From: Andrey Konovalov <andreyknvl@google.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: Linux ARM <linux-arm-kernel@lists.infradead.org>,
Linux Memory Management List <linux-mm@kvack.org>,
linux-arch <linux-arch@vger.kernel.org>,
Will Deacon <will@kernel.org>,
Dave P Martin <Dave.Martin@arm.com>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Peter Collingbourne <pcc@google.com>
Subject: Re: [PATCH v4 24/26] arm64: mte: Introduce early param to disable MTE support
Date: Fri, 22 Jan 2021 18:28:18 +0100 [thread overview]
Message-ID: <CAAeHK+y0hsm_syQuyU8rv0=NxesoB41fsz+DLi4FjjBke0t-pw@mail.gmail.com> (raw)
In-Reply-To: <20210122144141.GE8567@gaia>
On Fri, Jan 22, 2021 at 3:41 PM Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> > While this patch didn't land upstream, we need an MTE kill-switch for
> > Android GKI. Is this patch OK to take as is? Is it still valid?
>
> As you noticed, this code no longer exists. The CPUID is checked early
> during boot in proc.S, before the MMU is enabled, as you need to set up
> the MAIR register.
>
> Now, what do you mean by kill switch? There are multiple levels at which
> one can disable MTE or some of its effects: memory type (MAIR) level,
> tag allocation (TCR_EL1.ATA), tag checking (SCTLR_EL1.TCF). Apart from
> the latter, all the other bits are cached in the TLB which make them
> more problematic to toggle at run-time.
>
> For the kernel, we can currently disable tag checking via the kasan
> command line options. For user-space, we don't have a kill switch
> specific to MTE, however one can disable the tagged addr ABI and
> presumably the C library will avoid generating tagged heap pointers.
Just FTR: As discussed off-the-list, there won't be any need for a
kill-switch for userspace MTE.
Thanks!
WARNING: multiple messages have this Message-ID (diff)
From: Andrey Konovalov <andreyknvl@google.com>
To: Andrey Konovalov <andreyknvl@google.com>
Cc: linux-arch <linux-arch@vger.kernel.org>,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Peter Collingbourne <pcc@google.com>,
Linux Memory Management List <linux-mm@kvack.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Will Deacon <will@kernel.org>,
Dave P Martin <Dave.Martin@arm.com>,
Linux ARM <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v4 24/26] arm64: mte: Introduce early param to disable MTE support
Date: Fri, 22 Jan 2021 18:28:18 +0100 [thread overview]
Message-ID: <CAAeHK+y0hsm_syQuyU8rv0=NxesoB41fsz+DLi4FjjBke0t-pw@mail.gmail.com> (raw)
In-Reply-To: <20210122144141.GE8567@gaia>
On Fri, Jan 22, 2021 at 3:41 PM Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> > While this patch didn't land upstream, we need an MTE kill-switch for
> > Android GKI. Is this patch OK to take as is? Is it still valid?
>
> As you noticed, this code no longer exists. The CPUID is checked early
> during boot in proc.S, before the MMU is enabled, as you need to set up
> the MAIR register.
>
> Now, what do you mean by kill switch? There are multiple levels at which
> one can disable MTE or some of its effects: memory type (MAIR) level,
> tag allocation (TCR_EL1.ATA), tag checking (SCTLR_EL1.TCF). Apart from
> the latter, all the other bits are cached in the TLB which make them
> more problematic to toggle at run-time.
>
> For the kernel, we can currently disable tag checking via the kasan
> command line options. For user-space, we don't have a kill switch
> specific to MTE, however one can disable the tagged addr ABI and
> presumably the C library will avoid generating tagged heap pointers.
Just FTR: As discussed off-the-list, there won't be any need for a
kill-switch for userspace MTE.
Thanks!
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next prev parent reply other threads:[~2021-01-22 17:51 UTC|newest]
Thread overview: 123+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 17:15 [PATCH v4 00/26] arm64: Memory Tagging Extension user-space support Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 01/26] arm64: mte: system register definitions Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 02/26] arm64: mte: CPU feature detection and initial sysreg configuration Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 03/26] arm64: mte: Use Normal Tagged attributes for the linear map Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 04/26] arm64: mte: Add specific SIGSEGV codes Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 05/26] arm64: mte: Handle synchronous and asynchronous tag check faults Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 06/26] mm: Add PG_ARCH_2 page flag Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 07/26] arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 08/26] arm64: mte: Tags-aware copy_page() implementation Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 09/26] arm64: mte: Tags-aware aware memcmp_pages() implementation Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 10/26] mm: Introduce arch_calc_vm_flag_bits() Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 11/26] arm64: mte: Add PROT_MTE support to mmap() and mprotect() Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-27 18:57 ` Peter Collingbourne
2020-05-27 18:57 ` Peter Collingbourne
2020-05-27 18:57 ` Peter Collingbourne
2020-05-27 18:57 ` Peter Collingbourne
2020-05-28 9:14 ` Catalin Marinas
2020-05-28 9:14 ` Catalin Marinas
2020-05-28 11:05 ` Szabolcs Nagy
2020-05-28 11:05 ` Szabolcs Nagy
2020-05-28 11:05 ` Szabolcs Nagy
2020-05-28 16:34 ` Catalin Marinas
2020-05-28 16:34 ` Catalin Marinas
2020-05-28 18:35 ` Evgenii Stepanov
2020-05-28 18:35 ` Evgenii Stepanov
2020-05-29 11:19 ` Catalin Marinas
2020-05-29 11:19 ` Catalin Marinas
2020-06-01 8:55 ` Dave Martin
2020-06-01 8:55 ` Dave Martin
2020-06-01 14:45 ` Catalin Marinas
2020-06-01 14:45 ` Catalin Marinas
2020-06-01 15:04 ` Dave Martin
2020-06-01 15:04 ` Dave Martin
2020-05-15 17:15 ` [PATCH v4 12/26] mm: Introduce arch_validate_flags() Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 13/26] arm64: mte: Validate the PROT_MTE request via arch_validate_flags() Catalin Marinas
2020-05-15 17:15 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 14/26] mm: Allow arm64 mmap(PROT_MTE) on RAM-based files Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 15/26] arm64: mte: Allow user control of the tag check mode via prctl() Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-27 7:46 ` Will Deacon
2020-05-27 7:46 ` Will Deacon
2020-05-27 8:32 ` Dave Martin
2020-05-27 8:32 ` Dave Martin
2020-05-27 8:48 ` Will Deacon
2020-05-27 8:48 ` Will Deacon
2020-05-27 11:16 ` Catalin Marinas
2020-05-27 11:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 16/26] arm64: mte: Allow user control of the generated random tags " Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 17/26] arm64: mte: Restore the GCR_EL1 register after a suspend Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 18/26] arm64: mte: Add PTRACE_{PEEK,POKE}MTETAGS support Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-29 21:25 ` Luis Machado
2020-05-29 21:25 ` Luis Machado
2020-06-01 12:07 ` Catalin Marinas
2020-06-01 12:07 ` Catalin Marinas
2020-06-01 15:17 ` Luis Machado
2020-06-01 15:17 ` Luis Machado
2020-06-01 16:33 ` Catalin Marinas
2020-06-01 16:33 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 19/26] fs: Handle intra-page faults in copy_mount_options() Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 20/26] mm: Add arch hooks for saving/restoring tags Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 21/26] arm64: mte: Enable swap of tagged pages Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 22/26] arm64: mte: Save tags when hibernating Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 23/26] arm64: mte: Check the DT memory nodes for MTE support Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 24/26] arm64: mte: Introduce early param to disable " Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-18 11:26 ` Vladimir Murzin
2020-05-18 11:26 ` Vladimir Murzin
2020-05-18 11:31 ` Will Deacon
2020-05-18 11:31 ` Will Deacon
2020-05-18 17:20 ` Catalin Marinas
2020-05-18 17:20 ` Catalin Marinas
2020-05-22 5:57 ` Patrick Daly
2020-05-22 5:57 ` Patrick Daly
2020-05-22 10:37 ` Catalin Marinas
2020-05-22 10:37 ` Catalin Marinas
2020-05-27 2:11 ` Patrick Daly
2020-05-27 2:11 ` Patrick Daly
2020-05-27 2:11 ` Patrick Daly
2020-05-27 9:55 ` Will Deacon
2020-05-27 9:55 ` Will Deacon
2020-05-27 10:37 ` Szabolcs Nagy
2020-05-27 10:37 ` Szabolcs Nagy
2020-05-27 11:12 ` Catalin Marinas
2020-05-27 11:12 ` Catalin Marinas
2020-05-19 16:14 ` Catalin Marinas
2020-05-19 16:14 ` Catalin Marinas
2021-01-21 19:37 ` Andrey Konovalov
2021-01-21 19:37 ` Andrey Konovalov
2021-01-21 19:37 ` Andrey Konovalov
2021-01-22 2:03 ` Andrey Konovalov
2021-01-22 2:03 ` Andrey Konovalov
2021-01-22 2:03 ` Andrey Konovalov
2021-01-22 14:41 ` Catalin Marinas
2021-01-22 14:41 ` Catalin Marinas
2021-01-22 17:28 ` Andrey Konovalov [this message]
2021-01-22 17:28 ` Andrey Konovalov
2021-01-22 17:28 ` Andrey Konovalov
2020-05-15 17:16 ` [PATCH v4 25/26] arm64: mte: Kconfig entry Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 26/26] arm64: mte: Add Memory Tagging Extension documentation Catalin Marinas
2020-05-15 17:16 ` Catalin Marinas
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