From: Catalin Marinas <catalin.marinas@arm.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
kasan-dev <kasan-dev@googlegroups.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Evgenii Stepanov <eugenis@google.com>,
Elena Petrova <lenaptr@google.com>,
Branislav Rankov <Branislav.Rankov@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Will Deacon <will.deacon@arm.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 26/35] kasan, arm64: Enable TBI EL1
Date: Tue, 8 Sep 2020 15:41:41 +0100 [thread overview]
Message-ID: <20200908144140.GG25591@gaia> (raw)
In-Reply-To: <CAAeHK+zkWojbbq1WgoC2D6JuR=Jy+jSU78PF74qdmD0aTg6cQQ@mail.gmail.com>
On Tue, Sep 08, 2020 at 04:12:49PM +0200, Andrey Konovalov wrote:
> On Tue, Sep 8, 2020 at 4:06 PM Catalin Marinas <catalin.marinas@arm.com> wrote:
> > On Tue, Sep 08, 2020 at 03:18:04PM +0200, Andrey Konovalov wrote:
> > > On Thu, Aug 27, 2020 at 12:40 PM Catalin Marinas
> > > <catalin.marinas@arm.com> wrote:
> > > > On Fri, Aug 14, 2020 at 07:27:08PM +0200, Andrey Konovalov wrote:
> > > > > diff --git a/arch/arm64/mm/proc.S b/arch/arm64/mm/proc.S
> > > > > index 152d74f2cc9c..6880ddaa5144 100644
> > > > > --- a/arch/arm64/mm/proc.S
> > > > > +++ b/arch/arm64/mm/proc.S
> > > > > @@ -38,7 +38,7 @@
> > > > > /* PTWs cacheable, inner/outer WBWA */
> > > > > #define TCR_CACHE_FLAGS TCR_IRGN_WBWA | TCR_ORGN_WBWA
> > > > >
> > > > > -#ifdef CONFIG_KASAN_SW_TAGS
> > > > > +#if defined(CONFIG_KASAN_SW_TAGS) || defined(CONFIG_KASAN_HW_TAGS)
> > > > > #define TCR_KASAN_FLAGS TCR_TBI1
> > > > > #else
> > > > > #define TCR_KASAN_FLAGS 0
> > > >
> > > > I prefer to turn TBI1 on only if MTE is present. So on top of the v8
> > > > user series, just do this in __cpu_setup.
> > >
> > > Started working on this, but realized that I don't understand what
> > > exactly is suggested here. TCR_KASAN_FLAGS are used in __cpu_setup(),
> > > so this already happens in __cpu_setup().
> > >
> > > Do you mean that TBI1 should be enabled when CONFIG_ARM64_MTE is
> > > enabled, but CONFIG_KASAN_HW_TAGS is disabled?
> >
> > What I meant is that we should turn TBI1 only when the MTE is present in
> > hardware (and the ARM64_MTE option is on). But I probably missed the way
> > MTE is used with KASAN.
> >
> > So what happens if CONFIG_KASAN_HW_TAGS and CONFIG_ARM64_MTE are both on
> > but the hardware does not support MTE? Does KASAN still generate tagged
> > pointers? If yes, then the current patch is fine, we should always set
> > TBI1.
>
> No, the tag is always 0xFF when MTE is not supported.
>
> Should we then only enable TBI1 if system_supports_mte() or something
> like that?
You could add it do this block in __cpu_setup:
https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git/tree/arch/arm64/mm/proc.S?h=for-next/mte#n429
It needs a few changes to have "mov_q x10, TCR_..." before the MTE
check so that you can add the TBI1 bit in there.
system_supports_mte() would be called too late, you want this set before
the MMU is turned on.
--
Catalin
next prev parent reply other threads:[~2020-09-08 20:00 UTC|newest]
Thread overview: 94+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 17:26 [PATCH 00/35] kasan: add hardware tag-based mode for arm64 Andrey Konovalov
2020-08-14 17:26 ` [PATCH 01/35] kasan: KASAN_VMALLOC depends on KASAN_GENERIC Andrey Konovalov
2020-08-14 17:26 ` [PATCH 02/35] kasan: group vmalloc code Andrey Konovalov
2020-08-14 17:26 ` [PATCH 03/35] kasan: shadow declarations only for software modes Andrey Konovalov
2020-09-18 14:55 ` Marco Elver
2020-09-18 14:56 ` Andrey Konovalov
2020-08-14 17:26 ` [PATCH 04/35] kasan: rename (un)poison_shadow to (un)poison_memory Andrey Konovalov
2020-08-14 17:26 ` [PATCH 05/35] kasan: rename KASAN_SHADOW_* to KASAN_GRANULE_* Andrey Konovalov
2020-08-14 17:26 ` [PATCH 06/35] kasan: only build init.c for software modes Andrey Konovalov
2020-08-14 17:26 ` [PATCH 07/35] kasan: split out shadow.c from common.c Andrey Konovalov
2020-08-14 17:26 ` [PATCH 08/35] kasan: rename generic/tags_report.c files Andrey Konovalov
2020-08-14 17:26 ` [PATCH 09/35] kasan: don't duplicate config dependencies Andrey Konovalov
2020-08-14 17:26 ` [PATCH 10/35] kasan: hide invalid free check implementation Andrey Konovalov
2020-08-14 17:26 ` [PATCH 11/35] kasan: decode stack frame only with KASAN_STACK_ENABLE Andrey Konovalov
2020-08-14 17:26 ` [PATCH 12/35] kasan, arm64: only init shadow for software modes Andrey Konovalov
2020-08-14 17:26 ` [PATCH 13/35] kasan, arm64: only use kasan_depth " Andrey Konovalov
2020-08-14 17:26 ` [PATCH 14/35] kasan: rename addr_has_shadow to addr_has_metadata Andrey Konovalov
2020-08-14 17:26 ` [PATCH 15/35] kasan: rename print_shadow_for_address to print_memory_metadata Andrey Konovalov
2020-08-14 17:26 ` [PATCH 16/35] kasan: kasan_non_canonical_hook only for software modes Andrey Konovalov
2020-08-14 17:26 ` [PATCH 17/35] kasan: rename SHADOW layout macros to META Andrey Konovalov
2020-08-14 17:27 ` [PATCH 18/35] kasan: separate metadata_fetch_row for each mode Andrey Konovalov
2020-08-14 17:27 ` [PATCH 19/35] kasan: don't allow SW_TAGS with ARM64_MTE Andrey Konovalov
2020-08-27 8:04 ` Catalin Marinas
2020-08-27 9:54 ` Vincenzo Frascino
2020-08-27 12:02 ` Andrey Konovalov
2020-08-14 17:27 ` [PATCH 20/35] arm64: mte: Add in-kernel MTE helpers Andrey Konovalov
2020-08-27 9:38 ` Catalin Marinas
2020-08-27 10:31 ` Vincenzo Frascino
2020-08-27 11:10 ` Catalin Marinas
2020-08-27 11:24 ` Vincenzo Frascino
2020-08-27 12:46 ` Andrey Konovalov
2020-09-08 13:23 ` Andrey Konovalov
2020-09-08 14:50 ` Catalin Marinas
2020-08-14 17:27 ` [PATCH 21/35] arm64: mte: Add in-kernel tag fault handler Andrey Konovalov
2020-08-27 9:54 ` Catalin Marinas
2020-08-27 10:44 ` Vincenzo Frascino
2020-08-27 12:31 ` Andrey Konovalov
2020-08-27 13:10 ` Catalin Marinas
2020-08-27 13:34 ` Andrey Konovalov
2020-08-27 14:56 ` Catalin Marinas
2020-08-27 19:14 ` Evgenii Stepanov
2020-08-28 9:56 ` Catalin Marinas
2020-08-14 17:27 ` [PATCH 22/35] arm64: mte: Enable in-kernel MTE Andrey Konovalov
2020-08-27 10:01 ` Catalin Marinas
2020-08-27 10:46 ` Vincenzo Frascino
2020-09-08 14:39 ` Andrey Konovalov
2020-09-08 14:52 ` Catalin Marinas
2020-08-14 17:27 ` [PATCH 23/35] arm64: mte: Convert gcr_user into an exclude mask Andrey Konovalov
2020-08-14 17:27 ` [PATCH 24/35] arm64: mte: Switch GCR_EL1 in kernel entry and exit Andrey Konovalov
2020-08-27 10:38 ` Catalin Marinas
2020-08-27 10:56 ` Vincenzo Frascino
2020-08-27 12:16 ` Catalin Marinas
2020-09-08 14:02 ` Andrey Konovalov
2020-09-08 14:53 ` Andrey Konovalov
2020-09-08 15:39 ` Catalin Marinas
2020-09-08 19:41 ` Derrick McKee
2020-09-08 13:58 ` Andrey Konovalov
2020-09-08 15:16 ` Catalin Marinas
2020-08-14 17:27 ` [PATCH 25/35] kasan: introduce CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-08-27 11:33 ` Vincenzo Frascino
2020-08-27 12:22 ` Andrey Konovalov
2020-08-14 17:27 ` [PATCH 26/35] kasan, arm64: Enable TBI EL1 Andrey Konovalov
2020-08-27 10:40 ` Catalin Marinas
2020-08-27 11:05 ` Vincenzo Frascino
2020-08-27 11:13 ` Catalin Marinas
2020-08-27 11:17 ` Vincenzo Frascino
2020-08-27 12:43 ` Andrey Konovalov
2020-08-27 13:45 ` Vincenzo Frascino
2020-08-27 14:36 ` Andrey Konovalov
2020-09-08 13:18 ` Andrey Konovalov
2020-09-08 14:06 ` Catalin Marinas
2020-09-08 14:12 ` Andrey Konovalov
2020-09-08 14:41 ` Catalin Marinas [this message]
2020-08-14 17:27 ` [PATCH 27/35] kasan, arm64: align allocations for HW_TAGS Andrey Konovalov
2020-08-14 17:27 ` [PATCH 28/35] kasan: define KASAN_GRANULE_SIZE " Andrey Konovalov
2020-08-27 10:41 ` Catalin Marinas
2020-08-27 11:07 ` Vincenzo Frascino
2020-08-27 12:05 ` Andrey Konovalov
2020-08-14 17:27 ` [PATCH 29/35] kasan, x86, s390: update undef CONFIG_KASAN Andrey Konovalov
2020-08-14 17:27 ` [PATCH 30/35] kasan, arm64: expand CONFIG_KASAN checks Andrey Konovalov
2020-08-14 17:27 ` [PATCH 31/35] kasan, arm64: implement HW_TAGS runtime Andrey Konovalov
2020-08-27 10:45 ` Catalin Marinas
2020-08-27 11:35 ` Vincenzo Frascino
2020-08-27 12:37 ` Andrey Konovalov
2020-08-14 17:27 ` [PATCH 32/35] kasan, arm64: print report from tag fault handler Andrey Konovalov
2020-08-27 10:48 ` Catalin Marinas
2020-08-27 12:11 ` Vincenzo Frascino
2020-08-27 12:34 ` Andrey Konovalov
2020-08-27 14:21 ` Catalin Marinas
2020-08-14 17:27 ` [PATCH 33/35] kasan, slub: reset tags when accessing metadata Andrey Konovalov
2020-08-14 17:27 ` [PATCH 34/35] kasan, arm64: enable CONFIG_KASAN_HW_TAGS Andrey Konovalov
2020-08-14 17:27 ` [PATCH 35/35] kasan: add documentation for hardware tag-based mode Andrey Konovalov
2020-08-28 11:12 ` Marco Elver
2020-08-28 12:28 ` Andrey Konovalov
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