdef CONFIG_KASAN_SW_TAGS
> > +#define ARCH_SLAB_MINALIGN (1ULL << KASAN_SHADOW_SCALE_SHIFT)
> > +#endif
> > +
> > void kasan_init(void);
> > void kasan_copy_shadow(pgd_t *pgdir);
> > asmlinkage void kasan_early_init(void);
> > diff --git a/include/linux/slab.h b/include/linux/slab.h
> > index 11b45f7ae405..d87f913ab4e8 100644
> > --- a/include/linux/slab.h
> > +++ b/include/linux/slab.h
> > @@ -16,6 +16,7 @@
> > #include <linux/overflow.h>
> > #include <linux/types.h>
> > #include <linux/workqueue.h>
> > +#include <linux/kasan.h>
> >
>
> This still seems unadvisable. Like other architectures, arm defines
> ARCH_SLAB_MINALIGN in arch/arm/include/asm/cache.h.
> arch/arm/include/asm64/cache.h doesn't define ARCH_SLAB_MINALIGN
> afaict.
>
> If arch/arm/include/asm64/cache.h later gets a definition of
> ARCH_SLAB_MINALIGN then we again face the risk that different .c files
> will see different values of ARCH_SLAB_MINALIGN depending on which
> headers they include.
>
> So what to say about this? The architecture's ARCH_SLAB_MINALIGN
> should be defined in the architecture's cache.h, end of story. Not in
> slab.h, not in kasan.h.
Done in v3, thanks!
>
>
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^ permalink raw reply [flat|nested] 3+ messages in thread