From: Dave Martin <Dave.Martin@arm.com>
To: Will Deacon <will@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>,
linux-arch@vger.kernel.org, Szabolcs Nagy <szabolcs.nagy@arm.com>,
Andrey Konovalov <andreyknvl@google.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
linux-mm@kvack.org, Vincenzo Frascino <vincenzo.frascino@arm.com>,
Peter Collingbourne <pcc@google.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 15/26] arm64: mte: Allow user control of the tag check mode via prctl()
Date: Wed, 27 May 2020 09:32:20 +0100 [thread overview]
Message-ID: <20200527083218.GS5031@arm.com> (raw)
In-Reply-To: <20200527074658.GB9887@willie-the-truck>
On Wed, May 27, 2020 at 08:46:59AM +0100, Will Deacon wrote:
> On Fri, May 15, 2020 at 06:16:01PM +0100, Catalin Marinas wrote:
> > By default, even if PROT_MTE is set on a memory range, there is no tag
> > check fault reporting (SIGSEGV). Introduce a set of option to the
> > exiting prctl(PR_SET_TAGGED_ADDR_CTRL) to allow user control of the tag
> > check fault mode:
> >
> > PR_MTE_TCF_NONE - no reporting (default)
> > PR_MTE_TCF_SYNC - synchronous tag check fault reporting
> > PR_MTE_TCF_ASYNC - asynchronous tag check fault reporting
> >
> > These options translate into the corresponding SCTLR_EL1.TCF0 bitfield,
> > context-switched by the kernel. Note that uaccess done by the kernel is
> > not checked and cannot be configured by the user.
> >
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: Will Deacon <will@kernel.org>
> > ---
> >
> > Notes:
> > v3:
> > - Use SCTLR_EL1_TCF0_NONE instead of 0 for consistency.
> > - Move mte_thread_switch() in this patch from an earlier one. In
> > addition, it is called after the dsb() in __switch_to() so that any
> > asynchronous tag check faults have been registered in the TFSR_EL1
> > registers (to be added with the in-kernel MTE support.
> >
> > v2:
> > - Handle SCTLR_EL1_TCF0_NONE explicitly for consistency with PR_MTE_TCF_NONE.
> > - Fix SCTLR_EL1 register setting in flush_mte_state() (thanks to Peter
> > Collingbourne).
> > - Added ISB to update_sctlr_el1_tcf0() since, with the latest
> > architecture update/fix, the TCF0 field is used by the uaccess
> > routines.
> >
> > arch/arm64/include/asm/mte.h | 14 ++++++
> > arch/arm64/include/asm/processor.h | 3 ++
> > arch/arm64/kernel/mte.c | 77 ++++++++++++++++++++++++++++++
> > arch/arm64/kernel/process.c | 26 ++++++++--
> > include/uapi/linux/prctl.h | 6 +++
> > 5 files changed, 123 insertions(+), 3 deletions(-)
>
> Dave is working on man pages for prctl() (and I think also ptrace). I think
> it would be /very/ useful for us to have some RFC patches on top of his work
> adding documentation for the MTE interactions, as we found some other minor
> issues/inconsistencies as a direct result of writing and reviewing the man
> page for our existing interfaces.
I have a local draft for the address tagging and MTE prctls already btw.
I hadn't posted them yet so as to focus on nailing the "easy" stuff down
;)
If I have time I'll try and get them posted today so that people can
take a look before next week.
Cheers
---Dave
next prev parent reply other threads:[~2020-05-27 8:32 UTC|newest]
Thread overview: 58+ 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 ` [PATCH v4 01/26] arm64: mte: system register definitions 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 ` [PATCH v4 03/26] arm64: mte: Use Normal Tagged attributes for the linear map Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 04/26] arm64: mte: Add specific SIGSEGV codes 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 ` [PATCH v4 06/26] mm: Add PG_ARCH_2 page flag 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 ` [PATCH v4 08/26] arm64: mte: Tags-aware copy_page() implementation 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 ` [PATCH v4 10/26] mm: Introduce arch_calc_vm_flag_bits() Catalin Marinas
2020-05-15 17:15 ` [PATCH v4 11/26] arm64: mte: Add PROT_MTE support to mmap() and mprotect() Catalin Marinas
2020-05-27 18:57 ` Peter Collingbourne
2020-05-28 9:14 ` Catalin Marinas
2020-05-28 11:05 ` Szabolcs Nagy
2020-05-28 16:34 ` Catalin Marinas
2020-05-28 18:35 ` Evgenii Stepanov
2020-05-29 11:19 ` Catalin Marinas
2020-06-01 8:55 ` Dave Martin
2020-06-01 14:45 ` Catalin Marinas
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 ` [PATCH v4 13/26] arm64: mte: Validate the PROT_MTE request via arch_validate_flags() 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 ` [PATCH v4 15/26] arm64: mte: Allow user control of the tag check mode via prctl() Catalin Marinas
2020-05-27 7:46 ` Will Deacon
2020-05-27 8:32 ` Dave Martin [this message]
2020-05-27 8:48 ` Will Deacon
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 ` [PATCH v4 17/26] arm64: mte: Restore the GCR_EL1 register after a suspend Catalin Marinas
2020-05-15 17:16 ` [PATCH v4 18/26] arm64: mte: Add PTRACE_{PEEK,POKE}MTETAGS support Catalin Marinas
2020-05-29 21:25 ` Luis Machado
2020-06-01 12:07 ` Catalin Marinas
2020-06-01 15:17 ` Luis Machado
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 ` [PATCH v4 20/26] mm: Add arch hooks for saving/restoring tags 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 ` [PATCH v4 22/26] arm64: mte: Save tags when hibernating 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 ` [PATCH v4 24/26] arm64: mte: Introduce early param to disable " Catalin Marinas
2020-05-18 11:26 ` Vladimir Murzin
2020-05-18 11:31 ` Will Deacon
2020-05-18 17:20 ` Catalin Marinas
2020-05-22 5:57 ` Patrick Daly
2020-05-22 10:37 ` Catalin Marinas
2020-05-27 2:11 ` Patrick Daly
2020-05-27 9:55 ` Will Deacon
2020-05-27 10:37 ` Szabolcs Nagy
2020-05-27 11:12 ` Catalin Marinas
2020-05-19 16:14 ` Catalin Marinas
2021-01-21 19:37 ` Andrey Konovalov
2021-01-22 2:03 ` Andrey Konovalov
2021-01-22 14:41 ` Catalin Marinas
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 ` [PATCH v4 26/26] arm64: mte: Add Memory Tagging Extension documentation Catalin Marinas
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