From: Peter Collingbourne <pcc@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Alexander Potapenko <glider@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Evgenii Stepanov <eugenis@google.com>,
Linux Memory Management List <linux-mm@kvack.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 1/3] kasan: use separate (un)poison implementation for integrated init
Date: Wed, 12 May 2021 13:08:23 -0700 [thread overview]
Message-ID: <CAMn1gO7LJ0-rgwxg+jVy8EsZeTwG96sc9-kNNP8+rsJS3ibGOg@mail.gmail.com> (raw)
In-Reply-To: <20210512121035.GD14638@arm.com>
On Wed, May 12, 2021 at 5:10 AM Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> On Tue, May 11, 2021 at 04:54:24PM -0700, Peter Collingbourne wrote:
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index b1678a61e6a7..e35fa301d3db 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> [...]
> > @@ -113,8 +113,30 @@ static inline bool kasan_has_integrated_init(void)
> > return false;
> > }
> >
> > +static __always_inline void kasan_alloc_pages(struct page *page,
> > + unsigned int order, gfp_t flags)
> > +{
> > + /* Only available for integrated init. */
> > + BUG();
> > +}
> > +
> > +static __always_inline void kasan_free_pages(struct page *page,
> > + unsigned int order)
> > +{
> > + /* Only available for integrated init. */
> > + BUG();
> > +}
>
> Would these two work as BUILD_BUG()?
It looks like it. This creates a dependency on the compiler being
powerful enough to optimize away "if (0) undefined_function();" after
inlining, which I'm not really a big fan of, but it looks like we're
already doing similar things elsewhere in the kernel, so we might as
well do it here as well.
Peter
WARNING: multiple messages have this Message-ID (diff)
From: Peter Collingbourne <pcc@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>,
Alexander Potapenko <glider@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Evgenii Stepanov <eugenis@google.com>,
Linux Memory Management List <linux-mm@kvack.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v2 1/3] kasan: use separate (un)poison implementation for integrated init
Date: Wed, 12 May 2021 13:08:23 -0700 [thread overview]
Message-ID: <CAMn1gO7LJ0-rgwxg+jVy8EsZeTwG96sc9-kNNP8+rsJS3ibGOg@mail.gmail.com> (raw)
In-Reply-To: <20210512121035.GD14638@arm.com>
On Wed, May 12, 2021 at 5:10 AM Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> On Tue, May 11, 2021 at 04:54:24PM -0700, Peter Collingbourne wrote:
> > diff --git a/include/linux/kasan.h b/include/linux/kasan.h
> > index b1678a61e6a7..e35fa301d3db 100644
> > --- a/include/linux/kasan.h
> > +++ b/include/linux/kasan.h
> [...]
> > @@ -113,8 +113,30 @@ static inline bool kasan_has_integrated_init(void)
> > return false;
> > }
> >
> > +static __always_inline void kasan_alloc_pages(struct page *page,
> > + unsigned int order, gfp_t flags)
> > +{
> > + /* Only available for integrated init. */
> > + BUG();
> > +}
> > +
> > +static __always_inline void kasan_free_pages(struct page *page,
> > + unsigned int order)
> > +{
> > + /* Only available for integrated init. */
> > + BUG();
> > +}
>
> Would these two work as BUILD_BUG()?
It looks like it. This creates a dependency on the compiler being
powerful enough to optimize away "if (0) undefined_function();" after
inlining, which I'm not really a big fan of, but it looks like we're
already doing similar things elsewhere in the kernel, so we might as
well do it here as well.
Peter
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http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-05-12 20:08 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 23:54 [PATCH v2 0/3] arm64: improve efficiency of setting tags for user pages Peter Collingbourne
2021-05-11 23:54 ` Peter Collingbourne
2021-05-11 23:54 ` [PATCH v2 1/3] kasan: use separate (un)poison implementation for integrated init Peter Collingbourne
2021-05-11 23:54 ` Peter Collingbourne
2021-05-12 12:10 ` Catalin Marinas
2021-05-12 12:10 ` Catalin Marinas
2021-05-12 20:08 ` Peter Collingbourne [this message]
2021-05-12 20:08 ` Peter Collingbourne
2021-05-11 23:54 ` [PATCH v2 2/3] arm64: mte: handle tags zeroing at page allocation time Peter Collingbourne
2021-05-11 23:54 ` Peter Collingbourne
2021-05-12 12:12 ` Catalin Marinas
2021-05-12 12:12 ` Catalin Marinas
2021-05-11 23:54 ` [PATCH v2 3/3] kasan: allow freed user page poisoning to be disabled with HW tags Peter Collingbourne
2021-05-11 23:54 ` Peter Collingbourne
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