From: Dave Martin <Dave.Martin@arm.com>
To: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>,
linux-arch@vger.kernel.org, libc-alpha@sourceware.org,
Szabolcs Nagy <szabolcs.nagy@arm.com>,
Andrey Konovalov <andreyknvl@google.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Peter Collingbourne <pcc@google.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v9 29/29] arm64: mte: Add Memory Tagging Extension documentation
Date: Thu, 17 Sep 2020 17:15:53 +0100 [thread overview]
Message-ID: <20200917161550.GA6642@arm.com> (raw)
In-Reply-To: <20200917090229.GA10662@gaia>
On Thu, Sep 17, 2020 at 10:02:30AM +0100, Catalin Marinas wrote:
> On Thu, Sep 17, 2020 at 09:11:08AM +0100, Will Deacon wrote:
> > On Fri, Sep 04, 2020 at 11:30:29AM +0100, Catalin Marinas wrote:
> > > From: Vincenzo Frascino <vincenzo.frascino@arm.com>
> > >
> > > Memory Tagging Extension (part of the ARMv8.5 Extensions) provides
> > > a mechanism to detect the sources of memory related errors which
> > > may be vulnerable to exploitation, including bounds violations,
> > > use-after-free, use-after-return, use-out-of-scope and use before
> > > initialization errors.
> > >
> > > Add Memory Tagging Extension documentation for the arm64 linux
> > > kernel support.
> > >
> > > Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> > > Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
> > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > > Acked-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
> >
> > I'm taking this to mean that Szabolcs is happy with the proposed ABI --
> > please shout if that's not the case!
>
> I think Szabolcs is still on holiday. To summarise the past threads,
> AFAICT he's happy with this per-thread control ABI but the discussion
> went on whether to expand it in the future (with a new bit) to
> synchronise the tag checking mode across all threads of a process. This
> adds some complications for the kernel as it needs an IPI to the other
> CPUs to set SCTLR_EL1 and it's also racy with multiple threads
> requesting different modes.
>
> Now, in the glibc land, if the tag check mode is controlled via
> environment variables, the dynamic loader can set this at process start
> while still in single-threaded mode and not touch it at run-time. The
> MTE checking can still be enabled at run-time, per mapped memory range
> via the PROT_MTE flag. This approach doesn't require any additional
> changes to the current patches. But it's for Szabolcs to confirm once
> he's back.
>
> > Wasn't there a man page kicking around too? Would be good to see that
> > go upstream (to the manpages project, of course).
>
> Dave started writing one for the tagged address ABI, not sure where that
> is. For the MTE additions, we are waiting for the ABI to be upstreamed.
The tagged address ABI control stuff is upstream in the man-pages-5.08
release.
I don't think anyone drafted anything for MTE yet. Do we consider the
MTE ABI to be sufficiently stable now for it to be worth starting
drafting something?
Cheers
---Dave
next prev parent reply other threads:[~2020-09-17 16:26 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-04 10:30 [PATCH v9 00/29] arm64: Memory Tagging Extension user-space support Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 01/29] arm64: mte: system register definitions Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 02/29] arm64: mte: Use Normal Tagged attributes for the linear map Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 03/29] arm64: mte: CPU feature detection and initial sysreg configuration Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 04/29] arm64: kvm: mte: Hide the MTE CPUID information from the guests Catalin Marinas
2020-09-04 10:46 ` Marc Zyngier
2020-09-04 10:30 ` [PATCH v9 05/29] arm64: mte: Add specific SIGSEGV codes Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 06/29] arm64: mte: Handle synchronous and asynchronous tag check faults Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 07/29] mm: Add PG_arch_2 page flag Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 08/29] mm: Preserve the PG_arch_2 flag in __split_huge_page_tail() Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 09/29] arm64: mte: Clear the tags when a page is mapped in user-space with PROT_MTE Catalin Marinas
2020-09-10 10:23 ` Steven Price
2020-09-10 10:52 ` Catalin Marinas
2020-09-10 11:12 ` Steven Price
2020-09-10 11:55 ` Catalin Marinas
2020-09-10 12:43 ` Steven Price
2020-09-04 10:30 ` [PATCH v9 10/29] arm64: mte: Tags-aware copy_{user_,}highpage() implementations Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 11/29] arm64: Avoid unnecessary clear_user_page() indirection Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 12/29] arm64: mte: Tags-aware aware memcmp_pages() implementation Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 13/29] mm: Introduce arch_calc_vm_flag_bits() Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 14/29] arm64: mte: Add PROT_MTE support to mmap() and mprotect() Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 15/29] mm: Introduce arch_validate_flags() Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 16/29] arm64: mte: Validate the PROT_MTE request via arch_validate_flags() Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 17/29] mm: Allow arm64 mmap(PROT_MTE) on RAM-based files Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 18/29] arm64: mte: Allow user control of the tag check mode via prctl() Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 19/29] arm64: mte: Allow user control of the generated random tags " Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 20/29] arm64: mte: Restore the GCR_EL1 register after a suspend Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 21/29] arm64: mte: Allow {set,get}_tagged_addr_ctrl() on non-current tasks Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 22/29] arm64: mte: ptrace: Add PTRACE_{PEEK,POKE}MTETAGS support Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 23/29] arm64: mte: ptrace: Add NT_ARM_TAGGED_ADDR_CTRL regset Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 24/29] fs: Handle intra-page faults in copy_mount_options() Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 25/29] mm: Add arch hooks for saving/restoring tags Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 26/29] arm64: mte: Enable swap of tagged pages Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 27/29] arm64: mte: Save tags when hibernating Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 28/29] arm64: mte: Kconfig entry Catalin Marinas
2020-09-04 10:30 ` [PATCH v9 29/29] arm64: mte: Add Memory Tagging Extension documentation Catalin Marinas
2020-09-17 8:11 ` Will Deacon
2020-09-17 9:02 ` Catalin Marinas
2020-09-17 16:15 ` Dave Martin [this message]
2020-09-18 8:30 ` Will Deacon
2020-10-14 23:43 ` Peter Collingbourne
2020-10-15 8:57 ` Will Deacon
2020-10-15 11:14 ` Szabolcs Nagy
2020-09-22 16:04 ` Catalin Marinas
2020-09-22 15:52 ` Szabolcs Nagy
2020-09-22 16:55 ` Catalin Marinas
2020-09-23 9:10 ` Szabolcs Nagy
2020-09-22 12:22 ` Andrey Konovalov
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